basal ganglia Flashcards
what are the functions of the basal ganglia
Motor functions ( voluntary)
and non motor funcitons
what are examples of the motor functions that the basal ganglia controls
Action selection
Inhibition of competing movements
Enabling motor programs
what are examples of non motor funcitons that the basal ganglia controls
Cognition and emotion
Reward and addiction
what are the pathologies of the basal ganglia
( movment disorders) Hypokinetic
Hyperkinetic
-Cognitive and neuropsychiatric
symptoms
what are the intputs to the motor cortex ( area 4)
Thalamic nuclei VA & VL
Premotor cortex (area 6)
how can you see intergration in the motor cortex
- Cortex has subdivisions including the motor, sensory, and association cortexes.
- From the motor cortex, there are neurons that synapse to alpha motor neurons (blue) aka the pyramidal tracts
- Basal ganglia receive inputs from all areas of the cortex
- Basal ganglia then projects to the thalamic motor nuclei, VA and VL
- VA and VL project to the motor cortex.
what is the basal ganglia composed of
- globulis pallidus which is composed of the causdate and the putamen ( 1 nucleus)
what is another term of the caudate and putamen?
globulus pallidus
- neostriatum
- paleostriatum
what are the associated nuclei (midbrain)
- what are their recpriocal connections
- Substantia nigra
>Reciprocally connected to
caudateputamen
> Dopaminergic projection to striatum - Subthalamic nucleus
> Reciprocally connected to globus
pallidus
where is the sbstantia nigra
what is this
subthalmic nucleus
what are the symptoms of parkinsons disease
Tremor at rest (“pill rolling tremor”)
Rigidity
Bradykinesia ( walk slowly)
Motor blocks (“freezing”)
Loss of postural reflexes
Cognitive defects are common
what is parkinsons caused by
- due to loss of dopamine in th substantia nigra, degeneration of the substantia nigra
what does someone with parkinsons look like
what is the biosynthetic pathway of dopamine
syntheitc pathway stops at DOPA in the SN
how can you treat parkinsons disease?
why cant you give dopamine
- take L dopa which is the precusor of dopamine
- bc of the blood brain barrier will not allow it to cross but L dopa can cross
- the SN then converts L dopa to dopmaine
what is huntingtons chorea
- how does it present
Degeneration in caudate nucleus
Excess movements
Autosomal dominant ( inhertied - 50% of offspring half a likely hood of getting it )
what does huntingtons chorea eventually affect
- the prefrontal cortex
the pt becomes degenerate
when does huntingtons chorea present
- around 50 yo
what is the huntigintons chorea the oppoiste of how should you not treat it
- parkinsons
- DONT TREAT WITH L DOPA
what is ballismus
- how does it present
Damage in subthalamic nucleus by stroke
> typically affects half the body
Ballistic movements
- flinging movements fof limbs and tongue
what is athetosis
- how does it present
Excess movements
Writhing (twisting) movements
what are some other basal ganglia disorders
Dystonia
Tics
Tourette syndrome
what is the role of the basal in motor function
suppresses inappropriate
motor program
Activation of direct pathway
temporarily releases one motor
program from inhibition
Also involved in learning of motor
programs
what is the ventral tegmental area (VTA)
Dopaminergic projections to
prefrontal cortex and limbic cortex
Selection of emotional, executive and
cognitive programs
Dopaminergic projection to nucleus
accumbens
Reward and addiction
where is the ventral tegemtnal area
