Speaker
Description
Transcranial alternating current stimulation (tACS) is a technique for modulating cortical oscillations. The external application of electrical currents can influence cortical excitability and activity. But how the electric fields interact with individual neurons remains poorly understood. Thus, we use a biophysically and morphologically detailed model of human cortical pyramidal neurons and PV, SST, and VIP interneurons to simulations. Moreover, we used the NetPyNE/NEURON to incorporate recurrent excitation–inhibition architecture, short-term synaptic plasticity, tonic inhibition, synaptic background activity, spatial neuronal placement, and distance-dependent connectivity based on nanoscale electron microscopy reconstructions of human cortex. Firstly, we analize the effects of tACS on firing rate and entrainment across individual neurons considered. Furthermore, we then extend the analysis to a cortical network operating under in vivo-like conditions, in the simulations through systematic parametric sweeps of stimulation frequency and amplitude. In this study, we show that neural responses depend on the frequency and stimulation intensity. exhibit complex nonlinear phase-locking patterns and that tACS can either increase or decrease synchronisation. Our simulations show that entrainment efficacy is strongly state-dependent. Thus, baseline depolarisation substantially expands the firing regime, whereas specific combinations of stimulation frequency and amplitude induce transitions into irregular dynamics. These irregularities destabilise rhythmic synchronisation and alter how information is encoded. Therefore, this study provides a mechanistic framework for understanding the limits of stable neural coupling under tACS and supports the development of optimised, state-dependent neuromodulation protocols.
| Preferred Presentation | Poster Presentation |
|---|