Cerebral Cortex

Question 1

When do babies produce speech like babbling?

Answer 1

7 months

Question 2

When do babies lose their capability of phonemes that are not reinforced?

Answer 2

6 months and show no response to phonemes not part of their native language at 1 year

Question 3

Until when should a kid learn a language if he/she wants to be fluent like a native?

Answer 3

Until 7 - 8 years old

Question 4

Do congenitally deaf babies babble?

Answer 4

no

Question 5

What is Hebb’s postulate?

Answer 5

Synaptic terminals
1. strengthened by correlated activity during development will be retained or sprout new branches,
2. whereas those terminals that are persistently weakened by uncorrelated activity will eventually lose their hold on
the postsynaptic cell, either leading to the death of the cell that gives rise to those synapses, or to the stabilization and growth of synapses from that cell on another target behaviors not initially present.

Question 6

What is Hebb’s postulate?

Answer 6

Synaptic terminals
1. strengthened by correlated activity during development will be retained or sprout new branches, (strengthened synaptic connections)
2. whereas those terminals that are persistently weakened by uncorrelated activity will eventually lose their hold on
the postsynaptic cell, either leading to the death of the cell that gives rise to those synapses, or to the stabilization and growth of synapses from that cell on another target behaviors not initially present.

Question 7

What 3 phenomenons does Hebb’s postulate explains?

Answer 7

1. behaviours not initially present
   in newborns emerge and are shaped by experience through-
   out early life
2. there is superior capacity for acquiring
   complex skills and cognitive abilities during early life; and
3. the brain continues to grow after birth, roughly in parallel with the emergence and acquisition of increasingly complex behaviors and the addition of pre-and postsynap-tic processes (dendritic and axonal branches).

Question 8

What is critical period?

Answer 8

The time when experience and neural activity that reflects that experience have maximal effect on the acquisition or skilled execution of a particular behavior.

Question 9

What is Paleocortex? (or Allocortex when referred with archicortex)

Answer 9

Cortex with 3 layers (e.g. parahippocampal gyrus)

Question 10

What is neocortex? (or Isocortex)

Answer 10

Cortex with 6 layers (e.g. motor and visual)

Question 11

What is archicortex? (or Allocortex when referred with paleocortex)

Answer 11

Cortex with 3 or 4 layers (e.g. hippocampus)

Question 12

What is mesocortex?

Answer 12

Transitory form (4 - 5 layers)

Question 13

Is layer thickness the same across the brain?

Answer 13

Nope

Question 14

What are layer 3 and 2 of neocortex named as?

Answer 14

Supragranular layer

Question 15

What is layer 2 known as?

Answer 15

Extra granular layer

Question 16

What is layer 3 known as

Answer 16

Extra pyramidal layer

Question 17

What is layer 4 known as

Answer 17

Internal granular layer

Question 18

What does layers (or laminae) 1 - 6 do?

Answer 18

1. Only axons and dendrites (neuropil, dense network of interconnected axons etc)
2. Input from other cortical layers
3. Output to other cortical layers
4. Input from mainly thalamus and other non cortical areas
5. output to basal ganglia and spinal cord (non cortical targets)
6. Output mainly to thalamus

Question 19

Features of Laminae?

Answer 19

1. each cortical layer has a primary source of inputs and a primary output target.
2. each area has connections in the vertical axis(called columnar or radial connections) and connections in the horizontal axis (called lateral or horizontal connections).
3. cells with similar functions tend to be arrayed in radially aligned groups that span all the cortical layers and receive inputs that are often segregated into radial bands
   or columns.
4. interneurons within specific cortical layers give rise to extensive local axons that extend horizontally in the cortex, often linking functionally similar groups of cells.

Question 20

Where are Betz cells found in?

Answer 20

In Pyramidal neurons of cortical layer

Question 21

Which layers are the pyramidal cells/neurons?

Answer 21

3 and 5

Question 22

Which layers are the granulate/stellate cells/ neurons ?

Answer 22

Layer 2 and 4

Question 23

What can miswiring of parietal, temporal and frontal cortex leads to?

Answer 23

Synaesthesia

Question 24

What is synesthesia?

Answer 24

Synesthesia is a perceptual phenomenon in which stimulation of one sensory or cognitive pathway leads to automatic, involuntary experiences in a second sensory or cognitive pathway. People who report a lifelong history of such experiences are known as synesthetes.

Question 25

Contralateral neglect syndrome is mainly associated to damage to which part of the brain hemisphere?

Answer 25

Mainly to right parietal cortex

Question 26

What does parietal cortex do?

Answer 26

Mediates attention and awareness of the body and the stimuli that acts on it.

Question 27

Which thalamic nuclei projects to the parietal association cortices?

Answer 27

Pulvinar

Question 28

Which thalamic nuclei projects to the frontal association cortices?

Answer 28

Medial dorsal nuclei (related to memory)

Question 29

How do we define the prefrontal cortex?

Answer 29

1. Electrophysiological - no response to electrical stimulation
2. Histology - granular cortex (motor areas: agranular, hardly any granule cells)
3. Hodology - connects to medial dorsal thalamic nucleus or clear cut layer 4 (motor areas no connections to MD thalamic)

Question 30

Are signals in association cortices already preproccessed by pri cortices? Name an e.g.

Answer 30

Yes : thalamus input to association cortices - these inputs are already processed by pri cortices.

Question 31

Pri cortices receive input from which part of thalamic nuclei?

Answer 31

Thalamic nuclei related to cerebellum and basal ganglia.

Question 32

What is DTI?

Answer 32

Diffusor tensor imaging (MRI, non invasive)

Question 33

What are the sources of input to association cortices?

Answer 33

1. DM (Dopamine in Midbrain)
2. NSB (Noradrenagic, serotonergic in Brainstem)
3. CB( Cholinergic in Basal Forebrain)

Question 34

What is Synesthesia?

Answer 34

Miswiring in association cortices leading to people seeing colours in musical notes, seeing numbers in colours etc.

Question 35

What is contralateral neglect syndrome?

Answer 35

The hallmark of contralateral neglect
syndrome is an inability to attend to objects, or even one’sown body, in a portion of space, despite the fact that visual
acuity, somatic sensation, and motor ability remain intact.

Question 36

What is hemispherical asymmetry?

Answer 36

Right parietal cortex mediates attention between left and right body + extra personal space while left only right side space

Question 37

Does the brain has pain receptors?

Answer 37

nope

Question 38

Neglect vs agnosia

Answer 38

1. Neglect - attention, lack of awareness

2. Agnosia - unable to report things although aware they are there

Question 39

Where is the location of leison for prosopagnosia?

Answer 39

Usually in right temporal lobe

Question 40

Which part of the brain damage results in personality change, inability to plan, SEQUENCE CODING, execute and inappropriate behaviour( lack of social restraint) etc? (NOT ACTION)

Answer 40

frontal association cortices

Question 41

Which part of the frontal association cortices are related to short term memory and social restraint?

Answer 41

Short-term memory functions are situated more dorsolaterally, and planning and social restraint functions are located more ventromedially.