The sensitivity of human event-related potentials and reaction time to mobile phone emitted electromagnetic fields

There is some evidence to suggest that exposure to mobile phones (MPs) can affect neural activity, particularly in response to auditory stimuli. The current investigation (n = 120) aimed to test recent findings in this area, namely that N100 amplitude and latency would decrease, and that P300 latency and reaction time (RT) would increase under active relative to sham exposure during an auditory task. Visual measures were also explored. A double blind, counterbalanced, crossover design was employed where subjects attended two sessions 1 week apart. In both sessions participants (1) performed auditory and visual oddball tasks while electroencephalogram (EEG) was recorded with a MP set to sham exposure mounted over the temporal region, and (2) performed the same tasks while the handset was set to active/sham. When active, the MP transmitted for 30 min at 895 MHz (average power 250 mW, pulse modulated at 217 Hz, average SAR 0.11 W/kg). Paired t-tests compared difference scores from the sham/sham session to those from the sham/active condition. The study was designed to detect differences of 1\4 of a standard deviation with a power of 0.80. There was no significant difference between exposure conditions for any auditory or visual event related potential (ERP) component or RT. As previous positive findings were not replicated, it was concluded that there is currently no evidence that acute MP exposure affects these indices of brain activity.

The relationship between performance on the standardised field sobriety tests, driving performance and the level of Δ9-tetrahydrocannabinol (THC) in blood

The consumption of Delta9-tetrahydrocannabinol (THC) as cannabis has been shown to result in impaired and culpable driving. Testing drivers for the presence of THC in blood is problematic as THC and its metabolites may remain in the blood for several days following its consumption, even though the drug may no longer have an influence on driving performance. In the present study, the aim was to assess whether performance on the standardised field sobriety tests (SFSTs) provides a sensitive measure of impaired driving behaviour following the consumption of THC. In a repeated measures design, 40 participants consumed cigarettes that contained either 0% THC (placebo), 1.74% THC (low dose) or 2.93% THC (high dose). For each condition, after smoking a cigarette, participants performed the SFSTs on three occasions (5, 55 and 105 min after the smoking procedure had been completed) as well as a simulated driving test on two occasions (30 and 80 min after the smoking procedure had been completed). The results revealed that driving performance was not significantly impaired 30 min after the consumption of THC but was significantly impaired 80 min after the consumption of THC in both the low and high dose conditions. The percentage of participants whose driving performance was correctly classified as either impaired or not impaired based on the SFSTs ranged between 65.8 and 76.3%, across the two THC conditions. The results suggest that performance on the SFSTs provides a moderate predictor of driving impairment following the consumption of THC and as such, the SFSTs may provide an appropriate screening tool for authorities that wish to assess the driving capabilities of individuals suspected of being under the influence of a drug other than alcohol.

An evaluation of the sensitivity of the Standardised Field Sobriety Tests (SFSTs) to detect impairment due to marijuana intoxication

The Standardised Field Sobriety Tests (SFST) were developed to test for alcohol intoxication but are currently being used by the State Police of Victoria (Australia) to test for driving impairment associated with drugs other than alcohol. The aim of the present study was to assess whether the SFSTs provide a sensitive measure of impairment following the consumption of a drug other than alcohol: delta-9-tetrahydrocannabinol (THC or cannabis). In a repeated-measures design, 40 participants consumed cigarettes that contained either 0% THC (placebo), 1.74% THC (low dose) or 2.93% THC (high dose). For each condition, after smoking a cigarette, participants performed the SFSTs on three occasions: 5 min (Time 1), 55 min (Time 2) and 105 min (Time 3) after the smoking procedure had been completed. The results revealed that there was a positive relationship between the dose of THC administered and the number of participants classified as impaired based on the SFSTs. Results also revealed that the percentage of participants classified as impaired decreased from Time 1 to Time 3 and that the addition of a new sign, head movements or jerks (HMJ), increased the percentage of participants classified as impaired in both the low and high THC conditions. These findings suggest that impaired performance on the SFSTs is positively related to the dose of THC administered and that the inclusion of HMJ as a scored sign in the SFSTs improves their predictive validity when testing for THC intoxication.

The effects of dexamphetamine on simulated driving performance

RATIONALE

The number of road fatalities related to the presence of amphetamines in drivers has been relatively constant over the past 10 years. However, there remains uncertainty as to the extent that these drugs induce driving impairment, and whether any such impairments translate to an increase in road fatalities.

