Walking (and talking) the plank: dual-task performance costs in a virtual balance-threatening environment.

We evaluated the effects of engaging in extemporaneous speech in healthy young adults while they walked in a virtual environment meant to elicit low or high levels of mobility-related anxiety. We expected that mobility-related anxiety imposed by a simulated balance threat (i.e., virtual elevation) would impair walking behavior and lead to greater dual-task costs. Altogether, 15 adults (age = 25.6 ± 4.7 yrs, 7 women) walked at their self-selected speed within a VR environment that simulated a low (ground) and high elevation (15 m) setting while speaking extemporaneously (dual-task) or not speaking (single-task). Likert-scale ratings of cognitive and somatic anxiety, confidence, and mental effort were evaluated and gait speed, step length, and step width, as well as the variability of each, was calculated for every trial. Silent speech pauses (> 150 ms) were determined from audio recordings to infer the cognitive costs of extemporaneous speech planning at low and high virtual elevation. Results indicated that the presence of a balance threat and the inclusion of a concurrent speech task both perturbed gait kinematics, but the virtual height illusion led to increased anxiety and mental effort and a decrease in confidence. The extemporaneous speech pauses were longer on average when walking, but no effects of virtual elevation were reported. Trends toward interaction effects arose in self-reported responses, with participants reporting more comfort walking at virtual heights if they engaged in extemporaneous speech. Walking at virtual elevation and while talking may have independent and significant effects on gait; both effects were robust and did not support an interaction when combined (i.e., walking and talking at virtual heights). The nature of extemporaneous speech may have distracted participants from the detrimental effects of walking in anxiety-inducing settings.

Alcohol motivations associated with frequency of alcohol use, binge drinking, and alcohol problems among active duty junior enlisted soldiers and non-commissioned officers.

Problematic alcohol use is a serious threat to the behavioral health of active-duty Service Members (ADSM), resulting in numerous calls from governmental agencies to better understand mechanistic factors contributing to alcohol misuse within the military. Alcohol use motives are reliable predictors of alcohol-related behaviors and are considered malleable targets for prevention and intervention efforts. However, empirical research indicates that drinking motives vary across contextually distinct populations. Although some research has been conducted among veteran and reservist populations, limited work has been specifically focused on ADSM and no research has evaluated motives and alcohol metrics among ADSM based on military rank. Participants for the current study included 682 ADSM recruited from a large military installation in the U.S. Structural equation modeling evaluated associations between four drinking motives (i.e., enhancement, social, conformity, coping) and three alcohol misuse metrics (i.e., alcohol frequency, binge frequency, alcohol problems). Three models were evaluated: one full (combined) model and two separate models based on military rank - junior enlisted (i.e., E1-E4) and non-commissioned officers (NCOs) (i.e., E5-E9). Results for junior enlisted ADSM indicated that coping and enhancement motives were most strongly associated with all alcohol misuse metrics. However, among NCOs, results indicated that alcohol problems were only associated with coping motives. Notably, results also indicated that alcohol use motives accounted for substantively more variance across all alcohol-related metrics among NCOs. Findings generally support extant military-related literature indicating use of alcohol for coping (e.g., with anxiety) as the motivation most consistently associated with increased alcohol misuse. However, novel findings highlight enhancement motives - using alcohol to attain some positive internal reward - as another, often stronger, motivation impacting alcohol use outcomes. Further, findings highlight notable distinctions between alcohol use motives (i.e., coping vs. enhancement) and the impact of alcohol use motives (i.e., effect size) on alcohol metrics between junior enlisted and NCOs.

Measurement validity of the six-factor model of psychological well-being in a military sample: Implications for measuring well-being in service members.

Subjective well-being is a positive psychological construct that has important implications for the U.S. Military's goal to develop service members' strengths and support their overall thriving and downstream resilience. Despite this, the concept of well-being has not been well studied in military populations who have unique work demands, stressors, and autonomy/agency in daily life compared to civilians. To address this shortcoming in the literature, the present study assessed Ryff's measures of psychological well-being (PWB) in 1,333 U.S. service members prior to the deployments in the Middle East. Various methods attempting to validate the theoretical model purported by Ryff were unsuccessful, and exploratory factor analyses did not result in a novel model for this population. Future research should continue to evaluate proposed models of soldier well-being and propose novel theories, as well as measures, to assess this important construct. Implications are discussed. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

The effect of mobility-related anxiety on walking across the lifespan: a virtual reality simulation study.

