Cognition

Question 1

What is the definition of cognition?

Answer 1

The mental action or process of acquiring knowledge and understanding through thought, experiences and the senses.

Question 2

What does cognition involve?

Answer 2

Memory, attention, language, problem-solving and planning.

Question 3

What does integration of complex information require?

Answer 3

It requires inputs from multiple different brain areas. Here, circuits for emotional processing as well as cortical brain regions are crucial for cognitive tasks.

Question 4

The human brain is subdivided into multiple areas. Based on what technique was this subdivision made?

Answer 4

Based on cytoarchitecture differences (histological stainings).

Question 5

The human brain has also been functionally mapped. On what was this functional mapping based?

Answer 5

On responses from patients and monkeys undergoing brain surgery.

Question 6

Today, the human brain has been divided into many more cytoarchitectonic regions. On what was this based?

Answer 6

On lamination, cell density, cell types and specific connectivity with other brain regions.

Question 7

The cortex consists of columns with 6 different layers. Describe these layers.

Answer 7

• The upper (first) layer consists mainly of axons.
• The second and third layer consists of pyramidal cells (large neurons with long axons and dendrites).
• The fourth layer consists of stellate cells.
• The fifth layer consists of pyramidal cells that are much larger then the ones in layer 2.
• The sixth layer also consists of pyramidal cells, but these are again a little bit smaller.

Question 8

Describe the characteristics of pyramidal cells.

Answer 8

Pyramidal cells are the main excitatory neuronal types found in the deep and superficial layers of the cortex. Their dendrites and axons make specific projections across or within the cortical layers.

Question 9

The neocortex (e.g. motor or visual cortex) typically consists of 6 layers. But there are other cortical regions that have less than 6 layers. Name these.

Answer 9

The evolutionary-older brain regions, like the paleocortex and archicortex (hippocampus), have 3 and 4 layers respectively.

Question 10

Describe for the thalamus, brainstem and other cortical inputs where in one of the 6 cortical layers they project to.

Answer 10

• Thalamic input into layer 4
• Brainstem input across all layers
• Other cortical inputs across superficial and deep layers.

Question 11

The primary sensory and motor cortices make up a fraction of the human cortex and ‘only’ receive sensory information via thalamic nuclei. The association cortices make up a much larger part of the human cortex.

When do we refer to the association cortex and when do we refer to the primary sensory or motor cortices?

Answer 11

• We refer to the association cortex if it receives its inputs from different thalamic inputs that are not so specific.
• We refer to the primary sensory and motor cortices if it receives sensory information via thalamic nuclei.

Question 12

From what do these association cortices get their input from?

Answer 12

They get input from:

• Corresponding cortical areas or non-corresponding cortical areas
• Motor and premotor cortex
• Other primary and secondary sensory cortical regions.
• Thalamus

Question 13

What do lesions in the parietal association cortex cause?

Answer 13

Problems in spatial attention/perceptual awareness.

Question 14

What is visual neglect?

Answer 14

It is a neuropsychological disorder of attention in which patients exhibit a lack of response to stimuli in one half of their visual field that cannot be explained by primary damage to the visual geniculostriate pathways.

In the lecture, a video is shown where the patient draws daisies. But since she has visual neglect (and damage on the left side of the parietal cortex), she is only able to draw the right part of the daisy (and doesn’t even recognize that she only drew half of the daisy).

Question 15

Is the right or left part of the parietal cortex more important in visual/spatial attention?

Answer 15

The right part of the parietal cortex is more important here.

Question 16

What is seen in parietal cortex activation when asked to:

• attend to the left visual field
• attend to the right visual field

Also explain why this is.

Answer 16

• attend to the left visual field → parietal activation on the right side
• attend to the right visual field → parietal activation on the left and right side.

This is because the left parietal cortex mediates attention primarily to the right and also seems to be much more involved in language processing, whereas the right parietal cortex mediates attention to both left and right halves of the body and extrapersonal space.

Question 17

• So what happens when there’s a lesion in the right hemisphere of the parietal cortex?
• What happens when there’s a lesion in the left hemisphere of the parietal cortex?
• What happens when there’s a partial bilateral lesion in the parietal cortex?

Answer 17

• Right hemisphere lesion → severe left neglect (because the right hemisphere mediates attention to both left and right)
• Left hemisphere lesion → minimal right neglect (because the right hemisphere is still able to mediate attention to both left and right)
• Partial bilateral lesion → severe right neglect

Question 18

What is seen in an experiment with monkeys where monkeys are trained to selectively attend to particular objects or events and where the monkeys report their experience in a variety of nonverbal ways, typically by looking at a response target (thus allowing their eye movements to be monitored) or manipulating a joystick?

Answer 18

As might be expected from the clinical evidence in humans, neurons in specific regions of the parietal cortex of the rhesus monkey are activated when the animal attends to a target, but not when the same stimulus is ignored

Question 19

What is a function of the temporal lobe?

Answer 19

Facial recognition

Question 20

What can damage to the temporal lobe result in?

Answer 20

Agnosias → problems with recognition and identification of objects in the environment. (Examples of agnosias are depicted in the picture)

Question 21

What makes agnosia different from visual neglect?

Answer 21

An agnosia patient is aware of the object in the visual field but cannot report what it is (whereas a patient with visual neglect isn’t even aware of the object).

Question 22

There’s a specific part in our temporal lobe that is important for facial recognition. What part is this?

Answer 22

The right inferior temporal lobe region.

Question 23

This picture provides evidence for the role of the temporal lobe during face recognition. You see that when a face is clearly depicted, certain neurons fire, while if the face is distorted (like in picture 2 or 3) the activity of temporal lobe neurons decreases.

Answer 23

Ok

Question 24

Do single temporal lobe neurons respond to specific faces → i.e. do we have gnostic neurons (individual neurons that respond to individual faces)?

Answer 24

Yes, here you see neurons that only fire when they recognize the face of Jennifer Aniston (or even the name or the sound of the name).

Question 25

What is the function of the frontal association cortex?

Answer 25

Frontal lobes integrate complex information from sensory, motor, temporal and association cortices and are important in executive functions like planning, decision-making, social behaviours and working memory functions.

Question 25

What happens when there’s damage to the frontal association cortex?

Answer 25

Changes in personality, inconsiderate, inability to function socially, inability to plan.

Question 26

How can we study frontal lobe executive function (in regard to planning)?

Answer 26

By performing the Wisconsin card-sorting task. Here, the participant is asked to sort cards in a specific order, but doesn’t know beforehand what the order is. The researcher can only tell the participants if the card order is wrong or not. Also, during the experiment the order of cards can be changed, where beforehand the order of cards is correct and suddenly the order isn’t correct. So that the participant needs to start all over again.

Question 27

What is seen in patients with frontal lobe damage when they’re asked to do the Wisconsin card-sorting task?

Answer 27

That these patients cannot adapt to the changing of the rules/order of cards.