Biomedical Engineering Reference
In-Depth Information
Fig. 4.41.
A multi-channel multiplexed intracortical microprobe reported by Wise
and Najafi [161] (with permission: c
1991 American Association for the Advance-
ment of Science)
above, such as the control of prosthetic devices and the display of artificial
sensations.
In the next section, we review new microelectrode technologies which are
encouraged by the development of silicon microtechnology. In these technolo-
gies, the recording method is basically extracellular recording, as is the case
of the tungsten electrode.
4.8.3
A Microelectrode for the Neural Interface
The Probe Electrode.
Wise has reported many types of microelectro-
des (probe electrodes) which have multiple recording sites [160]. They have
also developed electrodes that have buffer amplifiers on their carrier shank
(Fig. 4.41). Their electrode is designed mainly for recording from cortical
neurons. But successful measurement is not accomplished easily. One of the
reasons may be that this electrode has its recording sites on the shank, so
it can record only from the neurons that are damaged by the passage of
the electrode [150]. Recently, CNCT (the Center for Neural Communication
Technology at the University of Michigan) has started to freely provides many
kinds of probe electrodes for researchers. The experiences of the researchers in
implantation and recording should improve the development of this electrode.
Nowadays, many groups around the world are developing nerve electrodes by
using a silicon microprocess.
The Needle Array Electrode.
Campbell et al. reported the Utah sili-
con needle array, which has 100 (10
×
10) electrodes [162]. In the fabrication
process, they used a diamond dicing saw followed by chemical etching. The
array was insulated with silicon nitride. Some types are currently commer-
cially available as a recording tool from cortical neurons for neuroscience
research. Figure 4.42 shows the typical type of electrode, which has a 100
μ
m