Older adults who report a fear of falling are more likely to subsequently fall, yet, some gait anxiety-related alterations may protect balance. We examined the effect of age on walking in anxiety-inducing virtual reality (VR) settings. We predicted a high elevation-related postural threat would impair gait in older age, and differences in cognitive and physical function would relate to the observed effects. Altogether, 24 adults (age (y) = 49.2 (18.7), 13 women) walked on a 2.2-m walkway at self-selected and fast speeds at low (ground) and high (15 m) VR elevation. Self-reported cognitive and somatic anxiety and mental effort were greater at high elevations (all p < 0.001), but age- and speed-related effects were not observed. At high VR elevations, participants walked slower, took shorter steps, and reduced turning speed (all p < 0.001). Significant interactions with age in gait speed and step length showed that relatively older adults walked slower (ß = - 0.05, p = 0.024) and took shorter steps (ß = - 0.05, p = 0.001) at self-selected speeds at high compared to low elevation settings. The effect of Age on gait speed and step length disappeared between self-selected and fast speeds and at high elevation. At self-selected speeds, older adults took shorter and slower steps at high elevation without changing step width, suggesting that in threatening settings relatively older people change gait parameters to promote stability. At fast speeds, older adults walked like relatively younger adults (or young adults walked like older adults) supporting the notion that people opt to walk faster in a way that still protects balance and stability in threatening settings.

Skill-Based Differences in the Detection and Utilization of Opponent Action Preferences Following Increasing Exposure and Changes in Tendencies.

We examined skill-based differences in the detection and utilization of contextual information over a period of increasing exposure to an opponent's action preferences in soccer. Moreover, we investigated the ability of athletes to adapt to changes in these action preferences over time. In an initial detection phase, the attacking opponent demonstrated a proclivity to either pass or dribble, with these preferences being reversed in a subsequent adaptation phase of the same length. Skilled soccer players showed superior anticipation accuracy across both phases compared with less-skilled counterparts. The skilled participants significantly enhanced their performance over both phases, despite a significant drop in performance immediately following the change in opponent action preferences. In contrast, the less-skilled group only improved over the detection phase. Gaze data revealed that the skilled participants fixated more on kinematically relevant areas, compared with the less-skilled group, and increased the time spent fixating the player "off the ball" following greater volumes of exposure. Our novel findings elaborate on how skilled performers use both action preferences and motion information to anticipate an opponent's impending actions in sport.

Recalling fearful memories modifies approach and avoidance behavior based on spatial context.

Motor responses are more efficient when there is a match (or congruency) between the motivational properties of an emotional state and the distance altering characteristics of the movement being executed to the emotion-eliciting stimulus. However, the role of spatial context in shaping motivational orientations to approach and avoid, particularly during whole-body movement tasks, remains less understood. We sought to narrow this knowledge gap by investigating whether an emotion (fear) relived from a previous experience affected movement initiation based on whether motor responses were implicitly coded as approach (i.e., incongruent) or avoidance (i.e., congruent) as per the location of the imagined threat stimulus. Participants (N = 29) completed a tone-initiated forward gait initiation task after recalling a previous fearful experience in which the stimulus from their memory was located either in front (incongruent) or behind (congruent) them. Facilitation versus inhibition of motor responses was indexed by reaction time (RT), displacement and velocity of postural movements prior to stepping, and step kinematics. Analyses revealed that participants initiating forward gait after recalling a fearful experience in which the fearful stimulus was congruent to the movement direction expedited RTs, greater displacement and velocity of anticipatory postural responses, and greater step length and velocity. Results provide support for the theoretical position that motivational orientations to approach and avoid are contextualized based on affective congruency, which includes the spatial orientation of real or imagined emotional stimuli. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Using error-estimation to probe the psychological processes underlying contextual interference effects.

