1. As ATP has a higher affinity for Mg2+ than ADP, the cytosolic magnesium concentration rises upon ATP hydrolysis. We have therefore used the Mg2+-sensitive fluorescent indicator Magnesium Green (MgG)

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ObjectiveThe aim of this study was to map the cortical representation of the lumbar spine paravertebral (LP) muscles in healthy subjects. MethodsTranscranial magnetic stimulation (TMS) was employed to map the cortical representations of the LP muscles at 2 sites. Stimuli were applied to points on a grid representing scalp positions. The amplitude of motor evoked potentials (n=6) were averaged for each position. ResultsThe optimal site for evoking responses in the contralateral LP muscles was situated 1cm anterior and 4 cm lateral to the vertex. Ipsilateral responses were evoked from sites lateral to the optimal site for evoking contralateral responses. Contralateral responses were also obtained from areas anterior to the optimal site. ConclusionsMaps of these muscles can be produced. The results suggest discrete contra and ipsilateral cortical projections. Anterior sites at which excitation can be evoked may indicate projections arising in the SMA are involved. SignificanceThis study provides normative data regarding the cortical representation of the paravertebral muscles and provides a technique for evaluating cortical motor plasticity in patients presenting with spinal pathologies.

The present study sought to further understanding of the brain mechanisms that underlie the effects of music on perceptual, affective, and visceral responses during whole-body modes of exercise. Eighteen participants were administered light-to-moderate intensity bouts of cycle ergometer exercise. Each exercise bout was of 12-min duration (warm-up [3min], exercise [6min], and warm-down [3min]). Portable techniques were used to monitor the electrical activity in the brain, heart, and muscle during the administration of three conditions: music, audiobook, and control. Conditions were randomized and counterbalanced to prevent any influence of systematic order on the dependent variables. Oscillatory potentials at the Cz electrode site were used to further understanding of time-frequency changes influenced by voluntary control of movements. Spectral coherence analysis between Cz and frontal, frontal-central, central, central-parietal, and parietal electrode sites was also calculated. Perceptual and affective measures were taken at five timepoints during the exercise bout. Results indicated that music reallocated participants' attentional focus toward auditory pathways and reduced perceived exertion. The music also inhibited alpha resynchronization at the Cz electrode site and reduced the spectral coherence values at Cz-C4 and Cz-Fz. The reduced focal awareness induced by music led to a more autonomous control of cycle movements performed at light-to-moderate-intensities. Processing of interoceptive sensory cues appears to upmodulate fatigue-related sensations, increase the connectivity in the frontal and central regions of the brain, and is associated with neural resynchronization to sustain the imposed exercise intensity.

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