Brain Overview - Sub Cortical

8/3/2019 Brain Overview - Sub Cortical

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Overview of Gross Neuroanatomy

References:

DeArmond, S.J., Fusco, M.M., Dewey M.M., (1988), Structure of the

Human Brain, 3rd Ed., Oxford, NY

Warner J.J., Atlas of Neuroanatomy with Systems Organization and

Case Correlations, 2001

University of Florida class notes on Medical Neuroscience

Carpenter,Human Neuroanatomy, 7th ed., 1976



Directional Terms



Rostral (beak) Caudal (tail)

Anterior (front) Posterior (back)

Dorsal (top) Ventral (belly)

Superior (top) Inferior (bottom)

Medial (midline) Lateral (side)

Axes on the brain



Planar cuts

Coronal

(parallel to face)

Axial

(parallel to ground)

Sagittal

(parallel to ears)



Parts of the brain



Interhemispheric fissure

- visible on coronals and axials

- separates R and L hemispheres

Fissures

Sylvian fissure

- present on both R and L

- separates the temporal lobe

- commonly asymmetric (L>R)

Sylvian

Interhemispheric



insula

Sylvian

Fissure

insula

Sylvian

Fissure



Layers inside the skull

R hemisphere

cerebellum



Meninges:- Dura mater: Opaque, tough, follows skull boundary and major fissures.

Consists of 2 parts: falx cerebri, falx cerebelli

- Arachnoid mater: Web-like, white, bridges over major folds

- Pia mater: Transparent, follows brain surface continuously- pial surface

dura



Gray Matter (GM): White Matter (WM):(functions of the brain) (connectivity of the brain)

- Neo-cortex: sulci, gyri - Association fibers

- Sub-cortical structures - Midline structures

neo-cortex sub-cortical

midline WM association fibers

neo-cortex

association fibers

sub-cortical

Tissue classes



Lobes



Lobes





Frontal Lobe: motor, executive learning, semantic processing, emotion

Boundaries: central sulcus, Sylvian fissure

Temporal Lobe: auditory processingBoundaries: Sylvian fissure

Parietal Lobe: somatosensory

Boundaries: central sulcus, parieto-occipital sulcus (imaginary projection)

Occipital Lobe: vision

parieto-occipital sulcus

Limbic Lobe: emotion, memory, learning

Boundaries: paracingulate sulcus, hippocampus, amygdala





Bottom view

Top view

Brain stem

Top

View

BottomView

Cerebellar peduncles

Superior colliculi

Inferior colliculi

Pons

Thalamus



Cerebellum



Blood and water supply



Blood-brain barrier:

Substances navigating inside the blood do not penetrate

into brain as in other organs. There is a selective penetration

Blood-CSF barrier:

Substances navigating inside the blood do not penetrate into

ventricles

Note:No CSF-brain barrier. When dyes are injected into ventricles,

the brain is stained.



Veins

Veins run in sub dural space





Arteries

Arteries run in sub arachnoid space





Ventricles

- CSF runs in ventricles, and subarachnoid space



Ventricles

Anterior Posterior



Choroid plexus:

Produces CSF

Septum pellucidum



Interhemispheric structures



WM: Anterior Comissure (AC) GM: Massa IntermediaPosterior Comissure (PC) (or interthalamic adhesion)

Corpus Calossum

anterior posterior



AC

PC

genu

splenium

body

septum pellicidummassa intermedia

rostrum



anterior

comissure

corpus

calossum



Subcortical structures



Subcortical GM:

Basal ganglia: caudate, putamen, globus pallidus, claustrum (initiating behavior)

Thalamus: Sensory gateway to the cerebral cortex

Hypothalamus: Autonomic nervous system (motivated behaviour)

Basal forebrain: Amygdala (emotion)

Hippocampal formation: (memory)

Adjacent WM:

Internal capsule

External capsule

Extreme capsule

Fornix

Ant

Post

Basal



Basal

Ganglia



Internal capsule



Internal capsule

Sk t h



Basal ganglia

Thalamic nuclei

Hippocampus and fornix

Temporal Lobe

Sketches

Posterior Anterior

fornixSections



insula

accumbens

uncus

3rd ventricle

internal capsule

external capsule

claustrum

hippocampus

globus palliduscorpus callossum

Sylvian fissure

interhemispheric fissure

fornix

hippocampus

putamen

caudate putamen caudate

thalamus

thalamus

corpus callossum

3rd ventricle

septum

pellucidum

Sections



Amygdala and hippocampus

amygdala

hippocampus



Fornix

fornixfornix

fornix

Anterior

comissureMamillary

Body

Ant

Post



Thalamus and Hypothalamus



Hints for identifying subcortical structures

Caudate: always on the walls of lateral ventricle

frontally, it is located superior to internal capsule

Putamen:runs on the inferior part of internal capsule

Globus pallidus: next to putamen seperated by wm tracts

Thalamus: on the walls of third ventricle

Hippocampus: inferior to the inferior horn of lateral ventricle

Amygdala: Inside part of uncus

Anterior Comissure: Close to the frontal horns of fornix

Claustrum: skinny GM between extreme capsule and insula



Developmental

and aging processes



3 weeks

4 weeks

6 weeks

8 weeks



12 week fetus

7 month fetus



healthy 3 year-old, male

healthy 36 year-old female

healthy 73 year-old female

V l t i h



Courchesne E. et.al., “Normal brain development and aging: Quantitative analysis atin Vivo MR imaging in healthy volunteers”, Radiology, 2000, 216: 672-682

Volumetric changes across ages



Courchesne E. et.al., “Normal brain development and aging: Quantitative analysis atin Vivo MR imaging in healthy volunteers”, Radiology, 2000, 216: 672-682



Volumetric changes vs performance in aging

reference

n=73

Walhovd et.al., 2005

S



Summary

• Whole brain and intracranial space grows about 25% between early

childhood and adolescence

• By age 80 this growth is reversed such that whole brain of agedpeople are about the same size of young children

• Between early to late childhood, GM increases about 13%.

• After the 4th decade of life, GM decreased about 13% until age 80.

• Increase in CSF between adolescence and old age is about 100%

• GM loss is not always bad. Effective pruning occurs twice: at 8

months old and at adolescence

Brain Overview - Sub Cortical

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