Ch. 2 Quiz

Brain imaging has made it possible to A. determine which areas of the brain are involved in different cognitive processes B. view individual neurons in the brain C. view propagation of action potentials D. show how environmental energy is transformed into neural energy

A

Groups of interconnected neurons are referred to as A. neural circuits B. potentiated somas C. spreading activations D. myelin sheaths

A

Recording from single neurons in the brain has shown that neurons responding to specific types of stimuli are often clustered in specific areas. These results support the idea of A. cortical association B. localization of function C. the information processing approach D. dissociation

B

The key structural components of neurons are A. cell body, cellular membrane, and transmitters B. cell body, dendrites, and axon C. transmitters, dendrites, and nodes of Ranvier D. axon, dendrites, and glands

B

Josiah is trying to speak to his wife, but his speech is very slow and labored, often with jumbled sentence structure. Josiah may have damage to his A. Extrastriate body area (EBA) B. Parahipocampal place area (PPA) C. Broca's area D. Wernicke's area

C

The idea of a grandmother cell is consistent with A. subtraction techniques B. primary receiving areas C. distributed coding D. specificity coding

D

The idea that specific cognitive functions activate many areas of the brain is known as A. aphasia B. localization of function C. modularity D. distributed processing

D

You are walking down the street and see a really nice car drive by. You notice many features of it: its color, movement, shape, location, and so forth. All of these features are processed A. by the grandmother cells in the brain B. in one local area of the brain C. through fMRI potentials D. in different parts of the brain

D

What are the two terms associated with representations by single neurons? Explain them.

Feature detectors-neurons in visual cortex that respond to specific stimuli, i.e. length, movement, orientation (Hubel & Wiesel cat study) **but complex stim can make 1000s of FDs fire Specificity coding-each neuron responds to a specific stimulus. i.e. when you look at Mary, neuron #4 fires but when you look at Jane, neuron #7 fires. **unlikely to be correct bc there are too many objects in the world to have specialized neuron for each

What are the two types of connections between hemispheres?

contralateral-the control centers for L side of body are located on the R side of the brain and vice versa ipsilateral-R hemisphere has ctrl centers for R side of body and vice versa there is hemispheric specialization which is when diff fns rely more heavily on one hemisphere than the other, but most rely on a combination of both

Describe the effect of a more intense vs. a less intense stimulus on action potential (i.e. pressing harder or lighter on skin)

there are smaller intervals when the stimulus is more intense. the firing rate of AP increases when intensity increases, but the size of AP doesn't change

What is the principle of neural representation?

what we perceive is just a representation in our NS but not actual contact with the stimulus. ex. when you look at someone, the stimulus (person) doesn't enter into your retina, but the light bouncing off of the person enters your retina and your brain creates a representation of the person so that's what you see

What is the principle of double dissociations? Use the examples of Broca's aphasia and Wernicke's aphasia.

when there are 2 reciprocal deficiencies showing that two brain areas/fns are separate i.e. if you have Broca's aphasia, you have trouble speaking but you understand what people say and know what you want to say. if you have Wernicke's, you can't understand/form comprehensible speech, but you can still speak fluently. the fact that you can have one but not the other shows these two fns (speech production/comprehension) are in separate areas of the brain

What can and can't we conclude from lesion studies? How does distributed representation play into this?

can-what brain areas are NECESSARY (i.e. specialized) for a specific fn can't-all the brain areas NORMALLY used distr. rep. says that brain areas are interconnected and many areas work together during one cog fn (NORMALLY used) but there may be small areas that are specialized for that fn (NECESSARY for fn) i.e.-lesion in broca's area-->can't produce speech. so broca's is necessary for speech, but other areas might be involved

Describe the structure of a neuron; describe the synapse and neural circuit mechanisms.

dendrites: receiving end of signal cell body: metabolic center, keeps cell alive axon: signal travels down it (electrical) myelin sheath: insulation synapse: space b/w neurons (chemical signal transmitted by neurotransmitters) neurons form specific connections to other neurons, it's not random

Describe an action potential. What is the all-or-none phenomenon?

electrical component of neural communication, when membrane potential (diff b/w inside/outside of axon) is reversed when not stimulated, neuron is at resting potential of -70mV. stim (NTs binding to dendrites) causes depolarization that moves MP up to and past the threshold (-55mV). flow of Na ions into cell creates electrical signal (AP) that flows down axon. AP peaks and then repolarization occurs until MP overshoots resting potential (hyperpolarization/refractory period) where neuron resets and gets ready to fire again. the signal generated by AP travels down neuron and can cause release of NTs

How might localization of function create a disadvantage if the brain were solely organized around that principle?

if one part is damaged, you would lose all functions associated with that one area. but actually there is distributed representations--many brain areas called in to one fn

How might cognition be more fragile if important specific functions were located solely in one area?

if that area were damaged, you would completely lose that important function

What are the different methods of studying localization of function?

lesion studies-either brain damaged patients (neuropsychology) or TMS (temporary lesions) double dissociations-X brain area/fn works in one patient but Y does not. in another patient, Y works but X does not. you can study the patients together to see if processes X and Y in areas X and Y are separate neuroimaging-MRI/CT (structural), PET, fMRI, ERP and single cell recording (function)

How did early brain researchers describe the brain in terms of a nerve net? How does the idea of individual neurons differ from the idea of a nerve net? (What is this idea called?)

nerve net theory said all neurons were interconnected, like a highway system with no stop signs. so the signal was uninterrupted (19th c.) Cajal's theory after that (neuron doctrine) said there are individual neurons that aren't continuous but separated by synapses. individual nerve cells transmit signals to each other w/i neural circuit (groups of interconnected neurons)

Which areas of the brain respond to simple stimuli and which respond to complex stimuli? What is the process that puts them together?

simple-visual cortex (feature detectors) complex-temporal lobe hierarchical processing is how info from lower (visual) areas goes to higher (temporal) areas of the brain. the order goes from less complex to more complex stimuli

How does distributed processing create greater opportunities for protecting cognitive function and allowing for restoration of cognitive function in the event of a loss related to brain damage?

since other brain areas are used for that one function (even though area specialized for that fn may be damaged), you can still have/partially have that fn because the other brain areas are called in to help

What is the difference between sparse and population coding?

sparse-only a few neurons fire while most remain silent to create a representation (for fns that don't require many neurons) population-a pattern of many neurons fire to create a representation (likely for the senses bc many stimuli can be represented)

What is localization of function? Describe brain imaging evidence.

specific areas of the brain responsible for specific functions fMRI subtraction technique: measure activity in brain areas before and after stimulation. subtract after - before and the difference shows brain areas used during that activity/stimulation FFA in temporal lobe responsible for facial recognition PPA responds to places EVA responds to bodies