PT  - JOURNAL ARTICLE
AU  - Bartosz Teleńczuk
AU  - Nima Dehghani
AU  - Michel Le Van Quyen
AU  - Sydney S. Cash
AU  - Eric Halgren
AU  - Nicholas G. Hatsopoulos
AU  - Alain Destexhe
TI  - Local field potentials primarily reflect inhibitory neuron activity in human and monkey cortex
AID  - 10.1101/052282
DP  - 2016 Jan 01
TA  - bioRxiv
PG  - 052282
4099  - http://biorxiv.org/content/early/2016/11/02/052282.short
4100  - http://biorxiv.org/content/early/2016/11/02/052282.full
AB  - The local field potential (LFP) is generated by large populations of neurons, but unitary contribution of spiking neurons to LFP is not well characterised. We investigated this contribution in multi-electrode array recordings from human and monkey neocortex by examining the spike-triggered LFP average (st-LFP). The resulting st-LFPs were dominated by broad spatio-temporal components due to ongoing activity, synaptic inputs and recurrent connectivity. To reduce the spatial reach of the st-LFP and observe the local field related to a single spike we applied a spatial filter, whose weights were adapted to the covariance of ongoing LFP. The filtered st-LFPs were limited to the perimeter of 800 μm around the neuron, and propagated at axonal speed, which is consistent with their unitary nature. In addition, we discriminated between putative inhibitory and excitatory neurons and found that the inhibitory st-LFP peaked at shorter latencies, consistently with previous findings in hippocampal slices. Thus, in human and monkey neocortex, the LFP reflects primarily inhibitory neuron activity.