Laser-fluorescent pulses as a probe to brain energy and efficiency

A specific electrode was made of quartz optic fibers with a thin metal membrane, the quartz core guided nitrogen laser beam (10 - 40 ??j/pulse, I pulse/sec.) into brain cortex, and got out fluorescent pulses emitted by brain NADH and FAD moleculars. The amplitudes of laser- fluorescent pulses represented brain NADH and FAD concentrations determined by HPLC methods. The metal membrane outside optic fiber (1*10 ??m2, 40 mm long) as a specific electrode rrrrrred neural discharges. The neural pulses represented neuron activities. The ratio of frequency changes of neural discharges to the amplitude changes of laser- fluorescent pulses was written as ?? = dFi/dAi, which ?? means neuron efficiency. The results showed that intensity of nitrogen beam increased the amplitudes of laser-fluorescent pulses and decreased the ?? value. Electric stimuli increased the frequency of neural discharges and increased the ?? value. The results mean that low power laser beam guided into brain by optic fibers can work as a stimulant factor as well as a probe to brain function.EI