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Abstract Many cognitive and sensory processes are characterized by strong relationships between the timing of neuronal spiking and the phase of ongoing local field potential oscillations. The coupling of neuronal spiking in neocortex to the phase of alpha oscillations (8-12 Hz) has been well studied in nonhuman primates but remains largely unexplored in other mammals. How this alpha modulation of spiking differs between brain areas and cell types, as well as its role in sensory processing and decision making, are not well understood. We used Neuropixels 1.0 probes to chronically record neural activity from somatosensory cortex, prefrontal cortex, striatum, and amygdala in mice performing a whisker-based selective detection task. We observed strong spontaneous alpha modulation of single-neuron spiking activity during inter-trial intervals while mice performed the task. The prevalence and strength of alpha phase modulation differed significantly across regions and between cell types. Phase modulated neurons exhibited stronger responses to both go and no-go stimuli, as well as stronger motor- and reward-related changes in firing rate, than their unmodulated counterparts. The increased responsiveness of phase modulated neurons suggests they are innervated by more diverse populations. Alpha modulation of neuronal spiking during baseline activity also correlated with task performance. In particular, many neurons exhibited strong alpha modulation before correct trials, but not before incorrect trials. These data suggest that dysregulation of spiking activity with respect to alpha oscillations may characterize lapses in attention. 

Pyramidal neurons in neocortex have complex input-output relationships that depend on their morphologies, ion channel distributions, and the nature of their inputs, but which cannot be replicated by simple integrate-and-fire models. The impedance properties of their dendritic arbors, such as resonance and phase shift, shape neuronal responses to synaptic inputs and provide intraneuronal functional maps reflecting their intrinsic dynamics and excitability. Experimental studies of dendritic impedance have shown that neocortical pyramidal tract neurons exhibit distance-dependent changes in resonance and impedance phase with respect to the soma. We, therefore, investigated how well several biophysically detailed multicompartment models of neocortical layer 5 pyramidal tract neurons reproduce the location-dependent impedance profiles observed experimentally. Each model tested here exhibited location-dependent impedance profiles, but most captured either the observed impedance amplitude or phase, not both. The only model that captured features from both incorporates hyperpolarization-activated cyclic nucleotide-gated (HCN) channels and a shunting current, such as that produced by Twik-related acid-sensitive K + (TASK) channels. TASK-like channel density in this model was proportional to local HCN channel density. We found that although this shunting current alone is insufficient to produce resonance or realistic phase response, it modulates all features of dendritic impedance, including resonance frequencies, resonance strength, synchronous frequencies, and total inductive phase. We also explored how the interaction of HCN channel current ( I h ) and a TASK-like shunting current shape synaptic potentials and produce degeneracy in dendritic impedance profiles, wherein different combinations of I h and shunting current can produce the same impedance profile. NEW & NOTEWORTHY We simulated chirp current stimulation in the apical dendrites of 5 biophysically detailed multicompartment models of neocortical pyramidal tract neurons and found that a combination of HCN channels and TASK-like channels produced the best fit to experimental measurements of dendritic impedance. We then explored how HCN and TASK-like channels can shape the dendritic impedance as well as the voltage response to synaptic currents.