CNS 2 - Cortex and Deep Nuclei

Question 1

Grey matter and white matter

Answer 1

• grey matter = unmyelinated, neurons communicated using graded potentials
• white matter = myelinated used for communication, connects right and left brain (corpus callosum)

Question 2

White matter communication

Answer 2

• brain = grey matter on the outside, white matter on the inside
  spinal cord = white matter on the outside, grey matter on the inside
• white matter tracts aid in communication

Question 3

Surface area of the cerebral cortex

Answer 3

• each cerebral hemisphere cortex has a total surface area of about 1.3 square feet
• the brain is all folded up in order to provide a more compact space

Question 4

Grooves in the cerebral cortex

Answer 4

• longitudinal fissure = separates left and right hemispheres
• lateral (sylvian) fissure = separates the temporal lobe from the parietal and frontal lobes
• central sulcus = separates the primary motor cortex (precentral gyrus) and primary sensory cortex (postcentral gyrus)

Question 5

Grey matter organization

Answer 5

• grey matter structure looks the same, but the programs that they run differ based on their location
• cerebral cortex is divided into columns

Question 6

Lobes of the cerebral cortex

Answer 6

• frontal = association cortex, intellect, premotor cortex, frontal eye field
• parietal = somatosensory, association cortex
• occipital = visual cortex
• temporal = auditory cortex

Question 7

Broca’s and Wernicke’s area

Answer 7

• Broca = frontal lobe, making the mouth and tongue move

- Wernicke = temporal lobe, understanding of speech

Question 8

Deficits in Broca’s and Wernicke’s area

Answer 8

• Broca = slurred speech, hard to understand

- Wernicke = grammar and words are mixed up

Question 9

Deeper areas of the cerebral cortex

Answer 9

• insular cortex = balance
• primary gustatory cortex = taste
• olfaction

Question 10

Dominance

Answer 10

• there is a dominance/preference of one side of another
• eg. hand dominance, eye dominance
• dominance of cortices are independent of one another

Question 11

Functions of the right cortex

Answer 11

• holistic
• intuitive
• creative
• artistic
• musical

Question 12

Functions of the left cortex

Answer 12

• analytical
• logical
• scientific
• mathematical
• language

Question 13

White matter tracts

Answer 13

• commissural fibres = between hemispheres (corpus callosum)
• association fibres = within hemispheres between lobes (fornix)
• projection fibres = to different parts of the CNS (internal capsule)

Question 14

Limbic system

Answer 14

• around the inside of the ventricles

- amygdala, hippocampus, fornix, mammillary bodies

Question 15

Basal ganglia (basal nuclei)

Answer 15

• around the outside of the ventricles

- caudate, lentiform nuclei, (amygdala)

Question 16

Hippocampus

Answer 16

• who/what/where/when
• long term memory formation
• episodic memory

Question 17

Fornix

Answer 17

• connects hippocampus to the cortex

Question 18

Mammillary bodies

Answer 18

• olfactory relay nucleus

Question 19

Amygdala

Answer 19

• analyses anger and fear expressions
• assesses danger and elicits fear response
• emotional memories
• output to hypothalamus –> sympathetic nervous system
• is easily impaired by substances that cross the blood-brain barrier (alcohol)

Question 20

Types of memory

Answer 20

• episodic (event) = medial temporal lobe (thalamus, amygdala, hippocampus)
• semantic (factual) = neocortex (auditory, somatosensory, visual cortices)
• procedural (muscle) = cerebellum, basal nuclei

Question 21

Loop of Papez (episodic memory)

Answer 21

• can be a past memory or an immediate event
• the sensory aspects will be connected in the cingulate cortex
• information will then travel to the hippocampus, then the entorhinal cortex (spatial - where)
• then, through the fornix to the mammillary bodies
• information is then sent to the anterior thalamus and back to the cingulate cortex

Question 22

Procedural memory

Answer 22

• vision, balance, position go towards the cerebellum, then to the thalamus and premotor cortex
• early experience goes towards the basal nuclei, then to the thalamus and premotor cortex
• the thalamus chooses between the information from the basal nuclei and the cerebellum

Question 23

Alzheimer’s disease

Answer 23

• atrophy of the entire cortex
• filaments clog up the cells causing cell death
• inability to recall recent and post memories
• lack of attention
• disorientation
• language problems
• lack of problem solving

Question 24

Hippocampal atrophy

Answer 24

• atrophy, loss of dendrites
• inability to store new memories of events after injury (anterograde amnesia)
• inability to consolidate events
• inability to recall past events (retrograde amnesia)

Question 25

Functions of the basal nuclei

Answer 25

- initiate, coordinate and stop motor movements - eliminates unnecessary movements - skills memory (slow, stereotypical movements)

Question 26

Components of the basal nuclei

Answer 26

- caudate (head) - lentiform (putamen, globus pallidus) - caudate (tail) - close connection to the substantia nigra

Question 27

Basal nuclei feedback

Answer 27

- cortex requests a plan to make a motor movement from the caudate nucleus - information is sent to the lentiform nucleus, then to the thalamus - if it is chosen, then the information will go back to the same side of the motor cortex

Question 28

Making a motor movement

Answer 28

- sensory information and frontal lobe intuition decide to undergo a movement - frontal cortex sends signals to three components - primary motor cortex = just do it - cerebellum = how to do it - basal nuclei = how fast to do it