Lecture 4: Basal Ganglia Flashcards
What is part of the Striatum
the Caudate and the Putamen
what is part of the Lenticular nucleus
the putamen and the globus pallidus
Basal Ganglia Circuitry
- collection of gray matter nuclei
- caudate and putamen are seperated by penetrating fibers of the internal capsule but remain together by cellular bridges
-variety of excitatory and inhibitory connectors utilizing different neurotransmitters
What is the BG involved in?
1) motor control
- hyper and hypo kinetic
- eye movement
- Associate function (cognitive)
- limbic
Functions of the Basal Ganglia (BG)
1) initiates and integrates behavior and movement
2) integrates executive functions, emotions and motor activity
3) removes unwanted and inappropriate movement
4) plans motor activity
5) associations with attention and time estimation
6) regulated motor habits (functional activities)
7) rewards and motivation
how does the cortex influence the BG
directly
How does the BG influence the cortex
through the thalamus
How does the BG information get to the spinal cord
through the brainstem
where do skilled movements arise from
the motor cortex through the corticospinal tracts and brainstem
where do the selection and initiation of motor programs come from
the BG to the brainstem and the BG to the thalamus
what are the pathways from the brain stem to the spinal cord?
Reticulospinal: maintains tone, balance and posture
Vestibulospinal: positioning of the limbs; supporting posture and maintaining posture
what does the spinal cord do
1) central movement pattern generation
2) muscle movement
3) sensory receptors
4) reflexes
How is the cortex connected to the BG
though parallel loops that are divided into the motor, associative, and limbic
Dysfunction of the BG leads to
movement disfunction (akensia, bradykinesia, and hyperkinesia)
BG inputs to what parts of the brain?
cerebral cortex and limbic
BG outputs
limbic, thalamus, midbrain
BG neurotransmitters inputs
Dopamine and Gluetamate
Pathologies Characterized by non-motor loops (emotional, cognitive, and psychiatic)
- OCD
-tourettes syndrome
-ADD
BG is involved in both
preparation and execution of movements as while as learning of sequences and habit (implicit learning)
Parkinsons common movement habits
1) slow walking
2) small and narrow steps
3) making perceptual decisions
Body movement loop
1) cortical input from the motor, premotor, somatosensory cortex
2) Striatum: putamen
3) Pallidum: lateral globus pallidus, internal segment
4) thalamus: ventral lateral and anterior
5) primary motor, premotor, supplementary motor cortex
Oculomotor loop
1) input: posterior parietal, prefrontal cortex
2) striatum: body of caudate
3) pallidum: globus pallidus, internal segment; substantia nigra pars reticulata
4) thalamus: mediodorsal and ventral anterior nuclei
5)frontal eye field , supplementary eye field
Prefrontal Loop
input: Dorsolateral prefrontal cortex
Striatum: anterior caudate
Pallidum: globus pallidus internal segment; substantra nigra pars reticulata
thalamus: mediodorsal and ventrical anterior nuclei
Dorsolateral prefrontal cortex
Limbic loop
Input: Amygdala, hippocampus, orbitofrontal, anterior cingulate, temporal cortex
Striatum: Ventral Striatum
Pallidum: Ventral Pallidum
Thalamus: Mediodorsal nucleus
