A human perspective: commentary on Swerdlow et al., 'Animal models of deficient sensorimotor gating: what we know, what we think we know, and what we hope to know soon'.
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Animals↗
Biomedical subjects
V Kumari
Publications and source records attributed to V Kumari.
Individual differences in mood reactions to d-amphetamine: a test of three personality factors.
Individual differences in self-reported mood following either 5 mg or 10 mg d-amphetamine challenge were examined in order to test the modifying role of three factors of personality, viz., the Eysencks' psychoticism, Cloninger's novelty seeking, and Depue and Collins' extraversion. In a double-blind study, mood measures (energetic arousal, tense arousal, and hedonic tone) were taken immediately following a single-dose of d-amphetamine and then again after 90 min. The results showed significant psychoticism x d-amphetamine interactions for both drug doses: d-amphetamine increased energetic arousal and hedonic tone, and reduced tense arousal, only in low psychoticism individuals; in high psychoticism individuals, it led to lowered energetic arousal and hedonic tone, and increased tense arousal. Neither novelty seeking nor extraversion modified the effects of d-amphetamine. These data suggest a link between psychoticism and dopaminergic functioning, although they do not rule out the involvement of other transmitter systems (e.g. noradrenergic). In common with other studies, such findings point to the important role that well-established factors of personality play in accounting for individual differences in reactions to psychoactive drugs. It is concluded that the routine inclusion of personality measures in future psychopharmacological studies may help to refine the characterization of drug effects.
Adult↗
Smoking withdrawal, nicotine dependence and prepulse inhibition of the acoustic startle reflex.
The present study examined the relationship between nicotine dependence as measured by the Fagerstrom Tolerance Questionnaire (FTQ) and prepulse inhibition (PPI) of the acoustic startle reflex measured after overnight smoking withdrawal in a non-clinical population of male smokers with no history of psychiatric disorders or drug/alcohol abuse. It was found that smokers who scored high (>median) on the FTQ showed significantly less PPI as compared to those scoring low (<median) on this scale. This finding further supports a role for nicotine in modulation of PPI, as has previously been found in rats and also in human beings.
Acoustic Stimulation↗
Modulation of the acoustic startle reflex by emotionally-toned film-clips.
It has been widely reported that the eyeblink component of the acoustic startle reflex can be modulated by emotionally-toned slide stimuli; pleasant slides reduce eyeblink amplitudes whereas unpleasant slides enhance them. The present study examines the modulation of the acoustic startle reflex by short (2-min) film-clips classified as pleasant, unpleasant or neutral, on the basis of subjective ratings. These film-clips were also evaluated with respect to their test-retest reliability in producing affective states as well as modulating startle reflexes. Overall, results showed significant reduction of startle during pleasant clips and augmentation during unpleasant clips. However, on first showing, one of the two unpleasant clips (a medical demonstration film depicting details of toe surgery) actually inhibited the startle reflex rather than augmented it. This is discussed in terms of the proposition that only stimuli which arouse fear can be guaranteed to augment startle; stimuli that are repulsive may produce perceptual and emotional 'blunting' that reduces startle amplitude.
Acoustic Stimulation↗
Normalization of information processing deficits in schizophrenia with clozapine.
OBJECTIVE: The authors tested the hypothesis that the use of an atypical drug, clozapine, for patients with schizophrenia is related to less impairment in information processing deficits (assessed by prepulse inhibition of the startle response) than is the use of typical antipsychotics. METHOD: Two groups of schizophrenic patients--receiving either clozapine or a range of typical antipsychotics--were tested for prepulse inhibition (a reduction in response to a starting stimulus, if preceded briefly by a weak, nonstartling stimulus; measured at prepulse-to-pulse intervals of 30 msec, 60 msec, and 120 msec) of the acoustic startle response and compared with a group of healthy volunteers. RESULTS: Patients receiving typical antipsychotics showed less prepulse inhibition with 30-msec and 60-msec prepulse trials than did comparison subjects. Clozapine-treated patients showed normal levels of prepulse inhibition. CONCLUSIONS: Clozapine is superior to typical antipsychotics in normalizing prepulse inhibition, presumably because of its pharmacological effects on prefrontal regions of the brain or its effects on a broader range of neuroreceptors.
