Groove Rhythm Enhances Exercise Impact on Prefrontal Cortex Function in Groove Enjoyers

A positive affective response modulates the effects of aerobic exercise on prefrontal executive function (EF). Groove rhythm (GR), eliciting the feeling of wanting to move to music, is useful for inducing positive affective response during exercise. Three minutes of listening to GR activated the left dorsolateral prefrontal cortex (l-DLPFC) and enhanced EF in participants who had higher psychological responses to GR. This finding prompted us to test the hypothesis that the combination of GR and exercise (GREX) induces positive psychological responses that enhance PFC function through entrainment of body movements and musical beats. 41 participants were administered two experimental conditions: three min of very light-intensity (30% V̇ O2peak) exercise combined with GR and combined with a white-noise metronome (WMEX). Before and after exercise, participants performed a Stroop task and were monitored for l-DLPFC activity with functional near-infrared spectroscopy. GREX enhanced EF and l-DLPFC activity in participants who experienced greater subjective feelings of audiomotor entrainment and increased excitement with GREX. These psychological responses were predictive of the impact of GREX on l-DLPFC activity and EF. These findings, together with previous results, support the hypothesis that GR allows us to boost the cognitive benefits of exercise via l-DLPFC activity only in those who enjoy groove, and suggest that subjective audiomotor entrainment is a key mechanism of this boosting effect.

Effects of high-intensity interval exercise and moderate-intensity continuous exercise on executive function of healthy young males

PURPOSE

This study compared the executive function (EF) performance induced by moderate-intensity continuous exercise (MICE) versus high-intensity interval exercise (HIIE), under two exercise modalities (i.e., running vs. cycling), and explored whether the changes in EF performance were related to the hemodynamics response of the cerebral prefrontal area of the brain.

METHODS

In a randomized cross-over design, 16 male participants completed 4 main trials, i.e., 40 min of moderate-intensity continuous running (MICR) or cycling (MICC) with 60% maximal oxygen consumption (VO_2max), 33 min of high-intensity interval running (HIIR) or cycling (HIIC). For HIIR or HIIC trials, the exercise intensity was 60% VO_2max for the first 5 min, followed by four 4-minute bouts of exercise at 90% VO_2max, separated by 3-minute active recovery at 60% VO_2max. EF was assessed via the Eriksen Flanker task (EFT) before (Pre), immediately after (Post 0), and 10 min after exercise (Post 10). Functional near-infrared spectroscopy (fNIRS) measured oxygenated hemoglobin (O₂Hb) and deoxygenated hemoglobin (HHb) concentrations in the prefrontal area. Each main trial measured the concentrations of blood glucose and lactate, heart rate, and rate of perceived exertion.

RESULTS

(1) Compared to the reaction time in EFT during the pretest, the corresponding reaction time was shorter at Post 10 (P < 0.01) but not at Post 0 (P = 0.06). Specifically, reaction time was shorter at Post 10 than in the pretest in HIIC (P = 0.04), MICC (P = 0.01), and HIIR (P < 0.01) but not MICR. (2) The fNIRS results revealed that O₂Hb concentrations in the left dorsolateral prefrontal cortex area were much lower during Post 10 than during the pretest. (3) The blood lactate concentrations were not associated with EF performance regarding both accuracy and reaction time.

CONCLUSION

Compared to the pretest, EF was greater after the 10-minute rest during recovery but not immediately after exercise. The different HIIE or MICE protocols adopted in the present study may elicit minor differences regarding their effects on EF.

Repeated Exposure to Illusory Sense of Body Ownership and Agency Over a Moving Virtual Body Improves Executive Functioning and Increases Prefrontal Cortex Activity in the Elderly

We previously showed that the illusory sense of ownership and agency over a moving body in immersive virtual reality (displayed in a first-person perspective) can trigger subjective and physiological reactions on the real subject’s body and, therefore, an acute improvement of cognitive functions after a single session of high-intensity intermittent exercise performed exclusively by one’s own virtual body, similar to what happens when we actually do physical activity. As well as confirming previous results, here, we aimed at finding in the elderly an increased improvement after a longer virtual training with similar characteristics. Forty-two healthy older subjects (28 females, average age = 71.71 years) completed a parallel-group randomized controlled trial (RCT; UMIN000039843, umin.ac.jp) including an adapted version of the virtual training previously used: while sitting, participants observed the virtual body in a first-person perspective (1PP) or a third-person perspective (3PP) performing 20 min of virtual high-intensity intermittent exercise (vHIE; the avatar switched between fast and slow walking every 2 min). This was repeated twice a week for 6 weeks. During the vHIE, we measured the heart rate and administered questionnaires to evaluate illusory body ownership and agency. Before the beginning of the intervention, immediately after the first session of vHIE, and at the end of the entire intervention, we evaluated the cognitive performance at the Stroop task with online recording of the hemodynamic activity over the left dorsolateral prefrontal cortex. While we confirm previous results regarding the virtual illusion and its physiological effects, we did not find significant cognitive or neural improvement immediately after the first vHIE session. As a novelty, in the 1PP group only, we detected a significant decrease in the response time of the Stroop task in the post-intervention assessment compared to its baseline; coherently, we found an increased activation on left dorsolateral prefrontal cortex (lDLPFC) after the entire intervention. While the current results strengthen the impact of the virtual full-body illusion and its physiological consequences on the elderly as well, they might have stronger and more established body representations. Perhaps, a longer and increased exposure to those illusions is necessary to initiate the cascade of events that culminates to an improved cognitive performance.