Although the learning benefits of interleaved practice schedules relative to blocked schedules are well-reported, the mechanisms underlying these effects are not fully understood. Researchers have generally suggested that random schedules of practice increase task-related information processing which arises due to switching between variations of the same task (or switching between different tasks). Thus, one potentially useful way to both probe and manipulate contextual interference is to pair it with error estimation during practice. Forced error estimation increases task-related information processing and recording these estimates provides insight into learners' self-awareness of their errors. In the present study, 84 participants were randomly allocated to four groups. Participants practiced a timing task under blocked or random schedules, with and without error estimations prior to feedback. During the acquisition phase, three target times were trained (1500, 1700, 1900 ms), with feedback delivered after every trial. We used delayed post-tests (24 hrs later) to evaluate the retention of these target times and their transfer to two new target times (1600, 1800 ms). Participants who practiced with a random schedule performed worse (i.e., greater absolute error) than those with a blocked schedule during acquisition (p = .006); however, randomly scheduled participants also showed reduced error (p = .004) on the retention and transfer tests. Although prompting error estimations led to greater self-reported mental effort being invested on the task (p = .001), error estimation was not reliably associated with superior learning (p = .133). The accuracy of error estimations did not differ as a function of practice structure (p = .070), although the accuracy of error estimations improved during acquisition (p = .006). Findings highlight the robustness of the contextual interference effect, but we did not find evidence that error estimations moderated the effect on this task. It is in some ways surprising that we found an effect of contextual interference, as past-work suggests that interference effects are attenuated (or eliminated) when participants switch between different parameters of the same task. We speculate that this might be due to the difficulty of the task; even though participants switched between parametric variations of the same task, the distinction between parameters was subtle (i.e., tenths of a second).

How Task Constraints Influence the Gaze and Motor Behaviours of Elite-Level Gymnasts.

Perception-action coupling is fundamental to effective motor behaviour in complex sports such as gymnastics. We examined the gaze and motor behaviours of 10 international level gymnasts when performing two skills on the mini-trampoline that matched the performance demands of elite competition. The presence and absence of a vaulting table in each skill served as a task-constraint factor, while we compared super-elite and elite groups. We measured visual search behaviours and kinematic variables during the approach run phase. The presence of a vaulting table influenced gaze behaviour only in the elite gymnasts, who showed significant differences in the time spent fixating on the mini-trampoline, when compared to super-elite gymnasts. Moreover, different approach run characteristics were apparent across the two different gymnastic tasks, irrespective of the level of expertise, and take-off velocity was influenced by the skill being executed across all gymnasts. Task constraints and complexity influence gaze behaviours differed across varying levels of expertise in gymnastics, even within a sample of international level athletes. It appears that the time spent fixating their gazes on the right areas of interest during the approach run is crucial to higher-level performance and therefore higher scores in competition, particularly on the mini-trampoline with vaulting table.

Interoceptive attention regulation in Ehlers-Danlos syndromes: associations between pain and psychiatric symptom severity.

High rates of comorbid chronic pain, anxiety, and mood disorders among individuals with the Ehlers-Danlos syndromes (EDS+) are becoming increasingly recognized, though this complex symptomology remains poorly understood and undertreated. The current project examined whether interoceptive attention regulation is protective against depressive and anxiety symptoms in individuals with suspected EDS+. Data were collected from individuals participating in a transdisciplinary diagnostic visit within an EDS+ specialty consultation clinic. Participants were included in the current analyses (n = 49) if they had complete data on the following measures: the PHQ-8, the GAD-7, the Pain Severity subscale from the West Haven-Yale Multidimensional Pain Inventory, and the Attention Regulation subscale from the Multidimensional Assessment of Interoceptive Awareness. Consistent with expectations, the sample showed high levels of clinically significant anxiety and depressive symptoms. Pain severity ratings were significantly correlated with depressive but not anxiety severity. Moreover, higher levels of perceived interoceptive attention regulation abilities were significantly associated with less severe anxiety and depressive symptoms; however, attention regulation did not moderate the associations of pain with anxiety and depressive symptom severity. CONCLUSIONS: The current project replicated recent findings that pain, anxiety, and depression are common in individuals with EDS+. The ability to focus and control somatic attention appears to be protective and a potential target for interventions in EDS+.

Nationality and sociocultural factors influence athlete development and sport outcomes: Perspectives from United States and Austrian youth alpine ski racing.

