Presented by Dr. Subrata NaskarMD Psychiatry trainee

Department of PsychiatrySilchar Medical College

Email: nsubrata09@gmail.com

PLAN OF PRESENTATION:

A BRIEF HISTORY OF BASAL GANGLIA

ANATOMY : MAJOR STRUCTURES

WHAT IS BASAL GANGLIA?

MAJOR STRUCTURES:OTHER STRUCTURES WHICH MAY BE INCLUDED AS PART OF BASAL GANGLIA :

• VENTRAL STRIATUM• VENTRAL PALLIDUM

The nuclei of the basal ganglia are shown from the lateral perspective. The caudate nucleus includes the head, body and tail.The lenticular (lentiform) nucleus consists of an apposition of two nuclei – the putamen laterally (seen here) and the globus pallidus medially (not seen on this view).

• The basal ganglia of the opposite side of the brain are shown, so they are being visualized from the medial perspective. This view therefore shows the globus pallidus, which is located medially, and its two subdivisions (internal and external segments).

• The putamen is located more laterally. These nuclei collectively form the lentiformnucleus.

• STRIATUM

• CORPUS STRIATUM

• LENTIFORM NUCLEUS

BRIEF DISCUSSION ON THE INDIVIDUAL STRUCTURES

• CAUDATE NUCLEUS :

• PUTAMEN:

• GLOBUS PALLIDUS:• DIENCEPHALIC IN ORIGIN

Latin• INNER COMPONENT OF LENTIFORM NUCLEUS• CONE-LIKE STRUCTURE WITH TIP DIRECTED MEDIALLY• BOUNDED MEDIALLY BY POSTERIOR LIMB OF INTERNAL CAPSULE• LATERALLY BY PUTAMEN• DIVIDED INTO EXTERNAL AND INTERNAL SEGMENTS BY MEDIAL MAMILLARY LAMINA

• SUBTHALAMIC NUCLEUS: ( of Luys)

SUBSTANTIA NIGRA

PARS COMPACTA : PARS RETICULATA : • VENTRAL PART • SPARSE NUMBER OF CELLS• USES THE NEUROTRANSMITTER GABA• m-RNA FOR DOPAMINE TRANSPORTER &

D2 RECEPTOR• CALBINDIN –VE• SENDS PROJECTIONS TO SENSORIMOTOR

REGIONS OF THE STRIATUM

• MAY BE ASSOCIATED WITH • PARKINSON’S DISEASE

MESENCEPHALIC IN ORIGINPRESENT IN MIDBRAIN CONSISTS OF TWO COMPONENTS:

DORSAL TIER NEURONS (FILLED CIRCLES) – pars compacta

VENTRAL TIER (OPEN CIRCLES) – pars reticulata

DORSOCELLULAR ZONE (STARS)

INTERNAL ORGANISATION

INTERNAL ORGANIZATION OF BASAL GANGLIA SHOWING MEDIUM SPINY NEURONES.

INPUTS TO THE BASAL GANGLIA

STRIATUM IS THE MAJOR RECIPIENT OF INPUTS TO THE BASAL GANGLIA.THREE MAJOR AFFERENT PATHWAYS ARE KNOWN TO TERMINATE IN THE STRIATUM.

• CORTICOSTRIATAL• NIGROSTRIATAL• THALAMOSTRIATAL

CORTICOSTRIATAL PATHWAY

NIGROSTRIATAL PATHWAY:

THALAMOSTRIATAL PATHWAY:

Nigrostriatal pathway

Thalamostriatal pathway

Corticostriatal pathway

TH -THALAMUSPT – PUTAMENCD - CAUDATE NUCLEUSCM – CENTRAL MEDIAN NUCLEUSSNC - SUBSTANCIA NIAGRA PARS COMPACTAVS – VENTRAL STRIATUMSNR – SUBSTANCIA NIAGRA PARS RETICULATA

CORTICOSTRIATAL PATHWAY

THALAMOSTRIATAL PATHWAYNIGROSTRIATAL PATHWAY

INTERNAL PROCESSING DIRECT AND INDIRECT PATHWAYS

MEDIUM SPINY NEURONES WHICH CONTAINS THE NEUROPEPTIDE SUBSTANCE P SENDS INHIBITORY PROJECTIONS TO GPi - DIRECT PATHWAY

A SUBPOPULATION OF THESE MEDIUM SPINY NEURONES CONTAINING ENKEPHALIN PROVIDES INHIBITORY PROJECTIONS TO GPe, WHICH SENDS INHIBITORY AFFERENTS TO GPi - INDIRECT PATHWAY

GPe PROJECTS TO Pars reticulate OF SUBSTANTIA NIAGRA.GPe ALSO GIVES INHIBITORY PROJECTIONS TO SUBTHALAMIC NUCLEUS.