Virtual training leads to real acute physical, cognitive, and neural benefits on healthy adults: study protocol for a randomized controlled trial

BACKGROUND

Keeping a certain level of physical activity has beneficial effects on the body itself but also, surprisingly, on cognition: specifically, physical high-intensity intermittent aerobic exercise (HIE) can show improvement on cognitive executive functions. Although, in some cases performing strength or aerobic training is problematic or not feasible. Immersive virtual reality (IVR) can induce the illusory feeling of ownership and agency over a moving virtual body, therefore showing comparable physiological reactions: for example, if an individual is sitting on a chair but his virtual body climbs a hill, the individual's heart rate increases coherently, as if he is actually walking. In this study, we investigate whether this same illusion can show beneficial consequences on the body as well as on executive functions (using the color-word matching Stroop task) and on its neural substrates (using functional near-infrared spectroscopy [fNIRS]).

METHODS

In a cross-over randomized controlled trial, 30 healthy young adults will experience HIE training in IVR (i.e. the virtual body will perform eight sets of 30 s of running followed by 30 s of slow walking, while the participant is completely still) according to two random-ordered conditions: during the experimental condition, the virtual body is displayed in first-person perspective (1PP), while in the control condition, the virtual body is displayed in third-person perspective (3PP). To confirm that individuals have the illusion of ownership and agency over the virtual body in 1PP (and not in 3PP), we will record the heart rate, in addition to subjective questionnaires. Before and after every IVR sessions (one week apart), we will measure cortical hemodynamic changes in the participants' prefrontal cortex using the fNIRS device during the Stroop task's execution.

DISCUSSION

From a theoretical perspective, we could prove that the sense of body ownership and agency can modulate physical and cognitive parameters, even in the absence of actual movements; from a clinical perspective, these results could be useful to train cognition and body simultaneously, in a completely safe environment.

TRIAL REGISTRATION

University Hospital Medical Information Network Clinical Trial Registry, UMIN000034255 . Registered on 1 October 2018.

Applications of Functional Near-Infrared Spectroscopy (fNIRS) Neuroimaging in Exercise⁻Cognition Science: A Systematic, Methodology-Focused Review

For cognitive processes to function well, it is essential that the brain is optimally supplied with oxygen and blood. In recent years, evidence has emerged suggesting that cerebral oxygenation and hemodynamics can be modified with physical activity. To better understand the relationship between cerebral oxygenation/hemodynamics, physical activity, and cognition, the application of state-of-the art neuroimaging tools is essential. Functional near-infrared spectroscopy (fNIRS) is such a neuroimaging tool especially suitable to investigate the effects of physical activity/exercises on cerebral oxygenation and hemodynamics due to its capability to quantify changes in the concentration of oxygenated hemoglobin (oxyHb) and deoxygenated hemoglobin (deoxyHb) non-invasively in the human brain. However, currently there is no clear standardized procedure regarding the application, data processing, and data analysis of fNIRS, and there is a large heterogeneity regarding how fNIRS is applied in the field of exercise⁻cognition science. Therefore, this review aims to summarize the current methodological knowledge about fNIRS application in studies measuring the cortical hemodynamic responses during cognitive testing (i) prior and after different physical activities interventions, and (ii) in cross-sectional studies accounting for the physical fitness level of their participants. Based on the review of the methodology of 35 as relevant considered publications, we outline recommendations for future fNIRS studies in the field of exercise⁻cognition science.

Signal Processing in Functional Near-Infrared Spectroscopy (fNIRS): Methodological Differences Lead to Different Statistical Results

Even though research in the field of functional near-infrared spectroscopy (fNIRS) has been performed for more than 20 years, consensus on signal processing methods is still lacking. A significant knowledge gap exists between established researchers and those entering the field. One major issue regularly observed in publications from researchers new to the field is the failure to consider possible signal contamination by hemodynamic changes unrelated to neurovascular coupling (i.e., scalp blood flow and systemic blood flow). This might be due to the fact that these researchers use the signal processing methods provided by the manufacturers of their measurement device without an advanced understanding of the performed steps. The aim of the present study was to investigate how different signal processing approaches (including and excluding approaches that partially correct for the possible signal contamination) affect the results of a typical functional neuroimaging study performed with fNIRS. In particular, we evaluated one standard signal processing method provided by a commercial company and compared it to three customized approaches. We thereby investigated the influence of the chosen method on the statistical outcome of a clinical data set (task-evoked motor cortex activity). No short-channels were used in the present study and therefore two types of multi-channel corrections based on multiple long-channels were applied. The choice of the signal processing method had a considerable influence on the outcome of the study. While methods that ignored the contamination of the fNIRS signals by task-evoked physiological noise yielded several significant hemodynamic responses over the whole head, the statistical significance of these findings disappeared when accounting for part of the contamination using a multi-channel regression. We conclude that adopting signal processing methods that correct for physiological confounding effects might yield more realistic results in cases where multi-distance measurements are not possible. Furthermore, we recommend using manufacturers' standard signal processing methods only in case the user has an advanced understanding of every signal processing step performed.