Spatial learning in the rat: impairment induced by the thiol-proteinase inhibitor, leupeptin, and an analysis of [3H]glutamate receptor binding in relation to learning

Rats were given continuous intraventricular infusion of saline or the thiol-proteinase inhibitor leupeptin, via subcutaneously implanted osmotic minipumps, while being trained on a spatial learning water task using spaced trials. Leupeptin caused overnight forgetting during training, but performance eventually reached asymptote in both groups. A retention test conducted 48 h later to assess spatial memory revealed no significant group differences, but did cause, in saline-treated rats only, a disruption of subsequent retraining back to the correct spatial location. The groups showed no differences in Cl-dependent [3H]glutamate receptor binding to hippocampal or entorhinal cortex membranes subsequent to training. In a second experiment, normal rats trained on the same task also showed no differences in Cl-dependent [3H]glutamate binding relative to rats exposed to the water task but given random spatial position training and handled controls. The results are discussed in relation to the hypothesis of Lynch and Baudry (Science (1984) 224, 1057-1063) that a calcium-dependent thiol proteinase is involved in memory formation through its ability to modify glutamate receptor distribution and dendritic spine shape.     

Opinion formation in evaluating the adjudicative competence and restorability of criminal defendants: a review of 8,000 evaluations

Evaluations of competence to stand trial (CST) are the most common type of criminal forensic evaluation conducted, and courts tend to defer to clinician opinions regarding a defendant's competence. Thus, it is important to study the ways in which clinicians arrive at opinions regarding adjudicative competence and the data they consider in forming their opinions. We reviewed 8,416 evaluations conducted by forensic evaluators in Virginia over a 12 year period, and examined (a) the clinical, demographic, and criminal characteristics of a defendant as related to opinions regarding competence, predicted restorability, and impairment on "prongs" of the Dusky standard, (b) process and outcome differences in evaluations conducted by psychiatrists versus psychologists and inpatient versus outpatient evaluators, and (c) the consistency of incompetence base rates over a 10 year period. Overall, clinicians opined that 19% of defendants were incompetent and considered 23% of these unlikely to be restored to competence. Not surprisingly, psychotic and organic/intellectual disorders were most strongly associated with findings of incompetence. However, there were some notable differences between evaluations by psychologists versus psychiatrists and between evaluations conducted in inpatient versus outpatient settings.