Basal Ganglia Flashcards
Basal Ganglia components
striatum
globus pallidus
subthalamic nuclei
substantia nigra
Primary function of basal ganglia
Planning and programming of movement
Main neurotransmitter
GABA
NT b/w striatum and substantia nigra
Dopamine
(-) the INHIBITORY INDIRECT pathway
D2 receptors
(+) the EXCITATORY DIRECT pathway
D1 receptors
Releases GLUTAMATE –> excites globus pallidus, internal segment
Subthalamic nucleus
Releases GABA –> (-) thalamus
Substantia Nigra Pars Reticulata
Releases Dopamine –> (-) striatum
Substantia Nigra Pars Compacta
Releases Ach –> (-) Substantia Nigra Pars Reticulata
Striatum
Releases GABA –> (-) subthalamic nucleus
Globus Pallidus External Segment
Lesion in the Globus pallidus
Inability to maintain posture
Lesion in the Subthalamic Nucleus
Wild, flailing movements
hemiballismus
Lesion in the Striatum
Quick, continuous, uncontrollable movements (i.e. Huntington disease)
Lesion in the Substantia Nigra
Tremors, cogwheel Rigidity, reduced voluntary movements (Akinesia), Postural problems (TRAP) - Parkinson’s Disease
Generates movement plan
Pre-Motor Cortex and Supplementary Motor Cortex (BA 6)
Executes movement
Epileptic event here causes JACKSONIAN SEIZURES (focal partial seizure)
Primary Motor Cortex (BA 4)
Caused by functional hemisection of the spinal cord
(+) contralateral loss of pain and temperature sensation beginning 1-2 segments below the lesion
(+) ipsilateral weakness and spasticity in certain muscles groups
Brown-Sequard Syndrome
(+) degeneration and loss of motor neurons in the motor cortex, spinal cord, brain stem and corticospinal tract
does NOT usually affect sensation
may present with UMN or LMN
Amyotrophic Lateral Sclerosis (ALS)
Have negative nitrogen balance as they catabolize large amounts of body protein because they are paralyzed below the level of transection
Patients w/ Transected Spinal Cords
Include Fragile X, Spinocerebellar ataxia type 3, Huntington Disease, Friedreich Ataxia
Trinucleotide Repeat Diseases
