Lecture 2 - Cerebral Cortex Flashcards
Rank 6 species discussed in class from highest # of neurons to lowest # of neurons
- Humans - 86-120 billion (whales and elephants might have more - 250?)
- Octopus
- Dog
- Cat
- Fruit Fly
- Lobster - 100,000
How thick is the cerebral cortex on average?
2-3mm
The cerebral cortex has wrinkles. How are those wrinkles classified?
Gyri/lobules - the hills
Sulci/fissures - the valleys
You can identify borders of different neural functions by following the patterns of the sulci (T/F)
F!
The bundle of white matter connecting the two hemispheres of the brain is known as the:
Corpus Callosum!
What are the 3 main fissures of the cerebral cortex?
Longitudinal
Central (Rolandic)
Lateral (Sylvian)
What are the 4 lobes of the brain?
Frontal, parietal, temporal, occipital
What are the two ‘hidden’ lobes of the cerebral cortex?
Limbic & insula
What structures comprise the limbic lobe? (5)
Cingulate gyrus
Hippocampus
Parahippocampal gyrus
Uncus
Subcallosal gyrus
What are the functions of the limbic & insula lobes?
Limbic - emotional drive & survival instinct
Insula - related to sensorimotor functions (apraxia of speech) and limbic functions (e.g. self-awareness, social emotion, etc.)
What structures are highlighted in the medial view of the brain? (7)
Cingulate gyrus
Corpus callosum
- Anterior commissure
- Genu, Body, Splenium
- Fornix
Lateral ventricle
Thalamus
Hypothalamus
Precuneus & Cuneus
Lingual gyrus
What structures are highlighted in the ventral view of the brain? (8)
Inferior temporal gyrus
Pre-occipital notch
Olfactory tracts and bulbs (smell)
Optic nerve and chiasm (vision)
Hypophysis (pituitary gland – homeostasis hormones)
Mammillary bodies (memory)
Parahippocampal gyrus (memory)
Uncus (smell, memory, emotion)
What structures are highlighted in the lateral view of the brain? (3)
Frontal lobe
- Precentral gyrus
- Primary motor cortex (4)
- Somatotopically organized
Premotor cortex (6)
- Supplementary motor area
- Superior frontal gyrus
- Middle frontal gyrus
Inferior frontal gyrus
- Contains Broca’s area (BA 44/45)
Who is Brodmann? What did he do?
German anatomist in the 19th century.
Created a cytoarchitectonic map – based on the type of cells and their density in various regions of the brain. Map was later enhanced by Canadian neurosurgeon Walter Penfield.
- “zapped” the map to determine function
- Epilepsy surgery
- Patients were awake!
Brodmann’s areas 41 and 42 make up what?
Auditory cortex
Brodmann’s areas 44 and 45 make up what? What is 44 specifically?
Motor speech - Broca’s is 44 specifically
Brodmann’s areas 1, 2, & 3 make up what?
Primary somatosensory cortex
Brodmann’s area 4 makes up what? What is its function?
Primary motor area (execution)
Brodmann’s area 6 makes up what? What is its function?
Premotor area (planning)
What are the primary and secondary/association Motor areas (Brodmann’s)
Primary- 4
S/A- 6, 9/10, 11, 44
What are the primary and secondary/association Sensory areas (Brodmann’s)
Primary - 1,2,3
S/A - 7, 39, 40
What are the primary and secondary/association Auditory areas (Brodmann’s)
Primary - 42
S/A- 22
What are the primary and secondary/association Visual areas (Brodmann’s)
Primary - 17
S/A - 18, 19
3 structures within the inferior frontal gyrus are the pars _____, ______, and _____ (“TOO”)
triangularis, orbitalis, opercularis
Describe the primary motor cortex
It’s a map of muscles in the body, a ‘homunculus” for contralateral side
The primary motor cortex is a pure homunculus without redundant representation of muscles (T/F)
F!
Not pure & it is redundant
There is not a 1:1 relationship within the primary motor cortex (T/F)
T. One mm^2 of neurons does not equal one muscle
Representation of the primary motor cortex is based on size (T/F)
F. Based on refinement - leg has small representation but are physically large body parts
T/F: The primary motor cortex is sensitive to environmental change
T. It is plastic!
The premotor cortex is referred to as what? What is it responsible for
A second map! Responsible for sequence of movements
How is the premotor cortex moderated?
by input from feedback centers (cerebellum, basal ganglia and thalamus)
If the primary motor area are construction workers, the premotor cortex is what?
The blueprint!
What two regions of the prefrontal cortex were highlighted in class?
Dorsal prefrontal region & orbital prefrontal region
What are the responsibilities of the dorsal prefrontal region of the prefrontal cortex?
Short-term memory, executive function (e.g. decision making), critical for learning!
Planning & problem-solving (e.g. Tower of Hanoi)
What are the responsibilities of the orbital prefrontal region of the prefrontal cortex?
Emotional regulation, adaptive behaviour, social cognition, inhibition/self control
- Affected in Fetal Alcohol Syndrome
