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Comment by babesh | Hacker News Reader

What do these inhibitory neurons do to manage short-term memories?

This is explained in the Nature article (summary on page 133) and shown as a diagrams in figure 6...

> In summary, these findings imply that robust inhibition of oppositely tuned inhibitory subpopulations is critical for memory maintenance in our RNN model. For example, a positive cue stimulus activates the inhibitory and excitatory subgroups selective for that stimulus and deactivates the negative stimulus subgroups. During the delay period, the inhibition strength between these two inhibitory subgroups dictates the stability of the cue-specific activity patterns generated during the stimulus window. The positive feedback provided by the similarly tuned excitatory neurons sustains the stimulus-specific activity of the inhibitory subgroups.

My intuitive understanding of these findings is that short term memory works by maintaining a consistent firing pattern in a particular region of the prefrontal cortex. By default a given firing pattern might activate other patterns because neurons tend to be a part of multiple potential pattern groups, and so left unchecked it could result in an unstable, random walk type of sequence. To stay in the attractor of one memory though, inhibitory neurons are used to turn off everything that isn't a part of the memory, thereby allowing it to remain in a more steady state.

To further clarify, I believe the authors are advocating a WM model where an excitatory subnet (activated by a Positive cue) sustains its firing (in the absence of that cue; the Delay period) by activating inhibitors of its own inhibitors. (these inhibitory subnets, like goldenshale mentions, also seem to inhibit excitatory subnets, diffusely).

model diagram: https://i.ibb.co/nrh1pVJ/figs.png

Optimistic guess: This information can be found in the paywall'ed article at [1]

> Dissecting our recurrent neural network model revealed strong inhibitory-to-inhibitory connections underlying a disinhibitory microcircuit as a critical component for long neuronal timescales and WM maintenance

If the article is worth the money, i would expect it to go into detail on it.

[1] https://www.nature.com/articles/s41593-020-00753-w

https://sci-hub.se/https://www.nature.com/articles/s41593-02...

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