Upload
mithun-chakkaravarthy
View
223
Download
0
Embed Size (px)
Citation preview
8/6/2019 Basal Ganglia 2011
1/45
BASAL GANGLIADr. TDS
8/6/2019 Basal Ganglia 2011
2/45
The pleasant aroma of freshly brewed coffeeand baked cinnamon rolls are enough tomotivate anyone of us to walk toward the
coffee and cinnamon rolls and taste them bylifting the coffee cup and roll to take a sip anda few bites
Tasting the cinnamon roll may elicit certainfacial expressions that may indicate to thoselooking at us that we are enjoying the delicious
tasting cinnamon roll.
8/6/2019 Basal Ganglia 2011
3/45
Furthermore, the warm cinnamon aroma may
evoke fond memories of the first time we
tasted a cinnamon roll
In this example, the olfactory system
(mediating the sense of smell), the limbic
system (processing emotions and memory),
and the basal ganglia involved in movement
are all interconnected
8/6/2019 Basal Ganglia 2011
4/45
Basal ganglia are involved in the planning and
programming of movement or, more broadly,
in the processes by which an abstract thought
is converted into voluntary action (initiates)
8/6/2019 Basal Ganglia 2011
5/45
8/6/2019 Basal Ganglia 2011
6/45
Much of the output of the basal ganglia, which
is mediated through the thalamus, is to reduceor dampen the excitatory input to the cerebral
cortex
8/6/2019 Basal Ganglia 2011
7/45
. When there is a disruption of this mechanism,
disturbances in motor function ensue
Discharge patterns of the basal ganglia become
excessive, abnormal slowing of movements
Lesions of the basal ganglia produce a reduced
output, presence of abnormal, involuntarymovements that occur during periods of rest
8/6/2019 Basal Ganglia 2011
8/45
BASAL GANGLIA STRIATUM
(NEOSTRIATUM)
VENTRAL
STRIATUM
LENTICULAR
NUCLEUS
CORPUS
STRIATUM
Caudate nucleus
Putamen
Globus pallidus
Subthalamicnucleus (of
ventral
thalamus)
Substantia nigra
(ofthemesencephalon
Caudate nucleus
Putamen
Ventralportion
ofcaudate
Nucleus
Putamen
Anteriorperforated
substance
Nucleus
accumbens
Putamen
Globus pallidus
Caudate
nucleus
Putamen
Globus pallidus
8/6/2019 Basal Ganglia 2011
9/45
8/6/2019 Basal Ganglia 2011
10/45
Componentsofthe Basal Ganglia
Input Nuclei Corpus Striatum
Caudate
Putamen
Output Nuclei GlobusPallidus Interna
SubstantiaNigraPars Reticulata*
Intermediate Nuclei GlobusPallidus Externa SubthalamicNucleus*
SubstantiaNigraParsCompacta*
8/6/2019 Basal Ganglia 2011
11/45
8/6/2019 Basal Ganglia 2011
12/45
Afferentsto Striatum
Sensory cortex
Motor cortex
Substantia nigra Intralaminar nucleiofThalamus
8/6/2019 Basal Ganglia 2011
13/45
8/6/2019 Basal Ganglia 2011
14/45
The putamen appears to be concerned
primarily with motor functions
The caudate nucleus, is involved with
cognitive aspects of movement, eye
movements, and emotional correlates of
movement
8/6/2019 Basal Ganglia 2011
15/45
Efferentsfrom Striatum
Globuspallidus
Substantia nigra
8/6/2019 Basal Ganglia 2011
16/45
8/6/2019 Basal Ganglia 2011
17/45
Afferentsto Globuspallidus
Caudate nucleus
Putamen
Subthalamic nucleus
8/6/2019 Basal Ganglia 2011
18/45
8/6/2019 Basal Ganglia 2011
19/45
EFFERENTS FROM GLOBUS
PALLIDU
S SUBTHALAMICNUCLEUS
SUBSTANTIA NIGRA
THALAMUS (VA and VL)
8/6/2019 Basal Ganglia 2011
20/45
8/6/2019 Basal Ganglia 2011
21/45
Functions
1. Planning and programming of movements
that is conversion of idea into action
2. Provides postural background for anymovement
3. Regulation of muscle tone
4. Helps to bring about subconsciousmovements like facial expressions
8/6/2019 Basal Ganglia 2011
22/45
PathwaysofMotor Loop
DirectPathway
Overall Excitatory
IndirectPathway Overall Inhibitory
8/6/2019 Basal Ganglia 2011
23/45
DirectPathway
CORTEX
PUTAMEN
(GPe)
(STN)
GP interna
VA/VL THALAMUS
Glutamate (+)
Glutamate (+)GABA (-)
GABA (-)
8/6/2019 Basal Ganglia 2011
24/45
IndirectPathway
CORTEX
PUTAMEN
GP externa
STN
GP interna
VA/VL THALAMUS
Glutamate (+)
GABA (-)
Glutamate (+) GABA (-)
GABA (-)
Glutamate (+)
8/6/2019 Basal Ganglia 2011
25/45
Modulatory RoleofDopamine
Activation of the dopaminergic pathway
excites the direct pathway but inhibits the
indirect pathway
Excites the facilitatory (direct) pathway via its
excitatory effects on dopamine D1
receptors in
regions of the neostriatum that project to the
medial pallidal segment
8/6/2019 Basal Ganglia 2011
26/45
Inhibiting the inhibitory (indirect) pathway
that projects initially to the lateral pallidalsegment because of the inhibitory effects on
dopamine D2 receptors in the neostriatum
8/6/2019 Basal Ganglia 2011
27/45
Movement Disorders
Hyperkinetic
Hemiballismus
Huntingtons DiseaseChorea
Hypokinetic
Parkinsons Disease
Drug Induced (Neuroleptics, MPTP)
8/6/2019 Basal Ganglia 2011
28/45
Parkinson's Disease
8/6/2019 Basal Ganglia 2011
29/45
Parkinson Disease
Neurological disease affecting over four millionpatients worldwide, over1.5 million people inthe U.S..
