DOI: 10.5061/dryad.1c59zw431
title: Local activation of CA1 pyramidal cells induces theta phase precession

description: Hippocampal theta phase precession is involved in spatiotemporal coding
 and generating multineural spike sequences, but how precession originates
 remains unresolved. To determine whether precession can be generated
 directly in hippocampal area CA1 and disambiguate multiple competing
 mechanisms, we used closed-loop optogenetics to impose artificial place
 fields in pyramidal cells of mice running on a linear track. More than a
 third of the CA1 artificial fields exhibited synthetic precession that
 persisted for a full theta cycle. In contrast, artificial fields in the
 parietal cortex did not exhibit synthetic precession. The findings are
 incompatible with precession models based on inheritance, dual-input,
 spreading activation, inhibition-excitation summation, or somato-dendritic
 competition. Thus, a precession generator resides locally within CA1.
description: # Local activation of CA1 pyramidal cells induces theta phase precession
 This dataset encompasses
 extracellular recordings obtained from freely-moving mice, integral to the
 research presented in our manuscript entitled “Local activation of CA1
 pyramidal cells induces theta phase precession”. The data are available at
 two levels of processing. **1.    Processed data**: MATLAB variable files
 containing details regarding each putative pyramidal cell (PYR) and
 interneuron (INT) described in the manuscript. These consist of: *
 **CA1_units.mat**: including 1,095 PYRs and 329 INTs recorded from
 hippocampal region CA1. * **PPC_units.mat**: including 195 PYRs recorded
 from the posterior parietal cortex (PPC). **2. Raw data:** Neuronal and
 auxiliary data recorded during every experimental session. The data
 include 69 sessions from CA1 and 22 sessions from the PPC. Files from
 every session are compressed into a .zip file carrying the session name. A
 list of each session, the animal it was recorded from, and the recorded
 brain region is available in a separate table. ## **Description of the
 data and file structure** **Processed data** Each of these two files
 contains structures with information on all the units used to generate the
 results in the manuscript. The files include only well-isolated units that
 were active and stable on the linear track, as detailed in the Materials
 and Methods section of the manuscript. Within every field of the structure
 r, each row corresponds to a single unit. The fields are: -      
 *session*: The session during which the unit was recorded. -      
 *shankclu*: The shank on which the unit was recorded (column 1) and the
 cluster (unit) number on the shank (column 2). -       *type:* The cell
 type: 0, INT; 1, PYR. -       *depth*: Depth of the unit within the
 pyramidal layer [μm]. Depth is defined only for a subset of units, as
 detailed in the Materials and Methods; for other units, the value is NaN.
 -       *spk_width*: Spike width [ms]. -       *burst_index:* Burst index.
 -       *Iact*: Number of postsynaptic units. -       *InhbMe:* Number of
 presynaptic INTs. -       *Illum_dist:* The horizontal distance between
 the shank to which the optical fiber employed for on-track illumination is
 coupled, and the shank on which the unit was recorded. 0, Same shank; 0.1,
 In dual-sided probes, the other side of the same shank; 1. One shank away;
 1.1, In dual-sided probes, the other side of the adjacent shank; 2, Two
 shanks away; 3, Three shanks away. -       *illumP:* Peak illumination
 power on the track [μW]. -       *illumInt:* Estimated peak light
 intensity at the estimated location of the soma [mW/mm2]. -      
 *off_lg_gain*: Gain in firing rate during illumination in the home cage
 (off the linear track). -       *lg_lim*: Spatial limits of illumination
 [cm]. -       *lg_gain*: Firing rate gain during on-track illumination.
 -       *lg_gain_pval:* P-value for an increase in firing rate during
 on-track illumination. -       *lgf_act:* Binary flag (0/1) for units that
 increase their firing rate during on-track illumination. -      
 *lgf_art_field*: Binary flag for units exhibiting an artificial field.
 -       *lgf_rate_amp*: Binary flag for units exhibiting a significant
 rate increase during Light trials. Units with artificial fields are not
 included (receive 0). -       *lgf_frate_dec*: Binary flag for units
 exhibiting a significant rate decrease during Light trials. -      
 *lg_fNC:* Binary flag for units that do not exhibit a significant change
 in firing rate during Light compared with Control trials. -      
 *co_bsFR:* Baseline firing rate on track during Control and Return trials.
 -       *co_spontFields:* Number of spontaneous place fields that appear
 during Control and Return trials. -       *co_spontTPP:* Binary flag for
 the occurrence of spontaneous precession within one of the spontaneous
 fields appearing during Control or Return trials. -       *co_SI:* Spatial
 information during Control trials [bit/spk]. -       *co_fieldSelec*:
 Field selectivity for the illuminated region during Control trials.