Geographical regions possess distinct sporting cultures that can influence athletic development from a young age. The United States (US) and Austria both produce elite alpine ski racers, yet have distinct sport structures (i.e., funding, skiing prominence). In this exploratory study, we investigated sport outcomes and psychological profiles in adolescent alpine ski racers attending skill development academies in the US (N= 169) and Austria (N= 209). Sport participation and psychological questionnaires (mental toughness, perfectionism, grit, coping, burnout) were administered to athletes. In Austria, athletes participated in fewer extracurricular sports, began competing and training younger, and accumulated less practice hours than athletes in the US. Athletes in the US reported greater burnout than athletes in Austria. Finally, in the US, women accumulated more practice hours and experienced more parental pressure than men, while men accumulated more practice hours in Austria. Austria's skiing-centric sport culture may encourage athletes to fully immerse into the sport, contributing to positive psychological outcomes. Reduced sport opportunities in the US beyond educational institutions may pressure athletes to practice more to ensure continued competitive skiing. Stressors for sport participation will be unique to gender in each country though, given their implicit gender stigmas for sport participation.

The direction of postural threat alters balance control when standing at virtual elevation.

Anxiogenic settings lead to reduced postural sway while standing, but anxiety-related balance may be influenced by the location of postural threat in the environment. We predicted that the direction of threat would elicit a parallel controlled manifold relative to the standing surface, and an orthogonal uncontrolled manifold during standing. Altogether, 14 healthy participants (8 women, mean age = 27.5 years, SD = 8.2) wore a virtual reality (VR) headset and stood on a matched real-world walkway (2 m × 40 cm × 2 cm) for 30 s at ground level and simulated heights (elevated 15 m) in two positions: (1) parallel to walkway, lateral threat; and (2) perpendicular to walkway, anteroposterior threat. Inertial sensors measured postural sway acceleration (e.g., 95% ellipse, root mean square (RMS) of acceleration), and a wrist-worn monitor measured heart rate coefficient of variation (HR CV). Fully factorial linear-mixed effect regressions (LMER) determined the effects of height and position. HR CV moderately increased from low to high height (p = 0.050, g = 0.397). The Height × Position interaction approached significance for sway area (95% ellipse; ß = - 0.018, p = 0.062) and was significant for RMS (ß = - 0.022, p = 0.007). Post-hoc analyses revealed that sagittal plane sway accelerations and RMS increased from low to high elevation in parallel standing, but were limited when facing the threat during perpendicular standing. Postural response to threat varies depending on the direction of threat, suggesting that the control strategies used during standing are sensitive to the direction of threat.

Perceived Competence, Achievement Goals, and Return-To-Sport Outcomes: A Mediation Analysis.

The purpose of this study was to explore the potential mediating effect of achievement goals on perceived competence and return-to-sport outcomes among college athletes sustaining a sport injury. Altogether, 75 male and female college athletes from the United States who returned to sport after having missed competition for an average of 3 weeks due to injury, completed valid and reliable inventories measuring perceived competence, achievement goals, and return-to-sport outcomes. Results indicated that task-approach goals significantly mediated the relationship between perceived competence and a renewed sport perspective. These data suggest the importance of promoting competence beliefs and a task-oriented focus among athletes returning to sport following athletic injury. From a practical standpoint, clinicians can foster competence perceptions by integrating progressive physical tests assessing functionality and sport-specific skills/abilities. Furthermore, these data suggest that coaches, physical therapists, and significant others may do well to use language that orients injured athletes towards attaining success as opposed to avoiding failure, to emphasize effort, task completion, and correct form, and to avoid comments that compare athletes to others or to their preinjury standards of performance. From a theoretical standpoint, our mediation findings extend previous achievement goal research into the sport injury domain, further highlighting the importance of task-approach goals.

Seeing isn't necessarily believing: Misleading contextual information influences perceptual-cognitive bias in radiologists.

A substantial number of medical errors in radiology are attributed to failures of perception or decision making, although it is believed that experience (or expertise) might buffer diagnosticians from some types of perceptual-cognitive bias. We examined how the quality of contextual information influences decision making and how underlying perceptual-cognitive processes change as a function of experience and diagnostic accuracy. Twenty-one radiologists dictated their findings on 16 deidentified musculoskeletal radiographic cases while wearing a mobile-eye tracking system. Patient histories were mismatched on a subset of cases to be miscued relative to the correct diagnosis. Experienced radiologists outperformed less-experienced participants, but no systematic differences in gaze behaviors emerged between groups. Miscued case notes increased perceptual-cognitive bias in both groups, resulting in an approximate 40% decrease in diagnostic accuracy. Most errors were judgment errors, meaning participants visually fixated on the abnormality for longer than a second yet still failed to make the correct diagnosis. Findings suggest a physician's confidence in their diagnosis might be misplaced after spending insufficient time extracting relevant information from key areas of the visual display, or when decisions are based primarily on a priori expectations derived from patient histories. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

The feasibility of using virtual reality to induce mobility-related anxiety during turning.

