Giuliano Fontani

Cognitive and physiological effects of Omega-3 polyunsaturated fatty acid supplementation in healthy subjects

Background  It has been reported that Omega‐3 fatty acids may play a role in nervous system activity and that they improve cognitive development and reference memory‐related learning, increase neuroplasticity of nerve membranes, contribute to synaptogenesis and are involved in synaptic transmission. The aim of this study was to examine the effects of Omega‐3 supplementation on some cognitive and physiological parameters in healthy subjects.

Blood profiles, body fat and mood state in healthy subjects on different diets supplemented with Omega-3 polyunsaturated fatty acids

Background  Diets and Omega‐3 polyunsaturated fatty acids have been considered as important factors to reduce the risk of cardiovascular and inflammatory diseases, but there are few details on the effects on healthy subjects. The aim of the present study was to examine the variation of several physiological parameters in healthy subjects on different diets supplemented with Omega‐3 fatty acids.

Effects of pain, morphine and naloxone on the duration of animal hypnosis

Previous research has shown that animal hypnosis (tonic immobility) in the rabbit may be elicited in a condition of prolonged nociceptive stimulation. These experiments show that long-lasting irritative pain, produced within 15 min of formalin injection, potentiates the duration of hypnosis. Morphine, in the absence of painful stimuli, also potentiates hypnosis duration and this effect is antagonized by naloxone. Naloxone reduces hypnosis duration, but only at high doses (15 mg/kg). In a condition of irritative pain, the potentiation of hypnosis duration is abolished by naloxone (5 mg/kg). Hypnosis response is abolished in 6 out of 7 morphine-tolerant rabbits, but prolonged pain restores the response. The hypothesis that an opioid mechanism may be activated during animal hypnosis is 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.

Reactivity and event-related potentials during attentional tests in athletes.

Abstract A series of attentional tests involving reaction times (RTs) was administered to 12 high-level young (age 17–18 years) volleyball players. During the tests, event-related potentials were recorded by electroencephalogram. In a simple reaction-time test (SRT), the subjects had to respond to a letter that appeared on a white screen. Other tests (attentional shifting tests) consisted of a go/no-go reaction time and a choice reaction time (CRT), divided into a short-latency CRT and a long-latency CRT. In the pre-stimulus period of these tests, there is a shift from broad attention to selective attention, represented by a crowding of black points on the computer screen, followed by the appearance of a letter in the centre of the crowding. The results show that RT increased from SRT to CRT. In the attentional shifting tests, averaged waves of event-related potentials showed a contingent-negative-variation-like wave that was closely related to selective attention (selective attention wave, SAW) before the onset of the stimulus. After the stimulus, a P3 complex was recorded. Correlations were found between the SAW amplitude and P3 latency and amplitude, and between these parameters and RT and its variability. Higher SAW and P3 amplitudes were accompanied by a shorter RT and a lower variability. The characteristics and the correlations that exist between the various parameters are consistent with a possible use of these tests in the analysis of the attentional styles of athletes, and in the evaluation of their progress with training.

A technique for long term recording from single neurons in unrestrained behaving animals.

Abstract A simple method is described which employs a bundle of six 25 μ nichrome wires, chronically implanted in the brain of freely moving animals. The bundle is fixed to the pial surface and moves with the brain: under these conditions, brain movements do not affect recording stability and several neurons in a narrow zone of the CNS can be studied. Nichrome electrode tip position can be rapidly and precisely localized in the nervous tissue. The system is easily constructed and useful for cortical and subcortical studies. Units are recorded without substantial amplitude variations, even when the animal is turned upside down.

Hippocampal electrical activity during social interactions in rabbits living in a seminatural environment

The aim of the present experiment was to study the effect on the electrical activity of the hippocampus of interactions between male rabbits. The behavioral and electrical correlates of social interactions were studied in 13 animals living in a seminatural environment. Rabbits carrying chronic microelectrodes implanted in the hippocampus were introduced singly into a large, natural open air enclosure and their spontaneous behavior observed until they had adapted to the environment. Hippocampal EEG was recorded by telemetry. Subsequently, a second rabbit (intruder) was introduced into the enclosure. Hippocampal EEG and the concomitant behavior of the resident were stored and analyzed. Alerting reactions, approaching and conflictual elements were characterized by typical electrical patterns and parameters. Power spectra of hippocampal EEG showed a significant increase in frequency passing progressively from environment-related behaviors to more specific elements directed towards the intruder. Behavioral elements belonging to the same modality, such as running, chase and flight had different hippocampal EEG frequency distributions. Seven residents showed a clear prevalence of offensive reactions (offensive rabbits) and six defensive elements (defensive rabbits). Defensive animals showed very high frequency levels during nose and flight. Exploration of offensive rabbits in the period preceding and following the introduction of the intruder was characterized by higher EEG frequency values than exploration of defensive animals.

Physiological characteristics of pressure immobility. Effects of morphine, naloxone and pain

Abstract This study is an attempt to detect the most important modifications of physiological parameters occurring during pressure immobility in rabbits and to compare them with those recorded during animal hypnosis. Like the latter, pressure immobility is characterized by the development of high voltage slow waves in the EEG, reduction in frequency and amount of rhythmic slow activity in the hippocampus (RSA) and depression of spinal polysynaptic reflexes. Systolic and diastolic blood pressures are not modified. Duration of two types of immobility is positively correlated within individuals. Treatment by a single dose of morphine (1 mg/kg) potentiates the duration and this effect is antagonized by naloxone (1 mg/kg). Repeated morphine injection up to tolerance reduces duration. Pressure immobility may also be produced under persistent nociceptive stimulation and is characterized by the development of high voltage slow waves in the EEG, as is typical in the absence of pain. Naloxone, (5 mg/kg) injected in a condition of persistent noxious stimulation, reduces immobility duration. In contrast to animal hypnosis, the duration of pressure immobility is neither potentiated by pain nor reduced by naloxone (1,5 or 20 mg/kg). It is suggested that the two immobilities are controlled by several mechanisms, some similar, some different.

Hippocampal rhythmic slow activity (RSA) during animal hypnosis in the rabbit

Hippocampal electrical activity has been studied in 12 unanaesthetized, unrestrained rabbits during hypnosis and spontaneous activity in the experimental cage, before and among hypnosis trials. Quantitative analyses showed that rhythmic slow activity (RSA) occurred during exploratory movements (mean frequency 7.2 Hz) and also during spontaneous immobility, but a lower percentage and frequency (6.5 Hz). RSA was always present during the induction of hypnosis, but its frequency decreased and disappeared at the beginning of immobility, when it was replaced by a large amplitude irregular activity (LIA). During hypnosis RSA occurred in short periods, at low frequency (5.7 Hz). During the initial part of hypnosis, the lowest percentage of RSA was recorded. In the sec ond and third part, RSA increased in number of episodes, total amount, duration of a single episode and mean frequency. RSA of higher frequency occurred at the end of hypnosis, preceding righting movements. The relationships between hippocampal RSA and animal hypnosis are discussed.