Charles H.M. Beck

Deviation and Laterality of Hand Preference in Monkeys

Summary The hand preferences of 10 monkeys were recorded during the performance of 17 tasks. The tests presented varying degrees of bait confinement, required varying numbers of sequential acts and required one handed or two handed manipulation. Incentive retrieval tended to be performed with the left hand whereas acts not directly involved in the picking up of the reward tended to be performed with the right hand. Some tests reliably elicited strong deviations from chance hand preference in all animals and some elicited weak hand preferences.

Chronic desipramine alters stress-induced behaviors and regional expression of the immediate early gene, c-fos

This experiment examined the effects of acute or chronic administration of the antidepressant drug desipramine on conditioned stress-induced behaviors and regional c-fos expression in the brain. To this end, rats were exposed to three sequential daily sessions of uncontrollable foot-shock and matched, on the basis of crouching, into one of four groups. Two of these groups were exposed to saline injections twice daily and two were exposed to injections of desipramine (5 mg/kg, SC) twice per day, for 9 days. On the 10th day one of the saline groups received saline and the other received desipramine before being exposed to the shock chamber without shock. Likewise, on the 10th day one of the desipramine groups received saline and the other received desipramine before being exposed to the shock chamber without shock. Detailed behavioral analysis showed that compared to the saline-treated controls only the group treated chronically with desipramine, including on the test day, exhibited statistically significant reductions in crouching and increases in exploration during the test session. Similarly, Fos immunohistochemistry revealed that the chronic desipramine group showing positive behavioral effects was the only group in which there were significant reductions in the number of stress-induced Fos-positive neurons in five of 60 structures surveyed. These structures included the anterior cingulate cortex, anterior claustrum, central nucleus of the amygdala, dentate gyrus of the dorsal hippocampus, and paraventricular nucleus of the thalamus. To the extent that repeated exposure to uncontrollable stress is an animal model of depression, these and previous results suggest that these structures are potentially important neural targets for the antidepressant effects of desipramine.

Initial environment influences amphetamine-induced stereotypy: subsequently environment change has little effect.

Saline-treated and amphetamine-treated (7 mg/kg, ip, immediate) male rats from a Sprague-Dawley substrain were observed in two test environments designed to elicit different investigative responses in normal rats. Snout contact with the substrate was generated by placing the rat in a small enclosed cage. Absence of snout contact was induced by placement of the rat on a square elevated platform. Detailed ethological records were kept of locomotion, rearing, sitting, grooming, gnawing, and sleeping throughout the 90-min session. Amphetamine-treated rats incorporated environmentally contingent bodily postures into their forms of stereotyped behavior. The postures were characteristic of those evinced initially by the saline-treated rats in the same test environment. The control rats showed appropriate changes in their investigative behavior when the apparatus was changed at 10 and at 30 min postinjection. The amphetamine-treated rats, however, were completely unresponsive to such changes at 30 min and only partially so at 10 min postinjection. It was concluded that there is a temporal gradient of decreasing readiness to modify repetitive behavior after a single, large dose of amphetamine.

The effect of the β-carboline FG 7142 on the behaviour of male rats in a living cage: An ethological analysis of social and nonsocial behaviour

The effects of FG 7142, a β-carboline benzodiazepine receptor partial inverse agonist, on the social behavior of pair-housed rats were investigated. Four 6-min dyadic social encounters in a living cage were observed in a paradigm in which one member of a pair of rats was injected. The four injection groups (n=8) were vehicle control, and FG 7142 at 2.5, 5.0 and 10.0 mg/kg, respectively. All injections were administered 2 min before the start of the first observation trial. Compared to the effects of vehicle alone, FG 7142 decreased aggressive behaviour but did not change the level of total social interaction. Thus there were compensating increases in approaching and avoiding behaviours following the administration of FG 7142. Locomotion declined marginally and immobility increased in FG 7142-injected rats. FG 7142 decreased the incidence of self-grooming. The evidence is consistent with a relatively selective reduction in intraspecies aggression in male rats after the injection of the β-carboline inverse agonist.

Solitary and social behavior of male rats in the open-field.