The fear of falling, or mobility-related anxiety, profoundly affects gait, but is challenging to study without risk to participants. PURPOSE: To determine the efficacy of using virtual reality (VR) to manipulate illusions of height and consequently, elevated mobility-related anxiety when turning. Moreover, we examined if mobility-related anxiety effects decline across time in VR environments as participants habituate. METHODS: Altogether, 10 healthy participants (five women, mean (standard deviation) age = 28.5 (8.5) years) turned at self-selected and fast speeds on a 2.2 m walkway under two simulated environments: (1) ground elevation; and (2) high elevation (15 m above ground). Peak turning velocity was recorded using inertial sensors and participants rated their cognitive (i.e., worry) and somatic (i.e., tension) anxiety, confidence, and mental effort. RESULTS: A significant Height × Speed × Trial interaction (p = 0.013) was detected for peak turning velocity. On average, the virtual height illusion decreased peak turning velocity, especially at fast speeds. At low elevation, participants decreased speed across trials, but not significantly (p = 0.381), but at high elevation, they significantly increased speed across trials (p = 0.001). At self-selected speeds, no effects were revealed (all p > 0.188) and only effects for Height were observed for fast speeds (p < 0.001). After turning at high elevation, participants reported greater cognitive (p = 0.008) and somatic anxiety (p = 0.007), reduced confidence (p = 0.021), and greater mental effort (p < 0.001) compared to the low elevation. CONCLUSION: VR can safely induce mobility-related anxiety during dynamic motor tasks, and habituation effects from repeated exposure should be carefully considered in experimental designs and analysis.

Emotional states influence forward gait during music listening based on familiarity with music selections.

Music elicits a wide range of human emotions, which influence human movement. We sought to determine how emotional states impact forward gait during music listening, and whether the emotional effects of music on gait differ as a function of familiarity with music. Twenty-four healthy young adults completed walking trials while listening to four types of music selections: experimenter-selected music (unfamiliar-pleasant), its dissonant counterpart (unfamiliar-unpleasant), each participant's self-selected favorite music (familiar-pleasant), and its dissonant counterpart (familiar-unpleasant). Faster gait velocity, cadence, and stride time, as well as longer stride length were identified during pleasant versus unpleasant music conditions. Increased gait velocity, stride length, and cadence as well as reduced stride time were positively correlated with subjective ratings of emotional arousal and pleasure as well as musical emotions such as happiness-elation, nostalgia-longing, interest-expectancy, pride-confidence, and chills, and they were negatively related to anger-irritation and disgust-contempt. Moreover, familiarity with music interacted with emotional responses to influence gait kinematics. Gait velocity was faster in the familiar-pleasant music condition relative to the familiar-unpleasant condition, primarily due to longer stride length. In contrast, no differences in any gait parameters were found between unfamiliar-pleasant and unfamiliar-unpleasant music conditions. These results suggest emotional states influence gait behavior during music listening and that such effects are altered by familiarity with music. Our findings provide fundamental evidence of the impact of musical emotion on human gait, with implications for using music to enhance motor performance in clinical and performance settings.

Forward leaning alters gait initiation only at extreme anterior postural positions.

