Influence of lateral posture on sweating: does posture alter the sympathetic outflow to the sweat glands?

Our unpublished observation that a lateral decubitus posture influences the pattern of sweating was systematically tested by measuring galvanic skin resistance (GSR). Changes in the GSR between two electrodes placed on skin was used to quantify the degree of sweating. In the lateral posture, sweating is inhibited on the lower half and stimulated on the upper half and reversal of the lateral posture induces sweating on the opposite half of the body. This observation suggests that the autonomic nervous system is controlled at least in part, by body posture.

A comparative study of the driving effects of dextroamphetamine and yogic meditation on muscle control for the performance of balance on balance board.

The work is aimed to compare the relative strength of dextroamphetamine and yogic meditation on the performance of 3 different groups of medical students to concentrate on the task to balance on a balance board. Group A subjects were mediators, group B subjects were given orally 5 and 10 mg of dextroamphetamine in a capsule, 1 hr prior to the test. Group C subjects were given same capsule but with lactose in place of the drug (placebo). This last groups served as control for the study. The balance index calculated taking into account their balance time and error score at each trial of 5 min duration showed that the performance of the group B (drug) had declined with overall percentile fall of 40.6% as compared to the performance of the controls (placebo) whereas, the performance of Group A (meditators) went on steadily and progressively increasing throughout the period of 10 trial days with overall percentile rise of 27.8%. The results were conclusive to confirm earlier reports that amphetamine is not of use for improvement of task rather, it deteriorates the task performance. Contrary to that, yogic meditation is of merit to achieve concentration for mental as well as physical task.

Effects of medial septal stimulation & its blockade with atropine on hippocampal rhythmical slow activity in free-moving rabbits.

The influence of the medial septal nucleus (MSN) on hippocampal rhythmical slow activity (RSA) was investigated in hunger motivated free-moving rabbits. Single unit activity of 29 CA3 dorsal hippocampal neurones was studied under two paradigms viz., electrical stimulation (3v/1msec/5Hz) and chemical blockade of atropine-sensitive medial septal cells (dose of 5 micrograms in 5 microliters). The analysis of interspike interval sample histograms recorded with Apple II, along with single unit neuronal spikes recorded on polygraph showed bimodal pattern with two peaks; one at bin 10-20 (high frequency) and second at bin 100-300 (theta frequency). On stimulation of MSN, there was total suppression of bin 100-300 with peaks at bin 1-20 and at bin greater than 1000 (very low frequency). Blockade of cholinergic receptors at MSN showed reduction of bin 100-300 and peak at bin 700- greater than 1000; this was followed by gradual decrease of spike's amplitude and thereafter its total abolition. The results indicate that the septal region is not a pacemaker per se in the genesis of hippocampal RSA (theta rhythm), but serves more in the nature of a relay station for a number of inputs and that its influence on the hippocampal electrical activity depends on the integrity of cholinergic inputs, be it from hippocampus proper or from mid-brain reticular formation.

Quantitative evaluation of muscle relaxation induced by Kundalini yoga with the help of EMG integrator.

The present work is aimed to quantify the degree of relaxation of muscle under the effects of Kundalini Yoga with the help of EMG integrator. The data collected from 8 individuals (4 males 4 females) on the degree of muscle relaxation at the end of meditation revealed a significantly decreased muscle activity amounting to 58% of the basal level in both the sexes.

Effect of dorsal hippocampal lesion compared to dorsal hippocampal blockade by atropine on reference memory in vision deprived rats.

In order to study the primacy of the hippocampus in place learning function 24 male adult albino rats were hippocampally-lesioned in dorsal hippocampus involving fornical damage (group I); sham operated for comparison with group I (group II); cannulated for instillation of atropine sulphate in the same loci as group I (group III); and cannulated for instillation of saline which served as control for group III (group IV). All the animals were enucleated and their reference memory (long-term memory) was tested, using open 4-arm radial maze. There was loss of reference memory in groups I and III. However, hippocampally-lesioned animals, showed recovery of reference memory deficit within a short period of 10 days or so. Whereas atropinized animals showed persistent reference memory deficit as long as the instillation effect continued. The mechanism involved in the recovery of reference memory in hippocampally-lesioned animals and persistent deficit of reference memory in atropinized animals has been postulated to explain the primacy of hippocampus in the place learning function under normal conditions.