 -       *co_lglim_mFR*: Mean firing rate within illumination limits during
 Control trials [spk/s]. -       *lg_SI:* Spatial information during Light
 trials [bit/spk]. -       *lg_fieldSelec*: Field selectivity for the
 illuminated region during Light trials. -       *lg_lim_mFR*: Mean firing
 rate within illumination limits during Light trials [spk/s]. -      
 *lgf_iTPP*: Binary flag for artificial fields with synthetic precession in
 either the spatial or temporal domain. -       *lgf_sp_iTPP*: Binary flag
 for artificial fields with synthetic spatial precession. -      
 *lgf_te_iTPP*: Binary flag for artificial fields with synthetic temporal
 precession. -       *lg_sp_TPP:* Four properties of spatial precession
 during Light trials: 1. a: Slope [cyc/cm]. 2. R: Fit to slope. 3. ηs:
 Spatial precession effect size. 4. Spatial precession occurance binary
 flag. -       *lg_tm_TPP*: Three properties of temporal precession during
 Light trials: 1. Spike frequency relative to LFP. 2. ηt: Temporal
 precession effect size. 3. Temporal precession occurrence binary flag.
 **Raw data** For every session, the zip file consists of multiple files,
 describing neuronal spike timing (clu and res files), local field
 potentials LFP and auxiliary data (an eeg file), animal movement and trial
 structure (trl and trlstm files), and other useful information for working
 with the dataset (xml and prm.xml files). The clu, res, and eeg files
 correspond to the format described in Hazan et al., 2006, Journal of
 Neuroscience Methods. The files are: -**.res. files:** ASCII files
 recording spike times, in samples per shank, sampled at 20 kHz. For
 instance, the file 'mDS2_20.res.1' contains spike times from the
 first shank recorded during session 'mDS2_20'. -**.clu. files:**
 ASCII files corresponding to the res files. These files label the spike
 units. The first element in every clu file denotes the total number of
 recorded units. -**.eeg file:** Binary (16 bit) files that contain the
 data sampled at 1250 Hz. These files incorporate both extracellular
 (neuronal) and auxiliary channels, such as those used for monitoring
 position in real time and the current applied to the on-head diodes during
 light stimulation. -**.xml file:** Each .xml file provides the
 meta-information necessary for interpreting the .eeg file. This includes
 details on the number of channels, sampling rates, and other technical
 specifications. -**.prm.xml file:** Contains additional metadata specific
 to each recorded channel, elaborating details related to the auxiliary
 channels. -**.trl file**: A MATLAB structure containing information
 regarding the position and speed of the animal and linear track trial
 structure. This file includes the following variables: * *tmov*: A
 structure with animal movement parameters, sampled at 20,000/512 = 39.0625
 Hz. * *spd*: Animal running speed, [cm/s]. * dir: Animal running angle,
 [rad]. * *ang*: The angle of the head of the animal. * *tidx*: Time index
 in the eeg file. * *pos_dirs*: The linearized position of the animal along
 the track, sampled at the movement sampling frequency. The first column
 contains the distance, in cm, from the right edge of the linear track,
 used for trials where the animal runs from right to left (marked as
 "1" in the *trials* variable). The second column contains the
 position in relation to the left edge of the linear track used for the
 return trials (marked as "2" in the *trials* variable). *
 *trials*: Each row corresponds to a linear track trial. The columns
 correspond to: 1. Trial start at movement sampling frequency (39.0625 Hz).
 2. Trial end at movement sampling frequency (39.0625 Hz). 3. Running
 direction (1 – right to left, 2 – left to right). 4. Trial start at
 spiking sampling frequency (20 kHz). 5. Trial end at spiking sampling
 frequency (20 kHz). 6. Optogenetic stimulation trial flag (1 – trial with
 stimulation, 0 – without). -**.trlstm file:** This MATLAB file contains
 information regarding linear track trial structure and optogenetic
 stimulation. Each file contains a structure with the following fields: *
 *LT_stimCh*: Channel/s recording the current applied to the diodes used
 for illumination on the track, numbered 1-6. * *stim_channels:* Channel/s
 recording the current applied to the diodes used for illumination,
 numbered as in the .eeg and .xml files. * *nstimCh:* Number of channels
 used for recording the current on the track. * *stim_targets*: The shank/s
 to which fibers used for illumination on the track were coupled to (i.e.,
 the target shanks). * *stim_dirs*: The running direction in which
 illumination occurred, corresponding to the third column of the *trials*
 variable in the .trl file. * *tr_rmv*: Binary flag for trials removed from
 analysis due to weak or irregular stimulation, corresponding to the rows
 of the *trials* variable. * *stim_lims:* Spatial limits of illumination,
 [cm]. * *analogmap:* 3D array reporting the illumination in every spatial
 bin at every trial (trials x spatial bins x stimulation channels), [μW].
 This variable contains all available stimulation channels, including those
 not employed for illumination on the track. For example, if the variable
 *LT_stimCh*=2, illumination would occur at *analogmap*( *trials*(:,6), :,
 2 ). * *binC*: Centers of spatial bins used for *analogmap*, [cm]. *
 *edges*: Edges of spatial bins used for *analogmap*, [cm].