Our history of microelectrode technology starts in the 1950s.
It wasn’t until 1953 that the first glass pipet microelectrode was used for extracellular recording (Rose, Science 1953). The glass pipette had a platinum wire inside, and it had a 10-micron tip. From there, there was a big development where Hubel developed the first microwire-based electrode (Hubel, Science 1957). This was a significant improvement because of the mechanical durability of wires compared to glass. He was able to record from the cat dorsal root for periods up to an hour. Later in that decade, Strumwasser reported using the first microwire bundle, an array consisting of four wires (Strumwasser, Science 1958). He was able to record for up to seven days.
Those involved in operant conditioning studies may be familiar with the Olds work from 1965 which used nine nichrome wires for recordings lasting up to seven days and with 50% yield of action potentials (Olds, Brain Research 1965). In 1967, Naka reported the use of tungsten microwires (Naka, Brain Research 1967). These were 127-micron diameter with 1-micron tips, and he was able to record up to one month with them.
In 1969 there began a revolution.
Wise reimagined what a neural electrode would look like, using silicon as a substrate and using MEMS-based technologies (Wise, Conf on Engineering in Med and Biol 1969). His was the first report of an electrode developed with silicon substrate and silicon dioxide dielectrics. Then, in 1971, the National Institutes of Health (NIH) formed the Neural Prosthesis Program to push the field forward by bringing researchers together to collaborate and to disseminate new developments within the area of neural engineering and neural interfaces. In 1973, the Bak electrode was reported, contributing the first flexible interconnect for microelectrode packaging (Salcman & Bak, IEEE Trans BME 1973). Schmidt then reported recordings with iridium wires coated with parylene C. He was able to record 223 days (about 7 and a half months) in monkey cortex (Schmidt, Experimental Biology 1976). Finally, in 1988 was the first report of the Michigan probe, a silicon probe in vivo (Drake et al., IEEE Trans BME 1988), which demonstrated the value of a laminar array: simultaneous recordings at multiple depths.
In 1994, the Center for Neural Communication Technologies (CNCT) was launched. This was an NIH-funded center that was in place for 10 years. It really amplified the efforts that were put into developing and refining the silicon probe technology, with a focus on acute probes. Acute probes are used temporarily and then taken out of the subject. The goal of CNCT was to disseminate silicon probes throughout the world for researchers that could use them.
Williams tested chronically implanted silicon probes in 1999 (Williams & Kipke, Brain Res Prot 1999). This work brought into context the electrode-electrolyte interface, as well as the value of impedance spectroscopy, which was used to understand that the failure mechanisms of silicon probes are both device or abiotic failure and biological foreign body response or biotic failure. Then, in 2003 and 2004 Kipke and Vetter reported the first chronic performance assessment of the Michigan probe, and were able to get reliable recordings for fifty-five weeks (over 1 year) in rats (Kipke & Vetter, IEEE Neural Sys & Rehab Eng 2003; Vetter & Kipke, IEEE Trans BME 2004).
In 2004, NeuroNexus was officially launched.
- 1953 = first glass pipet microelectrode for extracellular recording
- 1957 = first microwire-based electrode, one hour recording
- 1958 = first microwire bundle (4 wires), 7 days recording
- 1965 = nichrome wire bundle (9 wires), 7 days recording
- 1967 = tungsten microwires, 1 month recording
- 1969 = silicon, MEMS-based technology
- 1971 = NIH Neural Prosthesis Pogram
- 1973 = flexible interconnect packaging
- 1976 = parylene C-coated iridium wires, 7+ months recording
- 1988 = silicon probe
- 1994 = CNCT launched with acute silicon probes
- 1999 = chronic silicon probes
- 2003-4 = chronic silicon probes, 12+ months recording
- 2004 = NeuroNexus