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278 Cards in this Set
- Front
- Back
specialized nerve cells or nerve cell terminals that are able to detect specific stimuli
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sensory receptors
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sensory receptors that detect outside stimuli
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exteroceptors
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sensory receptors that detect inside stimuli
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enteroceptors
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the region of space where receptor will respond to adequate stimulus
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receptive field
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the conversion of the original form of energy into electrical energy (action potential)
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stimulus transduction
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graded change in membrane potential that requires a sufficient amplitude to trigger an action potential
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receptor potential
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the four attributes of a physical stimulus
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modality, intensity, duration, location
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type or form of energy
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modality
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level of stimulation; coded by frequency of action potentials
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intensity
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tells us how long the stimulus is present, whether the receptors are slow or fast adapting
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duration
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sensitivity of the region depends on receptor __
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density
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the minimal interstimulus distance required to perceive two simultaneously applied stimuli as distinct
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2-point discrimination
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these fibers transmit information from the periphery to the spinal cord, then to the brain
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sensory afferents
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the cell bodies of the sensory afferents are located here
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dorsal root ganglion
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the axons of the sensory afferent axons terminate on the interneurons in the __ __
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dorsal horn
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these sensory afferents are 13-22 micrometers in diameter, conduct at a rate of 70-120 m/s, and primarily function as alpha motor neurons and muscle spindle primary endings
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Aa; Ia, Ib
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these sensory afferents are 8-13 micrometers in diameter, conduct at 40-70 m/s, and function in touch, kinesthesia, muscle spindle secondary endings
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AB, II
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these sensory afferents are 4-8 micrometers, conduct at 15-40 m/s, and function in touch, pressure, and gamma motor drive
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Agamma
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these sensory afferents are 1-4 micrometers in diameter, conduct at 5-15 m/s, and function in pain, crude touch, pressure, and temperature
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Adelta, III
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these sensory afferents are 1-3 micrometers, conduct at 3-14 m/s, and function as pre-ganglionic autonomics
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B
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these sensory afferents are 0.1-1 in diameter, conduct at 0.2-2 m/s, and function in pain, touch, pressure, temperature, and post-ganglionic autonomics
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C, IV
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these two types of receptors in the somatic sensory system detect light touch, vibration, pressure, and cutaneous tension
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mechanoreceptors and proprioceptors
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these two types of receptors in the somatic sensory system detect pain and temperature
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nociceptors and thermoreceptors
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these receptors are located in the dermal papillae, the fingers, palms, and toes; they respond to light touch and detect the texture of objects and are low threshold and rapidly adapting
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Meissner's corpuscles
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Meissner's corpuscles represent __%of the sensory innervation of the hand
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40
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These receptors are in the epidermis, aligned with papillae beneath dermal ridges; they discriminate edges, shapes, and rough texture with light pressure; they have slowly adapting axons and are dense in the fingertips lips, and external genitalia (VERY sensitive)
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Merkel disks
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Merkel disks make up __% of the mechanoreceptors in the hand
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25
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These receptors are located in the subcutaneous tissue and are made up of a laminar capsule surrounding a single afferent nerve fiber; they detect deep pressure and high frequency and have large receptive fields, and are rapidly adapting and have a low response threshold
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Pacinian corpuscles
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Pacinian corpuscles account for __-__% of the innervation of the hand
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10-15
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these receptors are long and spindle shaped and are located deep in the skin, ligaments, and tendons; they are particularly sensitive to cutaneous stretch and are slowly adapting
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Ruffini Corpuscles
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Ruffini corpuscles account for __% of the receptors in the hand
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20
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these receptors are located in every tissue of the body except nervous tissue; they are unspecialized free nervous endings and do not adapt, and pick up pain
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nociceptors
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this type of pain usually occurs within 0.1 s after stimulation, and is transmitter over the Adelta fibers; it is an acute, sharp, pricking type of pain
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First (fast) pain
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this type of pain occurs 1 second or more after stimulation, and it increases in intensity over time; it is a chronic, burning, aching, throbbing pain and it is transmitted by the unmyelinated C fibers
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Second (slow) pain