The short-term effects of anxiolytic drugs have been assessed with tests of social affiliative behavior in rats. These tests must be completed in a brief time span, yet must include measures both of solitary activity and social behavior to dissociate affiliative from sedative and hypermotive drug effects. This study demonstrates that a paradigm of observation of alternating periods of solitary and social behavior of male rats yields data in accord with facts known about rats tested in separate, uninterrupted periods of solitary and social behavior. Agreement was obtained on the reliability of group and intersession behavior, on the levels of behavior, on the changes in behavior over trials and on the correlations between behaviors characteristic of rats tested separately in the two situations.

Mapping of forelimb afferents to the cuneate nuclei of the rat

Stumps of rat forelimb peripheral nerves were soaked in horseradish peroxidase solution. Impregnation of the median, ulnar, radial, and musculocutaneous nerves revealed that each nerve had definite projection zones in the cuneate nuclei. The radial nerve projected quite heavily to the lateral cuneate nucleus and to a narrow band along the dorsal edge of the main cuneate nucleus. Staining of the deep radial and superficial radial nerves showed that they projected heavily to the lateral and main cuneate respectively. The ulnar and median nerves projected primarily to medial and lateral portions of the main cuneate nucleus, ventral to the terminal field of the radial nerve. The rostral and caudal portions of the main cuneate nucleus were discriminable by cytoarchitectural characteristics and by terminal fibre orientation.

Behavioral analysis of diazepam-induced memory deficits: evidence for sedation-like effects

Rats were trained on a nonmatching-to-sample task with delays of 2, 5, and 10 min. Subsequently, performance was assessed in three groups of rats following treatment with saline or diazepam (2.0 mg/kg) administered acutely or tested chronically in six administrations. Relative to treatment with saline, diazepam produced a deficit in discrimination performance, which was greater in the acutely treated rats than in those treated chronically. The deficit was not dependent on the length of the delays. Diazepam-treated animals differed from controls in erring on trials in which they failed to investigate both test objects, failed to investigate the test object for a long enough period of time, and displaced the test object on the preferred side of the apparatus. The hypothesis that these effects represented a sedation-like reduction in behavioral variability was also supported by evidence of a diazepam-induced decrease in gross bodily activity, increase in inactivity, and increase in latencies to respond to objects. No support was found for the involvement of diazepam-induced changes in habituation, extinction, or reward effects.

Functional Implications of Changes in the Senescent Brain: A Review

The morphological, chemical, and physiological changes in the brain accompanying old age are reviewed. The deterioration of the striatal and hypothalamic dopaminergic systems were implicated in the onset of age related Parkinsonian-like slowing of performance and altered affect. Cholinergic hippocampal and neocortical systems were chemically and physiologically abnormal in the aged. The implications for slowed cognitive processing and persistance of the memory trace are presented.

Behavioral Mapping of Residents’ Activity in Five Residential Style Care Centers for Elderly Persons Diagnosed with Dementia: Small Differences in Sites Can Affect Behaviors

The principal purpose of the study was to investigate the day-long patterns of activity of residents and staff in five similar care centers for people with Alzheimers disease. The Therapeutic Environment Assessment Scale provided an architectural basis for assessing the significance of activity data gathered through behavior mapping. Slight architectural differences contributed to effects that were large and enduring, producing as much as a 50% differences between sites in the portion of residents involved. Taken together, the results suggest that resident status, use patterns, and architectural design details of a homelike residential setting have significant effects on the daily activities of residents.

The effect of apomorphine on the open-field behavior of rats: Alone and in pairs

Male rats were observed in the open-field while alone and while in pairs in an alternating series of trials. The trials extended over a 78 min session following injections of either saline (0.9%) or apomorphine (5.0 mg/kg, IP) into the observed member of each pair. Contrary to the literature on apomorphine stereotypy, apomorphine did not induce continuous sniffing of the environment and continuous gnawing in most rats. Sniffing of the environment remained at normal levels but there was an increase in nodding the head in the vertical plane while keeping the snout close to the floor. Apomorphine-induced hyperactivity was attributed to two factors: a sustained increase in the duration of bouts of locomotion and a failure of the frequency of bouts of locomotion to habituate to novelty. Apomorphine eliminated all social behavior directed toward the other rat, however apomorphine rats showed they were sensible to the presence of the other by increasing their locomotion and rearing when the partner was introduced.