Richard G. Burright

Presurgical rearing environment alters exploration, fluid consumption, and learning of septal lesioned and control rats

Abstract Rats were reared in either enriched, social cages or restricted individual cages from 25 days of age until they underwent septal or control surgery two months later. Rearing conditions differentially altered septal and control behavior as measured by: (1) exploration tests; (2) fluid consumption of water, saccharin, and quinine; and, (3) the learning of a spatial alternation task.

Prevalence of traumatic brain injury in psychiatric and non-psychiatric subjects.

Traumatic brain injury (TBI) and its sequelae may impact the expression and treatment of psychiatric disorders. The prevalence of TBI in psychiatric patients is unknown and investigations in the general population are limited. This study examined the prevalence of TBI with loss of consciousness in mental health setting patients (n = 231), general hospital and university staff and students (n = 534) and non-psychiatric medical clinical patients (n = 59). The Traumatic Brain Injury Questionnaire was used to assess TBI. A greater percentage of psychiatric patients reported TBI than medical patients or staff and students. Traumatic brain injuries were typically mild--moderate, medical assistance was frequently sought and use of alcohol and drugs was reported in a minority of TBI incidents. Multiple injuries were most common in psychiatric patients. The percentage of medical patients and staff and students reporting TBI was similar to previous research. The greater percentage of psychiatric patients reporting TBI indicates the need to assess TBI in this population. The role of TBI in the emergence, expression and treatment outcome of psychiatric disorders and the risk factors that leave psychiatric patients vulnerable to TBI should be further examined.

Experiential effects on acquisition and reversal of discrimination tasks by albino rats with septal lesions

Abstract Two experiments investigated the effect of septal lesions in rats on the repeated reversals of a simultaneous brightness discrimination task. In the first experiment, rats underwent surgery subsequent to acquiring a brightness discrimination, but prior to receiving three reversals of the same task. In the second experiment, rats learned the brightness discrimination postoperatively, were given four subsequent reversals on that problem, and then acquired a spatial discrimination followed by four reversals in a T-maze. In both experiments, rats with septal lesions exhibited increased perseverative tendencies on the reversal of the brightness discrimination but by the third reversal, lesioned animals performed comparably to control rats. Despite prior acquisition and reversal training on a brightness discrimination, performance of rats with septal lesions was inferior to that of controls on the spatial discrimination. Nonetheless both groups exhibited experiential effects. The results are discussed in terms of the importance of prior experience with the discriminanda and the response measure utilized.

Habenular lesions, water consumption, and palatability of fluids, in the rat

Abstract Using a single bottle technique, habenular lesions did not originally increase water consumption, but did decrease quinine intake re normal rats. Water intake following quinine availability increased more in the group with lesions. In contrast to septal lesions, habenular lesions did not increase saccharine intake.

Facilitation of passive, avoidance acquisition in rats with septal lesions

The effects of septal lesions were investigated on a passive-avoidance type of task where quinine, rather than electric shock, was the aversive stimulus. Contrary to typical results with shock, rats with gross septal lesions were superior to controls in inhibiting their approach to, and consumption of, quinine. The results indicate the presence of at least two dissociable effects associated with septal lesions, one mediating response perseveration and the other more dominant one mediating quinine rejection.

The septal region and behavior: An example of the importance of genetic and experiential factors in determining effects of brain damage

Abstract Recent findings suggest that the effects of specific brain damage may be greatly altered by the presurgical environment of the organism as well as the genetic constitution of the individual. The present review of the effects of septal lesions on behavior emphasizes those factors which have been shown to alter and sometimes even eliminate, classical effects of damage to the septal region. It is proposed that the consequences of septal lesions on behavior are a function of pre- and post-surgical history, genetic substrate, the environmental conditions present at the time of testing, and anatomical locus of the lesion. The broader implication of these findings for understanding the impact of brain damage on behavior is considered.