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these types of nociceptors are associated with unmyelinated C fibers and respond to chemical, thermal, and mechanical stimuli
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Polymodal
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these receptors are free nerve endings with receptive fields on the skin surface; they detect temperature changes
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thermoreceptors
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cool thermoreceptors are activated by temperatures between __ and __º C, with the highest firing rate being at __
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5-40, 25
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warm thermoreceptors are activated by temperatures between __ and __ºC, with the highest firing rate at __
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29-45, 45
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this is a phenomenon that occurs when you present a hot stimulus to a cold thermoreceptor, and it perceives it as cold
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paradoxical cold
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the sense of limb movement
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kinesthesia
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a sense of where limbs are in space
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limb position sense
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the two components of proprioception
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kinesthesia and limb position sense
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these receptors are small encapsulated sensory receptors that are arranged in parallel with striated muscle fibers; they provide information about the length of the muscle
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muscle spindles
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muscle spindles contain these types of sensory afferent fibers
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IA and II
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this is an intrafusal fiber that has single file nuclei, and are thin and short
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nuclear chain fibers
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this is an intrafusal fiber that has nuclei clustered at the center, and are thicker, and have both static and dynamic types
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nuclear bag fibers
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this is the primary, or annulospiral sensory afferent in muscle spindles; they encircle the center of all the intrafusals and are rapidly adapting (fire continuously throughout the stretch then cease once the stretch is finished)
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IA
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this is the secondary, or flower spray sensory afferent in muscle spindles; they innervate the end of the chain and the static bag and do not go to the dynamic bag; they are slowly adapting; they respond during stretch but maintain the firing rate after the muscle has stopped moving
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II
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these are the spindle efferent fibers that innervate the intrafusal muscle fibers and run in the peripheral nerves along with alpha motor neurons
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gamma motor neurons
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these gamma efferents innervate the chain and static bag fibers, and cause them to shorten, increasing the firing rate of IA and II afferents without a change in the extrafusal length
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static
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these gamma efferents innervate dynamic bag fibers, and cause the polar regions to contract, resulting in increased polar region resistance to stretch and thus increased sensitivity to velocity changes
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dynamic
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this organ is located in the muscle-tendon junction and is distributed among the collagen fibers of the tendon; it responds to muscle tension and force when the tendon pulls on the organ
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golgi tendon organ
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each golgi tendon organ is innervated by 1 of which type of afferent nerve?
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IB
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the somatosensory system is a __ neuron pathway
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3
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the first order neuron of the somatosensory system is located in the __ __ __, and the axon extends into the spinal cord via the dorsal horn to the synapse
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dorsal root ganglion
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the second order neuron of the somatosensory system is located in the___; the fibers cross the midline and ascend to the___ and synapse
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thalamus
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the third order neuron of the somatosensory system originates in the thalamus and travels to synapse on the __ __ __
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primary sensory cortex
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this pathway carries information from the mechanoreceptors about tactile discrimination (light touch), proprioception, and vibration
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dorsal column medial lemniscus
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the second order neuron of the dorsal column medial lemniscus pathway synapses at the __ __ __ nucleus of the thalamus
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ventral posterior lateral
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the two components of the posterior funiculus, which is made up of the dorsal columns of the spinal cord; the information ascends ipsilaterally into the medulla
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fasiculus gracilis and fasiculus cuneatus
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the third order neuron of the dorsal column medial lemniscus pathway terminates on the __ __ of the parietal lobe, in the __ __ cortex
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postcentral gyrus; primary somatosensory
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the four Brodmann's areas in the primary somatosensory cortex
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1,2 3a and 3b
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the primary somatosensory cortex projects to the __ __ cortex and other regions
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secondary somatosensory
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the spinothalamic pathway functions in perception of what three modalities
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pain, temperature, and crude touch
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where do the first order neurons of the spinothalamic pathway terminate?
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the dorsal horn of the spinal cord
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where do the second order neurons of the spinothalamic pathway terminate?
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the ventral posterior lateral nucleus of the thalamus
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where do the third order neurons of the spinothalamic pathway terminate?