Acoustic Stimulation↗
Effects of d-amphetamine and haloperidol on latent inhibition in healthy male volunteers.
Latent inhibition (LI) refers to a retardation of learning about the consequences of a stimulus when that stimulus has been passively presented a number of times without reinforcement. Acute positive-symptom schizophrenics, normal volunteers who score high on questionnaire measures of schizotypy and non-patients or animals treated with dopamine agonists show reduced LI. Neuroleptic drugs, such as haloperidol, administered at low doses, potentiate LI and effectively reverse disruption of LI induced by dopamine agonists in animals. However, a high dose of haloperidol, administered on its own, has been found to reduce LI. We examined the effects on LI of acute oral administration of an indirect dopamine-agonist, d-amphetamine (5 mg), and a nonselective dopamine receptor antagonist, haloperidol (5 mg), in normal male volunteers, using an associative learning task. Replicating previous reports, we found that d-amphetamine reduced LI; haloperidol also reduced LI, but only in subjects who scored low on the Psychoticism scale of the Eysenck Personality Questionnaire. In a subsequent study, no effect was found of 2 mg oral haloperidol administration on LI. The effect of 5 mg haloperidol on LI is interpreted as similar to that observed with a high dose of haloperidol in rats.
Adrenergic Agents↗
Effects of single oral administrations of haloperidol and d-amphetamine on prepulse inhibition of the acoustic startle reflex in healthy male volunteers.
The effects of acute administration of an indirect dopamine-agonist, d-amphetamine, and a non-selective dopamine receptor antagonist, haloperidol, were investigated in normal male volunteers on habituation and prepulse inhibition (PPI) of the acoustic startle reflex in two experiments. In Experiment 1, 40 male non-smoker volunteers were tested for habituation and PPI (defined as percentage reduction of the pulse-alone amplitude; prepulses 9 dB above background) before and after double-blind administration of either 2 mg haloperidol or placebo. No influence of haloperidol was observed on either habituation or PPI of the startle reflex in this experiment. In Experiment 2, 60 male volunteers underwent startle testing before and after double-blind administration of a single oral dose of 5 mg haloperidol, 5 mg d-amphetamine or placebo. Habituation and PPI (prepulses 15 dB above background) for the placebo group did not differ significantly from that observed for the d-amphetamine or for the haloperidol group. However, in a subgroup of smoking subjects, both d-amphetamine and haloperidol reduced PPI as compared to that observed prior to drug administration. The implications of these findings in relation to animal pharmacological studies and observed sensorimotor gating deficits in schizophrenia are discussed.
Acoustic Stimulation↗
Heparan sulfate modifies the effects of basic fibroblast growth factor on glial reactivity.
Our previous studies have shown that injection of basic fibroblast growth factor (bFGF) into a brain wound enhances astrocyte hypertrophy and macrophage-microglia proliferation in areas adjacent to the lesion. In the present study, designed to test the effects of co-administration of bFGF and heparan sulfate (HS), rats received injections of 200 ng bFGF, 200 ng bFGF with 50 microg HS, or 50 microg HS into a brain wound. Glial proliferation and astrocyte hypertrophy were evaluated in seven non-overlapping subfields in the mid-cortex including the wound edge. Our results show that bFGF-HS, compared to bFGF or HS alone, enhanced the total area of GFAP staining in all subfields except the one nearest to the wound edge. The combination of bFGF and HS did not increase total glial or astrocyte proliferation. We propose that the observed effects resulted from a greater diffusion of bFGF-HS complex into the brain parenchyma, where it bypassed low-affinity binding sites that would otherwise sequester free bFGF. Our results suggest that bFGF-HS complex, compared to bFGF alone, may gain entry into the brain more readily, reach higher concentrations and be more effective as a neurotrophic agent.
