In the 1960s and 1970s, many researchers in North America,Europe, Japan, and Australia experimented in the field of functional electrical stimulation (FES)。Devices were commercialized to treat drop foot caused by stroke and to treat pain by stimulating the spinal cord which caused a tingling effect (referred to as parathesia), which seemed to mask the pain。 Attempts were made to restore vision to blind patients by stimulating the occipital lobe but were not very successful。 A major center at Case Western Reserve University in Cleveland, OH (CWRU), performed a great deal of research on quadriplegic and paraplegic patients。 Most of their systems used percutaneous wire through the skin to activate paralyzed muscles。 They tended to use high current pulses with narrow pulse widths。 In June 1969, the National Institutes of Health (NIH)held a major conference on the artificial heart program。This was a serious multimillion dollar program to solve the many technical problems involved with implanting an artificial heart into the human body。 The program dealt with bio-compatibility, energy transfer, chemical sensors,thermal loading and solving the problem of having wires, and other items passing through the skin without infection like a deer’s antler and our nails。 The proceedings [2] became a handbook for the field of bioengineering。 In the early 1970s, the NIH started a program specifically for neural augmentation。 This  was  a multimillion dollar program to jump start the field of FES。 Many research grants were given in the western world to develop new technology for the FES field。 In about 1980, NASA at the request of the Veterans Administration offered a contract for 200 multichannel multiwired stimulators that were radio-frequency (RF) powered (i。e。, powered by an external ac magnetic field) to be used by the research team at Case。 This contract was awarded to a company in Cleveland。 By about 1990, CWRU researchers and others developed a multichannel multiwire stimulator for providing a function for paralyzed arms (The Free Hand System), which was also used to provide function to paralyzed legs。 Also in this period, Dr。 R。 Davis, working with the Praxis Corporation, modified a 22-channel cochlear implant made by Nucleus Corporation with a neural stimulator involving 22 wires for leg and other FES applications。 There were other multichannel multiwire FES RF powered stimulators developed in the United States and

Europe in the 1980s and 1990s。

It gradually became apparent that the FES RF powered multichannel, multiwired stimulators were not practical for restoring significant function to paralyzed limbs and other organs。 The problems with these multichannel, multiwired stimulators are listed below。

1、Brain stimulation

Brain stimulation has potentials to treat some disorders such as epilepsy。 In this method, scheduled stimulation is applied to specific cortical or subcortical targets。 There are available commercial devices[7] that can deliver an electrical pulse at scheduled time intervals。 Scheduled stimulation is hypothesized to alter the intrinsic neurophysiologic properties of epileptic networks。 The most explored targets for scheduled stimulation are the anterior nucleus of thethalamus and the hippocampus。 The anterior nucleus of the thalamus has been studied,    which    has    shown    a    significant     seizure     reduction     with     the stimulator onversus off during several months after  stimulator  implantation。[8]  Moreover, the cluster  headache (CH)  can  be  treated  by  using  a  temporary  stimulating      electrode at sphenopalatine ganglion (SPG)。 Pain relief is reported within several minutes of stimulation in this method。[9] To avoid use of implanted electrodes, researchers have engineered ways to inscribe a "window" made of zirconia that has been modified to be transparent and implanted in mice skulls, to allow optical waves to penetrate more deeply, as in optogenetics, to stimulate or inhibit inpidual neurons。[10]