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the somatosensory cortex
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this pathway/sensory system transmits information about touch and pressure and pain and temperature sensation from the face
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trigeminal pathway
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the first order neuron for touch and pressure of the trigeminal system terminates in the __ __
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principal nucleus
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the first order neurons for the trigeminal system enter the brainstem at the __
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pons
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the first order neurons for pain and temperature in the trigeminal system terminate in the __ __ of the medulla
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spinal nucleus
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the second order neurons of the trigeminal pathway terminate where?
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the ventral posterior medial nucleus of the thalamus
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the third order neurons of the trigeminal pathway terminate where?
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cortical neurons in layer IV of the somatosensory cortex
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this sensory pathway relays unconscious proprioceptive information to the cerebellum; the input comes from the body and provides information relative to the muscles and joints
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spinocerebellar
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the first order neurons of the spinocerebellar pathway synapse where?
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Clarke's column (C8-L3) and the gray matter above and below these levels
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the second order neurons of the spinocerebellar pathway synapse where?
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terminate as mossy fibers in the vermis of the cerebellum
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the second order neurons of the spinocerebellar pathway enter the cerebellum via the __ __ __.
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inferior cerebellar peduncle
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these levels of the spinocerebellar pathway provide sensory feedback from the upper extremities during evolving movements
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C1-C7 (aka spinocuneocerebellar)
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these levels of the spinocerebellar pathway provide the cerebellum with sensory feedback from the LE and trunk during evolving movements
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C8-L3 (aka dorsal spinocerebellar)
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these levels of the spinocerebellar pathway carry internally generated information about central locomotor rhythm
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L4-S1 (aka ventral spinocerebellar)
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this is the area of the skin that is innervated by the nerve fibers comprising a dorsal root
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dermatome
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Disruption of the medial lemniscal pathway by a lesion would result in loss of what sensations?
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light touch, proprioception, and vibration
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hemisection of the spinothalamic tract would result in loss of what sensations?
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pain, temperature, and crude touch
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this syndrome occurs when there is a hemisection of the spinal cord that results in contralateral loss of pain, temperature, and crude touch and ipsilateral loss of fine discrimination, active touch, proprioception, and vibration
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Brown-Sequard syndrome
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an infarct of the trigeminal pathway would result in a loss of what sensations contralateral to the lesion?
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pain/temperature and touch/pressure
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a lesion in the spinocerebellar pathway would lead to what issues?
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uncoordinated movement and a lack of body awareness (dysmetria and ataxia)
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a disease that is associated with impaired ability to judge distance or range of movement (overshooting)
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dysmetria
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this is a disease that is associated with uncoordinated movement and loss of order of joint motions
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ataxia
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the cervical spinal enlargement occurs at these levels
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C5-T1
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the lumbar spinal enlargement occurs at these levels
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L2-S3
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these are the two branches of spinal nerves
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ventral and dorsal
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this branch of the spinal nerve carries the axons of motor neurons
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ventral
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this branch of the spinal nerve carries the axons of sensory neurons
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dorsal
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this structure contains the cell bodies of the sensory neurons
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dorsal root ganglion
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this is a structure where spinal nerves join together to serve a particular area; each contains fibers from more than one spinal nerve
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plexus
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nerves that emerge from plexuses are __ nerves
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peripheral
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this is a fast, involuntary, unplanned sequence of actions that occur in response to a stimulus
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reflex
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this is the pathway followed by nerve impulses to produce a reflex
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reflex arc
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these are 1 or more regions of gray matter in the CNS that serve to accept sensory information and send it out via a motor neuron
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integrating center
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stretching leads to an increase in this afferent activity
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Ia
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the tendon reflex is mediated by which organ located in the muscle tendon?
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Golgi tendon organ
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this reflex prevents the muscle from being overloaded; it normalizes muscle tension in the optimal range and enables us to handle delicate objects while exerting a steady grip
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tendon reflex
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this is the sensory afferent that is being activated during the tendon reflex
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IB
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is the tendon reflex polysynaptic or monosynaptic?
