High Fidelity Theta Phase Rolling of CA1 Neurons

Abstract

Single hippocampal cells encode the spatial position of an animal by increasing their firing rates within "place fields," and by shifting the phase of their spikes to earlier phases of the ongoing theta oscillations (theta phase precession). Whether other forms of spatial phase changes exist in the hippocampus is unknown. Here, we used high-density electrophysiological recordings in mice of either sex running back and forth on a 150-cm linear track. We found that the instantaneous phase of spikes shifts to progressively later theta phases as the animal traverses the place field. We term this shift theta "phase rolling." Phase rolling is opposite in direction to precession, faster than precession, and occurs between distinct theta cycles. Place fields that exhibit phase rolling are larger than nonrolling fields, and in-field spikes occur in distinct theta phases in rolling compared with nonrolling fields. As a phase change associated with position, theta phase rolling may be used to encode space.

Hybrid Offspring of C57BL/6J Mice Exhibit Improved Properties for Neurobehavioral Research

“…Animals were held on a reverse dark/light cycle (dark phase, from 8 A.M. until 8 P.M.). Data recorded from CA1 during linear track behavior were used in a previous report ( Sloin et al, 2022 ). All animal handling procedures were in accordance with Directive 2010/63/EU of the European Parliament, complied with Israeli Animal Welfare Law (1994), and approved by the Tel Aviv University Institutional Animal Care and Use Committee (IACUC #01-16-051, #01-19-017, and #01-21-051).…”

“…Based on the linear track data, spatial information, place fields, and phase precession were determined for every PYR ( Sloin et al, 2022 ). Briefly, place fields were defined as regions spanning 15–100 cm in which the firing rate increased compared with the on-track spontaneous firing rate ( p < 0.05, Bonferroni-corrected Poisson test).…”

“…Theta phase precession was quantified for each place field using a circular-linear analysis ( Schmidt et al, 2009 ; Kempter et al, 2012 ). The circular-linear model yielded the precession slope, a , and the resultant length of the residuals, R , indicating model fit; statistical significance was determined by a permutation test ( Sloin et al, 2022 ). Precession effect size was quantified as the ratio between the fit of spikes to the circular-linear model, R , divided by the median of 300 model fits to randomly permuted phase/position pairs.…”

Hybrid offspring of C57BL/6J mice exhibit improved properties for neurobehavioral research

“…Animals were held on a reverse dark/light cycle (dark phase, from 8 AM until 8 PM). Data recorded from CA1 during linear track behavior were used in a previous report (Sloin et al, 2022). All animal handling procedures were in accordance with Directive 2010/63/EU of the European Parliament, complied with Israeli Animal Welfare Law (1994), and approved by the Tel Aviv University Institutional Animal Care and Use Committee (IACUC # 01-16-051, #01-19-017, and #01-21-051).…”

“…Based on the linear track data, spatial information, place fields, and phase precession were determined for every PYR (Sloin et al, 2022). Briefly, place fields were defined as regions spanning 15-100 cm in which the firing rate increased compared to the on-track spontaneous firing rate (p<0.05, Bonferroni-corrected Poisson test).…”