Willett, Shenoy et al. (2021) have developed a brain computer interface (BCI) that used neural signal collected from the hand area of the motor cortex (area M1) of a paralyzed patient. The patient had damage to his cervical spinal cord, which spared movements of the head, face, and eyes. The patient was required to imagine and attempt to use his right hand (contralateral to the brain implant) to write sentences on a sheet of paper using a pen, as sentences were presented to him on a computer screen. A character set of 31 items included the 26 letters of the alphabet and other symbols such as the spacing between words was used. The patient’s performance on the task (as measured neurally) improved over a one-month period and peaked at 90 characters per minute at an accuracy rate of 94.6% correctness, in the absence of any autocorrect procedure. This performance translates into 1.7 bits per second or under four possibilities per second [bit-rate corrected for information redundancy per letter, Reed and Durlach 1998]. The patient was also required to generate sentences spontaneously. Here the information transfer rate drops to 1.2 bits per second. It is noteworthy that the patient was observed moving his right hand contralateral to the implanted motor cortex during periods of attempted handwriting. Whether such movements are important for achieving the performance observed is unclear, but proprioceptive feedback from the muscles is necessary for sufficient M1-BCI activity (Tehovnik et al. 2013; Tehovnik and Chen 2015).
Recently, Elon Musk announced that his new BCI device transfers about 1 bit per second which is in keeping with the result of Willet, Shenoy et al. (2021). Musk then said on YouTube that over an entire day 1 bit per second adds up to a large amount of information. Clearly, Musk does not know what he is talking about. For example, language is based on the transfer rate of 40 bits per second or over 1 trillion possibilities per second (Reed and Durlach 1998). Transferring 1 bit per second over a 40 second period will not translate into over 1 trillion possibilities over 40 seconds but rather 80 possibilities over 40 seconds. Furthermore, Musk has created the illusion that he is the sole creator of brain computer interfaces by not mentioning any work done by others over the last two decades. And there has been much work done by individuals such as Miguel Nicolelis, Richard Andersen, Andrew Schwartz, and John Donoghue to start, and by now the list of investigators must be in the thousands. This neglect by Musk guarantees that he will be stuck at 1 bit per second.
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