HOWEVER, NEURONES IN SUBTHALAMIC NUCLEUS ALSO PROVIDES EXCITATORY PROJECTIONS TO Gpe & GPi

OUTPUT OF THE BASAL GANGLIA THE Gpi IS THE SOURCE OF MUCH OF THE INPUT OF THE BASAL GANGLIA.

THIS SEGMENT OF THE GLOBUS PALLIDUS PROVIDES A PROJECTION TO THE VENTRO-LATERAL (VL) AND VENTRO-ANTERIOR (VA) NUCLEI OF THE THALAMUSAND THE CENTRAL MEDIAN NUCLEUS.

THE PARS RETICULATA OF SUBSTANTIA NIAGRA ALSO PROVIDES PROJECTIONS TO VL & VA.

THESE PROJECTIONS OF VA & VL PROJECT TO PRE-MOTOR & PRE-FRONTAL COTICES.

PROJECTIONS OF THE PRE-MOTOR & PRE-FRONTAL CORTICES PROJECT TO PRIMARY MOTOR CORTEX, SO BASAL GANGLIA ARE ABLE TO INFLUENCE INDIRECTLY THE OUTPUT OF PRIMARY MOTOR CORTEX

FUNCTIONS OF BASAL GANGLIA

• TREMORS

TYPES OF TREMORS

• REST TREMOR

• POSTURAL TREMOR

• INTENTION TREMOR

• CHOREA:

• DYSTONIA:

• ATHETOSIS:

• HEMIBALISMUS:

MOVEMENT DISORDERS WHERE BASAL GANGLIA IS THE PRIMARY SITE OF NEUROPATHOLOGY.

PARKINSON’S DISEASE

CHARACTERISTIC TRIAD :-

RESTING TREMOR, RIGIDITY,BRADYKINESIA.ALSO ASSOCIATED WITH GAIT & POSTURAL DISTURBANCES

HUNTINGTON’S DISEASE

• PRIMARY INVOLUNTARY MOVEMENT ABNORMALITY

• ASSOCIATED VOLUNTARY MOVEMENT ABNORMALITIES

• PSYCHIATRIC MANIFESTATIONS

WILSON’S DISEASE

NEUROLOGICAL FINDINGS• TREMOR• DYSTONIA• RIGIDITY• CHOREOATHETOSIS• BRADYKINESIA• MASKED FACIES• MICROGRAPHIA

PSYCHIATRIC MANIFESTATIONS• PERSONALITY CHANGES• DEPRESSION• SUICIDALITY• ANXIETY DISORDERS• PSYCHOTIC DISORDERS

PROGRESSIVE SUPRANUCLEAR PALSY

NEUROLOGICAL FINDINGS• PSYCHIATRIC MANIFESTATIONS

• SUBCORTICAL DEMENTIA WITH BRADYPHRENIA• MEMORY DEFICITS• PREDOMINANT FRONTAL LOBE DYSFUNCTION

WITH EXECUTIVE AND ATTENTION DEFICITS.• FRONTAL BEHAVIORAL DISTURBANCES OF

APATHY AND DISINHIBITION• SLEEP DISTURBANCES• DEPRESSION• EMOTIONAL LABILITY INCLUDING

PATHOLOGICAL LAUGHTER AND CRYING• IRRITABILITY

•LOW D2 BLOCKADE

•MEDIUM D2 BLOCKADE HIGH D2 BLOCKADE

• FLUPHENAZINE

• PERPHENAZINE

• THIOTHIXENE

• HALOPERIDOL

• DROPERIDOL

• PIMOZIDE

• RISPERIDONE

• ARIPIPRAZOLE

NEUROLEPTIC-INDUCED MOVEMENT DISORDERS

NEUROLEPTIC INDUCED PARKINSONISM

CLASSIC TRIAD

NEUROLEPTIC INDUCED ACUTE DYSTONIA

OCCURS IN UPTO 10% PATIENTS MORE COMMON IN YOUNG MEN

NEUROLEPTIC-INDUCED ACUTE AKATHISIA

NEUROLEPTIC-INDUCED TARDIVE DYSKINESIA

SUMMARY