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polysynaptic
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this is the phenomenon by which the agonist is excited and the antagonist is inhibited, or vice versa during a reflex
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reciprocal innervation
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this reflex is produced by a noxious stimulus, and is polysynaptic; it results in ipsilateral flexor excitation and extensor inhibition; allows for withdrawal of the limb from the noxious stimulus while maintaining balance and posture
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flexor withdrawal reflex (crossed extension flexor withdrawal reflex)
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this is a proposed mechanism that is said to control the timing and coordination of complex movement patterns; it is a neural network of interneurons that is capable of generating a rhythmic pattern of motor activity in the absence of movement related sensory input from peripheral receptors
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central pattern generator
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the signs of this syndrome include damage to the descending pathways of the brain and brainstem, loss of voluntary movements, spasticity, increased tone, and overactive reflexes, and a positive Babinski's sign
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upper motor neuron syndrome
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this syndrome is damage to the cell bodies in the brain stem and spinal cord; muscles become weaker, reflexes are absent, there is decreased muscle tone, paralysis, and areflexia
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lower motor neuron syndrome
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this disease presents with a slow degeneration of the neurons controlling movement (both U and L motor neurons); the person has atrophy and weakness, and eventually voluntary movement is lost; may affect the diaphragm
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amyotrophic lateral sclerosis (ALS)
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these nociceptor axons conduct at 5-30 m/s and respond to dangerously intense mechanical stimuli or thermal stimuli
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A delta
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these nociceptor axons conduct at about 2 m/s and are polymodal; they respond to thermal, mechanical, and chemical stimuli
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C fibers
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thermal nociceptors are activated at temperature extremes of greater than __ and less than __ºC
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45, 5
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these types of afferent fibers modify the quality and characteristics of pain
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Aa and Ab (large diameter)
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this is the excitatory neurotransmitter of Adelta and C afferents that is used by nociceptive afferents to mediate synaptic transmission onto dorsal horn neurons
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glutamate
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this substance is released from C afferents; it enhances and prolongs the actions of glutamate and the excitability of the dorsal horn neurons
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neuropeptides (substance P)
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this is an altered pain response where there is enhanced sensitivity to stimulation in an area around injured tissue; mildly painful stimuli are perceived as significantly more painful
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hyperalgesia
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this is a pain response that occurs when non-painful stimuli are perceived as painful
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allodynia
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this is a phenomenon that occurs when previously unresponsive nociceptive endings become responsive (have a lower threshold for activation); it is caused by the release of chemicals that activate or decrease the threshold for nociceptors (histamine, prostaglandin, bradykinin)
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peripheral sensitization
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this is a stimulation of sensory neurons that leads to the release of inflammatory mediators (substance P and CGRP) that produces vasodilation, plasma extravasation, and hypersensitivity
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neurogenic inflammation
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this phenomenon occurs when there is a hyperexcitability of dorsal horn neurons; occurs when there is repetitive, continuous C fiber firing
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central sensitization
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where do the central pain pathways synapse?
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Rexed's laminae
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These are 10 layers of spinal gray matter that are arranged from dorsal to ventral and classified according to cellular structure
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Rexed's laminae
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this layer of Rexed's laminae contains the posteromarginal nucleus, and has pain and temperature pathways
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lamina I
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this layer of Rexed's laminae contains the substantia gelatinosa, and contains pain and temperature pathways that are by interneuron only
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lamina II
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this layer of Rexed's laminae contains the substantia gelatinosa and contains pathways for pain by mechanoreceptors
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lamina III
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these layers of Rexed's laminae contain the nucleus proprius and contains pain pathways by mechanoreceptors
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lamina IV, V, VI
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this layer of Rexed's laminae contains the nucleus dorsalis/Clarke's nucleus and interomedial nucleus; contains 2nd order proprioceptive neurons for LEs and preganglionic sympathetics
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lamina VII
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this layer of Rexed's laminae contains motor nuclei and transmits via interneurons
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lamina VIII
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this layer of Rexed's laminae contains motor nuclei and transmits via alpha motor neurons
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lamina IX
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this layer of rexed's laminae contains neurons surrounding the central canal and contains commissural neurons for pain and temperature sensation
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X
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the anterolateral system arises from second order neurons in which laminae?
