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Interbrain

Topics: Cerebrum / Pages: 3 (730 words) / Published: Oct 9th, 2013
INTERBRAIN (diencephalon)
a.k.a. talamencephalon or betweenbrain
-between midbrain and cerebrall hemisphere;link
-encloses third ventricle; found between two thalami 4 Divisions:
1. Epithalamus
2.Thalamus
3.Hypothalamus
3. SUbthalamus
*epi and thala:dorsally located

1. Epithalamus STRUCTURES:
a. habenula
 gray matter
 soma or body of the neurons
 found to link the limbic system with reticular formation(arousal)
b. stria medullaris
 fibers
 extension to the lower part of brain
c. epiphysis (pineal gland)
 secretes melatonin:sleep chemical;third eye

2. Thalamus-thalami(two hemisphere/parts)
 made up of nuclei
 last relay station except for smell
 screening structure 4 Divisions:
a. medial geniculate body: audition-temporal
b. lateral geniculate body: vision-occipital
c. ventral postero-lateral nucleus (VPL)
-center for somatosensation
-e.g. pain and temperature of the trunk and extremities
d. ventral postero-median nucleus (VPM)
-somtasensation in the head region

RELATED CONCEPTS:
1. Epicritic/Discriminative Sensibility
-fine touch
-tells the location and number of stimuli
2. Steriognosis
-ability to identify object through touch without the aid of the sense of sight
3. Astereognosia
-inability to identify object through touch alone
SOMATOSENSORY/BODY SENS-new term
SOMESTHETIC-old term

4. Hypothalamus
 chief subcortical center; regulation of autonomic activities
 emotion control, water and temperature regulation, sympathetic and parasympathetic activities PARTS:
a) Lateral hypothalamic nucleus (hunger)
b) ventromedial hypothalamic nucleus (satiety) *Hyperphagia- damage to VMHN *Hypophagia-damage to LHN

4. Subthalamus
 a.k.a. prethalamus
 forms part of extrapyramidal system

CEREBRAL CORTEX (telencephalon/cerebrum)
 largest part of the brain
 higher brain functions
 GM (cell bodies) outside
 WM (fiber tracts inside)
 2 hemisphere, 4 lobes
FUNCTIONS:
Left Right
Analytical thought Holistic thought
Logic Intuition
Language Creativity
Science and health Arts and music

*corpus callosum-bad of white fibers connecting the left and right hemispheres
LOBES: Frontal, Occipital, Parietal, Temporal
a) Frontal-voluntary skeletal muscle
-concentration, planning, complex problem solving, judging consequences of behavior
b) Parietal-somatosensations
-speech, words to express thoughts and feelings
c) Temporal-hearing
-visual scenes, music, complex sensory patterns
d) Occipital-vision
-vision with other sensory experiences

Cerebral Cortex (GM area)
 2-4 cm thick
 highly convoluted (wrinkled and folded) increasing the surface are of the cortex
1. sulcus-shallow grooves on the cortex
2. fissure-deep sulcus
3. gyrus-bumps/elevated ridges/convolution on the ridges

*lateral cortex-covers the sides
*medial cortex-covers the middle. lie within the longitudinal cerebral fissure

BRODMANN’S CLASSIFICATION
 one of the cortical areas mapped out on the basis of its cytocerchitectur (?)
MAJOR SULCI/FISSURE:
1. Median Longitudinal Fissure-seperates the left and right cerebral hemisphere. Center is corpus callosum
2. Central Sulcus/Rolando’s Fissue-frontal/parietal; runs from the median longitudinal fissure to the lateral sulcus/fissure
3. Lateral Sulcus/Sylvian Fissure-frontal and parietal from temporal
4. Parieto-occipital-parieto/occipital

BRODMANN’S AREAS AND MAJOR GYRIS
1. Frontal lobe-contains areas that Brodmann identified as involved in cognitive functions.
• Area 4-precentral gyrus-primary motor area/motor strip
• Area 6-premotor/supplementary motor area
• Area 8-anterior of premotor cortex;visual reflexes;eye movements
• Area 4s-suppresor band
• Areas 44,45-Broca’s area;speech motor area

The areas in the PARIETAL LOBE play a role in somatosensory processes
2. Parietal Lobe
• Areas 3,1,2-postcentral gyrus: primary somatosensory cortex
• Areas 5,7,40-presensory to sensory association area
• Area 39-angular gyrus-recognition of visual symbols

Areas involved in auditory processes
3. Temporal Lobe
• Areas 41,42-Heschl’s Gyri or anterior transverse temporal gyrus
• Area 41-primary auditory area
• Areas 21,22-auditory association area or wernicke’s area-understanding speech
• Area 37-object naming area

The occipital lobe contains areas that process visual stimuli
4. Occipital Lobe
• Area 17-primary visual area
• Area 18,19-secondary visual association area

FUNCTIONAL REGIONS OF THE CEREBRAL CORTEX
1) Primary motor area-frontal lobe; initiate skeletal movement
2) Motor speech area (BROCHI’S AREA)- speech articulation
3) Sensory area-interprets sensory information
Visual Sensory Area-occipital; seeing
Auditory Sensory Area-temporal; hearing
Cuttaneous Area-parietal; somatosensation

ASSOCIATED TERMS/ DISORDERS
Lobotomy-introduced by Moniz; procedure for cutting and removing part of the frontal lobe
• “gnosis”-to know
• “aphasia”- inability to understand or express the symbols connected with language that a person once knew

SENSORY APHASIA
1. Visual Aphasia-word-blindness, alexia; damage to Area 39; inability to read printed words
2. Auditory Aphasia-sound without meaning; damage in Area 22
3. Wernicke’s Aphasia-both visual and auditory aphasia; damage in Brocha’s area

MOTOR APHASIA
1. Verbal Aphasia-inability to talk even though vocal muscles are not paralyzed. Damage in Brocha’s area.
• apraxia-inability to carry out learned,voluntary acts though no paralysis is present
• agraphia-loss of writing ability
• agnosia-inability to recognize things
• finger agnosia- identifying fingers
• prosopagnosia-identifying faces
• anomia-loss of power to name objects and people;word finding, naming

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