The interface could allow people with neurological conditions to control phones or computers with their mind.Mr Musk argues such chips could eventually be used to help cure conditions such as dementia, Parkinson's disease and spinal cord injuries.
But the long-term ambition is to usher in an age of what Mr Musk calls "superhuman cognition", in part to combat artificial intelligence so powerful he says it could destroy the human race.
Gertrude was one of three pigs in pens that took part in Friday's webcast demo. She took a while to get going, but when she ate and sniffed straw, the activity showed up on a graph tracking her neural activity. She then mostly ignored all the attention around her.
The processor in her brain sends wireless signals, indicating neural activity in her snout when looking for food.
Facebook and startups like Elon Musk's Neuralink are pouring money into a new wave of neurotechnology with bold promises, like typing with your thoughts or, in Musk's words, merging with AI.All of these devices generate huge amounts of neural data, potentially one of the most sensitive forms of personal information.
Mr Musk said the original Neuralink device, revealed just over a year ago, had been simplified and made smaller.
"It actually fits quite nicely in your skull. It could be under your hair and you wouldn't know."Founded in 2017, Neuralink has worked hard to recruit scientists, something Mr Musk was still advertising for on Twitter last month and which he said was the purpose of Friday's demo.
The algorithm then interprets the data into various emotional states — for example, depression, anxiety, and rage — so managers can use the information to better plan break times and help everyone be efficient.The Chinese program uses the sensors to record electrical signals in the brain, which is called electroencephalography (EEG).
The device the company is developing consists of a tiny probe containing more than 3,000 electrodes attached to flexible threads thinner than a human hair, which can monitor the activity of 1,000 brain neurons.Ahead of the webcast, Ari Benjamin, at the University of Pennsylvania's Kording Lab, had told BBC News the real stumbling block for the technology could be the sheer complexity of the human brain.
"Once they have the recordings, Neuralink will need to decode them and will someday hit the barrier that is our lack of basic understanding of how the brain works, no matter how many neurons they record from.
"Decoding goals and movement plans is hard when you don't understand the neural code in which those things are communicated."Mr Musk's companies SpaceX and Tesla have captured the public imagination with his attempts to drive progress in spaceflight and electric vehicles respectively.