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I, IV, V
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in the gate control theory, these afferent fibers inhibit the firing of neurons in the nociceptive pathway, closing the gate
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Ab
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in the gate control theory, these afferent fibers excite spinothalamic neurons but inhibit the firing of lamina II inhibitory interneurons, opening the gate
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Adelta and C fibers
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electrical or chemical stimulation of this area in the midbrain can produce relief of pain by activating descending pain modulating pathways that inhibit nociceptive neurons in the spinal cord
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periaqueductal gray (PAG)
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this pain phenomenon is when there is a tingling or burning sensation of pain in an amputated body part that occurs when central pain processing circuits are still active in the absence of peripheral inputs
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phantom pain
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the cerebral cortex can best be seen in the __ plane of the brain
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coronal
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there are __ layers of the cerebral cortex that are primarily named for the shapes of the cell bodies within that layer
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6
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this type of stain shows the types of dendrites and axons within the layers of the cortex
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Golgi stain
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this type of stain shows the cell bodies within the layers of the cortex
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Nissi stain
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this type of stain shows the myelin and axons that are present within the layers of the cortex
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Weigert stain
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this layer of the cerebral cortex has granular cell bodies and the axons project horizontally
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I (molecular layer)
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this layer of the cerebral cortex has granular cell bodies and the axons project to deeper layers in the same cortical area
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II (External granular layer)
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This layer of the cerebral cortex has pyramidal cell bodies and has axons that project to other cortical areas or to the same area in the opposite hemisphere
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III (external pyramidal layer)
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this layer of the cerebral cortex has granular cell bodies and has axons that receive the bulk of input from the thalamus
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IV (internal granular layer)
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this layer of the cerebral cortex has pyramidal cell bodies with axons that project to subcortical centers
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V (internal pyramidal layer)
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this layer of cerebral cortex has fusiform cell bodies and has axons that project to other areas of cortex and to subcortical centers
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VI (multiform layer)
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neurons that are in one hemisphere of the cortex can project to the other hemisphere via this structure
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corpus callosum
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this is a ridge in the brain
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gyrus
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this is a valley in the brain
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sulcus
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this is a deep valley in the brain
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fissure
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the primary motor cortex is located in this area of the brain
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precentral gyrus
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The primary motor cortex is often labeled as Brodmann's area __
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4
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the premotor cortex is located in Brodmann's area __
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6
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this is an area in the brain that is located anterior to the primary motor cortex and is involved in motor planning
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premotor cortex
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these are the four components of the premotor cortex
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Premotor Dorsal (PMd), Premotor ventral (PMv), Supplementary Motor Area (SMA), and the Cingulate Motor Area (CMA)
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the function of this area of the brain is to execute voluntary movement through activation of the muscle via spinal motoneurons
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primary motor cortex
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the function of this section of the premotor cortex is to plan "where" to move; gives the body information about the location of an object
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Premotor Dorsal
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the function of this section of the premotor cortex is to plan "what" to move; gives the body information about the properties of the object
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Premotor Ventral
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this area of the premotor cortex is involved in sequence learning (series activation of movement) and imagined movements "motor imagery"
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Supplementary motor area
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this area of the premotor cortex is located on the very medial portion of the cortex, and it's function is still widely unknown, however it has been proposed that it is involved in planning voluntary movements with respect to reward
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Cingulate motor area
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this concept states that multiple pieces of information from multiple cortical neurons come together to activate a single spinal motoneuron
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convergence
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this concept states that a single piece of information is spread to multiple spinal motoneurons
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divergence
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this idea states that the use, or non-use, of a muscle can change its cortical representation (change in the somatotopic map)
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neuroplasticity
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this descending motor pathway is the most direct pathway from the cortex to the spinal motoneurons
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the corticospinal tract
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From where does the corticospinal tract originate?
