How synaptic input location shapes frequency modulation in a single neuron

[MakotoMiyakoshi]

The bottom-right plots show time-domain responses, so you have to Fourier-transform them in your mind; narrower the peak, flatter the PSD.

Rall W, Burke RE, Smith TG, Nelson PG, Frank K. 1967. Dendritic location of synapses and possible mechanisms for the monosynaptic EPSP in motoneurons. J Neurophysiol. 30:1169-1193.
DOI: 10.1152/jn.1967.30.5.1169, PMID: 4293410

[mgy42]

This is beautiful stuff, thank you for sharing, Makoto. I think we could certainly use this information to convincingly argue that a synaptic distance mechanism also contributes to the 1/f shape (potentially in addition to E:I balance, i.e., that we can see 1/f changes without changes in the relative contribution of EPSPs/IPSPs, just by changing the distance of E inputs from the soma). Now I will just have to double check how this differs from the dendritic filtering idea which has already been floated by others.

[mgy42]

Would the bottom right plot look the same (just with the signs flipped, and with larger average peak width) for IPSP?

[MakotoMiyakoshi]

Hi @mgy42,

Now I will just have to double check how this differs from the dendritic filtering idea which has already been floated by others.

I think they are the same things.

Would the bottom right plot look the same (just with the signs flipped, and with larger average peak width) for IPSP?

That's the place where Gao's AMPA/GABA_A difference comes in as an additional effect on extracellular potential field, but in terms of the cable theory (subthreshold), it should be the same (I could be wrong here.)

[mgy42]

Thanks, Makoto. This is Mate, by the way, I realised my account name is not very informative.

But if this is dendritic filtering, what is the novelty of our proposition? Is it to use to explain surface level M/EEG data? If yes, this is where I'd suggest again to focus on within-subject changes, i.e., can this framework account for rapid dynamic changes in 1/f? You discussed a task where the lemniscal vs extralemniscal pathways might be activated to different extents in different conditions, leading a testable prediction about 1/f change due to dendritic filtering, but I forget the details of the task. It involved novelty/surprise in some fashion, right?

[mgy42]

Also, sidenote, but I was looking at the classic Buzsaki, Anastassiou, & Koch (2012) paper for completelty unrelated reasons, and I think their Fig. 2a is also showing this same mechanism just from a different perspective.

[mgy42]

Their figure caption: "Computer-simulated local field potential (LFP) traces (left panel; grey) in response to an excitatory synaptic current input (a sink, shown by the blue circle) injected into the distal apical dendrite of a purely passive layer 5 pyramidal model neuron. The waveform of the injected current is illustrated in the box. Red and blue contour lines correspond to positive and negative values for the LFP amplitude, respectively. The calculated double logarithmic power spectra of the transmembrane potential are also shown (right panel), following injection of current into the apical dendrite near the injection site (blue trace), mid-apical dendrite (green trace) and soma (orange trace). Note that high-frequency activity decreases with the distance from the active synaptic site (that is, the sink)."