6.5a Basal Ganglia

BASAL GANGLIA

MA. CRISTINA S. ELMA-ZULUETA, M.D.Department of Anatomy

College of Medicine

UERMMMCI

LEARNING OBJECTIVESAt the end of the lecture, the learners

should be able to explain the manifestations of patients with movement disorders affecting the basal ganglia based on:

a.Structure/s involvedb.Pathway/s involved (direct and indirect)c.Neurotransmitter/s involved

VIDEO: What is wrong?

Patients’ProblemsTremorsAbsence of swaying of armsSlow movementRigidityStooped posture

Basal Ganglia & Cerebellum

Thalamus

Cerebral Cortex

Corticobulbar tract Corticospinal tract

LMNEx. Hypoglossal n.

LMNEx. Brachial Plexus

EPS

PYRAMIDAL

Basal Ganglia/Nuclei: Composition

Caudate nucleusPutamenGlobus pallidus

- externa

- internaSubstantia nigraSubthalamic nucleusAmygdala(?)



SUBTHALAMIC NUCLEUS (of Luys) a biconvex lens b/w thalamus & tegmentum

Substantia Substantia NigraNigra

PARTS: PARTS: 1. Pars compacta ( SNc ) 2. Pars reticulata ( SNr )- neurons are dopaminergic - inhibitory ( D2) & excitatory ( D1)-concerned with muscle

tone

Terminologies

VideoSummary of Basal Ganglia Anatomy

Basal ganglia: Functions and Connections

1. posture 2. automatic movements as swinging of arms 3. skilled volitional movements of the trunk & limbs and 4. in cognition

Movements influenced by the basal ganglia :\

Direct and Indirect Pathways

DISINHIBITION

Again... Again...Again with Afferent and Efferent Pathways

Synthesis…Questions1. Inhibition of the globus pallidus internus will

decrease the activity of the thamus. (True or False)

2. The subthamic nucleus is excitatory to _______ nuclei.

3. In the indirect pathway, increasing the inhibition of the globus pallidus externus to the next nucleus will excite the thalamus.(True or False)

General PrincipleBG acts by default to inhibit all upper motor

systemIt selects particular actions by releasingdistinct parts of upper motor system from

inhibition = disinhibitionBG controls upper motor system through

disinhibition

PRINCIPLES in PRINCIPLES in BASAL NUCLEI BASAL NUCLEI FUNCTIONSFUNCTIONS

BG / BN affects “final common path”/ LMN INDIRECTLY.

BG / BN effects are CONTRALATERAL to the side of the lesion

Strength persists in muscles but there is emergence of INVOLUNTARY MOVEMENT.

Problem in the circuitry: Parkinson’s and Huntington’s Disease

Lesions of the basal ganglia :Lesions of the basal ganglia : PARKINSON’S DIS PARKINSON’S DIS

Lewy bodies – inclusion bodies

LEWY BODIES

VIDEOLiving with Parkinson’s Disease

REFERENCES:

4. Lansang’s Modules in Neuroanatomy 4th ed

1 2 3

Belated Happy Valentine’s Day!!!!

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6.5a Basal Ganglia