Is high hypnotizability a trouble in balance control?

Hypnotizability is a cognitive trait measured by standard scales and associated with peculiar physiological responses to cognitive and physical stimulations. Hypnotizability-related differences can also be observed in non-hypnotic state and in the absence of specific suggestions. In the normal bipedal stance subjects with high hypnotizability (Highs) exhibit a higher tolerance of alteration of the visual and leg/neck proprioceptive input with respect to low hypnotizable individuals (Lows). Aim of the study was to investigate whether this characteristic represents a disadvantage during highly demanding postural tasks. Sixteen Highs and 16 Lows of both genders participated in an experimental session consisting of maintaining balance while standing with open or closed eyes on a seesaw platform allowing roll movements. The results did not show significant differences between Highs and Lows in inclination area and time, with the exception of a greater ability of Highs with respect to Lows when they began the task displacing the body weight from the left to the right leg. Thus, high hypnotizability does not represent a disadvantage for balance control during highly demanding postural tasks. Together with previous studies, the present findings suggest that the Highs' postural control might shift from a very "economic", preeminently centrally driven functioning mode, characteristic of easy postural tasks, to an efficaciously periphery-controlled mode, required by difficult postural tasks.

Effect of omega-3 and policosanol supplementation on attention and reactivity in athletes.

OBJECTIVE: The purpose of this study was to determine the effect of omega-3 fatty acids and policosanol supplementation on the cognitive processes involved in the control of reactivity in karateka engaged in attention tests. METHODS: Eighteen karateka were randomly assigned to 2 groups. One group (10 subjects) took the supplement of omega-3 fatty acids (2.25 g) plus policosanol (10 mg) (O3 + P) for 21 days, and the other group was supplemented with placebo (oleic sunflower oil). Subjects were tested at the beginning of the experiment (Test 1), after 21 days (Test 2), and after 42 days (Test 3). The experimental procedure consisted of an Alert and a Sustained Attention (SA) reaction time test: the subject had to react by pressing a key of a computer keyboard in Alert and a sequence of 3 keys in SA in response to stimuli, activating a complex go/no-go paradigm. For each test, we recorded the reaction time and the event-related potentials by electroencephalogram and electromyography (EMG) of the forefinger flexor muscle. The Profile of Mood States (POMS) test was also administered. RESULTS: After 21 days of supplementation, subjects who received O3 + P showed a reduced reaction time and increased vigor sensation associated with a reduction of the negative states measured with the POMS test. Analysis of the event-related brain potentials showed a reduced latency of the movement-related brain macropotentials. In particular, the potentials recorded in the premotor period and motor period occurred earlier and the latency of EMG activation was reduced. In the third test, 21 days after the last O3 + P supplementation, the positive effects on the mood state persisted, while the reaction time, EMG, and brain potential latencies increased, although their values remained lower than in the first test. The placebo group did not show any significant differences in Tests 2 and 3 compared to Test 1 for either POMS or reactivity and brain potentials. CONCLUSIONS: Supplementation with O3 + P may be effective in improving mood state and reactivity. The reaction time reduction appears to be due to a central nervous system effect, as shown by the reduced latency of movement-related brain macropotentials and EMG activation. These results are in line with previous experiments.

Heart-rate control during pain and suggestions of analgesia without deliberate induction of hypnosis.

Heart rate and heart-rate variability (HRV) were studied through a set of different methods in high (highs) and low hypnotizable subjects (lows) not receiving any deliberate hypnotic induction in basal conditions (simple relaxation) and during nociceptive-pressor stimulation with and without suggestions of analgesia. ANOVA did not reveal any difference between highs and lows for heart rate and for the HRV indexes extracted from the series of the interbeat intervals (RR) of the ECG in the frequency (spectral analysis) and time domain (standard deviation, Poincare plot) in both basal and stimulation conditions. Factors possibly accounting for the results and likely responsible for an underestimation of group differences are discussed.

Effect of mental imagery on the development of skilled motor actions.

