The evolutionary origin of the vertebrate basal ganglia and its role in action selection.
Level 5 - mechanism / opinion, no new human data
Narrative review and mechanistic comparative neurobiology
PubMed 23318875 · doi:10.1113/jphysiol.2012.246660
What was done
The authors reviewed and synthesized comparative neuroanatomical, cellular, and functional data across vertebrate phylogeny (notably comparing lampreys to mammals) to evaluate the evolutionary conservation of basal ganglia circuitry and its role in motor control and action selection.
What was found
The abstract reports no quantitative metrics or statistical test results. It describes qualitative findings showing that basal ganglia structure, synaptic properties, and neurotransmitters have been conserved over roughly 560 million years. Tonically active GABAergic output neurons maintain resting inhibition over brainstem motor centers controlling locomotion, posture, eye movement, and feeding. Motor programs are released via striatal GABAergic projections driven by cortex, thalamus, and dopamine; striatal neurons expressing dopamine D1 receptors facilitate movement via the direct pathway, while those expressing D2 receptors suppress movement via the indirect pathway in both lampreys and mammals.
Why it matters
This work demonstrates that the core dual-pathway circuitry responsible for action selection and motor inhibition is an ancestral vertebrate trait rather than a recent mammalian specialization.
Limits
The abstract contains no quantitative data, error margins, or sample sizes. The paper is a narrative review rather than a systematic meta-analysis, relying on comparative animal models (particularly the sea lamprey) to infer ancestral vertebrate brain organization.
Cited by
- supports Neurophysiology studies in the lamprey show that the basal ganglia function to link motivation signals to action.