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many areas in the frontal and parietal lobes
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about __% of the axons in the corticospinal tract come from the primary motor cortex
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30
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about __% of the axons in the corticospinal tract come from the non-primary motor areas (SMA, PM, CMA)
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30
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about __% of the axons in the corticospinal tract come from the parietal lobe (Brodmann's areas 1,2,3,5 and 7)
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40
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Corticospinal tract axons arise from the large and small pyramid-shaped cell bodies in cortical layer __
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V
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The axons of the corticospinal pathway pass through the __ __ after leaving the cortex
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corona radiata
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the axons of the corticospinal tract enter the brain where?
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the internal capsule
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within the internal capsule, the corticospinal neurons are located within the __ limb
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posterior
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the axons in the corticospinal tract that come from the nonprimary motor areas pass through the __ and the __ 1/3 of the internal capsule
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genu, anterior
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the axons in the corticospinal tract that come from the primary motor cortex pass through the __ 1/3 of the internal capsule
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middle
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the axons in the corticospinal tract that come from the parietal areas pass just __ to the M1 axons in the internal capsule
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posterior
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As the axons of the corticospinal tract descend through the internal capsule, they shift posteriorly and pass below the __
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thalamus
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After passing below the thalamus, the axons of the corticospinal pathway descend through the middle 1/3 of the __ __ of the midbrain
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cerebral peduncle
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After descending through the cerebral peduncle, the axons of the corticospinal pathway go to the __, where they pass around nuclei
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pons
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After they pass around nuclei in the pons, the axons of the cerebrospinal tract enter the __ to form pyramids
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medulla
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At this junction, the majority of the fibers of the corticospinal tract cross the midline (decussate) to become the lateral corticospinal tract
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spinomedullary junction
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At the spinomedullary junction, about __% of the corticospinal axons cross the midline to become the lateral CST
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85
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The remaining axons that did not cross at the spinomedullary junction continue to descend uncrossed as the __ corticospinal tract
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ventral
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axons traveling in the __ corticospinal tract tend to synapse on motoneurons and interneurons involved in the control of more distal musculature
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lateral
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axons traveling in the __ corticospinal tract tend to synapse on motoneurons and interneurons involved in the control of more proximal limb muscles and axial musculature
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ventral
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Less than __% of the axons in the corticospinal tract recross the midline in the spinal cord and terminate on the ventral horn ipsilateral to their origin
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10%
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the first order neurons in the vestibulospinal tract come from the __ __ in cranial nerve __
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vestibular ganglion, VII
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the first order neurons in the vestibulospinal tract enter the brainstem at the __ __ junction
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lateral pontomedullary
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the first order neurons in the vestibulospinal tract synapse on __ vestibular nuclei after entering the brainstem at the lateral pontomedullary junction
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4 (superior, lateral, inferior, and medial)
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some of the 1st order fibers of the vestibulospinal tract also go straight to the __ of the brain
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cerebellum
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the second order neurons from the lateral vestibular ganglion form the __ __ tract
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lateral vestibulospinal
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the second order neurons from the medial vestibular ganglion form the __ __ tract
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medial vestibulospinal
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the __ vestibulospinal tract prefers axial and proximal limb motorneuron pools
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lateral
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the __ vestibulospinal tract controls axial muscles related to head and neck movements
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medial
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the origin of the reticulospinal tract is the __ __
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reticular formation
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The most important source of input to the reticular formation are these areas
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the bilateral motor areas (primary motor cortex, premotor cortex, and supplementary motor area)
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the reticulospinal tract in man exists as a scattered bundle of fibers, terminating primarily in the __ portion of the spinal gray matter at or above the __ enlargement
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venteromedial, cervical
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this tract does motor control that is exerted chiefly over axial and proximal limb musculature to assist with postural control and orientation
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reticulospinal tract
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the origin of the rubrospinal tract is in the __ __ of the midbrain
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red nucleus
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the red nucleus of the midbrain receives input from the __ motor cortex
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ipsilateral
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the axons of the rubrospinal tract cross immediately to the opposite side in the __ __ __
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anterior tegmental decussation
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the axons of the rubrospinal tract that have crossed descend in the __ column of the spinal cord
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lateral
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the axons of the rubrospinal tract terminate in the dorsal and lateral parts of the __ __ of the spinal cord
