Modulation of Cortical Activity by High-Frequency Whole-Body Vibration Exercise: An fNIRS Study.

CONTEXT: Whole-body vibration (WBV) has shown many positive effects on the human body in rehabilitation and clinical settings in which vibration has been used to elicit muscle contractions in spastic and paretic muscles. OBJECTIVE: The purpose of this study was to investigate whether WBV exercise (WBVe) differently modulates the cortical activity associated with motor and prefrontal function based on its frequency. METHODS: A total of 18 healthy male adults (mean age: 25.3 [2.4] y) participated in this study and performed WBVe (Galileo Advanced plus; Novotec Medical, Pforzheim, Germany) under 3 different vibration frequency conditions (4-mm amplitude with 10-, 20-, and 27-Hz frequencies) and a control condition (0-mm amplitude with 0-Hz frequency). Each condition consisted of 2 alternating tasks (squatting and standing) every 30 seconds for 5 repetitions. All subjects performed the 4 conditions in a randomized order. MAIN OUTCOME MEASURE: Cortical activation during WBVe was measured by relative changes in oxygenated hemoglobin concentration over the primary motor cortex, premotor cortex, supplementary motor area, and prefrontal and somatosensory cortices using functional near-infrared spectroscopy. RESULTS: Oxygenated hemoglobin concentration was higher during the 27-Hz vibration condition than the control and 10-Hz vibration conditions. Specifically, these changes were pronounced in the bilateral primary motor cortex (P < .05) and right prefrontal cortex (P < .05). In contrast, no significant changes in oxygenated hemoglobin concentration were observed in any of the cortical areas during the 10-Hz vibration condition compared with the control condition. CONCLUSION: This study provides evidence that the motor network and prefrontal cortical areas of healthy adult males can be activated by 27-Hz WBVe. However, WBVe at lower frequencies did not induce significant changes in cortical activation.

Pre-conditioning with transcranial low-level light therapy reduces neuroinflammation and protects blood-brain barrier after focal cerebral ischemia in mice.

PURPOSE: Transcranial low-level light therapy (LLLT) has gained interest as a non-invasive, inexpensive and safe method of modulating neurological and psychological functions in recent years. This study was designed to examine the preventive effects of LLLT via visible light source against cerebral ischemia at the behavioral, structural and neurochemical levels. METHODS: The mice received LLLT twice a day for 2 days prior to photothrombotic cortical ischemia. RESULTS: LLLT significantly reduced infarct size and edema and improved neurological and motor function 24 h after ischemic injury. In addition, LLLT markedly inhibited Iba-1- and GFAP-positive cells, which was accompanied by a reduction in the expression of inflammatory mediators and inhibition of MAPK activation and NF-κB translocation in the ischemic cortex. Concomitantly, LLLT significantly attenuated leukocyte accumulation and infiltration into the infarct perifocal region. LLLT also prevented BBB disruption after ischemic events, as indicated by a reduction of Evans blue leakage and water content. These findings were corroborated by immunofluorescence staining of the tight junction-related proteins in the ischemic cortex in response to LLLT. CONCLUSIONS: Non-invasive intervention of LLLT in ischemic brain injury may provide a significant functional benefit with an underlying mechanism possibly being suppression of neuroinflammation and reduction of BBB disruption.