RESUMEN
BACKGROUND: The objective of this paper was to evaluate the potential individual and combined effects of acute exercise coupled with bilateral interhemispheric activation on episodic memory function. Six experiments were conducted. METHODS: Experiment 1 was a within-subject, counterbalanced experiment. Participants completed four visits, including 1) exercise and saccadic eye movements, 2) exercise only, 3) saccadic eye movements only, and 4) no exercise and no saccadic eye movements (control). A word-list memory assessment was employed, including a long-term (20-min delay) memory evaluation. In Experiment 2, we evaluated the effects of saccadic eye movements on prefrontal cortex oxygenation, a proxy for neuronal activity. Similarly, in our third experiment, we evaluated the effects of acute exercise on prefrontal cortex oxygenation. Thus, experiments 2 and 3 were employed to provide mechanistic insights from the results shown in experiment 1. Experiment 4 replicated Experiment 1, but instead of increasing prefrontal cortex activation via saccadic eye movements, we used a fist clenching protocol. Experiment 5 evaluated the effects of fist clenching on prefrontal cortex oxygenation. RESULTS: Collectively, these 5 experimental studies showed that acute exercise (Experiment 1), saccadic eye movements (Experiment 1), and fist clenching (Experiment 4) enhanced memory function, and that acute exercise (Experiment 3), saccadic eye movements (Experiment 2) and fist clenching (Experiment 5) all increased prefrontal cortex oxygenation. Experiment 6 demonstrated that prefrontal cortex oxygenation was positively associated with episodic memory function. CONCLUSION: These six experiments suggest that several behaviors, such as acute exercise, saccadic eye movements and fist clenching may improve memory function and may, potentially, do so via increases in prefrontal cortex oxygenation.
Asunto(s)
Memoria Episódica , Cognición , Ejercicio Físico/fisiología , Humanos , Corteza Prefrontal/fisiología , Movimientos SacádicosRESUMEN
Background and Objective: The objective of this study was to evaluate the potential independent and interactive effects of handedness and grip strength on episodic memory function, and whether biological sex moderated these relationships. Materials and Methods: 162 young adults (Mage = 20.7 years) completed a series of memory assessments including a subjective memory complaint evaluation and several objective measures of memory. Handedness (i.e., left-hand dominant, inconsistent handedness (ICH), and right-hand dominant) was evaluated using the Edinburgh Handedness Inventory. Handgrip strength was determined from a handgrip dynamometer. Results: When compared to ICH individuals, retrospective memory scores were statistically significantly worse for left-handed (p = 0.02) and right-handed (p = 0.03) individuals. Higher grip strength was statistically significantly associated with fewer retrospective memory complaints (b = 0.10, 95% CI: 0.01, 0.19, p = 0.04). Conclusions: The present study provides some suggestive evidence that ICH (inconsistent handedness) and greater grip strength are associated with fewer retrospective memory complaints. However, we did not observe any evidence of an interaction effect of handedness and grip strength on memory, and similarly, biological sex did not interact with these parameters to influence memory.
Asunto(s)
Lateralidad Funcional/fisiología , Fuerza de la Mano/fisiología , Memoria/fisiología , Factores Sexuales , Femenino , Humanos , Masculino , Pruebas de Estado Mental y Demencia/estadística & datos numéricos , Mississippi , Encuestas y Cuestionarios , Adulto JovenRESUMEN
BACKGROUND: Functional magnetic resonance imaging (fMRI) studies suggest that stroke-induced motor deficits are associated with an interhemispheric imbalance of motor activation. This meta-analysis aims to determine the changes of interhemispheric activation balance (IHAB) in motor-related cortices along with post-stroke motor recovery. METHODS: We searched PubMed for fMRI studies that investigated IHAB in stroke patients with motor recovery. Laterality indexes (LIs, (ipsilesional activation-contralesional activation)/(ipsilesional activation+contralesional activation)) before and after motor improvement were extracted as the outcome measures of IHAB. Data were synthesized by calculating standardized mean difference (SMD, Hedges' adjusted g) with 95% confidence intervals (CI). RESULTS: After the rejection of 459 studies, 22 trials fulfilled the inclusion criteria and were included in the systematic review and meta-analysis. The LIs of sensorimotor cortex (SMC, 22 trials, 195 subjects), premotor cortex (PMC, 12 trials, 93 subjects), supplementary motor area (SMA, 12 trials, 92 subjects), and cerebellum (CB, 4 trials, 31 subjects) were assessed. Studies sampling from stroke patients with motor improvement showed positive changes of LI in SMC (SMD, 0.71; 95% CI, 0.41-1.01; P<0.00001) and PMC (SMD, 0.68; 95% CI, 0.36-1.00; P<0.0001), but not in SMA (SMD, 0.07; 95% CI, -0.62 to 0.75; P=0.85) and CB (SMD, -0.17; 95% CI, -1.52 to 1.19, P=0.81). Studies involving stroke patients with poor motor recovery showed non-significant changes in all of the four motor-related cortices (P>0.05). CONCLUSIONS: This meta-analysis suggests that along with good motor recovery of stroke patients, the IHAB is up-regulated in SMC and PMC, but not significantly changed in SMA and CB. Because of the limited data, further studies are needed to verify the findings.