We investigated the impact of initial body position on the displacement and velocity of center of pressure adjustments made during gait initiation. Twenty-nine healthy adults (21 ±â€¯1y) initiated forward gait following six seconds of sustained forward posture based on percentage of their forward maximum voluntary lean (0, 5, 10, 20, 50%). Final center of pressure positions for each trial were back-calculated, as a percentage of maximum voluntary lean, using average anteroposterior constant error to the target during the last second of feedback. Scores were aggregated into percentage bands for analysis: Band 1 = -2-4.99%; Band 2 = 5-8.99%; Band 3 = 9-17.99%; Band 4 = 18-29%; Band 5 = 44-54%. Center of pressure displacement and velocity were evaluated during the decoupling, weight shift, and step initiation phases of gait initiation. Subsequent stepping parameters were also compared. During the decoupling phase, greater posterior displacement was observed in band 5 trials compared to 1, 2, and 3, and greater posterior velocity was found for band 5 compared to 1 and 3. During the weight shift phase, greater resultant displacement was found for band 5 compared to 3 and greater resultant velocity for band 5 compared to 2, 3, and 4. During step initiation, participants produced greater anterior displacement and resultant velocity during band 1, 2, and 3 compared to 5. Participants demonstrated greater swing step length and stance step time during band 5 trials compared to 3. These results suggest that only anterior postural positions greater than 44% of a person's maximum voluntary lean systematically alter spatiotemporal and kinematic indices of forward gait initiation in healthy populations. We discuss the conceptual implications of this work with respect to previous behavioral interventions.

Emotional state impacts center of pressure displacement before forward gait initiation.

Emotional states influence whole-body movements during quiet standing, gait initiation, and steady state gait. A notable gap exists, however, in understanding how emotions affect postural changes during the period preceding the execution of planned whole-body movements. The impact of emotion-induced postural reactions on forthcoming posturomotor movements remains unknown. We sought to determine the influence of emotional reactions on center of pressure (COP) displacement before the initiation of forward gait. Participants (N = 23, 14 females) stood on a force plate and initiated forward gait at the offset of an emotional image (representing five discrete categories: attack, sad faces, erotica, happy faces, and neutral objects). COP displacement in the anteroposterior direction was quantified for a 2 second period during image presentation. Following picture onset, participants produced a posterior postural response to all image types. The greatest posterior displacement was occasioned in response to attack or threat stimuli compared with happy faces and erotica images. Results suggest the impact of emotional states on gait behavior begins during the motor planning period before the preparatory phase of gait initiation, and manifests in center of pressure displacement alterations.

Autobiographically recalled emotional states impact forward gait initiation as a function of motivational direction.

The impact of self-generated affective states on self-initiated motor behavior remains unspecified. The purpose of the current study was to determine how self-generated emotional states impact forward gait initiation. Participants recalled past emotional experiences (anger, fear, happy, sad, and neutral), "relived" those emotional memories before gait initiation (GI), and then walked ∼4 m across the laboratory floor. Kinetic and kinematic data revealed GI characteristics consistent with a motivational direction hypothesis. Specifically, participants produced greater posterior-lateral displacement and velocity of their center of pressure (COP) during the initial phase of GI after self-generation of happy and anger emotional states relative to sad ones. During the second phase of GI, greater medial displacement of COP was found during the happy condition compared with sad, greater velocity was occasioned during happy and angry trials compared with sad, and greater velocity was exhibited after happy compared with fear memories. Finally, greater anterior velocity was produced by participants during the final phase of GI for happy and angry memories compared with sad ones. Steady state kinetic and kinematic data when recalling happy and angry memories (longer, faster, and more forceful stepping behavior) followed the anticipatory postural adjustments noted during GI. Together the results from GI and steady state gait provide robust evidence that self-generated emotional states impact forward gait behavior based on motivational direction. Endogenous manipulations of emotional states hold promise for clinical and performance interventions aimed at improving self-initiated movement.

Regulating emotions uniquely modifies reaction time, rate of force production, and accuracy of a goal-directed motor action.

We investigated how emotion regulation (ER) strategies influence the execution of a memory guided, ballistic pinch grip. Participants (N=33) employed ER strategies (expressive suppression, emotional expression, and attentional deployment) while viewing emotional stimuli (IAPS images). Upon stimulus offset, participants produced a targeted pinch force aimed at 10% of their maximum voluntary contraction. Performance measures included reaction time (RT), rate of force production, and performance accuracy. As hypothesized, attentional deployment resulted in the slowest RT, largest rate of force production, and poorest performance accuracy. In contrast, expressive suppression reduced the rate of force production and increased performance accuracy relative to emotional expression and attentional deployment. Findings provide evidence that emotion regulation strategies uniquely influence human movement. Future work should further delineate the interacting role that emotion regulation strategies have in modulating both affective experience and motor performance.