Four-arm radial open maze (FAROM) as a tool for assessing the effect of atropine in spatial memory of the rats.

Place learning behaviour for working (short term) memory and reference (long term) memory is studied with the Four-arm radial open maze (FAROM) in 18 rats divided equally in three groups. In group I, 0.5 mg of atropine was injected intra-peritoneally 30 minutes before the trial. In group II, saline and in group III Glycopyrrolate were injected instead. Twenty three hours hungry animals were tested on each day in the maze to search for food kept in one of the eight cul-de-sacs of maze. The latency i.e. the time to reach the goal cul-de-sacs, as well as the error score i.e. the number of entries in the non-goal cul-de-sacs were counted during six consecutive trials, per day. Each trial duration was 5 minutes or the time taken by the animal to search the goal compartment whichever was less. The inter-trials period was 10 min and the work was carried out for a period of 3 weeks. The results show that atropine does block effectively both the memory faculties i.e. working and reference memory and that level of memory deficit induced by atropine is related to the rate of drug uptake by the central cholinergic receptors.

Study of photic versus non-photic cues as entrainers of circadian running activity in rats.

Though relative dominance of photic/non-photic cues on rodent circadian running activity is known, the exclusive role of non-photic entrainers in rats deprived of photic entrainers is not demonstrated and hence present work using retino-hypothalamic pathway blocked male rats (n = 10) was initiated. Blocking is done by enucleation of eyeballs. Circadian running activity is studied before enucleation and after enucleation towards instinctual social cues, food, water and sexual cues provided in activity cage. Twenty four hour activity of rats was recorded kymographically for a fifteen day period before enucleation and for a similar period after enucleation. Analysis of the records revealed that eight animals had predominant diurnal rhythm whereas two animals had predominant nocturnal rhythm. Enucleation of diurnal rats neither altered total running activity pattern nor caused any significant change in the goal compartments thus showing absence of entrainment by photic cues. In contrast nocturnal rats showed gradual shift of activity towards day time on enucleation thus indicating that nocturnal animals were entrained by photic cues. The overriding influence of non-photic entrainers on photic entrainers is discussed.

Measure of motivational drive for hoarding in laboratory rats.

The drive for hoarding food pellets was studied in adult female rats kept on restricted food schedule, by using varying current strength applied through the metal grid. It was observed that the rats maintained higher hoarding score at proestrus and lowest at diestrus at all strengths of currents used in the experiment indicating stronger drive at proestrus.

Significance of spatial and temporal dysfunction exhibited by enhanced running activity in hippocampally-lesioned rats.

The present work is designed to study the role of Hippocampus in the control of circadian running activity of rats subject to discrete lesions in ventral hippocampus and having free access to the cues namely food, water, male rat and female rat provided in maze-cum-activity cage indigenously prepared for recording open field behavioral activities. The study was done with 8 male adult albino rats. Those in which lesion was confirmed to be located in antero-ventral hippocampus, exhibited marked increase in running activity with disruption of running activity pattern. There was increase of drive towards socio-sexual cues which were non-rewarding under the present experimental set up. The animals in which lesion was located in posteroventral hippocampal areas showed slight increase in the activity but without disruption of circadian running activity nor was there any significant change in the drive. The functional dissociation observed in present study is believed to be due to involvement of fimbrial/fornical system in the lesion process and therefore responsible for disruption of circadian running activity as well as increase of the running activity in hippocampally-lesioned animals. The present work emphasises the importance of Hippocampus-septum-hippocampus feedback loop in controlling relative time, functioning as internal "stop watch" thus providing a temporal reference and detecting phase relation during activity. Interruption of this loop in hippocampally-lesioned rat probably leads to failure to inhibit inappropriate responses and failure to discriminate rewarding and non-rewarding cues.

Maze-cum-activity cage with automatic recording system for evaluation of circadian incentive drives in rats.

Maze-cum-activity cage is devised in order to record the activity shift patterns of incentive drive of rats. The main features of this instrument are its low cost, simplicity or recording system and evaluation of time shift patterns of the activity when animal is moving for preferential cues such as food, water socio-sexual environment provided in the cage during a 24 hour period.