Hi Fergal,
Thanks. I would like to ask whether permanence be negative biologically?
We know the cell can be fired at a 'fire rate' and send the signal to
its connected cells. Can the cell sent another type of signal to its
connected cells and the signal can be treated as a 'inhibition' and
mathematically a negative weighted permanence?
Regards,
Roy
----
Hi Roy,
In the CLA, "inhibition" is done at the column level, either globally or
locally. The Spatial Pooler picks the 2% of columns with the highest
activation potential from either the whole region (global) or sub-regions
(local) and activates them. This mimics inhibition in the neocortex, in
which high-potential (or most active) cells suppress the potential or
activity of cells in neighbouring columns.
The overall effect is very similar, in that sparseness is imposed and the
"best" columns are activated. If we can achieve very similar outcomes, then
efficiency considerations justify the deviation from the actual process in
the neocortex.
A recent thread on this list discussed an alternate inhibition strategy for
the CLA. This proposal involves the idea of high-potential columns imposing
a "negative potential" effect on its neighbours. Initial tests suggest that
this method is significantly faster than the current local "inhibition"
algorithm, and it is also a closer analogue to the neocortex.
Regards,
Fergal Byrne
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