Cognitive functions and the organization of the cerebral cortex

Question 1

True or false: cognitive functions are a part of the lower order functions?

Answer 1

False: cognitive functions are a part of the higher-order functions and sensory functions lower order

Question 2

Cognition can be defined as….

Answer 2

Anything that happens “in between’: information recombination and transformation, mostly in the cortex.

Question 3

What is included in cognition and how is the info encoded?

Answer 3

Memory
learning
attention
executive functions
"Consciousness"
Info is coded in a more complex/multidimensional

Question 4

Where is cognition encoded in the brain and what are the inputs and the outputs?

Answer 4

-in the cortex: a wrinkled, 2-dimensional sheet of layered neurons
-Input:
➳-Sensory cortices: primary and secondary for auditory, visual, somatosensory, gustatory, and olfactive
➳Motor cortices: primary motor cortex, premotor and secondary motor
➳hippocampus, thalamus, and brainstem
-Outputs:
➳hippocampus, basal ganglia, cerebellum, thalamus and other cortical areas

Question 5

What is the role of the tertiary areas in the cortex and what would happen if they are lesioned?

Answer 5

They are association cortices: unimodal and multimodal
“regions of cortex where injury causes cognitive deficits that can not be explained by impairment of sensory or motor function alone”

Question 6

What are the differences between primary sensory areas and higher sensory areas?

Answer 6

➳Primary sensory areas : Receive input from thalamic sensory relay nuclei
Higher order sensory areas: Receive input from other thalamic nuclei and lower order areas if sensory cortex

➳Primary sensory areas : Small receptive fields
Higher order sensory areas: thicc receptive fields

➳Primary sensory areas : Arrangement into precise map of the sensory receptor surface
Higher-order sensory areas: Organized into more imprecise maps of the array of peripheral receptors

➳Primary sensory areas : Injury: simple sensory loss
Higher-order sensory areas: Injury: deficits of perception and cognition & intact detection of sensory stimuli

➳Primary sensory areas : Limited connections to other cortical areas: only nearby, same modality neurons
Higher-order sensory areas: Connected to nearby unmodal areas & distal areas in frontal and limbic lobes

Question 7

Information flow in the nervous system

Answer 7

1. Sensory information is processed serially
2. Each area carries certain computations and conveys them to the next area, going higher in complexity and in abstraction of representation
3. Higher-order areas project back to the lower-order areas from which they receive input.
4. Parallel pathways in each modality lead to dorsal and ventral association áreas
5. Goal directed motor behavior is controlled in the frontal lobe.

Question 8

Principles for the organization of functional areas in the cortex

Answer 8

1) all areas fall into a few functional categories
2) areas in a category occupy a discrete, continuous portion of the cortical sheet
3) areas that are functionally related occupy neighboring sites

Question 9

Number of layers in paleocortex, neocortex and archicortex aka hippocampus

Answer 9

Paleocortex: 3
Neocortex :6
Archicortex aka hippocampus: 4

Question 10

Cortical structure: canonical circuit

Answer 10

• Each layer has a primary source of inputs and a primary output target
• Connections in the vertical axis (columnar or radial connections)
• Connections in the horizontal axis (lateral or horizontal)
• Cells with similar function arranged in radiallyalignedgroups
• Interneurons within layers give rise to axons that extend horizontally (linking functionally similar groups)

Question 11

True or false: the regions in the cortex are very clear and what helps delimitate them?

Answer 11

False: they are gradients: 52 distinct cytoarchitectural areas
-Cortical organization: 
➳Cell density, cell size
➳Cortical thickness
➳Laminar size

Question 12

How did we know that the different areas of the cortex were also functionally distinct?

Answer 12

• They studied neurological cases like Phineas Gage
• EEGs in animals
• They studied neurosurgical pateints

Question 13

Modern cogsci/neuroscience studies in humans

Answer 13

• Neuropsychological testing: like the memory cards because you can test lots of skills
• Functional neuroimaging combined with psychological tasks
• Neuromodulation (magnetic pulse to activate or inhibit a spot in the brain) combined with psychological tasks

Question 14

Unique features of association cortices

Answer 14

1. Thalamic nuclei:
   pulvinar –parietal association medial dorsal
   –frontal association
2. Information that arrives from the thalamus has already been processed by sensory and motor áreas
3. Majority of input is from corticocortical connections
   same hemisphere–U shaped fibers/ long association fibers
   interhemispheric–long association through corpus callosum
   “Segregated columns that interdigitate inter-hemispheric with ipsilateral projections

Question 15

What is the subcortical nuclei important for?

Answer 15

Important source of innervation

association cortices are modified thanks to it

Question 16

What are cholinergic neurons important for and where do they synapse?

Answer 16

• Brainstem, basal, forebrain

- memory, learning and attention

Question 17

What are dopaminergic neurons important for and where where do they synapse??