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intermediate zone
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the primary somatosensory cortex contains these Brodmann's areas
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1, 2, 3a and 3b
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the primary somatosensory cortex is known by this symbol
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S1
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the secondary somatosensory cortex is known by this symbol
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S2
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this phenomenon explains that some areas of the body take up much more territory in the cortex than you would think based on their size (more receptor density)
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cortical magnification
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It is easier to measure plastic changes in __ because it is very strictly/intricately arranged somatotopically
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S1
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the primary sensory cortex is located in the __ gyrus of the parietal lobe
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postcentral
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__ __ at all levels of sensory pathways allows for accurate stimulus localization; it is known as the capacity of an excited neuron to reduce the activity of its neighbors
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lateral inhibition
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__ neurons provide information needed to precisely control hand and finger movements (e.g. grasping)
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S1
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these types of neurons in the sensory system respond to movement in all directions
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motion-sensitive
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these types of neurons in the sensory system respond to movement most in one direction
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direction-sensitive
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these types of neurons in the sensory system respond more to movement along one axis than to movement along another axis
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orientation-sensitive
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this is the capability of being molded; the capacity of representation (maps) in the central nervous system are able to be changed as a result of alterations in inputs and direct damage
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plasticity
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These are four ways to measure motor plasticity
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ICMS, PET scan, TMS, and fMRI
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this procedure is performed when the skull is opened and electrodes are inserted into a gridlike pattern; current is sent through the electrodes and which body part moves is observed
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intracortical microstimulation (ICMS)
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this procedure to measure motor mapping is when a person is asked to perform a task, and it is seen which areas of the brain have more blood flow to them during and after the task is performed
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fMRI
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there is a general trend for somatotopy with the trunk more __ and the jaw/face more __
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medial, lateral
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in this type of motor mapping technology, a device is put onto the outside of the head and a magnetic pulse induces brain current, which increases the EMG activity of a muscle (where? to what magnitude?)
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transcranial magnetic stimulation (TMS)
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motor __, not use, is associated with an M1 plasticity
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learning
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this is a large, functionally diverse set of nuclear structures that lie deep within the cerebral hemispheres and influence movement by acting upon/regulating upper motor neurons
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basal ganglia
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this is the relay center for the CNS
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thalamus
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these are the 6 nuclei that comprise the basal ganglia
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Striatum, subthalamic nucleus (STN), GPi, SNr, GPe, and SNc
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these are the two components of the striatum
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caudate and putamen
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this is the largest input to the basal ganglia
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the cerebral cortex
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cortical input to the basal ganglia is excitatory, and uses __ as its neurotransmitter
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glutamate
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the subthalamic nucleus receives __ input from the frontal cortex
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excitatory
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the striatum receives __ input from the thalamus and brainstem
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excitatory
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the striatum receives __ input from the brainstem and local interneurons
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inhibitory
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these two areas project to the posterior putamen
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somatosensory and motor cortices
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this area projects to the anterior caudate
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prefrontal cortex
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this area of the striatum is associated with movements of the body
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putamen
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this area of the striatum is associated with movements of the eyes
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caudate
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in the striatum, the cortical inputs terminate on these types of neurons
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medium spiny neurons (MSNs)
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the medium spiny neurons utilize __ as their neurotransmitter, which cause them to send inhibitory inputs to both the GP and the SN
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GABA
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these neurons send inhibitory output to structures outside of the basal ganglia, most importantly the ventral anterior and lateral nuclei of the thalamus
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GPi
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The GPi receives inhibitory input from these two structures
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Striatum and GPe
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the GPi receives excitatory input from this structure
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STN
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the SNr receives inhibitory input from these structures
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striatum, GPe
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the SNr receives excitatory input from this structure
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STN
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these neurons send inhibitory output to structures mainly outside the basal ganglia, namely the superior colliculus and frontal eye fields, as well as ventral anterior and lateral nuclei of the thalamus