Behavioral changes in mice following lead administration during several stages of development

How lead ingestion during different developmental periods influences activity of mice was investigated. Binghamton Heterogenous Stock (HET) mice were assigned to one of four groups defined by a 2 X 2 factorial in which the only available drinking fluid was either lead (L) or water (C) from the time of mating to birth or from birth to the end of the experiment. Thus, a control group (CC) received water throughout, whereas the other three groups received a 0.5% lead acetate solution at the time they were mated (LC) or when pups were discovered (group CL), or throughout the experiment (group LL). The effects of these exposure regimes on activity were assessed in an open field or a running wheel when the mice were 25 days of age and then again when they were 55 days old. Aspects of agonistic behavior were also examined in these animals. Mice that received lead only following birth (CL group) appeared most affected in the open field and in running wheels. But, both the direction and degree of this effect were influenced by the specific test situation and measures as well as by the age of the mouse when tested. For example, the CL group crossed the most squares in the open field at both ages. However, the CL group was less active during their first day in the running wheels when 25 days old, but not when 55 days old. In general, activity of the LC group was least affected by administration of lead, but the effects of continued exposure to this toxic substance (LL group) were not simply additive. In contrast to measures of activity, agonistic testing at 60 days of age showed that all groups that had been or were being exposed to lead (CL, LC, LL) displayed a shorter latency to fight when compared to the control group (CC).

Bodyweight and Food and Water Consumption in Septal Lesioned and Operated Control Rats

Food and water consumption were measured daily for 10 wk. in both light (60 day) and heavy (90 day) septal and control rats. Septal lesions increased water consumption and both the water/bodyweight and food/bodyweight measures but decreased the food/water ratio. These effects persisted in both heavy and light groups although lesion-control differences remained most marked in light animals. Despite these results, the rate at which weight was gained was similar for both lesioned and control rats. Finally, light Ss, regardless of surgical group, consumed more food/bodyweight and water/bodyweight than heavy rats.

The progression of behavioral and pathological effects of the parasite Toxocara canis in the mouse

Toxocara canis, the parasitic roundworm of the dog may infect aberrant hosts including mice and humans. The present study examined the behavioral and pathological changes at each of three postintubation periods (Period 1: 8-10 days, 2: 49-51 days, and 3: 84-86 days postintubation, respectively) in independent groups of mice intubated with 1000 eggs of T. canis. Eight-ten days after intubation Toxocara infected animals typically showed depressed levels of activity relative to saline-intubated controls. The scope and severity of behavioral changes were attenuated when different mice were tested 49-51 days after infection, and then became more severe when the third set of animals was tested 84-86 days after intubation. While brain pathology increased over the three periods, visceral organs showed marked pathology 8-10 days after intubation followed by a decrease in severity. These data suggest that Toxocara associated pathological changes in visceral organs and in the brain have behavioral consequences in mice. Given the similarity in migratory pathways of this parasite in rodents and humans, and the findings of T. canis larvae in human brain tissue, the results of this animal study may have implications concerning the possible etiology of behavioral disorders for children who have a known history of pica for dirt.

Environmental enrichment and restriction: Effects on reactivity, exploration and maze learning in mice with septal lesions

Abstract Following weaning, male, Heterogeneous mice were maintained either in socially/environmentally enriched conditions or in restricted conditions. Behavioral testing began when the mice were 60 days of age. The day after an initial handling-reactivity test, the mice were given either septal lesions or control surgery, and returned to their respective housing conditions. Following surgery, the mice underwent a successive battery of behavioral tests, consisting of the following: (1) handling reactivity; (2) open field exploration, as affected by the stress of a water swim; and, (3) performance on a water-maze spatial discrimination task. Restricted mice were more reactive than enriched mice before surgery, but with daily postsurgical handling, the reactivity of the restricted control group approached that of their enriched counter-parts. Also, there were no differences between enriched and restricted controls on acquisition or reversal of the spatial discrimination, or in exploration of a novel open field. The two intact groups did differ, however, in their open field behavior following the stress of a water swim. In contrast to the behavior of the control animals, the environmental housing conditions altered the behavior of the mice with septal lesions on each of the tests. The restricted mice with lesions were extremely reactive to handling, and displayed spatial reversal deficits; the enriched mice with lesions were much less reactive than the restricted septals, and showed no maze learning deficits. The open field tests, especially those following the water swim, revealed surgery by housing interactions as well, though not necessarily consistent with a “normalizing” effect of environmental enrichment for mice with septal lesions. The task-specific nature of this continuously maintained environmental manipulation, and the relative value of environmental stimulation in alleviating effects of septal damage are considered.