OBJECTIVES

To examine the acute effects of 0.42 mg/kg dexamphetamine on simulated driving performance, and to establish which, if any, simulated driving abilities become impaired following dexamphetamine administration.

METHODS

A repeated-measures, counter-balanced, double-blind, placebo-controlled design was employed. Twenty healthy volunteers completed two treatment conditions-0.42 mg/kg dexamphetamine and placebo. Performance was assessed using a driving simulator task. Blood and saliva samples were obtained prior to the driving tasks and immediately after task completion (120 min and 170 min post-drug administration, respectively).

RESULTS

Mean dexamphetamine blood concentrations were 83 ng/ml and 98 ng/ml at 120 min and 170 min, respectively. Results indicated a decrease in overall simulated driving ability following dexamphetamine administration during the day-time but not the night-time scenario tasks. Contributing to this performance reduction, "incorrect signalling", "failing to stop at a red traffic light" and "slow reaction times" were the behaviours most strongly affected by dexamphetamine.

CONCLUSIONS

The decrease in simulated driving ability observed during the day-time driving tasks are consistent with the perceptual narrowing or tunnel vision that is associated with dexamphetamine consumption.

Chronic MDMA (ecstasy) use, cognition and mood

RATIONALE

It has been suggested that 3,4-methylenedioxymethamphetamine (MDMA or ecstasy) causes damage to the serotonergic system, and that this damage results in cognitive and mood impairments.

OBJECTIVES

To examine the effect of chronic MDMA usage on a wide battery of cognitive tests and psychological abilities and processes.

METHODS

In the present study, the performance of 17 participants with a history of MDMA use was compared to the performance of 15 control subjects on a battery of neuropsychological tests. This battery included tests for depression, immediate word recall, delayed recall, attention and working memory.

RESULTS

Results indicated that the MDMA group had significantly higher scores for depression than the control group, and displayed poorer delayed recall and verbal learning than controls after accounting statistically for the effects of cannabis and depression.

CONCLUSIONS

These results suggest that MDMA users exhibit difficulties in coding information into long-term memory, display impaired verbal learning, are more easily distracted, and are less efficient at focusing attention on complex tasks.

Assessing inhibitory control: a revised approach to the stop signal task

The stop signal task (stop task) is designed to assess inhibitory control and is a frequently used research tool in clinical disorders such as ADHD and schizophrenia. Previous methods of setting stop signal delay and of assessing inhibitory control are problematic. The current study reports two modifications that improve the task as a measure of inhibitory control. The first modification was to set stop signal delays proportional to go mean reaction time (go MRT) to better account for inter-subject variability in go MRT. Twenty-eight normal children were tested, and all standard, stop task dependent measures were obtained when delays were set by this method. The second modification was to calculate a novel dependent measure called the area of inhibition (AOI) which provides a more complete measure of inhibitory control than the slope of the relative finishing time z-scores (ZRFT-slope). Implications for the assessment of inhibitory control in clinical populations are discussed.

Test-retest reliability of the emotional stroop task: examining the paradox of measurement change

The Emotional Stroop (ES) task (I. H. Gotlib & C. D. McCann, 1984) has been proposed as an experimental measure to assess the processing of emotion or the bias in attention of emotion-laden information. However, study results have not been consistent. To further examine its reliability for empirical research, the authors of this study administered the ES task to 33 participants on 2 separate occasions separated by 1 week. Results indicated that retest reliabilities for reaction times (RTs) derived from the 3 separate emotion conditions (manic, neutral, and depressive) across the 1 week interval were very high. However, consistent with previous research, the reliabilities were very low for the interference indices (manic and depressive). These low reliabilities reflect the very high intercorrelation between the RTs derived from the 3 conditions. The authors concluded that a better indicator of the reliability for this task is the individual RTs from each emotion condition.

The effects of transdermal nicotine on inspection time

RATIONALE

The acute administration of nicotine via a cigarette has been demonstrated to enhance inspection time (IT), a measure of rapid visual information processing, while the nicotinic antagonist mecamylamine impairs IT. However, as transdermal nicotine patches provide a slow delivery of nicotine, it is unclear if they produce similar effects to nicotine administered by more rapid methods.

OBJECTIVES

To examine the effects of transdermal nicotine on inspection time.

