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Biomedical subjects

M Weinrich

Publications and source records attributed to M Weinrich.

51 records · Page 3Linked to original sources
PubMed1985

Decrement of somatosensory evoked potentials during repetitive stimulation.

In normal subjects, cerebral potentials were evoked by brief, passive extension of the wrist joint at various interstimulus intervals (ISIs). The resulting somatosensory evoked potentials (SEPs) were found to decrease during repetitive stimulation. The greatest decrement occurred between the first and second responses of each series. After cessation of stimuli, the SEP amplitude returned to control values over a prolonged, exponential time course. The authors postulate that the observed response decrement may be a form of habituation, which provides a model for studying the neuronal substrates of behavior.

Adult↗
PubMed1985

Gating of somatosensory perception following movement.

Tactile stimuli were applied to the right index finger at selected times following rapid movements of the thumb. The probability of detecting a stimulus was found to be impaired for at least 250 ms after completion of a voluntary movement. This finding complements previous work showing that somatosensory evoked potentials are reduced for a comparable period following movement.

Adolescent↗
PubMed1984

A neurophysiological study of the premotor cortex in the rhesus monkey.

The frontal agranular cortex consists of at least three major subdivisions: the precentral motor cortex, the supplementary motor cortex, and the premotor cortex. Of these, the premotor cortex is by far the least intensively studied by neurophysiological methods in spite of recent evidence that it is important in higher order aspects of the cerebral control of movement ( Moll and Kuypers , 1977; Roland et al., 1980b ; Halsband and Passingham , 1982). We have accordingly studied neuronal activity in the premotor cortex of Rhesus macaques operantly conditioned to perform a visually guided motor task. We have concluded that many premotor cortex neurons appear to reflect motor set. Further, these and other premotor cortex neurons show activity patterns during and before the execution of an abstractly guided movement that are strikingly similar to what has been observed in association with movements made directly to visuospatial targets. Finally, a functional relationship of some premotor cortex unit activity to the execution of voluntary movement is supported by its close temporal correlation with the onset of movement, a significant correlation with the acceleration of the limb in some cases, and a uniform specificity for movement execution rather than the visuospatial cues that guide the movement.

Animals↗
PubMed1984

Cerebral evoked potentials and somatosensory perception.

In normal subjects, somatosensory evoked potentials (SEPs) were produced by increases or decreases of the load on the biceps muscle during voluntary contraction. The stimuli lasted only 20 msec and caused less than 2 degrees of elbow flexion or extension. When the stimulus was applied during voluntary movement of the elbow, the SEP was attenuated, and the subject was less able to discriminate between loading and unloading pulses. In each of eight subjects, there was a positive correlation between the percentage of correct responses and the size of the SEP. The measurement of both SEPs and perceptual accuracy under various test conditions provides a refined technique for studying the relations between electrical events and sensory processes.

Adult↗
PubMed1983

Motor aspects of cue-related neuronal activity in premotor cortex of the rhesus monkey.

Neurons in the premotor cortex of rhesus monkeys were studied under two conditions: (1) visuospatial cues were given to guide the amplitude, direction, and onset time of forearm movements or (2) physically identical visual cues were given when reward was contingent on withholding movement. Neurons with sustained activity following the cues were preferentially active when the cues triggered a movement. Thus, activity of certain neurons in this cortical field is linked to motor set, i.e. intention to make a movement in response to the cue, rather than the visual cue per se.

Animals↗
PubMed1983

Anaemia in Asians in London.

Many Asian subjects were seen in London in the early 1970s with megaloblastic anaemia; in a majority of cases, this was dietary in origin. Pernicious anaemia occurs in Asians, but the incidence is probably lower than in Caucasians. Megaloblastic anaemia is now less common in this group, but a population survey in Punjabi females in the late 1970's showed anaemia in 32%, and one or more features of iron deficiency in 76%.

Adolescent↗
PubMed1982

The premotor cortex of the monkey.

The relationship of single unit activity to limb movements guided by visuospatial cues supports the view that the premotor cortex is a distinct cortical field within the somatic sensorimotor cortex. The premotor cortex is similar to the precentral motor cortex (MI) in that most of its units are clearly related to voluntary movements but differs from MI by its higher threshold for microstimulation-evoked movements, its cytoarchitecture, and the presence of a larger population of neurons with activity related to the occurrence of visuospatial signals rather than, or in addition to, the movement cued by those signals.

Animals↗
PubMed1978

Mitogen responsiveness and suppressor cell function in multiple sclerosis. Influence of age and disease activity.

Mitogen responsiveness and suppressor cell function were determined in patients with multiple sclerosis. Mitogen response to concanavalin A, expressed as stimulation index, decreased with age in both patients and controls. Although responses in the overall group of young patients did not differ from controls, the stimulation index was reduced in clinically inactive patients. Patients with recent flare-ups showed responses comparable to controls. Suppressor cell activity increased with age in both disease and control groups. Among young patients, suppressor activity was borderline low in inactive patients but increased significantly in those with recent exacerbations.

