Effects of intrahippocampal injections of the cholinergic neurotoxin AF64A on open-field activity and avoidance learning in the rat

The effects of direct intrahippocampal administration of the cholinergic neurotoxin, AF64A, were investigated in male rats. Bilateral injections of AF64A (5 nmole/2 microliters) produced a significant decrease in choline acetyltransferase (CAT) activity in the dorsal hippocampus (25%) and overlying frontoparietal cortex (30%) but no changes in the striatum. Rats lesioned with AF64A exhibited increased levels of open-field activity, which was most marked at 1 week after the lesion; however, the rates of intrasession habituation were similar in lesioned and control rats. Lesioned rats also displayed deficits in acquisition and retention of a passive avoidance task and less dramatic deficits in acquisition of two-way shuttle box avoidance. These findings indicate that lesioning of cholinergic terminals in the hippocampus and/or cerebral cortex with AF64A leads to long-term deficits in learning and memory as well as increases in open-field activity.     

Involvement of 5-HT1A receptors in animal tests of anxiety and depression: evidence from genetic models

Clinical studies have suggested the involvement of 5-HT1A receptors in anxiety and depressive disorders because partial 5-HT1A receptor agonists such as buspirone are therapeutic. The present review considers evidence from genetic animal models that support a role for 5-HT1A receptors in anxiety-like and depressed-like behavior in animals. Selective breeding for differential hypothermic responses to a selective 5-HT1A receptor agonist led to the development of the high DPAT sensitive (HDS) and low DPAT sensitive (LDS) lines of rats. The HDS rats differ from the LDS rats on several behavioral measures reflective of anxiety or depression, including reduced social interaction, reduced responding in a conflict task and exaggerated immobility in the forced swim test. However, they do not differ from the LDS rats in the elevated plus maze task, which is a commonly used test of anxiety. Nor do the HDS rats exhibit a typical anxiogenic response to the hippocampal administration of the 5-HT1A agonist. Although the HDS rats do exhibit elevations in 5-HT1A receptors in regions of the limbic cortex, it is not clear whether these increases account for the behavioral differences. Paradoxically, 5-HT1A receptor knockout mice also exhibit anxiety-like behavior in the plus maze, open field and conflict tests compared to wild type mice. However, the knockouts exhibited less immobility in the forced swim test than wild type control mice. Recent studies using selective regional reinstatement of the receptor have implicated the postsynaptic 5-HT1A receptors in these changes in anxiety-like behavior. Thus, preliminary evidence from two different types of genetic animal models suggests that anxiety-like behavior can arise if the 5-HT1A receptor function is eliminated or overexpressed. Further study with additional tests of anxiety are needed to confirm this intriguing relationship.     

Outcomes of Peak,Typical, and Variability in Performance of College Football Teams

Purpose

The purpose of this study was to investigate the typical, peak, and variability in performance of both the offensive and defensive units of college football teams over the course of a season in predicting three objective team-level outcomes (win percentage, fan home game attendance, and bowl game payout).

Design/Methodology/Approach

Data were obtained from an archival sports database for 193 Bowl Subdivision college football teams for three separate seasons.

Findings

When all three types of performance were considered simultaneously, only typical performance significantly predicted win percentage and bowl game payout outcomes, and it explained between 19 % (for bowl game payout) and 49 % (for record) of the variance. All interactions between typical performance and performance variability were non-significant.

Implications

These null results point to a boundary condition in the relationship between performance variability and outcomes: whether the outcome is subject to evaluator attributional processes (e.g., raises, performance evaluations) or is more objective in nature. Although null, the present results question a sometimes implicit assumption that performance inconsistency is detrimental to organizational functioning.

Originality/Value

This is one of the first studies to examine outcomes of peak performance, typical performance, and performance variability at the team level. Additionally, most studies examining the outcomes of such performance use subjective outcomes such as performance ratings, whereas this study provides one of the first examinations using objective outcomes such as bowl game payout.