Michael W. Torello

Correlations between abnormal auditory P300 topography and positive symptoms in schizophrenia: A preliminary report

P300 component amplitude in the left temporal scalp region, shown in three previous studies to differentiate normals from schizophrenics, was found to be significantly correlated with the Thought Disorder Index (TDI) and the Scale for the Assessment of Positive Symptoms (SAPS). These correlations occurred primarily in the P300 waveform derived from the Goodin paradigm. These findings suggest a brain processing disturbance in positive symptom schizophrenia that may be reflected by electrophysiological abnormalities detectable in the temporal scalp region.

The paleocerebellum and the integration of behavioral function

The role of the cerebellum in motor function is well documented. Additional data clearly implicate the cerebellum in the regulation of sensory processes and autonomic functions, and more recent findings establish an influence of cerebellar systems on the regulation of emotional and motivational behaviors. The cerebellum provides extensive projections to brainstem and limbic mechanisms that have been implicated in behavioral regulation, and experimental manipulations of the cerebellum have been found to profoundly affect behavioral processes. In the present paper, we review some of these findings and offer a conceptual view of cerebellar function that reconciles these apparently disparate actions. We suggest that the cerebellum exerts functionally similar influences at all levels of sensorimotor and behavioral organization. This model provides a conceptual framework for understanding the behavioral consequences of cerebellar dysfunctions, which we suggest can be viewed as behavioral parallels to the classical cerebellar motor syndromes. Data implicating cerebellar systems in the pathogenesis of developmental disturbances in behavioral processes are also considered in the context of the present conception of cerebellar-behavioral function.

Neuropsychological deficit in schizophrenic subtypes: Paranoid, nonparanoid, and schizoaffective subgroups

Schizophrenic patients were carefully diagnosed and screened for a history of neurological disorders. Diagnosis and subtyping was based on DSM-III-R criteria, using the Structured Clinical Interview for DSM-III-R, which was administered by trained interviewers and confirmed by a research psychiatrist. The schizophrenic patients were compared with an age-matched control group on an extensive battery of neuropsychological measures. The undifferentiated/disorganized schizophrenic patients were consistently the most impaired on a broad range of tasks. When the effect of symptom severity and drug level were statistically controlled (analysis of covariance), however, the magnitude and number of differences were substantially reduced. The perseverative error score from the Wisconsin Card Sort Test showed the greatest difference between the groups. However, the strongest and most consistent effects were observed in relation to symptom ratings. These data indicate the importance of controlling for medication and symptom severity, and suggest that current diagnostic classifications may not be the most useful factors for studies of the cognitive correlates of schizophrenia.

Evoked potentials in subjects at risk for Alzheimer's Disease

Evoked potential (EP) changes accompanying dementing processes have been documented in a number of studies. However, EPs have not been studied in subjects who are at heightened risk for the development of Alzheimers Disease (AD). Nineteen volunteers with no immediate family members with a history of AD and 33 healthy subjects with at least one first-degree relative with AD were studied. Of the 33 subjects with a positive family history of AD, the illness of the sick relative was classified as possible AD in 10 subjects, probable AD in 17 subjects, and definite (autopsy-proven) AD in 6 subjects. Mid-latency evoked potentials (P50, N100, and P200) and P300 event-related potentials were recorded in an oddball paradigm. The amplitudes of the P50 responses to the frequent stimuli and of the P300 responses were significantly higher in the subjects whose relatives had definite AD as compared with the other three groups. The amplitude of the N100 component was also larger in the same group, but the difference was only statistically significant from the group of healthy volunteers without a family history of AD. A process of increased sensitivity to incoming stimuli may be reflected in the increased P50, N100, and P300 amplitudes in the subjects at increased risk for developing AD.

An automated method for measurement of circling behavior in the mouse

Circling behavior in animals lesioned unilaterally in one striatum with 6-hydroxydopamine is widely used to test pharmacological compounds with dopaminergic activity. Although automated techniques employed to record this behavior have previously been reported, most of these methods either limit the movement of the animal or are less reliable for various reasons. This paper describes a new method which allows the free movement of the animal in addition to recording the circling behavior automatically. Furthermore, this device provides new and unique data on the diameter and total area of the circles that are circumscribed by the animal. Consequently, the present device may prove to be a better and more reliable tool to assess the pharmacological effect of drugs on the striatal dopaminergic system.

Attenuation of septal hyperemotionality by cerebellar fastigial lesions in the rat

Abstract Lesions of the cerebellar fastigial nucleus were found to greatly attenuate the hyperemotionality produced by simultaneous septal lesions in the rat. Lesions dorsal or lateral to the fastigial nucleus had no effect. This lesion-related attenuation of emotionality produced by fastigial destruction appeared quite specific. Other motivated behaviors such as food intake and activity were not affected. Further, the characteristic increase in social contacts seen after septal destruction was not altered by the fastigial lesions. The results support the view that the cerebellar fastigial nucleus is part of a complex limbic-brainstem network involved in the control of emotional and motivational behaviors.

Topographic Mapping of EEG and Evoked Potentials in Psychiatry: Delusions, Illusions, and Realities

SummaryThis paper reviews the utility of topographic mapping of EEG and evoked potentials in psychiatry. Further, a wide variety of caveats related to this technique are reviewed including cerebral and extracerebral sources of artifact. Moreover, both questionable and legitimate uses of mapping in psychiatry are addressed and possible future applications of this technique are considered. Finally, multidisciplinary approaches to the study of the brain are discussed.

An atlas of the deep cerebellar nuclei and subtentorial brainstem of the cat with compensation for skull-size

The bony tentorium in the cat precludes a stereotaxic approach, in the coronal plane, to widespread areas of the cerebellum and underlying brainstem. To facilitate the application of the stereotaxic method in these areas, an atlas of the subtentorial brainstem was prepared, with plates (30 degrees from the vertical) based on an angle of entry which avoids the tentorium. In addition, a placement error regression function, based on a measure of skull size, was derived to provide atlas coordinate corrections for different brain sizes. The application of this regression function, together with the present atlas plates, can greatly increase placement accuracy.

Supercomputer assisted brain visualization with an extended ray tracer

The process of volume rendering is computationally intensive especially when high quality imaging is required. We present an approach to realistic volume rendering which is based on a distributed system with a workstation front-end for scene composition andprevisualization, and a supercomputer serving as the primary rendering engine. We report on a new, expedient method for extending arbitrary su

Expression of magnus tonic neck reflexes in distal muscles of prehension in normal adults

ace-based ray tracers to support realistic rendering of volumes. In aadition, we describe a method for supporting ray tracing of a volume manipulated by CSG operations. Finally, an eficient, forward projection algorithm which exploits the multiprocessor, vector-arithmetic capabilities of the CRAY Y-MP supercomputer is described.