METHODS

Ten moderate smokers were administered nicotine (21 mg/day) or placebo via a transdermal patch in a randomized, double-blind, repeated measures design. Subjects were administered the IT task at baseline, then 1, 3, and 6 h subsequent to patch application.

RESULTS

The change in IT from baseline was significantly different in the nicotine condition, relative to placebo, at 3 h but not 1 or 6 h.

CONCLUSIONS

The findings suggest that nicotine administered via transdermal patches improves IT, but this improvement may be subject to tolerance. Data from previous studies on tolerance to the cognitive effects of nicotine have been inconclusive. However, the slow delivery of nicotine from patches may be more likely to produce such effects.

Evidence of an early information processing speed deficit in unipolar major depression

BACKGROUND

Slowing of the speed of information processing has been reported in geriatric depression, but it is not clear if the impairment is present in younger patients, if motor retardation is responsible, or if antidepressant medications play a role.

METHOD

Twenty unmedicated unipolar depressed inpatients were compared with 19 medicated depressed in-patients and 20 age-, sex- and verbal IQ-matched controls on inspection time (IT), a measure of speed of information processing that does not require a speeded motor response. We also examined the relationship between IT and current mood and length of depressive illness.

RESULTS

Unmedicated depressed patients showed slowing of information processing speed when compared to both medicated depressed patients and controls. The latter two groups were not significantly different from each other. Slowing of IT was not associated with current mood, but was negatively correlated with length of illness since first episode. No differences in IT were found between patients receiving medication with anticholinergic effects and patients receiving medication with no anticholinergic effects.

CONCLUSIONS

The findings indicate that unipolar depression is associated with a slowing of speed of information processing in younger patients who have not received antidepressant medication. This does not appear to be a result of motor slowing.

Deficits in emotional intelligence underlying adolescent sex offending

The present study investigated whether a battery of tests designed to measure different levels of emotional intelligence could differentiate adolescent sex offenders from a non-offender control group. Fifteen male adolescent sex offenders ranging in age from 14 to 17 years were recruited through Health and Community Services (VIC, Australia) and 49 non-offender males, matched for age, completed the battery. The battery comprised the Trait Meta-Mood Scale (TMMS), Davis' Interpersonal Reactivity Index (IRI), the Inventory of Interpersonal Problems (IIP-32), the Revised Toronto Alexithymia Scale (TAS-20) and the Openness to Feelings facet of the NEO PI-R. Discriminant analyses using all five tests showed that 89.9 per cent of the sample were correctly allocated their respective groups. Overall the sex offenders were higher on aggression and attention to feelings, less clear about their feelings and less capable to repair unpleasant moods and prolong positive ones. It was concluded that these findings could be the focus of treatment approaches for adolescent sex offenders.

Inspection time: a neuropsychophysiological test for measuring the functional integrity of the cholinergic system

Inspection time (IT) is a measure of the speed of early information processing, demonstrating reliable correlation with psychometric intelligence. We now provide evidence that it may serve as a marker for the integrity of the cholinergic system. Cholinergic agonists improve and antagonists impair IT, while modulators of the monoamine systems are without effect. Furthermore impairments in IT correlate with disease severity in Alzheimer's disease, a disorder of compromised cholinergic system function. Taken together, available data suggest that IT may be a useful physiological marker of functional status of the cholinergic system.

A preliminary investigation on the acute pharmacodynamic effects of hypericum on cognitive and psychomotor performance

Research has indicated that the herb St John's Wort (Hypericum perforatum) has comparable efficacy to conventional antidepressants in the treatment of depression. Although clinical studies have demonstrated that hypericum has a superior side-effect profile compared to standard antidepressants, no study has directly compared the cognitive and psychomotor effects of hypericum with those of other antidepressants. The aim of the current study was to examine the acute effects of hypericum on cognitive and psychomotor function, and to compare its effects with those of amitriptyline. Thirteen healthy volunteers received an acute dose of placebo, amitriptyline (25 mg, positive control) or hypericum (900 mg or 1800 mg) in a double-blind, placebo-controlled design. Cognitive and psychomotor tests and subjective measures of sedation were administered before and 1, 2 and 4 hours after drug administration. Amitriptyline impaired performance on a battery of psychological tests, which included critical flicker fusion (CFF), choice reaction time (CRT), digit symbol substitution test (DSST), profile of mood states (POMS) and the line analogue rating scale (LARS), while hypericum had neutral effects on performance in these tests. However, hypericum induced a dose-related impairment on DSST. Current findings suggest that clinical doses of hypericum do not impair attention, sensorimotor function or information processing.