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SNr
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the GPe receives inhibitory projections from this nucleus
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striatum
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this nucleus sends inhibitory projections to both the SNr and the GPi
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GPe
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these nuclei are large dopamine containing cells, and send projections back to the striatum that are dependent upon the type of dopamine receptor located on the striatal neuron
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SNc
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the SNc receives inhibitory projections from this area
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striatum
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the GPi contains __ dopamine receptors
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D1
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the GPe contains __ dopamine receptors
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D2
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the direct pathway functions via the medium spiny neurons that contain __ dopamine receptors
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D1
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the indirect pathway functions via the medium spiny neurons that contain __ dopamine receptors
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D2
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this pathway inhibits the tonically active inhibitory firing of the Gpi neurons, resulting in upper motor neurons being released from their tonic inhibition
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direct pathway
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this pathway increases the tonic firing of the GPi neurons, thus increasing the inhibitory output from the basal ganglia and inhibiting the upper motor neurons (surround inhibition of competing movements)
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indirect pathway
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the net effect of this neurotransmitter is to allow movement to take place more easily
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dopamine
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these disorders occur when there is an overactive indirect pathway that increases inhibitory output from the BG, resulting in excessive inhibition of upper motor neurons; due primarily to increased drive from the STN
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Hypokinetic disorders
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these disorders result from an underactive indirect pathway, which causes reduced inhibitory output of the BG and unwanted excitation of the upper motor neurons (uncontrollable movements)
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Hyperkinetic disorders
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types of hypokinetic disorders
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Akinesia, bradykinesia, rigidity, tremor at rest
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types of hyperkinetic disorders
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Athetosis, Ballismus, chorea, dystonia, dyskinesias, Huntington's disease
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this is a disease that is predominantly manifested in the 4th or 5th decade, and the prominent symptom is chorea; it includes other hyperkinetic symptoms and there are emotional and cognitive changes as well
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Huntington's disease
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this is a hyperkinetic symptom that is manifested in rapid, jerky ballistic movements (dancelike)
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chorea
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this disease is characterized by violent, involuntary movements of the limbs due to lesion of the STN; the movements are due to discharges of the upper motor neurons that are now less tonically inhibited
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hemiballismus
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hemiballismus manifests itself in the side of the body __ to the lesion
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contralateral
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this disease is characterized by sustained muscle contractions that cause twisting, repetitive movements and abnormal postures
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dystonia
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This disease has many hypokinetic symptoms (tremor, rigidity, etc) that results in postural instability, a flexed forward posture, mask-like face, shuffling gait, and monotonous speech
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Parkinson's disease
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This disease is caused by loss of SNc neurons, causing loss of dopamine, and the BG output becomes abnormally inhibitory
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Parkinson's disease
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These are all of the sensory pathways that ascend from the periphery to the CNS
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(1) Dorsal column medial lemniscus
(2) Spinothalamic (3) Trigeminal (4) Spinocerebellar |
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These are all of the motor pathways that descend from the CNS to the periphery
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(1) Corticospinal
(2) Reticulospinal (3) Rubrospinal (4) Vestibulospinal |
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what are the two types of rapidly adapting sensory receptors?
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Pacinian corpuscles and Meisner's corpuscles
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what are the two types of slowly adapting sensory receptors?
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Merkel discs and Ruffini corpuscles
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Brodmann's area 3a in the primary somatosensory cortex are associated with what proprioceptive structure?
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muscle spindles
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Brodmann's areas 3b and 1 in the primary somatosensory cortex are associated with what sensory receptors?
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cutaneous
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Brodmann's area 2 in the primary somatosensory cortex is associated with what sensory receptors?
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deeper receptors within joints and muscles
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which layers of Rexed's laminae are located in the dorsal horn of the spinal cord?
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I-VI
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what are the two nuclei of the basal ganglia that receive input from structures outside the BG?
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Straitum and STN
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what are the two nuclei of the basal ganglia that send output to structures outside the BG?
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GPi and SNr
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what are the two nuclei of the basal ganglia that are intrinsic (all projections are inside the BG)?
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GPe and SNc
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During deep brain stimulation, which brain region would be targeted in order to reduce tremors?
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thalamus
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During deep brain stimulation, which brain structure would be targeted in order to reduce dyskinesia and choreic movements?
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GPi
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During deep brain stimulation, which brain region would be targeted in order to reduce bradykinesia and axial motor symptoms?
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STN
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