Watch what I do, not what I say I do: Computer-based avatars to assess behavioral inhibition, a vulnerability factor for anxiety disorders.

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.

Acquired equivalence in U.S. veterans with symptoms of posttraumatic stress: reexperiencing symptoms are associated with greater generalization.

The severity and number of reexperiencing symptoms (e.g., flashbacks) show considerable variability across individuals with posttraumatic stress disorder (PTSD). 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 test was used to assess associative learning and generalization in 114 U.S. veterans who were also given a test of declarative memory. PTSD symptoms were rated by the veteran. After adjusting for demographic variables, psychoactive medication use, and initial learning, regression analyses showed that the number of PTSD reexperiencing symptoms significantly improved the model for generalization (ß = -.23, R(2) = .34) 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.

Medial septum-diagonal band of Broca (MSDB) GABAergic regulation of hippocampal acetylcholine efflux is dependent on cognitive demands.

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.