Anatomy and function of the basal ganglia Flashcards
Anatomical parts of the basal ganglia
Caudate nucleus
Thalamus
Putamen
Globus pallidus
Globus pallidus
Split into pars externa and pars interna
Pallidum
Globus pallidus internal and external
Lentiform nucleus
Putamen and globus pallidus
Corpus striatum
Caudate
Putamen
Pallidum
Divided by internal capsule
Neostriatum
Caudate and putamen
Motor loop
Motor, premotor, somatosensory cortex
Putamen
Lateral globus pallidus, internal segment
Ventral lateral and ventral anterior nucleus
Oculomotor loop
Posterior parietal, prefrontal cortex
Caudate (body)
Globus pallidus, internal segment substantia nigra
Mediodorsal and ventral anterior nuclei
Prefrontal loop
Dorsolateral prefrontal cortex
Anterior caudate
Globus pallidus, internal segment, substantia nigra
Mediodorsal and ventral anterior nuclei
Limbic loop
Amygdala, hippocampus, orbitofrontal, anterior cingulate, temporal cortex
Ventral striatum
Ventral pallidum
Mediodorsal nucleus
Excitatory
Glutamate
Inhibitory
GABA
The direct pathway
Cortex -> excitatory
Striatum -> inhibitory
GPi -> inhibitory
Thalamus -> excitatory
Cortex
The indirect pathway
Cortex -> excitatory
Striatum -> inhibitory
GPe -> inhibitory
STN -> excitatory
GPi -> inhibitory
Thalamus -> excitatory
Cortex
The hyperdirect pathway
Cortex -> excitatory
STN -> excitatory
GPi -> inhibitory
Thalamus -> excitatory
Cortex
Pathways conundrum: transmitters
2 populations of striatum cells
Specialised dopamin receptors
Substantia nigra
Releases dopamine
Striatum neurons and dopamine
Direct D1
Indirect D2
Causes release of DA which tips pathway towards promotion of movement
Striatum neurons and acetylcholine
ACh opposes effects of DA
Tips pathway towards prevention of movement
Pathway balance
Balance of activity between 2 medium spiny neurone populations determines likelihood of movement
Balance regulated by dopamine and acetylcholine
Influenced by cortical inputs to striatum
