Elite pistol shooters: physiological patterning of best vs. worst shots

Frontal midline theta in the pre-shot phase of rifle shooting: differences between experts and novices

In the present study the time course of frontal midline theta (Fmtheta) during the aiming period in rifle shooting was investigated. Experts (n=8) and novices (n=10) had to shoot repeatedly while EEG was recorded, and the time course of Fmtheta during the aiming period was significantly different between the two groups, showing a steady increase of power for the last 3s before the shot only for experts, but not for novices. Source analysis (LORETA) indicated a significantly stronger theta activity for experts strictly located at the anterior cingulate area and medial frontal cortex, locations well known for focused attention. The results suggest that experts and novices use different strategies during the aiming period. While novices keep a relatively constant amount of attention to the target, experts are able to increase attention exactly to the time point of the trigger pull.

Timing of caffeine's impact on autonomic and central nervous system measures: clarification of arousal effects

The timing of caffeine effects on arousal levels was examined. From previous work in our laboratory, an increase in skin conductance level (SCL) was used as the marker of arousal increase, and we sought to identify the timing of this and related effects following caffeine ingestion. A single oral dose of caffeine (250 mg) was used in a randomised double-blind placebo-controlled repeated-measures cross-over study. Eyes-closed resting electroencephalogram (EEG) and autonomic data (SCL, heart rate, respiration rate, and systolic and diastolic blood pressure) during 2 min epochs that commenced every 4 min after ingestion, were analysed. The SCL placebo data were used to identify potential arousal measures prior to examining caffeine effects. Caffeine was associated with increased SCL, increased respiratory rate and a global reduction in alpha power. There were no significant cardiovascular effects of caffeine-induced arousal. These caffeine results are consistent with our recent electrodermal and EEG studies of arousal, and confirm the potential use of caffeine as a simple means of experimentally modifying arousal levels without task-related confounds.

Event-related potential correlates of phasic and tonic measures of the orienting reflex

We examined putative central nervous system (CNS) indices of tonic and phasic aspects of the orienting reflex (OR) in a passive event-related potential (ERP) dishabituation paradigm. Pre-stimulus skin conductance level (SCL) and the subsequent skin conductance response (SCR) were used as tonic and phasic OR "yard-sticks", respectively. Their stimulus-response patterns were used to assess two ERP components: the tonic pre-stimulus contingent negative variation (CNV) and the subsequent phasic late positive complex (LPC). SCLs and SCRs derived from each trial of the first train presented were compatible with traditional OR studies. Across-train means were also derived for each of the four measures examined. Arousal changes, as indexed by the SCL, were weak in the CNV which showed an additional expectancy effect. The LPC showed a stimulus-response pattern across trials identical to that of the SCR. This study clarifies links between the traditional autonomic measures of the indifferent OR and its CNS correlates, and encourages an OR perspective and/or interpretation of ERP effects.

Promise versus reality in relation to the unitary orienting reflex: A case study examining the role of theory in psychophysiology

We commonly teach beginning science students that theory generates hypotheses which direct our research, framing our experimental observations; and that in turn, these supply the data which support or contradict theory, allowing its self-correction and further development. These propositions are explored here in the context of psychophysiology, concentrating on examples in relation to the Orienting Reflex (OR). It is demonstrated that the realist approach generally portrayed in our teaching about theory and theory testing is not the dominant ethos in this field. Indeed, we pay little more than lip-service to the ideal we teach about. One outcome described here is that the promise offered us by the OR in the 1960s has not been realised. It is argued that this failure may be symptomatic of much of science, suggesting that we need to consciously work to raise the perceived value of theory. The ideation element of theoretical activity can be fostered, and it is argued that we need to do so explicitly at a number of levels in the education of our students, beginning in the early coursework stages and continuing in their research training and development.

A relação entre o nível de condicionamento aeróbico, execução de uma pista de obstáculos e o rendimento em um teste de tiro

A preparação do militar para o combate é baseada na instrução militar que tem como fundamento a representação do campo de batalha. Entre as principais instruções estão a pista de obstáculos e a execução do tiro. O objetivo deste estudo foi verificar a influência do nível de condicionamento aeróbico sobre o rendimento na execução de uma pista de obstáculos e a realização de um teste de tiro em integrantes do Exército Brasileiro. Procurou-se, também, verificar a influência da execução de uma pista de obstáculos sobre a execução de um teste de tiro. O citado rendimento foi avaliado pelo tempo de execução de uma pista de obstáculos e resultado no teste de tiro (considerou-se a diferença entre o resultado do tiro pós e pré-esforço como índice de performance no tiro IPT). A amostra foi constituída de 28 militares homens, de 19 a 20 anos de idade. Inicialmente foi estimado o VO2máx dos indivíduos por meio do teste de Léger-Boucher. Posteriormente os militares da amostra executaram um teste de tiro, uma pista de obstáculos e, novamente, um teste de tiro. Verificou-se uma diferença significativa entre o tiro pré-esforço e pós-esforço (43,79 ± 4,02 para 40,54 ± 4,10 pontos, p < 0,05). Os resultados da correlação de Pearson foram os seguintes: Pista de Obstáculos e VO2máx r = -0,612 (significativo); IPT e VO2máx r = -0,403 (significativo) e VO2máx e Tiro pré-esforço r = 0,310 (não-significativo). Concluiu-se que o nível de condicionamento aeróbico afeta o tempo de execução de uma pista de obstáculos e que existe relação entre o nível de condicionamento aeróbico e o IPT; entretanto, não se observou relação entre o resultado do teste de tiro e o condicionamento aeróbico.

