Cerebral Cortex

4 components of neural tube

forebrain

midbrain

hindbrain

spinal cord

Forebrain is also called

prosencephalon

midbrain is also called

mesencephalon

hindbrain is also called

rhombencephalon

what does the forebrain (prosencephalon) differentiate into?

telencephalon and diencephalon

What does the telencephalon become?

cerebral hemispheres (cortex, basal ganglion, hippocampus, amygdala)

What are the three big segments of brain?

cerebrum

cerebellum

brainstem

What are the parts of the cerebral hemispheres?

cortex

basal ganglion

hippocampus + amygdala

What comes from the cerebrum?

cerebral hemispheres

diencephalon

What is part of the diencephalon?

epithalamus, thalamus, hypothalamus

Where are CN I + II from?

cerebellum

What makes up the brainstem?

midbrain, pons, medulla oblongata

What does the diencephalon become?

thalamus, hypothalamus, epithalamus

What overarching structure does the prosencephalon give rise to?

cerebrum

What does the mesencephalon become?

nothing, it stays as the midbrain

What does the hindbrain (rhombencephalon) differentiate into?

metencephalon

myelencephalon

What does the metencephalon become?

pons and cerebellum

What does the myelencephalon become?

medulla oblongata

What separates the cerebral hemispheres?

longitudinal fissure

The frontal lobe is located where?

anterior to central sulcus and cranial to lateral fissure

What are the 4 main gyri of the frontal lobe?

pre central gyrus

middle frontal gyrus

superior frontal gyrus

inferior frontal gyrus

inferior frontal gyrus sections

opercular

triangular

orbital

Where is the parietal lobe?

posterior to central suclus + anterior to parties-occuital sulcus

Lobules of parietal lobe are split by?

intrapariteal suclus

lobules of the parietal lobe

superior parietal lobule

inferior parietal lobule

Where is the supramarginal gyrus located?

in parietal lobe at end of lateral fissure

Where is the angular gyrus located?

in pariteal lobe at end of superior temporal sulcus

Parts of temporal lobe in lateral view

2 sucli:

superior temporal sulcus

inferior temporal sulcus

3 gyri:

superior, middle, and inferior temporal gyrus

parts of temporal lobe in inferior view

inferior temporal gyrus

lateral occipitotemporal gyrus

media occipitotemporal gyrus

parahippocampal gyrus (contains uncus)

Where is the occipital lobe?

below pariteo-occipital suclus + above preoccipital notch

What divides the occipital lobe into two?

calcarine sulcus

What is the gyrus above the calcarine sulcus?

cuneus gyrus

what is the gyrus below the calcarine suclus?

lingual gyrus

What are the layers of cortex

1. molecular

2. external granular

3. external pyramidal

4. internal granular

5. internal pyramidal

6. multiform layer

Cortex is all

grey matter

What do stellate cells do?

receive input (lots of dendrites)

what do pyramidal cells do?

send output (long + thick axon)

What is in the molecular layer and what is its function?

few cell bodies

integrates info from layers below for communication

What is in the external granular layer and what is its function?

stellate cells

receives input from other cortical regions

What other layer does the external granular layer (#2) work with?

Layer 3 (external pyramidal)

What is in the external pyramidal layer and what is its function?

pyramidal cells

sends output to other cortical areas

Layers 2 and 3 of cortex communicate via?

association and commissural fibers

What is in the internal granular layer and what is its function?

stellate cells

recipes input from thalamus + other brainstem areas

How does layer 4 of Cortex (internal granular) receive input?

via corticopedal fibers

What layer is very thick in sensory areas of cortex?

layer 4 (internal granular)

What is the striate cortex? Why is it called this?

primary visual cortex of occipital lobe (layer 4 is so thick it looks like a line)

What is in the internal pyramidal layer and what is its function?

pyramidal cells

sends output to brainstem and spinal cord

What kind of fibers does layer 5 (internal pyramidal) use?

corticobulbar + corticospinal

What layer is very thick in motor areas of cortex?

