Regional Neuroanatomy I (4)

6 lobes of brain

frontal, parietal, occipital, temporal, limbic, insular

main functions of frontal lobe

high cognitive & executive functions - planning, decision making, attention

voluntary motor function

borders/landmarks to find frontal lobe

central sulcus, lateral (sylvian) sulcus, singulate sulcus

gyra

folds/ridges of brain

sulci

grooves on the cortical surface

label central sulcus

label lateral sulcus

label parieto-occipital sulcus

label preoccipital notch

main gyra of frontal cortex & important regions

precentral gyrus → primary motor cortex

superior frontal gyrus

middle frontal gyrus

inferior frontal gyrus → frontal operculum, very involved with language

where is primary motor cortex located

precental gyrus of frontal lobe

important parts of inferior frontal gyrus

pars opercularis

pars triangularus

pars orbitalis

Broca’s area → function, location

required for processing language and producing speech; located in the pars opercularis and pars triangularus of inferior frontal gyrus in frontal lobe

label precentral gyrus

has primary motor cortex

label postcentral gyrus

has primary somatosensory cortex

label superior temporal gyrus

has auditory cortex

label inferior frontal gyrus and relevant pars

parts of the frontal operculum

pars opercularis & pars triangularis (Broca’s area)

important parts of frontal lobe’s medial surface

cingulate sulcus

anterior paracentral gyrus

paracentral gyrus

label cingulate sulcus - why is it important?

separates frontal and limbic lobes

label anterior paracentral gyrus - why is it important?

it contains the medial aspect of the primary motor cortex, which controls the legs

label paracentral sulcus

most important parts of frontal lobe’s ventral surface

olfactory sulcus

gyrus rectus

orbital gyri

label important parts of frontal lobe’s ventral surface

parietal lobe main functions

high cognitive activity

multisensory integration

attention

spatial awareness

parietal lobe location & landmarks

between frontal and occipital lobes - look for central sulcus, lateral sulcus, and parieto-occipital sulcus

main gyra of parietal lobe & important parts

postcentral gyrus → primary somatosensory cortex

superior parietal lobule

supramarginal gyrus & angular gyrus → visuo-spatial awareness, reading, writing

parietal operculum → secondary somatosensory area

label supramarginal gyrus

label angular gyrus

regions of parietal lobe most involved in visuo-spatial awareness and written language (ability to read and write to receive/communicate information)

supramarginal gyrus

angular gyrus

most important regions of parietal lobe medial surface & important parts

posterior paracentral gyrus → medial aspect of primary somatosensory cortex

precuneus → polymodal/multisensory integration

label important parts of parietal lobe’s medial surface

main functions of temporal lobe

audition

multisensory integration

memory

emotion

where is temporal lobe/landmarks

on bottom of brain; look for lateral sulcus, collateral sulcus

label collateral sulcus

main gyra of temporal lobe, important parts

superior temporal lobe → Wernicke’s area in left hemisphere

middle temporal lobe

inferior temporal lobe

temporal operculum → auditory cortex (includes part of superior temporal gyrus)

what is located in parietal operculum

secondary somatosensory area

what is located in temporal operculum

part of superior temporal gyrus → auditory cortex

location and importance of Wernicke’s area

in the left superior temporal gyra of temporal lobe

required for language comprehension; damage causes fluent aphasia, where a person can speak fluently/easily, but their words lack meaning or may be made up

label superior temporal gyrus

label middle temporal gyrus

label Wernicke’s area

label operculum and its specific parts

important parts of temporal lobe ventral surface

collateral sulcus

occipitotemporal gyri

label important parts of temporal lobe ventral surface

occipital lobe main functions

vision

multisensory information

occipital lobe location/landmarks

back of brain, adjacent of temporal and parietal lobes; lateral surface below parieto-occipital sulcus and preoccipital notch

main gyra/structures of occipital lobe

cuneus

lingual gyrus

primary visual cortex (borders calcarine sulcus)

label calcarine sulcus

label parieto-occipital sulcus and preoccipital notch

label cuneus, calcarine sulcus, and lingual gyrus

limbic lobe main functions

learning

memory

emotion

limbic lobe location

not visible from surface laterla view; outside of insular lobe but inside. of the four other lobes

main limbic lobe gyra

cingulate gyrus

parahippocampal gyrus

uncus → part of olfactory cortex

label cingulate gyrus

label uncus

label parahippocampus gyrus

main functions of insular lobe

taste

motivation

where is insular lobe

inside limbic lobe

label insular cortex, importance

receives nociceptor and viscerosensory inputs

2 major arterial systems supplying brain with blood

internal carotid artery (ICA)

vertebro-basilar

where does ICA enter brain

go into the dura mater near the optic chiasm

generally where the ICA goes/what it does

internal carotids branch out after entering dura and form the Willis circle system, which distributes blood to the cerebral hemispheres, basal ganglia, and diencephalon

all ICs (branches of ICA)

ophthalmic artery

anterior choroidal

anterior cerebral artery (ACA)

middle cerebral artery (has 4 segments)

posterior communicating arteries (PCom)

ICs NOT in circle of willis

opthalmic artery

anterior choroidal

ICs IN circle of willis

anterior cerebral artery

middle cerebral artery

posterior communicating arteries

opthalmic artery supplies blood to?

cenrtal artery of retina; issues cause vision loss

anterior choroidal artery supplies blood to?

to choroid plexus of lateral ventricles

anterior cerebral artery supplies blood to?

low extremity of motor cortex → optic chiasm, anterior paracentral

low extremity of somatosensory cortex → anterior and posterior gyrus, medial surface of frontal and parietal lobes, posterior paracentral

there are 2 ACAs, one on the right and left

how 2 ACAs connect; importance of this region

with anterior communicating artery; around 30-35% aneurysms are found here

segments of middle cerebral artery

M1, M2, M3, M4

M1 supplies blood to?

basal ganglia → deep in cerebral hemisphere

M2 supplies blood to?

insular cortex

M3 supplies blood to?

this is the opercular segement → blood to frontal, parietal, and temporal opercula, including Broca’s area, motor & somatosensory areas, and the auditory cortex

M4 supplies blood to?

above/below lateral fissure in frontal, parietal, temporal, and occipital lobes

what is the Willis circle, its parts, and where it supplies blood to

ring of vessels connecting anterior and posterior circulation of brain around the optic chiasm

includes ACAs, anterior communicating artery, MCA, PCom, PCA (not IC)

Posterior cerebral artery

PCA → artery that is not an IC branch but is part of the Willis circle. branch off basilar artery that supplies blood to the ventral and medial surface of temporal and occipital lobes. it also has branches supplying the mesencephalon and thalamus.

willis circle looks like/label: