Cerebral Hemisphere

ORGANIZATION AND FUNCTIONS OF CEREBRAL HEMISPHERE: 

ORGANIZATION AND FUNCTIONS OF CEREBRAL HEMISPHERE Under the guidance of:- Dr. Monika M.P.T. ( Neuro ) Presented by:- Jaya Bisht B.P.T. (final year)

CONTENTS : 

CONTENTS 1) Brain’s external features. 2) Anatomy of Cerebral Hemisphere. 3) External features of Cerebral Hemisphere. 4) Internal features of Cerebral Hemisphere. 5) Corpus Callosum . 6) Blood supply of C.H. 7) Cerebral dominance. 8) Brodmann’s areas. 9) Homunculus. 10) Functions of C.H. 11) Lobes of C.H. and related impairments. 12) Biblography .

BRAIN EXTERNAL FEATURES:-: 

BRAIN EXTERNAL FEATURES:- 1. CEREBRAL HEMISPHERE 2. CEREBELLUM 3. BRAINSTEM

Slide 4: 

Brain is surrounded by three layers of connective tissue :

Anatomy of cerebral hemisphere: 

Anatomy of cerebral hemisphere The cerebral hemispheres make up the largest portion of the human brain. It is a heavily bilobed structure. The two lateral halves are seperated by a deep midline sagittal fissure. In the depth of the fissure the corpus callosum connects the hemisphere across the midline. The surface of each cerebral hemisphere is thrown into folds or gyri which are seperated from each other by sulci and gyri .

EXTERNAL FEATURES OF CEREBRAL HEMISPHERE : 

EXTERNAL FEATURES OF CEREBRAL HEMISPHERE

POLES: 

POLES 1. Frontal pole. 2. Occipital pole. 3. temporal pole.

SURFACES AND BORDERS: 

SURFACES AND BORDERS SURFACES 1.Superiolateral. 2.Medial. 3.Inferior. BORDERS 1.Superiomedial. 2.Superciliary. 3.Inferolateral. 4.Inferomedial./ Hippocampal . 5.medial occipital.

LOBES: 

LOBES 1. Frontal lobe. 2. Parietal lobe. 3. Temporal lobe. 4. Occipital lobe. 5. insula .

INSULA/ISLAND OF REIL/CENTRAL LOBE: 

INSULA/ISLAND OF REIL/CENTRAL LOBE The insula is the submerged (hidden) portion of cerebral cortex,in the floor of the lateral sulcus . It has been submerged from the surface during development of brain due to overgrowth of surrounding areas. It can be seen only when the tips of the lateral sulcus are widely pulled apart.

Main Sulci & Fissures: 

Main Sulci & Fissures The surfaces of the cerebral hemispheres contain many fissures and sulci that separate the frontal, parietal, occipital, and temporal lobes from each other . The lateral cerebral fissure ( Sylvian fissure ) separates the temporal lobe from the frontal and parietal lobes. The hemispheres are separated by a deep median fissure, the longitudinal cerebral fissure . The central sulcus (the fissure of Rolando ) arises about the middle of the hemisphere, and separates the frontal lobe from the parietal lobe . The parieto -occipital fissure separates the parietal lobe from the occipital lobe.

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Cerebral Cortex Each gyrus , sulcus , and fissure You don't need to know all of You will need to know the foll Central Sulcus Precentral Gyrus Postcentral Gyrus Longitudinal Fissure Parietooccipital Sulcus Lateral Fissure/Sulcus

INTERNAL FEATURES OF CEREBRAL HEMISPHERE: 

INTERNAL FEATURES OF CEREBRAL HEMISPHERE

The Lateral Ventricle: 

The Lateral Ventricle It is an internal cavity in each cerebral hemisphere that consists of a central body and three cornua including an anterior one curving forward and outward, a posterior one curving backward, and an inferior one curving downward . The two ventricals are seperated from each other by the “SEPTUM PELLUCIDUM”

The Caudate Nucleus/basal ganglia: 

The Caudate Nucleus/basal ganglia Is an elongated, curved mass of gray matter situated within each cerebral hemisphere. It is a large C- shaped,closely related to lateral ventrical .

The White Matter: 

The White Matter These are the myelinated fiber . This region covers the parts of the brain which performs basic functions and is under the lobes or gray matter.

Corpus Callosum: 

Corpus Callosum The corpus callosum connects the two hemispheres It is a large bundle of myelinated and nonmyelinated fibers , that crosses the longitudinal cerebral fissure and interconnects the hemispheres. The corpus callosum permits the C.H. to communicate with each other. Most parts of the cerebral cortex are connected with their counterparts in the opposite hemisphere by axons that run in the corpus callosum .

Blood supply of..Circle of Willis: 

Blood supply of..Circle of Willis

Gold: ACA Pink: MCA Blue: PCA: 

Gold: ACA Pink: MCA Blue: PCA

Slide 31: 

Cerebral Dominance Dominence Hemisphere refers to the side concerned with the perception and production of language/speech. Dominant Hemisphere (left hemisphere) Language,Verbal S peech , Writing Calculation,Analytical,Mathematical Non-dominant Hemisphere (right hemisphere) Almost non verbal, Musical R ecognition of faces,Creative acts of arts Playing musical instrument,Geometrical .

Slide 32: 

HEMISPHERE DOMINENCE may be demonstrated by the injection of SODIUM ANYTAL into the INTERNAL CAROTID ARTERY. On the dominant side this will produce an arrest of speed for upto 30 sec- WADA TEST. Such a test may be important before temporal lobectomy for epilepsy when hemisphere dominance is in doubt.

Slide 33: 

Language Speech Writing Calculation 3D perception Singing Playing Musical instrument

brodmanns areas / ACCORDING TO THE LOBES OF C.H.: 

brodmanns areas / ACCORDING TO THE LOBES OF C.H. FRONTAL LOBE:- a) Motor areas (4) b) Premotor areas (6) d) Frontal eye field (6,8) e) Broca’s area (44,45) PARIETAL LOBE:- a) Somatosensory areas (1,2,3) b) Gustatory areas (43) c) Wernicke’s area (39,40)

Slide 36: 

TEMPORAL LOBE:- a) Olfactory areas (28) b) Auditory areas (22,41,42) NOTE:- WERNICKE’S AREA CONNECT TO BROCA’S AREA BY A BUNDLE OF NERVE FIBERS C/A “ ARCUATE FASCICULUS ” OCCIPITAL LOBE:- a) Visual area (18,19)

HOMUNCULUS : 

HOMUNCULUS The specific regions within the areas are responsible for movements in the specific parts of the body. The human body is represented in a upside down manner in the precentral gyrus .(inverted homunculus)

Slide 38: 

Sensory Homunculus

Slide 39: 

Motor Homunculus

Function of Hemispheres: 

Function of Hemispheres Right hemisphere judging the position of things knowing body position understanading and remembering things we do and see controls the left side of the body Left Hemisphere understanding and use of language (listening, reading, speaking and writing ) memory for spoken and written messages detailed analysis of information Controls the right side of the body The left hemisphere is dominent in right handed people

Slide 41: 

LOBES OF CEREBRAL HEMISPHERE AND RELATED IMPAIR M ENTS

Frontal Lobe: 

Frontal Lobe Judgments How we initiate activity in response to our environment. Controls our emotional response. Controls our expressive language. Attention span Involves word associations (language planning) Memory for habits and motor activities (short term memory) Voluntary movement Perseverance

Frontal Lobe Deficit—Problems : 

Frontal Lobe Deficit—Problems Loss of simple movement of various body parts ( Paralysis ). Inability to plan a sequence of complex movements needed to complete multi-stepped tasks, such as making coffee (Sequencing ). Loss of spontaneity in interacting with others . Persistence of a single thought ( Perseveration ). Inability to focus on task (Attending ). Mood changes ( Emotionally Labile ). Changes in social behavior. Changes in personality. Difficulty with problem solving. Inablility to express language ( Broca's Aphasia).

Parietal Lobe Function: 

Parietal Lobe Function Visual attention. Touch perception. Goal directed voluntary movements. Manipulation of objects. Integration of different senses that allows for understanding a single concept.

Parietal Lobe deficit-PROBLEMS: 

Parietal Lobe deficit-PROBLEMS Inability to attend to more than one object at a time. Inability to name an object ( Anomia ). Inability to locate the words for writing ( Agraphia ). Problems with reading ( Alexia ). Difficulty with drawing objects. Difficulty in distinguishing left from right. Difficulty with doing mathematics ( Dyscalculia). Inability to focus visual attention . Difficulties with eye and hand coordination.

Temporal Lobe Function: 

Temporal Lobe Function Hearing ability Memory acquisition Some visual perceptions Categorization of objects.

Temporal Lobe Deficits—Problems : 

Temporal Lobe Deficits—Problems Difficulty in recognizing faces ( Prosopagnosia ). Difficulty in understanding spoken words ( Wernicke's Aphasia). Disturbance with selective attention to what we see and hear. Difficulty with identification of, and verbalization about objects. Short-term memory loss. Interference with long-term memory Increased or decreased interest in sexual behavior. Inability to catagorize objects ( Catagorization ). Increased aggressive behavior.

Occipital Lobe Function: 

Occipital Lobe Function Vision

Occipital Lobe Deficits--Problems: 

Occipital Lobe Deficits--Problems Defects in vision ( Visual Field Cuts ). Difficulty with locating objects in environment. Difficulty with identifying colors ( Color Agnosia ). Production of hallucinations Visual illusions - inaccurately seeing objects. Word blindness - inability to recognize words. Difficulty in recognizing drawn objects. Inability to recognize movement of an object ( Movement Agnosia ). Difficulties with reading and writing.

Biblography: 

Biblography Clinical Neuroanatomy by RICHARD S.SNELL . Clinical Neuroanatomy by VISHRAM SINGH . Neurology by KENNETH W. LINDSAY . Wekepiedia.com

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