Sibling recognition in thirteen-lined ground squirrels: effects of genetic relatedness, rearing association, and olfaction

I investigated sibling-sibling recognition in captive thirteen-lined ground squirrels ( Spermophilus tridecemlineatus ) by cross-fostering lab-born pups shortly after birth. When young reached about 45 days of age, I observed dyadic interactions in a test arena of pairs from four relatedness X rearing groups, and recorded the frequency of “exploratory” encounters between individuals. Sibs-reared together and nonsibs-reared together exhibited significantly fewer exploratory encounters than either sibs-reared apart or nonsibsreared apart. Young reared together were equally exploratory, regadless of relatedness; similarly, young reared apart, whether they were sibs or nonsibs, showed similar levels of exploration. Thus, the differential treatment of siblings in the lab appears to be based on rearing association and not genetic relatedness per se. I interpret this recognition based on association (rearing familiarity) in the context of the species' social organization and compare my results on S. tridecemlineatus with similar studies on S. beldingi, S. parryii , and S. richardsonii . I also used an olfactory impairment technique (zinc sulfate) and found that differential treatment in thirteen-lined ground squirrels was influenced by olfactory cues.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46871/1/265_2004_Article_BF00299622.pd

The effect of different high-pass filter settings on peak latencies in the event-related potentials of schizophrenics, patients with Parkinson's disease and controls.

Eighteen schizophrenic patients, 16 patients with idiopathic Parkinson's disease, and the same numbers of age, sex and education matched controls were examined with oddball experiments for the generation of P3. Individual averages were high-pass filtered at different cut-off frequencies with single-pole digital filters with equivalent analogue Butterworth filter profiles. The purpose of this procedure was to simulate analogue high-pass filters used in clinical studies from different centres and to examine their potential effect on group differences. Increasing high-pass filters resulted in a phase lead for all peaks examined (N1, P2, N2, P3). The only group differences were found for P3, which showed a greater phase lead in controls than in the patient groups, usually resulting in a more pronounced group difference. Similar wave forms and filter properties could be modelled by synthetic wave forms consisting of sine waves of different frequencies

P300 and smooth eye pursuit: concordance of abnormalities and relation to clinical features in DSM-III schizophrenia.

Twenty-five DSM-III-diagnosed schizophrenics and 37 normal and age-matched controls were examined using an oddball paradigm for the generation of P300 and smooth eye-pursuit tasks. Results were compared between groups and related to clinical characteristics, including a family history of psychiatric illness. Group differences were found for P300 amplitudes, latencies and eye-tracking. A family history of psychiatric illness was associated with normal eye-tracking in patients. Small P300 amplitudes alone and in combination with long P300 latencies were associated with a family history in controls

Event related potentials, reaction time, and cognitive performance in idiopathic Parkinson's disease.

Sixteen non-demented patients with idiopathic Parkinson's disease (PD) with varying degrees of cognitive impairment and sixteen age-, sex- and education-matched normal controls were examined with (1) an auditory oddball paradigm requiring counting or a motor response in separate determinations, (2) a reaction time task with movement time component and (3) a detailed clinical and neuropsychological test battery. Patients were impaired on a number of neuropsychological tests. They also showed an increased P2 and N2 latency, but no significant increase in P3 latency. Their response initiation times and reaction times during the oddball experiment were not different from controls, whereas movement time was significantly increased. Increased peak latencies, particularly for N2, were moderately associated with Parkinsonian motor impairment in patients and with the Benton Multiple Choice Visual Retention Test in patients and controls. Movement time was associated with P3 latency only in controls and in both groups with the Benton Multiple Choice Visual Retention Test. The observed pattern of results suggests that in non-demented PD patients ERP peak latencies, visuo-spatial task performance and Parkinsonian motor impairment share a significant degree of variance. While impairments in neuropsychological tests and delay in the earlier peaks P2 and N2 do not appear to be sensitive to medication with L-DOPA, normal P3 latencies might indicate good pharmacological symptom control in the absence of dementia