Behavioral inhibition (BI), a tendency to withdraw from or avoid novel social and non-social situations, is a personality trait which can confer risk for anxiety disorders. Like many personality traits, BI is often assessed via self-report questionnaires where respondents rate themselves for frequency of certain behaviors or feelings. However, questionnaires have inherent limitations, particularly in psychiatric populations where there may be unawareness of deficit. A viable alternative may be virtual environments, in which the participant guides an on-screen “avatar” through a series of onscreen events meant to simulate real-world situations. Here, we report on initial development of such an assessment tool, involving several onscreen scenarios with choice points where the participant can select from response options corresponding to inhibited or uninhibited behaviors. In two experiments involving over 300 college students, scores on the computer-based task were strongly correlated with BI scores attained through self-report questionnaire (r>.780, p<.001); this relationship held regardless of participant gender and experience with computer games. The results suggest that virtual environments may hold promise as alternative formats for assessment of personality traits in populations unsuited to traditional paper-and-pencil questionnaire formats due to psychopathology, limited attention span, or poor vocabulary and/or literacy skills.

The septohippocampal pathway contains cholinergic, GABAergic, and glutamatergic projections and has an established role in learning, memory, and hippocampal theta rhythm. Both GABAergic and cholinergic neurons in the medial septum-diagonal band of Broca (MSDB) have been associated with spatial memory, but the relationship between the two neuronal populations is not fully understood. The present study investigated the effect of selective GABAergic MSDB lesions on hippocampal acetylcholine (ACh) efflux and spatial memory during tasks that varied in memory demand. Male Sprague Dawley rats were given GABAergic lesions of the MSDB using GAT1-saporin (GAT1-SAP) and examined on spontaneous exploration (Experiment 1) and non-matching to position without (NMTP; Experiment 2) and with a delay (DNMTP; Experiment 3), while concurrently using in vivo microdialysis to measure hippocampal ACh efflux. Intraseptal GAT1-SAP treatment did not alter baseline or behaviorally stimulated hippocampal ACh efflux or maze exploration (Experiment 1). Moreover, GAT1-SAP did not alter evoked hippocampal ACh efflux related to NMTP nor did it impair working memory in NMTP (Experiment 2). In contrast, both ACh efflux and performance in DNMTP were impaired by intraseptal GAT1-SAP. Thus, GABAergic MSDB neurons are important for spatial working memory and modulate hippocampal ACh efflux under conditions of high memory load. The relationship between the septohippocampal cholinergic and GABAergic systems and working memory will be discussed.

Comparing different rewards automatically produces dynamic relative outcome effects on behavior. Each new outcome exposure is to an updated version evaluated relative to alternatives. Relative reward effects include incentive contrast, positive induction and variety effects. The present study utilized a novel behavioral design to examine relative reward effects on a chain of operant behavior using auditory cues. Incentive contrast is the most often examined effect and focuses on increases or decreases in behavioral performance after value upshifts (positive) or downshifts (negative) relative to another outcome. We examined the impact of comparing two reward outcomes in a repeated measures design with three sessions: a single outcome and a mixed outcome and a final single outcome session. Relative reward effects should be apparent when comparing trials for the identical outcome between the single and mixed session types. An auditory cue triggered a series of operant responses (nosepoke-leverpress-food retrieval), and we measured possible contrast effects for different reward magnitude combinations. We found positive contrast for trials with the greatest magnitude differential but positive induction or variety effects in other combinations. This behavioral task could be useful for analyzing environmental or neurobiological factors involved in reward comparisons, decision-making and choice during instrumental, goal-directed action.

The severity and number of reexperiencing symptoms (e.g. flashbacks) show considerable variability across individuals with post-traumatic stress disorder. One interpretation of reexperiencing symptoms invokes generalization: specifically, the traumatic memory may be stored in such a way that neutral stimuli that only vaguely resemble some feature of the traumatic event are sufficient to trigger the memory. If this is the case, then individuals with higher levels of reexperiencing symptoms might show greater generalization, even in contexts unrelated to trauma. In the current study, an acquired equivalence (AE) test was used to assess associative learning and generalization in 114 veterans, who were self-assessed for posttraumatic stress disorder (PTSD) symptoms and given a test of declarative memory. After controlling for demographic variables, psychoactive medication use, and initial learning, regression analyses indicated that the number of PTSD reexperiencing symptoms significantly improved the model for generalization (β = −.23) but not associative learning or declarative memory. The results support the idea that generalization is linked to reexperiencing symptoms, is not limited to learning about traumatic events, and can emerge even in a relatively innocuous computer-based learning task.