Basal Ganglia

glutamate from cerebral cortex, glutamate and ACh from pedunculopontine nuclei, serotonin from dorsal raphe nuclei

afferent signals into basal ganglia

GABA to thalamus, pedunculopontine nuclei, and reticular formation

efferent signals from basal ganglia

GABA, glutamate, dopamine

signals within basal ganglia

oculomotor loop

basal ganglia circuitry that makes decisions about spatial attention and eye movements, saccades to targets of interest

goal-directed behavior loop

basal ganglia circuitry that makes perceptual decisions, plans and makes decisions based on context

social behavior loop

basal ganglia circuitry that recognizes social cues, regulates self-control, selects relevant from irrelevant information, judgement

emotion loop

basal ganglia circuitry for seeking rewards, reward-guided behaviors, self-awareness, and acts as the connection between emotion, cognitive and motor systems

head of caudate, globus pallidus

basal ganglia involved in goal-directed behavior loop

head of caudate, substantia nigra reticularis

basal ganglia involved in social behavior loop

ventral striatum, ventral pallldum

basal ganglia involved in emotion loop

caudate body, substantia nigra reticularis

basal ganglia involved in oculomotor loop

putamen, globus pallidus

basal ganglia involved in motor loop

motor loop

basal ganglia circuitry that regulates muscle contraction, muscle force, and multijoint movements

disinhibition

involves at least two inhibitory neurons in series and a target neuron, occurs when another neuron inhibits the inhibitory neuron, thus allowing increasing activity in the target neuron

hyperdirect, direct, indirect

3 pathways required for normal movement activity so that desired movements are produced and unwanted movements are suppressed

motor thalamus, pedunculopontine nucleus, midbrain locomotor region

3 regions the basal ganglia inhibit to allow for normal movement

lateral corticospinal and rubrospinal

by the basal ganglia inhibiting the motor thalamus, it allows for normal activity in the __ tracts

reticulospinal

by the basal ganglia inhibiting the pedunculopontine nucleus, it allows for normal activity in the __ tracts

reticulospinal

by the basal ganglia inhibiting the midbrain locomotor region, it allows for normal activity in the __ tracts

voluntary movements

by the basal ganglia inhibiting the motor thalamus, it allows normal level of facilitation to the motor neurons that innervate __

postural and girdle muscles

by the basal ganglia inhibiting the pedunculopontine nucleus, it allows normal level of facilitation to the motor neurons that innervate __

stepping pattern generators

by the basal ganglia inhibiting the midbrain locomotor region, it allows normal level of facilitation to the motor neurons that innervate __

inhibition, voluntary movement

hyperdirect pathway results in __ of motor thalamus which leads to a suppression of __

cerebral cortex excites STN, STN excites GPi, GPi inhibits motor thalamus

steps of hyperdirect pathway

hyperdirect pathway

will strongly inhibit ongoing motor programs and will stop irrelevant movements prior to a voluntary movement

disinhibition

direct (go) pathway results in __ of motor thalamus

direct pathway

increased excitatory drive to motor cortex and corticospinal neurons

putamen inhibits GPi, decreased inhibition from GPi to motor thalamus

steps of direct (go) pathway

inhibition

indirect (no-go) pathway results in __ of motor thalamus

indirect pathway

decreased excitation of motor cortex and suppression of unwanted movements

putamen inhibits GPe, decreased inhibition from GPe to STN to excite GPi, GPi inhibits motor thalamus

steps of indirect (no-go) pathway

dopamine, substantia nigra compacta

the motor loop is dependent on __ which is supplied by __

excite go pathway

dopamine binding to D1 receptors will __

inhibit no-go pathway

dopamine binding to D2 receptors will __

hypokinesia in upper body and rigidity or resting tremor

parkinson's disease affects voluntary and automatic movements which leads to:

postural instability gait difficulty and tremor dominant

2 common subtypes of parkinson's disease

dopamine, ACh

pathology of parkinson's disease results in death of __ producing cells in substantia nigra compacta and __ producing cells in pedunculopontine nuclei

no-go

if dopamine producing cells are no longer present with parkinson's disease, which pathway is biased?

bradykinesia, trunk and girdle rigidity, freezing gait

since there is decreased dopamine, it affects all 3 pathways of the motor loop which will lead to affects with movement:

L-dopa

treatment for parkinson's disease

blood brain barrier

L-dopa is a proper treatment for parkinson's because it can cross the __ to act as dopamine to excite the Go pathway and inhibit the No-Go pathway