“
“Long-term memory can be based on general familiarity or detailed recollection. Although familiarity is thought to be a continuous/graded process, the nature of recollection is currently under debate. In the present functional MRI spatial source memory study, we evaluated the pattern of activity in the hippocampus to assess whether this region operates in a threshold/all-or-none or

a learn more continuous manner during recollection. During the study phase, abstract shapes were presented to the left or right of fixation. During the test phase, old and new shapes were presented at fixation, and participants classified each shape as old-left, old-right, or new, followed by a sure-unsure confidence rating. Accurate spatial memory for old-left shapes produced a single activation in the left hippocampus. The corresponding event-related activation profile revealed a threshold above which old-left-sure responses produced positive activity for old-left but not old-right Rigosertib molecular weight shapes. This hippocampal activation profile was used to generate a source memory receiver operating characteristic that was adequately fit by a threshold model of recollection but was not adequately fit by a continuous model of recollection. By contrast, there was no evidence of a threshold in the behavioral response profile, which is consistent with previous behavioral source memory receiver operating

characteristic results indicating that recollection is a continuous process. The present results indicate that the hippocampus can operate in a threshold manner during spatial source

memory and further suggest that this discrete signal is transformed into a continuous process through the operation of other brain regions that also contribute to behavioral performance. NeuroReport 24:265-269 (C) 2013 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.”
“Background. Individuals with schizophrenia and individuals with high-functioning autism (HFA) seem to share some social, behavioral and biological features. Although marked impairments in social cognition have been documented in both groups, little empirical work has compared the social cognitive functioning of these two clinical groups.

Method. Forty-four individuals with schizophrenia, 36 with HFA and 41 non-clinical controls completed a battery of social cognitive either measures that have been linked previously to specific brain regions.

Results. The results indicate that the individuals with schizophrenia and HFA were both impaired on a variety of social cognitive tasks relative to the non-clinical controls, but did not differ from one another. When individuals with schizophrenia were divided into negative symptom and paranoid subgroups, exploratory analyses revealed that individuals with HFA may be more similar, in terms of the pattern of social cognition impairments, to the negative symptom group than to the paranoia group.

Conclusions.