Answer 17

midbrain

–pleasure, salience, motivation, reward-learning

Question 18

What are noradrenergic neurons important for and where do they synapse?

Answer 18

–brainstem

wakefulness, stress reaction

Question 19

What are serotoninergic neurons important for and where do they synapse?

Answer 19

–brainstem

–mood, memory processing, sleep

Question 20

“Each association area is defined by a …..

Answer 20

“Each association area is defined by a distinct, if overlapping, subset of thalamic, corticocortical and subcortical connections”

Question 21

Functional specialization of association areas:

Answer 21

1. Parietal –attention & perceptual awareness
2. Temporal –Categorization, recognition, semantic memory
3. Frontal –planning & regulation of behavior (decision making and behavioral inhibition)

Question 22

Parietal association cortex: what does it do?

Answer 22

• Attention and awareness of the body and stimuli around it
• Integrates somatic, visual, acoustic, and vestibular sensory information -spatial cognition and motor control of the eyes and the extremities.

Question 23

Where does the IPS project do ?

Answer 23

projects to:  the premotor area
 ➳the frontal eye fields
 ➳prefrontal area 
-controls: 
 ➳ocular movements
 ➳ reaching and grasping of the upper extremities ➳spatial working memory

Question 24

Inferior parietal lobule and precuneus project to …. and what does it do?

Answer 24

Inferior parietal lobule and precuneus project to the parahippocampal and entorhinal cortices
-strongly associated with hippocampal functions for long-term memory formation

Question 25

What is a disease that can happen because of a lesion in the parietal association cortex?

Answer 25

•Contralateral neglect syndrome–role in spatial awareness
•Attention sensitive neurons
-Important role in multimodal/sensorimotor integration
-Usually on the left because the right side can usually do a little bit of left, so if right is lost then you are in deep trouble

Question 26

What is in the temporal association cortex?

Answer 26

• Auditoryassociationcortices–including Wernickes(language-comprehension area)
• Ventral –WHAT-pathway –recognition of sensory stimuli –faces/words / objects
• Representation of knowledge –Semantic memory -meaning
• Strong connection to the limbic system.

Question 27

What happens when there is a problem in the temporal association cortex?

Answer 27

it is usually important for recognition
Ventral/Inferior temporal surface(“What” pathway) –Agnosia
➳specific type of stimuli according to región.
➳More anterior: associative// More posterior: Apperceptive
-Anterior pole –Semanticdementia–cannot associate words with their meanings (fluent aphasia, anomia, impaired comprehension of word meaning, and associative visual agnosia)

Question 28

Prosopagnosia and alexia not sure about this one

Answer 28

Prosopagnosia

• Can’t recognize faces
• usually in right temporal lobe
• these things happen tp the right because of language and facial recognition happens more to the right

alexia
“alexia” –Visual Word Form Area(VWFA)left temporal lobe

Question 29

Frontal association cortex

Answer 29

• last one to develop
• helps us to follow social rules
• Largest lobe/widespread connectivity/ most complex functional anatomy
• Integrates information from sensory & motor cortices, and parietal & temporal association cortices.
• Appreciation of self in relation to the world–allows selection, planning, and execution of appropriate behavior (social contexts)
• Damage in the frontal lobe –change in “character“ or “personality”

Question 30

Frontal association cortex: functional deficits, examples and main cause:

Answer 30

-Cognitive disabilities
- impair restraint
-disordered thought
-perseveration
-inability to plan appropriate action.
•Phineas Gage–Became“inconsiderate, intemperate, could not cope with normal social intercourse nor practical planning”.
•Joe A –“showed little restraint, was unable to match the appropriateness of what he said, lostability to plan for the future, lost initiative and creativity”
•Usually because of Frontal lobotomies

Question 31

Limbic association cortex

Answer 31

At the edge of the cortical surface, the medial view of the hemispheres
•It used to be understood as a unitary system“the limbic lobe” :homeostatic and instinctual drives
•Orbital and ventromedial cortex–connected to amygdala and hippocampus: emotional processes
•Hippocampal formation–mediates the formation of long-term memories and then transfers them to the neocortex.
•Otherdivisions–intermediaries between hippocampal formation and association cortices

Question 32

True or false: the frontal association cortex is working on short term memory

Answer 32

True: short term memory functions and planning more dorsolateraly

Question 33

True or falseL value (subjective to what you like more) and decision making is made more laterally:

Answer 33

FALSE: it is more ventromedially

“used remembered info to plan and guide appropriate sequences of behavior”

Question 34

Functional specialization of association areas: key points

Answer 34

• Areasare NOT separate modules -gradient
• They are organized into large, denselyi interconnected networks that function together→LARGE SCALE BRAIN NETWORKS
• Within these NETWORKS, there are hierarchical organization.
• As areas goup in hierarchy, information is more abstract and distant from peripheral sensors. (think primary visual cortexes. Temporal association cortices)