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Biomedical subjects

L Schweitzer

Publications and source records attributed to L Schweitzer.

65 records · Page 4Linked to original sources
PubMed1980

Cerebral lateralization: relation to subject's sex.

Patterns of reflective LEM's have been correlated to a number of cognitive and personality variables, bu the relationship to sex, education, and mental illness is unclear. In this study females produced significantly more R-LEM overall indicating a preferential use of left hemisphere mechanisms when they initiate reflective thought. Females also produced more R-LEM for verbal nonemotional material, suggesting stronger lateralization of language abilities to their left hemisphere. Emotional and spatial stimuli were less well lateralized to the right hemisphere in females, and education was an unimportant variable for both sexes. Schizophrenia was independently associated with increases in total R-LEM indicating increased left hemisphere activity in this group.

Educational Status↗
PubMed1980

Second-order conditioning of the pigeon's key-peck using an autoshaping procedure.

Second-order conditioning of the pigeon's key-peck was established using an autoshaping procedure. In the first experiment, pigeons came to peck a response key, the second-order conditioned stimulus (CS2), when it was paired with another key (CS1) that had previously been paired with food delivery. In the second experiment, pigeons again came to peck a key (CS2) when it was followed by a clicker (CS1) which had been paired with food delivery, even though the clicker itself had not evoked pecking. Responses to a second-order stimulus, therefore, need not resemble responses to the first-order CS. Furthermore, in both experiments, extinction of the first-order IS led to reduction in pecking CS2. These results were discussed in terms of the nature of the associations being formed during second-order conditioning.

Animals↗
PubMed1979

Differences of cerebral lateralization among schizophrenic and depressed patients.

Conjugate lateral eye movements (LEMs) have been used as a measure of contralateral frontal hemisphere activation when individuals carry out reflective tasks. In a previous study, schizophrenics were noted to produce significantly more R-LEMs than controls suggesting that they use the left hemisphere in general more often than controls when initiating thought. More specifically, schizophrenics initiated thought on spatial emotional material in their left hemisphere more often than normals. In an effort to replicate these findings, the present study contrasted a new sample of 13 schizophrenics first with the original schizophrenic sample, and then with 13 psychotic depressives, and the original controls. In addition, other group comparisons are reported. The data obtained replicate the original findings of increased R-LEM (i.e., increased left hemisphere activity) and the excessive processing of spatial and to a lesser extent emotional material in the left hemisphere of schizophrenics. Psychotic depressives were found to initiate reflective tasks more often in their right hemisphere than either schizophrenic or the original sample of normal controls. Significant group differences among schizophrenics, normal controls, and psychotically depressed patients were obtained. The data are consistent with emerging concepts of a left hemisphere locus of disturbance in schizophrenia and right hemisphere disturbances in affective disorders.

Adult↗
PubMed1978

Abnormalities of cerebral lateralization in schizophrenia patients.

Initial lateral eye movements (LEMs) have been shown to be associated with activation of the contralateral frontal lobes. Using LEM as a criterion measure of activation, schizophrenics were compared to normals with respect to the processing of four types of stimuli: verbal nonemotional (VNE), verbal emotional (VE), spatial nonemotional (SNE), and spatial emotional (SE). Our results indicate that schizophrenics initiate thought in their left hemisphere significantly more often than controls when one compares all test conditions and on VNE, VE, and SE material. Neither medication nor level of education had an appreciable effect on LEM in either group. However, sex was a significant variable; women irrespective of diagnosis consistently used the left hemisphere more often than men. The inappropriate initiation of thought on SE material as well as the overall increase in left hemisphere activity suggest left hemisphere disorder. This is consistent with other findings that suggest a left hemisphere locus of disturbance in schizophrenia.

Adult↗
PubMed1978

Community characteristics that affect hospitalization and rehospitalization rates in a municipal psychiatric hospital.

