Effects of olfactory bulb ablation and androgen on marking and agonistic behavior in male Mongolian gerbils (Meriones unguiculatus).

Male Mongolian gerbils, selected for high marking frequency, were paired with male opponents, and marking and fighting behavior were recorded. Animals then underwent castration, bilateral bulbectomy, unilateral bulbectomy, the combined operations, or a sham operation; and their behavior was again observed. All operated animals showed drastic reduction in both marking and aggressive encounters. Injections of testosterone propionate (TP) produced complete restoration of marking in castrates, but not in bilaterally or unilaterally bulbectomized animals or combined operates. The exhibition of aggression after injections of TP, however, was enhanced to supernormal levels in bulbectomized or bulbectomized-castrated animals. The results suggest the following: that removal of the olfactory bulbs may eliminate a critical neural input necessary for the normal expression of marking and agonistic; that although marking and fighting are influences by olfactory input and gonadal steroids, their regulatory mechanisms may not be identical; and that removal of the bulbs may sensitize a neural mechanism controlling aggression, thus potentiating its elicitation following administration of exogenous androgen.     

A comparison of administration procedures for the Rey-Osterrieth Complex Figure: flowcharts versus pen switching

The Rey-Osterrieth Complex Figure (ROCF) is commonly used to assess visuospatial skills, visuoconstruction, visual memory, and executive functioning. Two different methods are traditionally used to record the order in which the figure is drawn: the flowchart method and the pen-switching method. Although it has been suggested that pen switching may interfere with performance, to date no research has been conducted to assess whether ROCF performance significantly differs due to administration method. As part of routine neuropsychological evaluation, 100 inpatients and outpatients were randomly assigned to either method. Using the Boston Qualitative Scoring System and the traditional 36-point scoring method, the authors unexpectedly found that the pen-switching group generally performed better than the flowchart group, and productions drawn with pen switching were also significantly faster to score.     

Issues associated with repeated neuropsychological assessments

Distinguishing practice effects from other factors in repeated neuropsychological assessments are discussed in the context of research studies and clinical/forensic assessments. Potential methodological procedures for reducing the impact of practice effects in research settings are outlined. In contrast, the potential clinical utility and interpretation of practice effects in clinical assessments and forensic evaluations are highlighted.     

Neuropsychological Functioning in Chronic Lyme Disease

Lyme disease is currently the most common vector-borne illness in the United States. The disease is multisystemic, and chronic disease, in particular, may be associated with neuropsychological deficits. However, to date, only a few empirical studies exist, which examine the neuropsychological sequelae associated with chronic Lyme disease. A review of the literature shows that the deficits observed in adults with chronic Lyme disease are generally consistent with the deficits that can be seen in processes with primarily frontal systems involvement. These observations are generally consistent with neuroradiologic findings. The clinical presentation in chronic Lyme disease and the nature of the neuropsychological deficits are discussed, as are several central issues in understanding neuropsychological functioning in chronic Lyme disease, such as the impact of chronic illness, response to treatment, and the relationship between neuropsychological performance and depression, fatigue, and neurological indicators of disease.