Layer 5 (internal pyramidal)

What does layer 6 (multiform layer) do?

sends axons to thalamus to modulate what info thalamus sends to cortex (aka what we perceive/pay attention to)

What fibers does layer 6 (multiform) use?

corticothalamic, corticogeniculate

What is apriori decision?

deciding what the brain pays attention to

What later is commonly damaged with TBI? what does this cause?

layer 6 (multiform layer)

sensory overload, brain can't turn down signals like background noise and light

What are association fibers?

fibers that connect cortex in same hemisphere

What do association fibers never do?

NEVER crosses midline

What do commissural fibers do?

connect cortex in one hemisphere to cortex in a different hemisphere

What do projection fibers do?

connect cortex to non-cortex like thalamus, brainstem, and spinal cord

What are corticopedal fibers?

afferent fibers that come from non-cortex and go to cortex

ex: geniculocortical

What are corticofugal fibers

efferent fibers that come from cortex and go to non-cortex

ex: corticobulbar

What are Brodmann's areas?

divisons of cortex based ONLY on the thickness of layers

What type of axons come from primary motor cortex?

corticobulbar

what is the BA for the primary visual cortex?

BA 17

Primary Vision cortex receives input from? via ?

from LGN via optic radiations

What does the primary visual cortex process?

very general lines and orientations and circles of color

Where is the primary visual cortex located?

half above and half below the calcarine sulcus

Cuneous section of primary visual cortex gets input from what part of retina? What part of visual field?

upper retina

therefore

lower visual field

Lingual section of primary visual cortex gets input from what part of retina? what part of visual field?

lower retina

therefore

upper visual field

If you damage your right lingual gyrus, what will you get? What is it called?

lose your left superior visual field in both eyes

(left superior quadrantanopsia)

if you damage your left cuneous gyrus, what will you get? what is it called

lose your left inferior visual field in both eyes

(left inferior quadrantanopsia)

secondary visual cortex (V2) is what brodmann area?

BA 18

What does the secondary visual cortex (V2/BA18) do?

receives input from primary visual cortex, processes it, and then sends info to V3/BA 19

Where is the secondary association visual cortex located?

above and below primary visual cortex

Where is tertiary association visual cortex (V3/BA 19) located?

above + below secondary visual cortex

Where do we first start seeing cells that analyze depth?

V3/BA 19

What does the primary motor cortex (BA 4) do?

signals to move skeletal muscle

What does the premotor area do? example?

integrative muscle movement

ex: to flex biceps you must inhibit triceps

What responds first, primary visual cortex or premotor cortex?

premotor

Premotor area brodmann area?

BA 6

Frontal Eye Field brodmann area? location?

BA 8

located on superior and middle frontal gyrus

Frontal eye field function

saccades (both eyes, contralateral field)

Firing of right frontal eye field would cause?

saccade in both eyes to the left

Broca's area brodmann's area? location?

44, 45

located on opercular + triangular region of frontal lobe

Wernicke's Area brodmann area?

22, 39, 40

Wernicke's area location

superior temporal gyrus + inferior parietal lobule

Wernicke's area function

comprehending language

Primary Auditory Cortex brodmann area? location?

BA 41

superior temporal gyrus

Primary auditory cortex function?

process sound to primitive tones

Where does the primary auditory cortex get its input from? what layer must be thick?

from MGN in thalamus

thick later 4

Where does the primary auditory cortex send info to? What layer is thick?

Secondary auditory cortex/Association Auditory (BA 42)

thick layer 3

Secondary Auditory Cortex/Association Auditory (A2) brodmann area? location

42

superior temporal gyrus

Auditory association area (A3) BA? location?

BA 22

superior temporal gyrus

Auditory Association area 3 (A3/BA22) function?

processes sound into words

What happens in damage to BA 44/45?

Broca's Aphasia

What is Broca's aphasia?

expressive aphasia: patient knows what they want to say, but can't say it

What is Wernicke's aphasia?

receptive aphasia: patient talks a lot, but doesn't make sense and doesn't understand you

How many layers does the LGN have? How are they split?

6 layers

2 have large cell bodies (magnocellular)

4 have small cell bodies (parvocellular)

Magnocellular cells

responds fast and in time domain

parvocellular cells

responds in spatial domain

What is midtemporal region?

bottleneck of fibers on the way to parietal lobe

After vision is processed in the occipital lobe, what re the two main outputs? what bundles do they use?

dorsal stream (occipital --> parietal)

ventral stream (occipital --> temporal)

both use occipital fugal bundles