The chronic effects of an extract of Bacopa monniera (Brahmi) on cognitive function in healthy human subjects

RATIONALE

Extracts of Bacopa monniera have been reported to exert cognitive enhancing effects in animals. However, the effects on human cognition are inconclusive.

OBJECTIVE

The current study examined the chronic effects of an extract of B. monniera (Keenmind) on cognitive function in healthy human subjects.

METHODS

The study was a double-blind placebo-controlled independent-group design in which subjects were randomly allocated to one of two treatment conditions, B. monniera (300 mg) or placebo. Neuropsychological testing was conducted pre-(baseline) and at 5 and 12 weeks post drug administration.

RESULTS

B. monniera significantly improved speed of visual information processing measured by the IT task, learning rate and memory consolidation measured by the AVLT (P<0.05), and state anxiety (P<0.001) compared to placebo, with maximal effects evident after 12 weeks.

CONCLUSIONS

These findings suggest that B. monniera may improve higher order cognitive processes that are critically dependent on the input of information from our environment such as learning and memory.

Neuropsychological sequelae of 50 Hz magnetic fields

PURPOSE

The effects of occupational levels of 50 Hz magnetic fields on cognitive function were studied on 30 human volunteers.

MATERIALS AND METHODS

The exposure system consisted of Merrit-type modified Helmholtz coils forming a 2 m cube, employing two orthogonal sets of coils producing a 28 microT (resultant) circularly polarized 50 Hz magnetic field. Subjects sat at a desk within the coils where they undertook a series of verbal and written tests of cognitive function. After these tests were concluded (approximately 30 min) subjects were either exposed or sham-exposed to fields (double-blinded) for 50 min. A second set of tests (employing alternate versions) was administered 20 min from the start of this period. Each subject returned after 7 days to repeat the sequence, but with the opposite field/sham status.

RESULTS AND CONCLUSIONS

The majority of the results indicated no significant effect of exposure on cognition. However, verbal recall of a list of 15 words after an interference (the different list) was significantly impaired in the 'field on' condition. This is indicative of a reduction in short-term memory of words. The mean baseline score was somewhat higher in the 'field on' condition. However, this difference is within the parameters of normal variation. The other significant result occurred during performance of a trail-making task (alternating 1-A-2-B-3-C, etc.), with a decrease in performance as a result of exposure to the 50 Hz field. This task requires executive functioning with a working memory load, involving parietal spatial processing coordinated by prefrontal executive processing. In summary, the data are suggestive of detrimental effects on cognitive processes, particularly short-term learning and executive functioning. However, larger sample sizes are required to demonstrate statistically a more specific pattern of cognitive effects.

Cholinergic modulation of speed of early information processing: the effect of donepezil on inspection time

RATIONALE

Selective cholinergic receptor agonists and antagonists have been shown to modulate inspection time, a measure of speed of early information processing.

OBJECTIVE

The present study aimed to examine the effects of globally increasing cholinergic function with the acetylcholinesterase inhibitor donepezil on inspection time.

METHODS

Fourteen healthy subjects participated in a randomised double-blind, placebo controlled trial in which all subjects were tested under either acute placebo or donepezil (5 mg) treatment conditions. Testing was conducted pre- and 90 min post-drug administration.

RESULTS

There was a significant decrease in inspection time in the donepezil condition compared to the placebo condition (F = 12.86; P < 0.01).

DISCUSSION

The decrease or improvement of inspection time following donepezil administration is consistent with the role of the cholinergic system in modulating speed of information processing, and adds evidence that inspection time may serve as a physiological index of the integrity of the cholinergic system.