To test the effect of imagery in the training of skilled movements, an experiment was designed in which athletes learned a new motor action and trained themselves for a month either by overt action or by mental imagery of the action. The experiment was carried out with 30 male karateka (M age = 35 yr., SD = 8.7; M years of practice = 6, SD = 3) instructed to perform an action (Ura-Shuto-Uchi) that they had not previously learned. The athletes were divided into three groups: Untrained (10 subjects who did not perform any training), Action Trained (10 subjects who performed Ura-Shuto-Uchi training daily for 16 minutes), and Mental Imagery (10 subjects who performed mental imagery training of Ura-Shuto-Uchi daily for 16 minutes). The subjects were tested five times, once every 7 days. During each test, they performed a series of 60 motor action trials. In Tests 1, 3, and 5, they also performed a series of 60 mental imagery trials. During the trials, an electroencephalogram (EEG), electromyography (EMG), muscle strength and power, and other physiological parameters were recorded. The results differed by group. Untrained subjects did not show significant effects. In the Action Trained group, training had an effect on reactivity and movement speed, with a reduction of EMG activation and reaction times. Moreover, muscle strength, power, and work increased significantly. The Mental Imagery group showed the same effects on muscle strength, power, and work, but changes in reactivity were not observed. In the Mental Imagery group, the study of Movement Related Brain Macropotentials indicated a progressive modification of the profile of the waves from Test 1 to Test 5 during imagery, showing significant variations of the amplitude of the waves related to the premotor and motor execution periods. Results show that motor imagery can influence muscular abilities such as strength and power and can modify Movement Related Brain Macropotentials, the profile of which potentially could be used to verify the effectiveness of motor imagery training.

Attention in athletes of high and low experience engaged in different open skill sports.

In this study were examined differences in attentional style of athletes engaged in two open skill sports requiring high reactivity (karate and volleyball) in groups with high or low experience. 42 healthy men, 24 volleyball players, 12 of High Experience (first division Italian League players whose M age was 28 yr. (SD=5) and 12 of Low Experience (prejunior Italian team athletes whose M age was 19 yr. (SD= 2). and 18 karateka, 9 of High Experience (3rd and 4th dan black belt athletes whose M age was 31 yr., SD=5) and 9 of Low Experience (1st and 2nd dan black belt karateka whose M age was 32 yr., SD=5). Tests involved different types of attention: Alert, Go/No-Go, Divided Attention, and Working Memory. For each one, the reaction time (RT), variability, change in RT, and number of errors were analysed. Karateka of High Experience reacted faster than those of Low Experience on the simple RT test, Alert (M RT: 204 vs 237 msec., p< .01), while on the Divided Attention test, the High Experience subjects performed more poorly and committed more errors (M errors: 4.89 vs 1.44, p <.003). Young volleyball players of Low Experience reacted faster than colleagues of High Experience on the Alert (M RT: 187 vs 210 msec., p<.01) and Divided Attention tests (M RT: 590 vs 688 msec., p<.001) but committed more errors (Divided Attention test, M errors: 6.50 vs 3.08, p<.007). For the Divided Attention and Working Memory tests, correlations were positive among errors, RT, and RT variability but only for volleyball athletes of High Experience, suggesting they showed higher attention and stability in complex reactions than the group with Low Experience. No significant correlations were noted for either group of karateka on complex reactions. Results suggested that the attentional resources were engaged in different ways in the two groups of athletes and, in each group, there were differences between persons of High and Low Experience.

Attentional, emotional and hormonal data in subjects of different ages.

The differences in attentional style among subjects of different ages and the influence of emotionality on the attentional components were studied for a limited experimental period. Variation in the hormonal data and its relation to behavioural parameters were also evaluated. The subjects enrolled in the study were divided into four age groups (A 18-29, B 30-45, C 46-59, D 60-77 years). The attentional tests involved different types of attention: alert, go/no-go, divided attention and working memory. Emotionality was assessed on the basis of skin conductance, heart rate and frontalis muscle tone. Testosterone (T), free testosterone (fT), non-specifically bound testosterone (NST), sex hormone binding globulin (sHBG), oestradiol, cortisol and adrenocorticotrophic hormone were determined in the plasma. The data were analysed to identify endocrine and behavioural differences related to sex and age. The results showed an influence of age on reaction time (RT) and RT variability. This was particularly evident for groups C and D with respect to A in the simple (alert) and complex RT tests (go/no-go and working memory). Divided attention, with the highest RT, showed a clear distinction between group A and the other groups. The difference in frontalis electromyography (EMG) (test vs control) increased with age, while the autonomic responses (skin conductance and heart rate) did not vary. In most attentional tests, the age-related reduction of RT was associated with increased T, fT and NST and decreased cortisol.

