Module 33 - Cognition

Question 1

What are the key brain structures in red? (IMAGE)

Answer 1

Red = primary motor cortex + primary visual cortex and primary auditory cortex

Question 2

What are the key brain structures in yellow? (IMAGE)

Answer 2

Yellow = unimodal association cortices
NOTICE → One type of sense = unimodal, for example the visual association cortex will only get vision information

Question 3

What are the key brain structures in green? (IMAGE)

Answer 3

Green = heteromodal association cortex

Question 4

What are the key brain structures in blue? (IMAGE)

Answer 4

Limbic cortex

Question 5

What does unimodal mean?

Answer 5

One type of sense = unimodal, for example the visual association cortex will only get vision information = yellow

Question 6

What is the function of the heteromodal association cortex?

Answer 6

• They put together information provided by various unimodal association areas to accomplish more complex functions
• This follows the concept that information continues to be processed at higher and higher levels as it travels through the brain.
  
  • For example, follow the pathway of information that will start in the primary visual cortex (red), move to the visual association cortex (yellow) and then to the lateral parietal and temporal heteromodal association cortex (green) which will combine information from both vision and motor or audition through a variety of sensory inputs.

Question 7

Which cortices cover most of the cerebral surface of the brain?

Answer 7

Association cortices (green)

Question 8

What are the association cortices responsible for?

Answer 8

Responsible for complex processing that goes on between the arrival of input to the primary sensory cortices and the generation of behavior

Question 9

What is the function of the association cortices?

Answer 9

Loosely referred to as “cognition”

Question 10

What is cognition?

Answer 10

It is a process by which we come to know the world

Question 11

What are the 3 main tenants of cognition? And their corresponding main cortex?

Answer 11

• Attending to complex stimuli (parietal cortex)
• Identifying these stimuli (temporal cortex) → recognize
• (Responding) Planning appropriate responses (frontal lobes)
  
  • Restraint
  • initiative
  • Order

Question 12

Why is the frontal cortex very important?

Answer 12

The frontal cortex integrates complex information from sensory and motor cortex, and parietal and temporal association cortices.

Question 13

In order to achieve their functions, association cortices are connected to many of the brain regions. Name the main areas.

Answer 13

• Primary motor and sensory areas
• Thalamus
• Brainstem
• Hippocampus
• Basal ganglia
• Cerebellum

Question 14

What are the three broad areas of association cortices and functions?

Answer 14

• Parietal association cortex = 1. Attention
• Temporal association cortex = 2. Recognition
• Frontal association cortex = 3. Planning and decision making

Question 15

What would damage (typically to the right) parietal association cortex yield?

Answer 15

• CONTRALATERAL neglect
• Apraxia = lack ability to plan movement
  
  • We know that the left hemisphere is generally specialized for language, so it leaves the right to mediate things like attention.
  • Therefore, when there is damage to the right we see the inability to attend to things on the left.
  • We also know that the WHERE pathway, happens in the parietal association cortex, and it analyses the location and movement of visual objects in space.

Question 16

What would damage (typically to the right) temporal association cortex yield?

Answer 16

• Visual agnosia (e.g. prosopagnosia)
• Typically people can acknowledge and describe the stimulus but they are unable to recognize or report what it is

Question 17

What would damage (typically to the left) temporal association cortex yield?

Answer 17

• Aphasias
• Because the left side of the brain is typically for language, we see a deficit in language = aphasias

Question 18

What is the frontal association cortex responsible for other than planning and decision making?

Answer 18

• It is also associated with our personality
• It allows us to appreciate our self in relation to the world, which will allow us to dictate our behaviors to be a plan and executed as we wish them to be
• It plays a big role in our society in terms of social context.

Question 19

What type of general lesions to these association cortexes produces?

Answer 19

Lesions to association cortex produce characteristic disorders

Question 20

How did the man with no memory (who had visual agnosia) recognize people?

Answer 20

Through auditory system = hearing the people’s voice

Question 21

Where does information from various senses come together?

Answer 21

Heteromodal association cortex = green

Question 22

What is the general patterns of cortical connectivity in our sensory systems?

Answer 22

• Visual
• Eye + retina = rods and cones to the…
  
  • Optic nerve then to the …
  • Lateral geniculate nucleus to the …
  • Primary visual cortex…
  • And now we can add another area = unimodal association areas = so the information can now go to a secondary visual cortex
  • And then we can add another layer to this hierarchy = green areas = heteromodal association cortices → this is where information from various senses will get put together.
• Touch
  
  • Skin
  • Dorsal column/spinothalamic nuclei
  • Thalamus
  • Primary sensory cortex (S1)
  • The information from these two systems might also combine and come together

Question 23

What describes most of the cortex covering the cerebral hemispheres?

Answer 23

The neocortex

Question 24

How is the neocortex divided?

Answer 24

It is divided into 6 cellular layers (laminae) with distinct cell populations.

Question 25

What are the similarities between the different cell layers of the neocortex?

Answer 25

In each layer, these cells have similar density, size, and shape.

Question 26

What are the differences between the different cell layers of the neocortex?

Answer 26

Where they differ is on their inputs and their outputs.

Question 27

What are the common features of all cortical regions?

Answer 27

* The primary source of inputs and outputs * Vertical and horizontal axis connections * Radial alignment * Interneurons connect functionally similar cell groups

Question 28

What are the three primary courses of input to the neocortex?