An investigation into the acute nootropic effects of Hypericum perforatum L. (St. John's Wort) in healthy human volunteers

Hypericum perforatum L. (St. John's Wort) is a complex herb that has been used for centuries for its putative medicinal properties, and has current therapeutic relevance as a treatment of mild to moderate depression. Recently, two studies in rodents have suggested that hypericum may also have memory-enhancing effects. It has a complex pharmacology, in that acute administration modulates numerous neurotransmitter systems that have previously been observed to either augment or impair a variety of memory processes in humans. This study aimed to examine whether acute administration of standardized hypericum extract could exert a nootropic effect in normal human subjects. The study employed a double-blind, crossover, repeated-measures design. Twelve healthy young subjects completed the Cognitive Drug Research (CDR) memory battery, following administration of placebo, 900 mg and 1800 mg hypericum (Blackmore's Hyperiforte). The findings suggested that hypericum does not have an acute nootropic effect in healthy humans at these doses. However, there was some evidence for an impairing effect on accuracy of numeric working memory and delayed picture recognition at the higher dose. This observed impairment could be due to a sensitivity of these specific tasks to modulation by neurotransmitters that have been noted to have memory-impairing effects (e.g. y-aminobutyric acid (GABA), serotonin).

The acute effects of an extract of Bacopa monniera (Brahmi) on cognitive function in healthy normal subjects

The Ayurvedic medicine Bacopa monniera (Brahmi) has been shown to exert cognitive enhancing effects in animals. The current study examined the acute effects of an extract of Bacopa monniera on cognitive function in normal healthy human subjects. The study was a double-blind, placebo-controlled independent group design in which subjects were randomly allocated to one of two treatment conditions, Bacopa monniera (300 mg) (n = 18) or placebo (n = 20). Neuropsychological testing was conducted before and 2 h after drug administration. No significant changes were found on any of the tests. The findings suggest that Bacopa monniera, at least for the dose administered, has no acute effects on cognitive functioning in normal healthy subjects. Copyright 2001 John Wiley & Sons, Ltd.

Neuropsychological changes after 30-day Ginkgo biloba administration in healthy participants

Ginkgo biloba extract (EGb) from the world's oldest living tree has been reputed to ameliorate cognitive decline in the elderly and slow cognitive deterioration in patients with dementia of the Alzheimer's type. EGb remains as one of the most popular plant extracts to alleviate symptoms associated with a range of cognitive disorders such as Alzheimer's disease, vascular dementia and age-related amnesic conditions. EGb is known to contain a range of chemically active components that have antagonistic effects on platelet-activating factor, free-radical scavenging activity and direct effects on the cholinergic neurotransmitter system. Recently there has been much speculation, that EGb may act as a 'smart drug' or nootropic agent in the healthy young to improve intelligence. We conducted a 30-d randomized, double-blind, placebo-controlled clinical trial in which 61 participants were administered a battery of validated neuropsychological tests before and after treatment. Statistical analysis indicated significant improvements in speed of information processing working memory and executive processing attributable to the EGb.

Psychophysiological correlates of the NEO PI-R openness, agreeableness and conscientiousness: preliminary results

Eysenck (1983) has previously proposed biological mechanisms for his three personality dimensions. From a psychometric perspective there has been a growing acceptance of a five-factor model of personality incorporating two of Eysenck's dimensions Extraversion (E) and Neuroticism (N) together with Openness to Experience (O), Agreeableness (A) and Conscientiousness (C). Despite the growing acceptance of the 'Big 5' model of personality there has been very few studies that have examined the biological basis of O, A and C. In an exploratory study we report the correlations between photic driving at alpha, beta-1, beta-2, delta and theta bands and O, A and C from the NEO PI-R in 16 participants. Significant correlations between the EEG at frontal, occipital-parietal and central-temporal areas at different driving frequencies with O, A and C are discussed.

Evaluation of cognitive performance in the heat by functional brain imaging and psychometric testing

Military operations in tropical environments have imposed a significant challenge to the Australian Defence Forces (ADF). The hot and humid conditions are known to cause debilitating effects on soldiers deployed to northern regions of Australia, with the consequence that the effectiveness and efficiency of operations are severely compromised. While the adverse effects of thermal stress on soldiers' physiological capability are well established, this has not been confirmed for cognitive performance. A select range of psychometric tests were administered and functional brain electrical activity imaging was performed to investigate the impact of thermal stress on cognitive performance. The brain electrical activity of subjects was measured while undertaking a range of cognitive tasks. Steady State Probe Topography (SSPT), a novel brain imaging technology, was employed to monitor the changes in regional brain activity and neural processing speed of subjects under thermal stress. The psychometric test batteries included the following tasks; Rey Auditory Verbal Learning Test; Inspection Time; Digit Span test; a spatial working memory task; and the AX-continuous performance task. These tasks measure a range of cognitive processes including attention, memory, verbal learning, information processing and concentration. The functional brain imaging provided topographical information, which showed changes in electrical activity in response to thermal stress during cognitive performance. These changes in brain electrical activity and neural speed induced by thermal stress may help to identify the type of cognitive functions that are likely to be impaired under operational conditions. Results indicated that subjects experienced increasing cardiovascular strain through thermally neutral to thermally straining conditions. The results from the psychometric test battery showed some promising effects given the small sample size including deficits in working memory, in information retention and in information processing. There was also marked differences in the electrical responses of the brain when subjects were thermally strained. The Steady-State Visual Evoked Potential recordings showed an increase in amplitude and a decrease in latency, suggesting an increase in the utilisation of neural resources or effort by subjects to maintain the same level of performance as under thermally neutral conditions. The data are suggestive of the high sensitivity of brain imaging techniques with high temporal resolution to identify important decrements in cognitive performance in hostile environments.