IFN-gamma production in rabbits: behavioral and endocrine correlates.

Freely interacting male rabbits were studied to establish the effect of exogenous testosterone on interferon-gamma (IFN-gamma) production in peripheral blood mononuclear cells (PBMCs) and to evaluate if this effect is related to season, social rank, plasma corticosterone and glucocorticoid receptors (GcR) in PBMCs. Dominance behavior increases after testosterone propionate (TP) administration only in rank 1 animals, while submission behavior increases after TP only in rank 4 animals, indicating a reinforcing effect of TP on the behavior. Corticosterone and IFN-gamma production are higher and GcR binding capacity is lower in spring than in autumn, suggesting that seasonal fluctuations in the immune system may be related to the pattern of secretion of immunomodulatory hormones. In autumn, corticosterone decreases after TP treatment and increases after social interaction, while GcR binding capacity decreases after TP treatment and social interaction. IFN-gamma production decreases in spring and increases in autumn after TP treatment plus social interaction, indicating that the modulating action of testosterone is related to the current immune status. The relationship between dominance, testosterone and the immune system in spring is suggested by the finding that GcR binding capacity after TP treatment is directly related to social rank, as confirmed by the positive correlation with dominance behavior frequency. The dominance index is positively correlated with GcR binding capacity and negatively with IFN-gamma production before TP treatment, indicating that high receptor activity in immunocompetent cells and low immunoreactivity could be prerequisites for dominance behavior. The immunosuppressive effect of corticosterone and the mechanism of down-regulation on GcR are confirmed by the negative correlations with IFN-gamma production and GcR binding capacity.

Reactivity and event-related potentials in attentional tests: effect of training.

To study the effects of training on reactivity and event-related potentials a complex attentional shifting test involving reaction time was administered (Test 1) to 24 healthy, young students. After five days, 12 subjects were tested with the same procedure (Test 2) without training (Untrained Subjects) while 12 repeated the test at the fifth day after four days of training (Trained Subjects). During Tests 1 and 2, event-related potentials were recorded by electroencephalogram. The task consisted of each subject responding to a stimulus of a letter appearing in the centre of a geometric figure on the screen of a computer monitor. In the prestimulus period black points were drawn and crowded randomly into a zone of the screen. The geometric figure and the letter were shown in the centre of the crowding. There were two letters and four geometric figures randomly combined in different ways. The subject had to press different keys of the computer keyboard when specific combinations appeared. The averaged event-related potentials were characterized by a negative wave with a close relationship to selective attention before the onset of the stimulus of a geometric figure followed by letters. After the stimulus onset, a P3 complex was recorded. Trained subjects were no different from untrained subjects in Test 1, while in Test 2 they had a shorter reaction time, an earlier peak of the selective attention related wave and P3, and a higher amplitude for the P3 complex. These measures and the correlations between them can be considered an index of the training effect. Thus, these tests could be used for evaluation of the attentional style and its modification with training.

Hippocampal Electrical Activity and Behaviour in Rabbits during Adaptation to a Novel Semi-Natural Environment.

The aim of the present experiment was to show possible modifications in behaviour and hippocampal electrical activity during adaptation to a novel semi-natural environment. Rabbits with chronic implanted electrodes in the hippocampus were introduced into a large, natural, open-air enclosure. Their spontaneous behaviour was studied for 3 days. Electrical activity was recorded by telemetry, stored with behaviour on a video-tape, and then analysed. Behaviour was divided into categories and variables. The categories were: activity directed towards the environment (including exploratory movements, scanning, marking, etc.) and self-directed activities (such as eating, drinking, self-grooming, etc.). Exploratory elements were observed and classified according to a spatial and a temporal criterion. The rabbits showed a progressive adaptation to the environment with quantitative and qualitative reduction in exploration and an increment in quiet immobility and inspective activities. Three EEG patterns were recognized from autocorrelation and spectral analysis: high rhythmicity theta (HRSA) with specific relationship to voluntary movements, such as exploration and running; low rhythmicity theta (LRSA) in signalling activities or self-directed behaviour and during postural and reactive immobility; and irregular activity (IA) sometimes seen in the same immobile behaviour. The results show that some behaviours (exploration, alert and postural immobility, self-directed activity) are correlated to specific patterns of electrical activity in the hippocampus and, as exploratory behaviour decreased with time, there was a concomitant increase in EEG frequency.