While it can affect individuals at any age, it ismost common in the elderly.
The average age of onset is 55 years, althoughapproximately 10 percent of cases affect thoseunder age 40.
8/6/2019 Basal Ganglia 2011
30/45
Appears Later in Life
Continuous Progressive Neurological
Disease, thereby causing increasing disability
of movement no cure
8/6/2019 Basal Ganglia 2011
31/45
Etiology
Cerebral atherosclerosis
Viral encephalitis Side effects of several antipsychotic drugs
(i.e., phenothiazides, butyrophenones,
reserpine)
8/6/2019 Basal Ganglia 2011
32/45
Environmentalfactorsand neurotoxins
Pesticides, herbicides, industrial chemicals -
contain substances that inhibit complex I in the
mitochondria
8/6/2019 Basal Ganglia 2011
33/45
8/6/2019 Basal Ganglia 2011
34/45
UsuallyOther Accompanied Autonomic Deficits Seen
Later in Disease Process:
Orthostatic Hypotension
Dementia
Dystonia
Ophthalmoplegia
Affective Disorders
8/6/2019 Basal Ganglia 2011
35/45
Parkinson Disease Neurochemistry
Loss of Dopaminergic (DA) Cells Located in
Basal Ganglia; most symptoms do not appear
until striata DA levels decline by at least 70-
80%.
8/6/2019 Basal Ganglia 2011
36/45
CORTEX
PUTAMEN
(GPe)
(STN)
GP interna
VA/VL THALAMUS
Glutamate (+)
Glu(+)GABA (-)
GABA (-)
Parkinsons Disease
(--)
CORTEX
PUTAMEN
GP externa
STN
GP interna
VA/VL THALAMUS
Glutamate (+)
GABA (-)
GABA (-)
GABA (-)
Glutamate (+)
DA(+)
Glu(+)
8/6/2019 Basal Ganglia 2011
37/45
Imbalance primarily between the excitatory
neurotransmitter Acetylcholine and inhibitory
neurotransmitter Dopamine in the Basal
Ganglia
ACh
DA
8/6/2019 Basal Ganglia 2011
38/45
Drug Therapy
Drug Therapy Against Parkinson
Disease Is Aimed at Bringing the
Basal Ganglia Back to Balance
DecreaseCholinergic Activity Within BasalGangliaandthisCan Be Done Two Ways:
Activating Dopamine receptorsin SubstantiaNigrafeedingback toCholinergicCellsin the
striatum Turn offtheCholinergicCells, Then Things Are
Brought Back to Balance
Antagonize Acetylcholine receptors
8/6/2019 Basal Ganglia 2011
39/45
Agentsthat Increase Dopaminefunctions
Increasing the synthesis of dopamine - l-Dopa
Inhibiting the catabolism of dopamine selegiline
Stimulating the release of dopamine amphetamine
Stimulating the dopamine receptor sites directly -bromocriptine&pramipexole
Blocking the uptake and enhancing the release of dopamine -amantadine
8/6/2019 Basal Ganglia 2011
40/45
Chorea
Chorea ischaracterizedby rapid,involuntary
"dancing" movements
8/6/2019 Basal Ganglia 2011
41/45
Huntingtons Disease
Autosomal dominant Loss of cholinergic and GABAergic neurons in
the striatum
Trinucleotide repeat defect on chromosome 4 Characterized by multiple quick, random
movements most prominent in the
appendicular muscles.
Athetosis (slow, wormlike, involuntary
writhing movements) most noticeable in the
fingers and hands.
8/6/2019 Basal Ganglia 2011
42/45
Huntingtons Disease
CORTEX
PUTAMEN
GP externa
STN
GP interna
VA/VL THALAMUS
Glutamate (+)
GABA (-)
Glutamate (+) GABA (-)
GABA (-)
Glutamate (+)
+
8/6/2019 Basal Ganglia 2011
43/45
Hemiballismus
Wild flinging movements of half of the body
Injury usually to STN
8/6/2019 Basal Ganglia 2011
44/45
CORTEX
PUTAMEN
GP externa
STN
GP interna
VA/VL THALAMUS
Glutamate (+)
GABA (-)
GABA (-)
GABA (-)
Glutamate (+)
Glutamate (+)
Hemiballismus
+
8/6/2019 Basal Ganglia 2011
45/45
THANKYOU