Basal Ganglia Lec22 Flashcards
in the direct basal ganglia circuit
the cortex has a ___ inputs on the striatum
excitatory
in the direct pathway the striatum sends ___ projections to the ____.
striatum inhbiitory to intenral globus pallidus
in the direct pathway
the intneral globus pallidus sends ___ projetions to the ___.
inhibitory projections to the thalamus
“the break”
when active, the direct pathway ___ the brake on the thalamic positive input on the cortex
inhibits
it removes the break
the ___ pathway turns the brake on
indirect
in the indirect pathway
the cortex has a ____ projection to the striatum
excitatory
in the indirect pathway
the striatum sends ____ projection to the ____
inhibitroy on the external globus pallidus
in the indirect pathway
the external globus pallidus sends ____ projection to the ____
inhibiotry projection to the subthalamic nculeus
in the indirect pathway
the subthalamic nucelus sends ____ projection to the ____
excitatory projection to the internal globus pallidus (which when activated inhibits the thalamus)
what is the mechanism in which the indirect pathway turns on the brake?
it removes inhibition on the inhibiotyr neuron (from the globus pallidus) acting on the subthalamic nucleus
which sitmulates the external globus pallidus
which inhibits the thalamus
most common basal ganglia neuron?
Medium Spiny Stellate Neuron
what do the Medium Spiny Stellate Neuron do?
Connect input and output portions of basal ganglia
medium spiny stellate neurosna re Mostly in the ___ & ACh(+)
matrix
some medium spiny stellate neurons are in the
____ & are ACh(-)
striosome
where are spindle neurons located
globus pallidus and STN
where in the thalamus do the spindle neurons project to?
va/vl
where in the globus pallidus does spindle neurons projec tto?
intenral GP
where do the pigmented neurosn project to?
striatum, GP, STN
inputs of striosome spiny stellate neurons?
limbic cortex and SNpc
outputs of strosome med. spiny stellate neurons
substantia nigra
inputs to matrix med. spiny stellate neurons
cortex, intenruons of substantia nigra
outputs of matrix med. spiny stellate neurons
globus pallidus
output structures of the basal ganglia project back to the
thalamus first ebfore the cerbral cortex
what keeps the basala ganglia chain moving?
dopamine supplied by the substantia nigra
inputs from the cortex go into the
caudate and the putamen
outputs from basal ganglia leave by the
globus pallidus and substrantia nigra
Dopamine enhances___pathway
D1/direct
doapmine inhibits___ pathway
D2/indirect
dopamine causes ___ of the thalamus
disinhibition
dopamine promotes ___ receptors
D1
D1 receptors on striatum ___ of the thlaamus by the ____
remove inhibition by the internal globus pallidus
all basal ganglia inputs are
excitatroy, glutamate
all basal ganglia outputs are
ihbiitory, gaba
the ___ path is involved in reward
striosomal
The basal ganglia are known to be involved in forms of “habit learning” which
require the creation of novel associations between ___ and ___
stimuli and motor responses
The neurons most involved in habit learning are giant cholinergic interneurons in the ____
striatum
giant cholinergic interneurons (tonically active neurons) in the striatum interactive with ___
doapmine inputs from substantia nigra at the level of the MSSNs
TANs and SNpc neurons do NOT display simple relationships to __ or __
movements or
body parts
TANs and SNpc are activate by___ or ____
rewards or stimuli that predict the
occurrence of rewards
when activated by reward, Tan and ssubstantia nigra modfiy the bactivity of ___ based on this to form part of the neuronal susbtate underlyign behaviroal reinformcent
medium spinal stellate neurons
HD kills ___
neurons in striatum
ENK
HD kills ENK
neurons in striatum,
leads to unchecked ___
D1 tone (which enhances the disinhbiiton of the thalamus)
parkinsons leads to loss of dopamine in the substantia nigra, leading to a ___
hyperactive break
acute lesions of the basal ganglia can lead to
cognitive
deficits, hallucinations and even OCD
Are there high order consequences of basal ganglia damage?
neurosn in the BG are very active in simple mvoements of the ___ and ___
limbs and visually guided movements
where in the thalamus does the basal ganglia project to
- VL and VA nculei of the thalamus - with body mvoement loop
- mediodorsal and ventral anterior nuclei – with oculomotor loop
gp receive input to and from areas projecting back to prefrontal areas involved in ____
short term memory
___ was activated in difficult mtoor task
globus pallidus
hyperdirect: goes directly from the
__ to the ___
cortex to the subthal.
striasomal path: arises from cortical areas concerned with limbic function
reward cortical areas can therefore affect the release of ___
dopamine
taught to make saccade towards a target cue
place cells firing is dependent
on reward direction
true in ___ and ___ (in substantia nigra)
caudate and in level of pars
compacta cells
also in GP
nonmotor functions of GP
expts showed heightened activation with
difficult motor task
working memory
reward drivign activity
hyperkinetic is associated with ____ levels of basal ganglia output
low (which disinhbit the thalamus
___ can be caused by an autonimmune reaction, particularly to the striatum
sydenhams chorea
huntingtons is associated with atrophy in the
neostriatum, particularly the enkephalin expresisng neurons in the cuadate
chronic tx with hutningtons can cause
tardive dyskinesias
tx of ___ includes antidopamine drugs, antibiotics, immunomodulants, consider plasmapheresis.
syndenhams chorea
huntgints treatment involves
anti-dopaminergic or dopamine-depleting drugs
what does tx of parkinsons include
ldopa, doapminetics, MAO inhbiitors (prevent degradation of da0
anticholinergixcs
side effects of l dopa includes
dyskinesias and hallucinations
surgical tx of parkinsons include
destroying the break by
X intenral globus pallidus or ventrolateral thalamus
surgical tx of parkinsons include
putting ___ back into the basal ganglia
dopamine, fetal nigral transplant
deep brain stimulation in parksindons is either to the
globus apllidus or subthalamus
drives them into normal rhtym, not inhbiited state
