Hello,
In today’s tutorials(week 1, day 1), there was very brief mention of implementation of balanced excitation/inhibition in the LIF model. I would like to know if there are some biological instances of such balance i.e do we have neurons that actually function this way? Would this sort of reflect a refractory period?
Thank you and apologies if this is not the right place for this thread.
Hi!
Yes, there is growing evidence of the biological relevance of excitation/inhibition balance in information processing. Interestingly, many neuropsychiatric diseases (e.g. autism and schizophrenia) seem to be connected to an impairment in this balance (see this paper as example, but there is definitely much more out there).
Xue et al., Nature 2014 here from Scanziani group described that there is a critical ratio of excitation to inhibition across cellular types and different cortical layers. What that means is that every single cortical layer (suprgranular or subgranular) or cell type (excitatory or different inhibitory types) receive a different excitation/inhibition value, also called excitation/inhibition ratio, (E/I ratio). They do not need to sum zero.
At the functional level, this ratio permit the proper function of the cellular types and networks (e.g., there are networks that operate on a higher E/I ratio, and other types a lower levels).
Over the years, it has been hypothesised that some diseases may alter this ratio. The most classic disease is in epilepsy, where higher E/I ratio leads to neuronal hyper-excitability and makes the tissue prone to seizures.
Hope it helps!
Jose
Lots of debate about this in terms of psychiatric disease as to whether the pathology is actually in response to a loss of excitation/inhibition balance or it is secondary to disease and just a symptom. The best example I can think of is epilepsy, as in when there is too much excitation within a system.
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