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Biomedical subjects

S C Fowler

Publications and source records attributed to S C Fowler.

At least 73 records · Page 4Linked to original sources
PubMed1981

Deficits in contralateral and ipsilateral forepaw motor control following unilateral motor cortical ablations in rats.

Two force transducers which were interfaced with a minicomputer were used as operant manipulanda to assess changes in peak force and rate of response produced by unilateral motor cortical lesions in rats. Spatial arrangement of the manipulanda permitted a subject to respond on Transducer I exclusively with his left forepaw and on Transducer II exclusively with his right. Permanent deficits as measured by both force and rate of response were observed for the limb contralateral to the lesion. In the forelimb ipsilateral to the lesion rate of response was severely depressed immediately following the lesion and, although there was marked recovery during the 10-12 days following surgery, post-lesion rates never attained pre-lesion levels.

Animals↗
PubMed1981

Effects of alternative control procedures for electromyographic biofeedback relaxation training.

Twenty-four college students participated in a single session of electromyographic (EMG) biofeedback in a comparison of three experimental control procedures commonly employed in biofeedback relaxation training research. One group received contingent EMG biofeedback from the forehead area, and each subject in this group served as his or her own control. Subjects in a second group received noncontingent EMG feedback from a tape recorder but were instructed to use the feedback signal to relax their forehead muscles (single blind). Subjects in a third group received the same auditory feedback as those in the second group but were not told the purpose or source of the feedback stimulus (yoked control). The contingent feedback group showed significantly less EMG activity when compared to the other two groups. However, this group did not exhibit significant EMG level decrements from the beginning to end of the session. This seemingly contradictory finding may have been due to statistically capitalizing on the artifactually high EMG level of the experimental and control groups, although the single-blind and yoked-control groups showed nonsignificant increases across the session. The single-blind group's data had a variance several times larger than the other two groups' variance. Findings are discussed with respect to a "probing" hypothesis as opposed to the previously offered frustration hypothesis. Of the three control procedures, the data suggest the yoked control as the procedure of choice for EMG biofeedback relaxation research.

Adolescent↗
PubMed1981

Use of operant response duration to distinguish the effects of haloperidol from nonreward.

Prior experimentation, making exclusive use of operant response rate, has offered conflicting evidence regarding the role of reinforcement and motor effects in neuroleptic-induced changes in operant responding. In the present work, response rate and response duration were recorded for 12 rats responding under a fixed-ratio 10 schedule of food reinforcement. On six consecutive days separate groups of animals were given haloperidol or saline-with-extinction. Although both drug treatment and extinction produced elevated durations compared to pre-treatment baseline, the haloperidol group exhibited response durations that were significantly higher than those of the no-drug-extinction group. In view of these results, and since prior work has shown that response duration provides information which is nonredundant with response rate, it is suggested that response duration may be a valuable tool in future work attempting to partial out the motivational and motor effects of neuroleptics on operant responding.

Animals↗
PubMed1981

Porcine granulosa and cumulus cell properties. LH/hCG receptors, ability to secrete progesterone and ability to respond to LH.

In order to compare the properties of isolated cumulus and granulosa cells, granulosa cells and cumulus cells surrounding oocytes were harvested from small (1-2 mm), medium (3-5 mm) and large (6-12 mm) porcine antral follicles and the number of LH/hCG receptors was measured by the binding of [125I]hCG. The ability of the cells to secrete progesterone in culture was examined in the presence and absence of hCG and LH. In 3 separate experiments of 1-h incubations at 37 degrees C using cells harvested from medium-sized follicles, granulosa cells bound 10--15-fold more iodinated hCG than an equivalent number of cumulus cells. During a 2-day culture period, cumulus cells secreted less progesterone than granulosa cells from medium- and large-sized antral follicles (p less than 0.01). The potential of both cumulus and granulosa cells to secrete progesterone in culture increased as the follicle progressed from small to large size. Also, the ability of the oocyte to mature in culture increased with antral follicle size. Concurrently the ability of cumulus-oocyte complexes to form monolayers in culture decreased as the follicle matured. Cumulus and granulosa cells harvested from small- and medium-sized follicles responded similarly to LH and hCG with a stimulation in progesterone secretion after 2-6 days in culture.

Animals↗
PubMed1981

Nonretarded and mentally retarded children's performance on a manual-control task with and without visual feedback.

Performance differences between 10 nonretarded and 10 retarded persons on a manual-control task were examined. More specifically, the focus was on possible relationships between the subjects' abilities to control their response forces and the focus of their attention. The subjects, who were closely matched for MA, were required to exert force on a transducer within a selected force bandwidth for 3 seconds to obtain a reinforcer. Results suggested that the ability to discriminate internal cues is related to IQ differences.

