Table 1.

Clinical and theoretical homologues

Neurological syndrome	Clinical sign	Synthetic lesion	Functional role
Cerebellar	Pendular reflexes	λ	Smoothness of random fluctuations
	Dysmetria	λ
Corticospinal	Brisk reflexes	Π	Precision (inverse variance) of likelihood distributions
	Preserved coordination	Π
Parkinsonian	Slow movements	γ	Precision (inverse temperature) of policy priors
	Small amplitude movements	γ
	Delay in movement initiation	γ
Executive	Impaired ‘immediate recall’	A	Precision (inverse temperature) of empirical (hierarchical) priors