Transcranial Direct Current Stimulation Integration with Magnetic Resonance Imaging, Magnetic Resonance Spectroscopy, Near Infrared Spectroscopy Imaging, and Electroencephalography

2019 ◽  
pp. 293-345 ◽  
Author(s):  
Adam J. Woods ◽  
Marom Bikson ◽  
Kenneth Chelette ◽  
Jacek Dmochowski ◽  
Anirban Dutta ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Infrared Spectroscopy ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Near Infrared ◽  
Resonance Spectroscopy ◽  
Resonance Imaging

Simultaneous in vivo measurements of HbO2 saturation and PCr kinetics after exercise in normal humans

1994 ◽  
Vol 77 (1) ◽  
pp. 5-10 ◽  
Author(s):  
K. K. McCully ◽  
S. Iotti ◽  
K. Kendrick ◽  
Z. Wang ◽  
J. D. Posner ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Time Constant ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Plantar Flexion ◽  
Resonance Spectroscopy ◽  
Ph Values

Simultaneous measurements of phosphocreatine (PCr) and oxyhemoglobin (HbO2) saturation were made during recovery from exercise in calf muscles of five male subjects. PCr was measured using magnetic resonance spectroscopy in a 2.0-T 78-cm-bore magnet with a 9-cm-diam surface coil. Relative HbO2 saturation was measured as the difference in absorption of 750- and 850-nm light with use of near-infrared spectroscopy. The light source and detectors were 3 cm apart. Exercise consisted of isokinetic plantar flexion in a supine position. Two 5-min submaximal protocols were performed with PCr depletion to 60% of resting values and with pH values of > 7.0. Then two 1-min protocols of rapid plantar flexion were performed to deplete PCr values to 5–20% of resting values with pH values of < 6.8. Areas of PCr peaks (every 8 s) and HbO2 saturation (every 1 s) were fit to a monoexponential function, and a time constant was calculated. The PCr time constant was larger after maximal exercise (68.3 +/- 10.5 s) than after submaximal exercise (36.0 +/- 6.5 s), which is consistent with the effects of low pH on PCr recovery. HbO2 resaturation approximated submaximal PCr recovery and was not different between maximal (29.4 +/- 5.5 s) and submaximal (27.6 +/- 6.0 s) exercise. We conclude that magnetic resonance spectroscopy measurements of PCr recovery and near-infrared spectroscopy measurements of recovery of HbO2 saturation provide similar information as long as muscle pH remains near 7.0.

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