Adolescent↗
PubMedDate not supplied

Program evaluation of a sex education curriculum for women with mental retardation.

The effectiveness of a sexual education and health promotion program for 252 women with mental retardation was analyzed using an evaluation model. We used confirmatory factor analysis (LISREL) to explain the pathways of learning and related the number of instructional contacts with the outcomes. Three factors (hygiene, social interaction, and sexual experience) affected sexual knowledge directly. An increase in sexual knowledge was directly associated with a greater number of instructional contacts. The analysis indicates that our program is effective and adds to our understanding of factors contributing to sexual knowledge for adults with mental retardation.

Adult↗
PubMedDate not supplied

Recruitment of African Americans into prostate cancer screening.

PURPOSE: Both incidence and mortality rates for prostate cancer are significantly higher in African American men than in white men. This report identifies community sites for the optimal recruitment of African American men into prostate cancer screening. DESCRIPTION OF STUDY: A descriptive study was conducted, providing an educational program to 1369 African American men, 1264 of whom completed a survey on demographic data, prostate cancer knowledge, and prostate cancer screening history. The programs were offered at six different types of community sites, including various work sites, churches, housing projects, National Association for Advancement of Colored Persons (NAACP) sites, barber shops, and a state fairground. Free prostate cancer screening was offered to all participants. RESULTS: The advertised mass screening site (state fairground), the most common method used nationally to recruit African American men for cancer screening, was the least effective site, with only 16 men completing the survey. Of the 1264 men completing the survey at all community sites, 597 men (47%) did so at work sites and 438 (35%) did so at churches. Per site, the largest percentage of men who had never been screened was at work sites (n = 276, 46%) and NAACP sites (n = 22, 33.8%). The highest percentage of men who obtained free screening were at the state fairground (14 of 16), churches (256 of 438), and work sites (336 of 597). The most prostate cancers were detected at the housing projects, where 3 of 38 (7.9%) men who were screened received diagnoses of prostate cancer. CLINICAL IMPLICATIONS: To reduce prostate mortality rates in African American men, healthcare providers need to make a concerted effort to increase prostate cancer education and screening in this population. To be effective, recruitment of African American men must move from a provider/health site orientation to a consumer/community orientation. These findings indicate that recruitment strategies are more successful if efforts are based in the community or where a large number of African American men live and/or work. Because a history of screening has been shown to be a predictor for current participation, programs need to target men who have not had previous screening ever or within the last year. In addition, the large percentage of men recruited at work sites who had not been screened previously indicates an opportunity for collaboration with healthcare professionals in employee health programs. Efforts to increase participation in prostate cancer screening will be enhanced significantly by eliciting the active involvement of community leaders.

Adult↗
PubMedDate not supplied

Self-efficacy in normal adolescents.

This descriptive study, one component of the Carolina Adolescent Health Project (CAHP), measured self-efficacy in a voluntary sample of 432 normal freshmen and sophomore urban high school students. Using Coppel's Self-Efficacy Scale (SES), which is based on Bandura's conceptualization of self-efficacy, the research also examined the effect of gender, race, socioeconomic status, and self-reported religiosity on self-efficacy. The teenagers in this sample had a moderately high degree of self-efficacy with a mean SES score of 45.37 (SES range = 13-65). A series of t tests and one-way and two-way analyses of variance indicated no significant difference in SES scores by race, gender, socioeconomic status, or religiosity. Findings did not support the investigators' original expectation that these demographic and psychosocial variables would affect self-efficacy. The study provides normative data for future comparative studies using the SES.

Adolescent↗
PubMedDate not supplied

At the interface: convergence of neural regeneration and neural prostheses for restoration of function.

The rapid pace of recent advances in development and application of electrical stimulation of the nervous system and in neural regeneration has created opportunities to combine these two approaches to restoration of function. This paper relates the discussion on this topic from a workshop at the International Functional Electrical Stimulation Society. The goals of this workshop were to discuss the current state of interaction between the fields of neural regeneration and neural prostheses and to identify potential areas of future research that would have the greatest impact on achieving the common goal of restoring function after neurological damage. Identified areas include enhancement of axonal regeneration with applied electric fields, development of hybrid neural interfaces combining synthetic silicon and biologically derived elements, and investigation of the role of patterned neural activity in regulating various neuronal processes and neurorehabilitation. Increased communication and cooperation between the two communities and recognition by each field that the other has something to contribute to their efforts are needed to take advantage of these opportunities. In addition, creative grants combining the two approaches and more flexible funding mechanisms to support the convergence of their perspectives are necessary to achieve common objectives.

Axons↗