Achievement↗
PubMed1979

Effects of clozapine and chlorpromazine upon operant response measures in rats.

Rats responded under a FR20 schedule of water reinforcement by paw-pressing a silent, isometric, force-sensing manipulandum. Two seven-animal groups differed in terms of the force requirement for reinforcer delivery, i.e., a low-force condition (4-g requirement for reinforcer delivery) or a high-force condition (32-g requirement for reinforcer delivery). Oral dose ranges of chlorpromazine (1.0, 3.0, 9.0 mg/kg) and clozapine (2.5, 5.0, 10.0 mg/kg) were evaluated for their effects on intensitive measures of response (i.e., peak force and duration), in addition to the conventional rate measure. Peak force, duration, and rate of response were recorded with a laboratory computer system. Conjoint examination of these three dependent variables revealed that clozapine, a new anti-psychotic agent which produces virtially no extrapyramidal side effects in man, affected FR responding in the same way as did chlorpromazine. More specifically, response rate and peak force declined as a function of dose for each drug. Duration of response tended to be increased at the highest dose for both clozapine and chlorpromazine, but this effect was limited primarily to the high-force condition.

Animals↗
PubMed1978

Some effects of chlordiazepoxide and d-amphetamine on response force during punished responding in rats.

Rats were reinforced with water on a continuous reinforcement schedule and were also punished with electric shock for every fifth response applied to a silent, isometric, force-sensing manipulandum. Oral doses of chlordiazepoxide (3.0, 9.0, 27.0 mg/kg) increased both conventional rate and force of punished responding. In contrast, d-amphetamine (0.8, 1.6, 3.2 mg/kg, by gavage) further decreased conventional rate and force of response, but this latter drug increased the rate of recorded responses that were lower than the 15-g force criterion for response consequences. The results for chlordiazepoxide are viewed in terms of its anxiolytic properties, while the d-amphetamine data appear to support a theory of amphetamine effects based on the concept of stereotyped behaviors.

Animals↗
PubMed1977

Drug discrimination and generalization in pigeons.

In a three-key operant conditioning situation six pigeons were trained to select the response key which was associated with each of three drug treatment conditions: d-amphetamine (2 mg/kg), pentobarbital (5 mg/kg), and saline. Thus, the drug state served as a discriminative stimulus for food reinforcement. After 20 sessions of discrimination training in each of the three conditions, more than 90% of the responses were correctly emitted in the presence of the appropriate drug or saline stimulus. Acquisition of the discrimination progressed at approximately equal rates for the three treatments. Subsequent to discrimination training, generalization gradients were obtained for several doses of the training drugs and for dose ranges of cocaine, morphine, and methocarbamol. The pigeons responded to morphine by choosing the key paired with pentobarbital during training; further, cocaine administration resulted in choice of the amphetamine key. However, metocarbamol, over the doses used, produced responding more characteristic of saline than of the other training drugs. The data suggest that a three-key operant discrimination procedure using pigeons provides a sensitive method for investigating the stimulus properties of relatively low doses of behaviorally relevant drugs.

Animals↗
PubMedDate not supplied

Identification of a target cell antigen recognized by nonspecific cytotoxic cells using an anti-idiotype monoclonal antibody.

Nonspecific cytotoxic cells (NCC) are the teleost equivalent of mammalian natural killer (NK) cells. In the present study an anti-idiotypic monoclonal antibody (mAb 7D12) was generated against idiotopes on an mAb (mAb 6D3.2) that recognizes a putative receptor on NCC. The idiotypic specificity of mAb 7D12 was determined in competition assays by incubating biotinylated mAb 7D12 with mAb 6D3.2 hybridoma cells following preincubation with combinations of biotinylated 7D12 with either nonbiotinylated homologous or heterologous mAb. The ligand recognized by mAb 7D12 (determined by flow cytometry) was found on cells from the anterior kidney, spleen, thymus, PBL, liver, and brain. NCC lysis of IM-9 targets was inhibited 76% following preincubation of the target cells with different concentrations of mAb 7D12. The involvement of the ligand recognized by mAb 7D12 in the NCC lytic cycle was determined by showing that this mAb produced 50% inhibition of NCC conjugate formation with NC-37 target cells. Biochemical analysis using SDS-PAGE and Western blotting revealed that mAb 7D12 recognized 54 and 65 M(r) proteins in IM-9 target cell lysates. These studies demonstrated that an idiotope on a NCC specific anti-receptor mAb was an "internal image" of a target cell ligand. The anti-id mAb generated against this image (idiotope) inhibited NCC cytotoxicity and thus was equivalent to an NCC receptor that binds to a target cell ligand involved in NCC recognition.

Animals↗