Sensitivity of primary phasic heart rate deceleration to stimulus repetition in an habituation procedure: influence of a subjective measure of activation/arousal on the evoked cardiac response

The post-stimulus primary bradycardia--sometimes labelled as the first evoked cardiac response, ECR1--is regarded as a response which is independent of the stimulus novelty factor. Despite this however, in our previous research we have observed a noticeable variation of this response, which made us suspect that there could be some additional factor influencing it. To test this, we designed a habituation procedure to measure susceptibility of the ECR1 to stimulus repetition. In our experimental design, we also included a measure of the level of activation (arousal) as a possible additional factor influencing the time-course of the cardiac response. The level of arousal over the study was measured by the Activation-Deactivation Adjective Check List (AD ACL). Our results show that mere stimulus repetition does not influence the time-course of ECR1. However, another pattern of results appeared when one of the dimensions of AD ACL, namely Tense Arousal, was taken into account. We observed different ECR time-courses during the initial stimulus presentations for subjects with high and low levels of Tense Arousal. These results are interpreted within the framework of Preliminary Process Theory in terms of the different attentional patterns in subjects with high and low levels of Tense Arousal.

Arousal and Activation in a Continuous Performance Task

Abstract: The concepts of arousal and activation have had a confused history in Psychophysiology, and there is no widely accepted consensus on their usefulness in the field. This study aimed to explore whether these concepts could be separated in terms of their effects on the phasic Orienting Response (OR) and behavioral performance. We defined arousal at a particular time to be the energetic state at that time, reflected in electrodermal activity and measured by skin conductance level. Task-related activation was defined as the change in arousal from a resting baseline to the task situation. A continuous performance task was used with normal children. The magnitude of the mean phasic OR elicited by target stimuli was dependent on arousal, but not on task-related activation. Two performance measures (mean reaction time and number of errors) improved with increasing activation, but not with arousal. These data suggest the value of conceptualizing arousal and activation as separable aspects of the energetics of physiological and behavioral responding in future studies of attention, cognition, and emotion.

Differential relations between heart rate and skin conductance, and public speaking anxiety

The present pilot study tested whether the lack of consistent findings of relations between autonomic nervous system (ANS) activity and non-clinical levels of public speaking anxiety (PSA) can be explained by methodology. An ambulatory protocol was utilised to test whether the interaction of belief structure with each of an undergraduate student speaker's heart rate and skin conductance level predicted state speech anxiety better than their linear summation. Results suggest that in a non-clinical population, the interaction of ANS activity and belief structure is an important determinant of PSA, and may account for variable findings in the literature.

Fixation stability and saccadic latency in élite shooters

This study tested the hypothesis that elementary visuo-motor functions involved in visual scanning, as measured by fixation and saccadic tasks, are better in a group of high-level clay target shooters (N=7) than in a control group (N=8). In the fixation task, subject were told to keep fixation as still as possible on a target for 1 min, both in the presence and absence of distracters. For shooters, time did not have an effect on fixation stability, and they had more stable fixation than controls in the distracters condition. Results indicate a difference between groups on both the temporal span of attention and selective attention. In the saccadic task, subjects were asked to saccade, as fast as possible, towards a peripherally displayed target. Two conditions were used: simple reaction to target onset and discrimination between targets and distracters. Shooters had faster saccadic latency to targets than controls in both conditions. Finally, to evaluate the effect of exercise on saccadic latency, we trained one control subject to saccade to a target displayed at a constant spatial position. At the end of the training, saccadic latency reached a value comparable to that recorded in shooters. Learning was largely retinotopic, not showing transfer to untrained spatial positions.

The Physiological Activation Effect on Performance in Shooting

Abstract The present study was devised to analyze the relationship between sporting performance and physiological activation. Fourteen subjects participated in a modern pentathlon shooting competition. Six autonomic nervous system (ANS) parameters were simultaneously recorded in real time: Skin Potential, Skin resistance, Instantaneous Heart Rate and Respiratory Frequency, Skin Temperature, and Skin Blood Flow. The duration of concentration was considered the time lapse between the “start” order and the shot. Subjects tried to keep their arm and pistol stable during this phase. Results showed a complex relationship between activation, relaxation, and performance. ANS activity indicated an increase in physiological activation and at the same time, relaxation: activation was observed through electrodermal activity, while thermovascular indices indicated relaxation. Tonic level variations were, thus, a reliable indicator of the contrasting requirements of this sporting activity. Finally, the results challenge theories that have suggested that autonomic activity is undifferentiated.

The Influence of Emotionally Relevant Context on the Evoked Cardiac Response Triggered by an Irrelevant Stimulus

Abstract The effect of stimulus valence was examined in the evoked cardiac response (ECR) elicited by the exposition of neutral and negative slides as well as by an innocuous auditory stimulus presented on the affective foregrounds generated by the slides. The exposition of the aversive slide produced prolonged cardiac deceleration in comparison with the neutral slide. Similar prolonged deceleration accompanied exposition of the neutral auditory stimulus on the negative visual foreground in comparison with the neutral foreground. We interpret these results as an autonomic correlate of extended stimulus processing associated with the affective stimulus. The initial deceleration response, covering two or three slower heart beats, may be prolonged for several seconds before HR reaches the baseline level again. In such a case the evoked cardiac deceleration can be functionally divided into two parts: the reflexive bradycardia (ECR1) elicited by neutral stimuli and a late decelerative component (LDC). We can speculate that the latter is associated with an additional voluntary continuation of processing of the stimulus. This must involve some cognitive aspect different from the mental task performance which leads to the accelerative ECR2, and we suggest that processing of a stimulus with negative valence is involved in generating the LDC.