172. Neural correlates of procedural learning: a functional MRI study

Abstract

This study examined the neural correlates of procedural learning (PL) using functional resonance magnetic imaging (fMRI). Six normal subjects and six schizophrenic patients (all males) participated as subjects. All patients were on conventional antipsychotics and served as negative controls (i.e., not expected to show PL). All subjects carried out a 5-minute task while undergoing fMRI. The task consisted of two 30-s alternating experimental conditions: Random Trials (OFF) and Pattern Trials (ON). Subjects were presented with a white target stimulus on the black screen. This target moved between four locations on the screen, which was divided into four equal quadrants by two intersecting white lines. The target movements were predictable during the Pattern Trials but were random during the Random Trials. The increase (over five blocks) in difference between the mean reaction times to Random and Pattern Trials represented the amount of PL. The number of activated pixels and degree of signal intensity change between ON and OFF conditions were inferred using the techniques developed at the Institute of Psychiatry. Normals showed significant PL (p < 0.05), but schizophrenic patients, as expected, did not. The ON condition, contrasted with the OFF condition, elicited significant activation in normals in anterior-middle cingulate gyrus (right), striatum (caudate nucleus; left), thalamus (right), insula (left), cerebellum (left), and precuneus (left) regions, but not in patients. Our findings are consistent with previous clinical and pharmacological literature in showing the involvement of striatum, cerebellum, thalamus and cingulate regions in PL.