Cog Psych: Chapter 2

Is the study of the physiological basis of cognition.

Refers to the idea that a topic can be studied in a number of different ways, with each approach contributing its own dimension to our understanding.

Staining the brain reveal a network that was believed to be continuous, like a highway system in which one of the street connects directly to another, but without stop signs or traffic lights.

the idea that individuals cells transmit signals in the nervous system, and that these cells are not continuous with other cells as proposed by nerve net Theory.

-Cajal's discovery that individual units called neurons were the basic building blocks of the brain was the center piece of the neuron doctrine.

is the metabolic center of the neuron; it contains mechanisms to keep the cell alive.

Function of dendrites that branch out from the cell body is receive signals from other neurons.

Also called nerve fibers, are usually long processes that transmit signals to other neurons.

a small gap between the end of a neuron's axon and the dendrites or cell body of another neuron.

Neurons are not connected indiscriminately to other neurons, but form connections only to specific neurons. This forms groups of interconnected neurons, which together form neural circuits.

are similar to brain neurons in that they have an axon, but they have specialized receptors that pick up information form the environment.

small shafts of hollow glass filled with a conductive salt solution that can pick up electrical signals at the electrode tip and conduct these signals back to a recording device.

how with its recoding tip inside the neuron, and a "reference electrode" located some distance away so it is not affected by the electrical signals. The difference in charge between the recordingg and reference electrodes is fed into a computer and displayed on the computers screen.

This value, which stays the same as long as there are no signals in the neuron, is called the resting potential. In other words inside the neuron has a charge of 70 mV more negative than the outside, and this difference continues as long as the neuron is at rest.

When the neuron's receptor is stimulated so that the "nerve impulse" is transmitted down the axon.

As the impulse passes the recording electrode, the charge inside the axon rises to +40 millivolts compared to the outside. As the impulse continues past the electrode, the charge inside the fiber reverses course and starts becoming negative again until it returns to the resting potential.

Action potential lasts about 1 millisecond

When signals reach the synapse at the end of the axon, a chemical called a "neurotransmitter" is released. This neurotransmitter makes it possible for the signal to be transmitted across the gap that separates the end of the axon from the dendrite or cell body of another neuron.

States that everything a person experiences is based not on direct contact with stimuli,, but representations in the person's nervous system.

the layer of neurons that lines the back of the eye.

Image, because it is the image created by light reflected by Mary that gets into Gil's eye, not Mary herself.

the area at the back of the brain that relies signals from the eye.

Found that each neuron in the visual area of the cortex responded to a specific type of stimulation presented to a small area of the retina. Called feature detectors because they responded to specific stimulus features such as orientation, movement, and length.

What is happening is that neurons in the visual cortex respond to relatively simple stimuli send their icons to higher levels of the visual system, where signals from many neurons combine and interact; neurons at this higher level, which respond to more complex stimuli such as geometrical objects, then send signals to higher areas, combing and interacting further and creating neurons that respond to even more complex stimuli such as faces. Progression from lower to higher areas of the brain is called hierarchical processing.

refers to how neurons represent various characteristics of the environments.

The idea that an object could be represented by the firing of a specialized neuron that responds only to that object, is called specificity coding.

is the representation of a particular object by the pattern of firing of a large number of neurons.

Occurs when a particular object is resperesntep by a pattern of firing of a large number of neurons, with the majority if neurons remaining silent.

Specific functions are served by specific areas of the brain.

Most cognitive function are served the cerebral cortex, which is a layer of tissue about 3 mm thick that covers the brain. Cortex is the wrinkled covering you see when you look at an intact brain.

the study of behavior of people with brain damage.

1879, Carl Wernicke studied another group of patients with damage in an area of the temporal lobe, whose speech was fluent and grammatically correct but tended to be incoherent.

Brain damage where the visual cortex is located., resulted in blindness, and that there was a connection between the area of the occipital lobe that was damaged and the place in visual space where the person was blind. Damage to left part of occipital lobe would cause an area of blindness in the upper right part of the visual field.

Auditory cortex, which received signals from the ears, is in the upper "temporal lobe," and is responsible for hearing.

The somatosensory cortex which recieves signals from the skin, is in the parietal lobe and is responsible for perceptions of touch, pressure, and pain.

Receives signals from all of the senses and is responsible for coordination of the senses, as well as higher cognitive functions like thinking and problem solving.

An inability to recognize faces. Can tell a face is a face, but can't recognized whose face it is, even for friends and family and even themselves in some cases.

Occurs if damage to one area of the brain causes function A to be absent while function B is present, and damage to another area causes function B to be absent while function A is present.

Makes it possible to determine which areas of the brains of humans are activated by different cognitions.

Made it possible to create images of structures within the brain, was introduced for clinical practice; since then, it has become a standard technique for detecting tumors and other brain abnormalities. Does't indicate neural activity.

Has enabled researchers to determine how various types of cognition activate different areas of the brain.

Which are small cube-shaped areas of the brain about 2 or 3 mm on a side. Voxels are not brain structures but are simply small units of analysis created by the fMRI scanner. Like small pixels

It is in the fusiform gyrus on the underside of the temporal lob, is the same part if the brain that is damages in cases of prosopagnosia.

Perceiving pictures representing outdoor and indoor scenes activates the parahippocampal place area. What is important for this area is information about spatial layout, because increased activation occurs when viewing pictures both of empty rooms and of rooms that are completely furnished.

Activated by pictures of bodies and parts of bodies (but not by faces).

Idea that specific cognitive functions activate many areas of the brain is called distributed representation.

Groups of neurons or structures that are connected together.

is based on detection of how water diffuses along the length of nerve fibers.