New Miscellany (General)

by David Turell , Wednesday, January 22, 2025, 18:57 (8 days ago) @ dhw

I’m reluctant to devote whole threads to subjects which we shall only discuss very briefly, and so as you can see, I’m putting them under “New Miscellany”.
To David: please carry on with your own new headings, as usual. I’ll do the sorting.

LUCA

DAVID: Using mutation rates and times of obvious change in forms allows looking backward in time. Of course, the results are estimates.

dhw: And how do you and the authors know the length of time it normally takes for life to appear and complexify?

The molecular clock approach uses sheer estimates. Earliest life was quite complex as LUCA is described.

The brain: concept cells

I’m a bit reluctant to comment, as again I find parts of it difficult to understand, but I’m afraid the following made me laugh out loud:

QUOTE: "Concept cells could code for anything and everything, but they are not used for object recognition. They’re too slow for that: These cells fire after a delay of about 300 milliseconds. “It’s unclear why it takes so long,”

dhw: 300 milliseconds = so long? I wonder how “long” it takes for cells to recognize objects. Ah well, it’s all relative, as Einstein might have said. Any idea how they measure such timings?

The electrodes record any new activity in neurons. Article:

https://newsnetwork.mayoclinic.org/discussion/science-saturday-understanding-the-speed-...

"Called the human connectome, this structural system of neural pathways develops as people age. A new study shows transmission speed among brain regions increases into early adulthood. Learning more about neuron transmission may improve the understanding of psychological disorders."

QUOTE: "It’s possible that these neurons can play different roles and take on different identities based on the task at hand,” Buffalo said. When it needs to be a concept cell for Jennifer Aniston, that’s what it is. When it needs to be a place cell to help you navigate toward the martini at the bar, it is a place cell. “That cell is like a Swiss Army knife,” Miller suggested.

dhw: I do like this. It suggests to me that cells are living, cognitive entities which can perform different activities and take on different roles according to different requirements. Very much in line with Shapiro, wouldn’t you say?

DAVID: very early tentative research into memory function. Identifying specific neuron function is amazing. Animals must have place neurons but not concept ones I assume.

Does that mean your dog doesn't recognize you?

He sees me and reacts immediately.