Chapter 2

Question 1

What is Capgras syndrome

Answer 1

A typical accompaniment to alzheimer’s but also results from brain injuries. The victim can recognize family and friends but believes they are imposters

Question 2

What are the two systems involved in facial recognition, which is disrupted in Capgras syndrome?

Answer 2

1. cognitive appraisal (recognition of physical features)
2. Emotional appraisal (Sense of familiarity/warmth)
   > the second is distrupted in Capgras syndrome

Question 3

What brain areas have been shown to play a role in Capgras syndrome?

Answer 3

1. MRI scans show damage in the right temporal lobe disrupting circuits involving the amygdala the “emotional evaluator” of the brain
2. fMRI shows diminished activity in the right prefrontal cortex which is responsible for careful analysis. With diminished functioning it becomes hard to tell what’s real and what’s not

Question 4

In what 3 circumstances is the prefrontal cortex less active

Answer 4

1. Capgras syndrome
2. Schizophenics experiencing hallucinations
3. While dreaming

Question 5

What are 3 functions of the amygdala?

Answer 5

1. supports the feeling of familiarity
2. helps people remember emotional events
3. Helps in emotional decision making

Question 6

What does capgras syndrome teach us about brain function

Answer 6

Even the simplest tasks involve the working together of multiple brain areas

Question 7

What are commissures? what is the largest?

Answer 7

Thick bundles of fibers that carry information b/w the 2 hemispheres allowing integration
> Largest = Corpus Callosum

Question 8

How does one become a split brain patient?

Answer 8

By severing the corpus callosum, thus having two intact halves that cannot communicate

Question 9

What are the R and L hemispheres responsible for (in general)

Answer 9

L = language
R = Spatial judgement

Question 10

Define Neuropsychology and clinical neuropsychology

Answer 10

1. study of the brain’s structures and how they relate to brain function
2. Understanding undamaged brains by scrutinizing brain damage cases

Question 11

Explain the experiment with the spoon and fork performed on split brain patients

Answer 11

The left side of the brain will see the fork on the R side of the body and be able to verbalize it. The Right side of the brain sees the spoon on the L side, cannot verbalize it but when reaching to pick it up selects the correct object

Question 12

define lesion

Answer 12

specific area of damage

Question 13

Describe how the CT scan functions

Answer 13

• Used to study structure
• Relatively stable results
• Relies on X-rays to create a 3D picture of the brain
• The map tells us the shape, size and position of sturctures

Question 14

Describe how a PET scan functions

Answer 14

• Used to study brain activity
• Highly variable results
• involves introducing a tracer substance (glucose) tagged with radioactivity to track which tissues are using more glucose and are thus more active
• The maps shows which regions are active

Question 15

Describe how MRI and fMRI differ

Answer 15

MRI: relies on magnetic properties of the atom in brain tissue to yield detailed pictures
fMRI: measures oxygen content in blood which provides precise pictures of the brains moment by moment activities

Question 16

What are neurotransmitters?

Answer 16

Chemical signals neurons use to communicate

Question 17

What are the 2 types of communication among neurons?

Answer 17

Between neuron - a neuron releases the transmitter and activates or de-activates neurons adjacent to it
Within neuron - Movement of the signal from a neuron’s input to it’s output via an electrical pulse made possible by the flow of charged atoms moving through the neurons

Question 18

What is an EEG

Answer 18

Recording of voltage changes occurring at the scalp that reflect activity in the brain

Question 19

What is a TMS

Answer 19

Creates strong magnetic pulses at specific location on the scalp to temporarily “turn off” a certain brain area in otherwise healthy patients

Question 20

what is localization of function

Answer 20

Different portions of the brain all have their own jobs to do!

Question 21

where are rodes and cones located on the eye and what are their functions

Answer 21

Cones - located most densely in the fovea allow for better acuity
Rods - Located more densely in the peripheries are light-sensitive and can see better in dim lighting

Question 22

Once visual input hits the rods and cones where does it go next??

Answer 22

These photoreceptors stimulate bipolar cells which excite the ganglion cells whose axons converge and form the optic nerve which carries (and analyzes) the visual input through the lateral geniculate nucleus and finally to the occipital lobe

Question 23

Explain single cell recording and what it tells us

Answer 23

An electrode is placed near a single neuron to observe how often it fires when viewing certain stimulus. This allows us to define the cell’s receptive field

Question 24

What is a center-surround cell

Answer 24

A cell that fires maximally when the stimulus is in the centre of the receptive field and minimally when the stimulus is on the edge of the feild. When it’s on both the firing rate doesn’t change from it’s baseline level

Question 25

What are “edge detector” cells

Answer 25

Cells that fire maximally to an edge of a specific orientation and the further the edge is from it’s preferred angle the weaker the firing of the cell

Question 26

What are movement detector cells?

Answer 26

Fire maximally to movement in a certain direction

Question 27

What type of processing does the visual system rely on?

Answer 27

Parallel processing - A system in which many different steps/ forms of analysis are occurring simultaneously
ex. Area MT is processing movement while V4 is processing color and shape

Question 28

What is serial processing

Answer 28

steps are carried out one at a time

Question 29

What are the advantages of parallel processing?

Answer 29

1. speed

2. Mutual influence : each type of analysis can be informed by the other

Question 30

Whats another example of parallel processing in the occipital cortex?

Answer 30

1. P cells (input for LGN’s parvocellular cells and responsible fpr spatial analysis) and M cells (input for LGN’s magnocellular cells and responsible for movement and depth perception)
2. Rods and cones

Question 31

Describe the What and where systems/pathways

Answer 31

WHAT: travels from the occipital cortex to the temporal lobe and plays a role in identification of objects
WHERE: travels from the occipital cortex to the parietal cortex and guides our actions based on location of objects

Question 32

What occurs when the What/Where pathways are damaged

Answer 32

WHAT (Ventral): visual agnosia - can’t identify an object but can reach for it
WHERE (Dorsal) : the opposite - they can identify but have trouble reaching

Question 33

What is the binding problem?

Answer 33

The task of reuniting various elements of a scene that are initially processed by different brain areas so that we see a coherent whole.

Question 34

how does spatial postioning solve the binding problem?

Answer 34

By overlaying spatial maps one over the other (color, shape, movement..)

Question 35

How does neural synchrony solve the binding problem

Answer 35

rhythms caused by neural firing that sync up are registered as belonging to the same object

Question 36

How does attention solve the binding problem

Answer 36

Attention is essential for synchrony of neurons to occur. When attention is focused elsewhere people mak conjunction errors likewise people with ADHD struggle with tasks requiring feature conjuction

Question 37

What are the 3 components of visual perception

Answer 37

• Form perceptions (what is it)
• Depth perception (where)
• Motion perception (what is it doing)

Question 38

What is edge enhancement?

Answer 38

• Occurs in a very early stage of visual processing.
• Caused by lateral inhibition - the cell on the edge of the lighter band fires more than the other cells in the white band because on one side it has the cell from the darker band which is firing slower and thus provides less inhibition. The edge cell on the darker side fires even less than all other dark cells because the bright edge cell beside it (as just mentioned) is firing higher than all other bright cells and thus inhibits the dark edge cell more.