[moontear]

I am not an expert, but what I thought was remarkable is the 12000 channels Musk talked about. New cochlear implants have 120 channels - one channel is one neuron (AFAIK) - more neurons is better results.

I would love some expert take on this, but my first reaction was „12000 sounds like a lot - they all work? That’s cool“.

Also check out this wait but why article which I think explains the resolution pretty well: https://waitbutwhy.com/2017/04/neuralink.html

[thornjm]

I’m very much not an expert. I think the state of the art for measuring brain activity is the functional MRI. fMRIs have limits on their spatial, temporal and ‘activity’ resolution. I think they also measure ‘only’ blood flow and not electrical activity.

My guess is that if Neuralink does nothing more than provide a more sophisticated tool for investigating the brain than the current state of the art then it will have been a success.

A quick google suggests the highest resolution fMRIs currently have about 1 million voxels of spatial resolution at a sample rate of about 1/sec. EEGs can measure electrical activity but only at very low resolution and on the surface.

[hprotagonist]

It depends on what you mean by "measuring brain activity". fMRI has a spatial resolution on the order of the summed activity of tens of thousands of neurons and a temporal resolution of 2-4 seconds, so it's often very imprecise if you want to know what one neuron in particular is up to.

I've seen single-unit recordings done with electrodes and simultaneous Ca2+ imaging with a 2-photon microscope. You trade real-time speed and single unit specificity for a loss of knowledge about the population.

MEG can give you real-time summed behavior, but the inverse problem is indeterminate so you're less sure of _where_ that activity is coming from.

"what's the good tool to measure brain activity" is very often a function of "what do i want to find out about the brain?"

[hprotagonist]

and of those 120, about 18-24 actually wind up being useful on average.

Also, CIs are not brain implants.

In 2016 I got the chance to do a few month’s work on some cortical recodings in mice with a 512-electrode patch, and when i left the lab was complaining about how to modernize up to 1024 while still keeping their calcium imaging working well.

[me_me_me]

a honey bee has roughly 960,000 neurons.

To do bee stuff.

It just show a scale off human brain. And while its brain size is not equivalent to the intelligence/capabilities, pluggin into our brain is going to be a bit more complicated than 12000 wires.