Age-specific rates of psychiatric admissions for Brooklyn are almost exclusively explained by socioeconomic measures. A measure of interpersonal contact explains an additional small increment of the variance. When the same age-specific rates are compared for whites and blacks, the relative importance of socioeconomic measures lessens and social and family structures emerge as significant predictors. The existence of unique ethnic-related factors as intervening variables in hospital admissions is strongly suggested by the data. A measure of interpersonal contact best predicts the percentage readmitted. In contrast the percentage admitted is strongly related to social and family structure measures.

Adolescent↗
PubMed1977

Population density and the rate of mental illness.

An examination of age specific rates of psychiatric admissions within Brooklyn, New York, indicated that population density may function as an intervening variable in the production of mental illness. Measures of household and family contact were found to be significantly correlated to four rates of hospital utilization. These same measures carried unique components that were also significantly related to service use. Other measures of density such as people per acre and structures per acre were found to be unrelated to the rates of psychiatric utilization. The results of this study suggest that if density does produce mental illness its likely mechanism of action will be routed through household contact.

Adolescent↗
PubMed1975

The role of testicular conflicts in a countertransference reaction.

A case is presented in which a patient's presenting symptoms of impotence and a pervasive inhibition of productivity are dynamically related to a cryptorchild condition which was discovered and treated during childhood. The importance of the cryptorchid condition and its relationship to the patient's later psychopathology are examined. However, it is the therapist's reaction to the clinical material that is the paricular focus of his paper. The therapist obtained the history of cryptorchism in the fifth month of treatment, and then subsequently repressed this data. In addition, a persistent countertransference reaction developed that threatened to disrupt the treatment relationship. In reviewing the course of the therapy, it was possible to determine that the therapist's repression of the patient's cryptorchism and his subsequent countertransference response were directly related to his own repressed testicular conflicts. The implications regarding the existence of similar conflicts in other therapists are discussed.

Anxiety↗
PubMedDate not supplied

Glutamate neurotoxicity in rat auditory system: cochlear nuclear complex.

In other systems such as the hypothalamus and hippocampus, it has been shown that cells postsynaptic with respect to glutamatergic inputs degenerate when exposed to large doses of glutamate ("glutamate neurotoxicity"). We have shown that large doses of glutamate administered intraperitoneally are toxic to spiral ganglion cells in the inner ear of the rat. In the present study, we have investigated whether similar levels of glutamate cause alterations in the neurons of the cochlear nuclei. Specifically, we have studied the morphology and size of the cochlear nuclear complex and its subdivisions as well as the size and density of cochlear nucleus neurons following administration of glutamate. The morphological evidence indicates that glutamate caused severe anatomical alteration of the cochlear nuclei. The changes were most pronounced in the anteroventral cochlear nucleus, especially in the neurons that receive terminals of the end bulbs of Held from the cochlear nerve. This could be a direct effect of glutamate in the cochlear nuclei or secondary to degeneration of cochlear nerve fibers in the inner ear.

Animals↗
PubMedDate not supplied

Reevaluation of things past. A test of the "retrospection hypothesis" using a CER procedure with rats.

The ability of rats to reevaluate previously presented information in light of subsequently provided information was evaluated using a CER (conditioned emotional response) procedure. In Experiment 1, rats suppressed responding to a compound light + tone stimulus that was repeatedly paired with shock. Groups of rats were then presented with only one element of the compound (the tone), either presented alone or paired with shock, for 15 days. During this 15-day period, two control groups received trials with the shock alone or neither stimulus nor shock. All of the rats were then tested with the other element of the compound (the light). Rats that had received the tone paired with shock during the intervening training continued to suppress to the light, whereas rats that had received the tone alone showed rapid extinction of the CER to light. The control groups showed that this effect was not due to the number of shock presentations received. A subsequent experiment also demonstrated that these results were not due to nonspecific stimulus effects. Apparently, a subsequent change in the associative strength of one element results in a similar change to the other element of a previously established compound stimulus.

Animals↗