Animals↗
Studies on aluminium leaching from cookware in tea and coffee and estimation of aluminium content in toothpaste, baking powder and paan masala.
Studies were conducted in order to assess the level of aluminium (Al) in samples of Indian tea, coffee, toothpaste, paan masala (mouth freshener) and baking powder. Leaching of Al from cookware while preparing tea and coffee was also studied. Experiments were also conducted to study the sequential leaching of Al from cookware by preparing tea and coffee in the presence of standard size Al sheets (coupons). A small amount of Al was found to have leached from coupons during preparation of tea. Tea leaves, were found to be a rich source of Al and a maximum of 2.2% Al is extracted in tea infusions. Coffee powder on the other hand was not found to be a rich source of Al. Baking powder was found to be a rich source of Al and 1 kg of cake prepared with 1-3 teaspoon of baking powder may contain 2-12.7 mg of Al in each serving (25 g). Toothpaste also contains a significant quantity of Al, more so, when packed in Al tubes. Ingestion pattern of Al from these items by humans is also discussed.
Alum Compounds↗
Effects of acute administration of d-amphetamine and haloperidol on procedural learning in man.
The effects of an indirect dopamine-agonist, d-amphetamine, and a non-selective dopamine receptor antagonist, haloperidol, were investigated in normal male volunteers using a between-subjects double-blind design in a procedural learning task, thought mainly to involve unconscious/automatic learning. The results showed: (1) d-amphetamine facilitated response speed, whereas haloperidol inhibited it, in comparison to placebo; (2) the linear increase in procedural learning corresponded with pharmacological manipulation of degree of dopaminergic activity, i.e. subjects given haloperidol showed the least, and subjects given d-amphetamine the greatest, procedural learning. The implications of these findings are discussed in relation to investigation of abnormalities of procedural learning processes in schizophrenia.
Adolescent↗
Effect of acute subcutaneous nicotine on prepulse inhibition of the acoustic startle reflex in healthy male non-smokers.
In a double-blind placebo-controlled trial, the effects of two doses (6 micrograms/kg, 12 micrograms/kg) of acute SC nicotine were investigated on prepulse inhibition (PPI) of the acoustic startle reflex in healthy non-smoker male volunteers. Each subject received three injections [placebo (saline), 6 micrograms/kg nicotine, 12 micrograms/kg nicotine] on separate occasions, 2 weeks apart. No influence of either 6 micrograms/kg or 12 micrograms/kg nicotine was observed for the amplitude and habituation of the startle response over pulse-alone stimuli, relative to the saline-treated condition. Percent of PPI (expressed as percent reduction of non-prepulse trials) was significantly greater, but PPI as measured by absolute difference scores was not significantly different, when subjects were given the 12 micrograms/kg dose of nicotine than saline. There was an increase in percent of PPI from saline through low to high doses of nicotine, but PPI observed under the low dose did not differ significantly from either the high dose or placebo. These results provide some support for previous findings showing an enhancement in PPI by cigarette smoking in overnight smoking-deprived smokers and by acutely administered nicotine in experimental animals. The findings indicate that previously observed effects of smoking on percent of PPI in smoking-deprived subjects were not attributable to the restoration of a deficit induced by smoking withdrawal, but represent a direct pharmacological action of nicotine.
Adult↗
Hindi translation of the Gray-Wilson Personality Questionnaire: a cross-cultural replication of sex differences.