Answer 28

* Brainstem modulatory systems (goes to layers = 6,5,4,3,2,1) * Other cortical areas (goes to layers 5,4,2,1) * Thalamus (goes to layer 2)

Question 29

Is the thalamus involved in our hierarchies that we have covered so far?

Answer 29

Yes, the thalamus is on the pathway, in both the dorsal column medial lemniscus as well as the optic tract

Question 30

Is the Lateral geniculate nucleus of the thalamus inputs to the association cortices? Why or why not?

Answer 30

* LGN --\> gets information from the visual cortex * These parts of the thalamus receive information from the periphery → not from the cortex

Question 31

Is the VPL and VPM parts of the thalamus inputs to the association cortices Why or why not?

Answer 31

* VPM and VPL --\> typically gets information and gives it to the somatosensory cortex and receives information from the PCML as well as the spinal thalamic tracts * These parts of the thalamus receive information from the periphery → not from the cortex

Question 32

What are inputs to the association cortices?

Answer 32

* Pulvinar → parietal association cortex * Medial dorsal nuclei → frontal association cortex * They receive information from the cortex = they are receiving information that has already been processed

Question 33

What is the consequence of having these inputs to the association cortices?

Answer 33

* The consequence of this is that signals going into the association cortex, from these different nuclei, reflect information that has already been processed by = the primary and secondary sensory and motor areas of the brain. TAKE AWAY FROM ALL OF THIS INFORMATION IS THAT THE THALAMUS IS A HUGE RELAY CENTER!!!

Question 34

Where do the prefrontal cortex and parieto-occipital relay their information?

Answer 34

* They send it to heteromodal association cortices.

Question 35

What are the two thalamic nuclei that provide much of the subcortical input to the association cortex?

Answer 35

* Pulvinar → parietal association cortex * Medial dorsal nuclei (MD) → frontal association cortex * \*\*\*These nuclei receive information from other regions of the cortex (rather than receiving peripheral sensory information).

Question 36

Where does medial dorsal nuclei (MD) send their information?

Answer 36

To the frontal association cortex

Question 37

Where does the pulvinar send its information?

Answer 37

To the parietal association cortex

Question 38

What are other cortical areas that input to association cortices?

Answer 38

Cortico-cortical connections They are the main source of input to association cortices

Question 39

What is the main source of input to association cortices

Answer 39

Cortico-cortical connections

Question 40

What are the two types of cortico-cortical connections?

Answer 40

1. Ipsilateral connections 2. Inter-hemispheric connections

Question 41

Where do these ipsilateral connections (cortico-cortical connections) come from?

Answer 41

From primary and secondary sensory and motor cortices on the same side of the brain

Question 42

What are the inter-hemispheric connections (cortico-cortical connections)?

Answer 42

From corresponding and non-corresponding regions of cortex on the other side of the brain (via corpus callosum and anterior commissure.

Question 43

What is an example of a corresponding inter-hemispheric connection?

Answer 43

* Information coming from the contralateral hemisphere, corresponding cortical areas. * For example, this means frontal association cortices from the right will give information to the frontal association cortices on the left.

Question 44

What is an example of a non-corresponding inter-hemispheric connection?

Answer 44

* For example, this means that the right temporal association cortices will give information to the frontal association cortices on the left.

Question 45

What are the brainstem modulatory centers?

Answer 45

* A bit like “dimmer switches” - turn overall activity up or down * Involved in learning, motivation, arousal, etc.

Question 46

Where doe these brainstem modulator centers connect?

Answer 46

* They connect up to the association cortices = other primary and secondary sensory cortical regions

Question 47

What are the brainstem modulatory centers and their neurotransmitters?

Answer 47

* Midbrain → dopaminergic * Reticular formation → noradrenergic, serotonergic * Basal forebrain → cholinergic

Question 48

With this image = explain the 3 main inputs to the association cortices.

Answer 48

* Thalamus * Corresponding and non-corresponding cortical areas = contralateral hemisphere * Ipsilateral cerebral cortex * Brainstem modulatory inputs --\> goes to the association cortices * There is also some connections between the cerebellum and the association cortices

Question 49

True or false: Each cortical layer has a primary source of input and they all have the same primary source of output.

Answer 49

FALSE = Each cortical layer has a primary source of input and a primary source of output.

Question 50

True or false: Each cortical layer has both vertical and horizontal connections.

Answer 50

True

Question 51

True or false: Cells with similar functions wired together into columns arranged radially.

Answer 51

True

Question 52

How is connectivity different from primary cortices and unimodal association cortices.

Answer 52

1. Inputs come from other regions of the cortex (rather than periphery) 1. The information has already been processed 2. Cortical -cortical connections 1. Ipsilateral (primary and secondary sensory/motor cortices) 2. Contralateral (corpus callosum and anterior commisure) 3. Subcortical connections 1. Midbrain (dopaminergic nuclei) 2. Reticular formation 3. Brainstem

Question 53

Where do axons from the periphery input?

Answer 53

Primary somatosensory cortex

Question 54

Where do association cortices get the majority of their input? 1. Axons from the periphery 2. The frontal lobe 3. Other parts of the brain 4. I literally have no clue

Answer 54

* Answer = c. Other parts of the brain