Serotonin, noradrenaline and cognitive function: a preliminary investigation of the acute pharmacodynamic effects of a serotonin versus a serotonin and noradrenaline reuptake inhibitor

Comparisons of the behavioural side-effect profiles of antidepressants that inhibit either serotonin or both serotonin and noradrenaline reuptake, may reveal differences in cognitive and psychomotor functions, which may be attributed to their relative pharmacological selectivity for potentiating monoamine neurotransmission in the central nervous system. The aim of the present study was to determine the acute pharmacodynamic effects of citalopram and venlafaxine, on cognitive and psychomotor performance. Nine healthy male volunteers received a single clinical dose of citalopram, venlafaxine or amitriptyline (positive control) in a double-blind placebo-controlled design. Cognitive and psychomotor tests and a subjective measure of sedation were examined before and 1, 2 and 4 hours after drug administration. Citalopram improved psychomotor responses to sensory stimuli and sustained attention, with significant decreases in movement times of the choice reaction time test and an increase in critical flicker fusion threshold. Venlafaxine did not affect performances on any of the cognitive or psychomotor tests examined. Differences may be related to relative potencies of the compounds for monoamine reuptake inhibition.

The effects of nicotine on the 13 Hz steady-state visually evoked potential

OBJECTIVES

The high alpha/low beta range of the spontaneous EEG appears to be particularly sensitive to the effects of nicotine. The present study examined the acute effects of nicotine on the topography of the 13 Hz steady-state visually evoked potential (SSVEP).

METHODS

Thirteen moderate smokers participated in a repeated-measures design. The amplitude and latency of the SSVEP elicited by an unstructured sinusoidal 13 Hz flicker following a <0. 05 mg nicotine cigarette were compared to those following a 0.8 mg nicotine cigarette.

RESULTS

The nicotine condition was associated with an increase in the amplitude of the SSVEP, when compared to the placebo condition, and this increase was greatest in central and right parietal regions. The latency of the SSVEP was reduced in the nicotine condition in bilateral frontal and right parietal regions.

CONCLUSIONS

These results are similar to the effects of nicotine seen in studies examining spontaneous EEG, and are consistent with other studies indicating that the 13 Hz SSVEP indexes brain electrical activity in the high alpha/low beta range. The findings are discussed in terms of possible functional significance of nicotine-induced cortical activation in this frequency range.

Effects of the nicotinic antagonist mecamylamine on inspection time

RATIONALE

Several lines of evidence suggest that nicotinic acetylcholine receptors (nAchRs) are involved in speed of information processing, and inspection time appears to be particularly sensitive to nicotinic manipulation.

OBJECTIVE

The present study sought to examine the effects of the nAchR antagonist mecamylamine on inspection time. Furthermore, the extent to which the anticholinesterase donepezil would reverse the effects of mecamylamine on inspection time was also examined.

METHODS

A double-blind, repeated measures design was employed. Subjects (n = 6) received placebo, mecamylamine (20 mg PO) or mecamylamine (20 mg PO) and donepezil (5 mg PO). Inspection time and physiological measures were then assessed.

RESULTS

The mecamylamine condition and the mecamylamine and donepezil condition were associated with an increase in heart rate, when compared to the placebo condition. There was a significant slowing of inspection time in the mecamylamine condition; compared to placebo, which was partly reversed by donepezil.

CONCLUSIONS

The slowing of inspection time following mecamylamine is consistent with the role of nAchRs in speed of information processing, and add to the evidence that IT may in part index nAchR system integrity.