The Gray-Wilson Personality Questionnaire (GWPQ) was translated into Hindi and administered to 246 male and 191 female university students. It measures six animal-learning paradigms corresponding to Gray's (1987) three-emotion systems model of personality. Sex differences previously reported from the United Kingdom and Japan were replicated: Women scored significantly higher on the Active Avoidance and Flight subscales, men on the Approach subscale. In the Indian sample, women scored higher than men on the Extinction subscale; this difference, although in the same direction, was not significant in the United Kingdom and Japan. In India, as in Japan and the United Kingdom, women were relatively punishment sensitive, and men were relatively reward sensitive. Consistent with Gray's model, scores on Fight and Flight subscales were positively correlated, as were Passive Avoidance and Extinction subscale scores; however, contrary to the model were the negative correlation between subscale scores for Approach and Active Avoidance and the positive correlation between subscale scores for Approach and Passive Avoidance, also observed previously in the United Kingdom and Japan.
Adolescent↗
Effect of clonidine on the human acoustic startle reflex.
The present study investigated in healthy human volunteers whether clonidine reduced the amplitude of the acoustic startle reflex and whether this effect, if found, was due to an accelerated rate of habituation. Subjects were presented with startle-eliciting noise-bursts after intravenous (iv) infusion of clonidine (1.5 microgram/kg) and saline on separate days. Clonidine significantly reduced the amplitude of the acoustic startle reflex (as indexed by the eyeblink component) relative to the saline treated condition. This effect was neither due to an accelerated rate of habituation of the startle reflex nor to the sedative effect of clonidine. These findings complement an earlier report (Morgan et al. 1993) that yohimbine augments the amplitude of the startle reflex in man. Taken together, the two reports indicate a new model for the clinical investigation of central alpha2 adrenoceptor function in humans.
Acoustic Stimulation↗
Effect of cigarette smoking on prepulse inhibition of the acoustic startle reflex in healthy male smokers.
The present study investigated the effects of cigarette smoking on prepulse inhibition (PPI) of the acoustic startle reflex in healthy men. Cigarette smoking in a group of overnight smoking-deprived smokers increased PPI as compared to the smoking-deprived condition. This finding is consistent with previous animal studies showing that nicotine increases PPI of the acoustic startle reflex. In addition, cigarette smoking also reduced startle amplitude during the first 6-7 min of the post-smoking session.
Acoustic Stimulation↗
Eysenck personality inventory: impulsivity/neuroticism and social desirability response set.
The Hindi version of the Eysenck Personality Inventory and the Trait scale of the Hindi version of the State-Trait Anxiety Inventory were administered to 945 female Indian students (M age = 20.4 yr., SD = 1.4) to study the personalities of those scoring low and high on the Lie scale, and the association of Lie scale scores in the intercorrelation between Impulsivity and Neuroticism under no motivation to fake good. The group with low scores on the Lie scale had lower scores on Impulsivity and higher scores on Neuroticism and Trait Anxiety than a group scoring high on the Lie scale. No association of Lie scale scores was observed with scores on Extraversion. Lie scale scores were differentially associated with scores on Impulsivity and Neuroticism. The need to consider the Lie scale in addition to other scales in studies of personality is emphasised.
Adult↗
Menstrual cycle, arousal-induction, and intelligence test performance.
Regularly menstruating students (aged 19 to 25 yr.) were tested in the morning under high and low arousal-induction conditions (with time-pressure instructions vs without time-pressure instructions) during either midcycle (n = 16 or menstruation phase (n = 16) to study the interactive effects of menstrual phases and time-pressure stress-induced arousal on intelligence test scores on Raven's Standard Progressive Matrices and Hundal's General Mental Ability Test. A crossover interactive effect of menstrual phase and stress-induced arousal was found on performance of the Hundal test, suggesting that performance of subjects who were tested during the midcycle phase (putatively High Basal Arousal) was impaired under the time-pressure instructions condition (High-induced Arousal) as compared to performance under the without time-pressure instructions condition (Low-induced Arousal), with the reverse pattern of effects being true for subjects who were tested during the menstruation phase. Scores on Hundal's test conform to the Yerkes-Dodson (1908) law which relates arousal to task performance and suggests that the menstrual cycle and performance on the intelligence test was arousal-based. No effects, however, were observed for Raven's Matrices, raising the possibility that task characteristics may mediate the relationship between arousal and performance.
Adult↗