Hippocampal theta oscillations coordinate neuronal firing to support memory and spatial navigation. The medial septum (MS) is critical in theta generation by two possible mechanisms: either a unitary “pacemaker” timing signal is imposed on the hippocampal system, or it may assist in organizing target subcircuits within the phase space of theta oscillations. We used temperature manipulation of the MS to test these models. Cooling of the MS reduced both theta frequency and power and was associated with an enhanced incidence of errors in a spatial navigation task, but it did not affect spatial correlates of neurons. MS cooling decreased theta frequency oscillations of place cells and reduced distance-time compression but preserved distance-phase compression of place field sequences within the theta cycle. Thus, the septum is critical for sustaining precise theta phase coordination of cell assemblies in the hippocampal system, a mechanism needed for spatial memory.
- Cooling the medial septum slowed down theta oscillations in the hippocampus
- The spatial representation in the hippocampus remained intact
- Choice errors increased in a spatial task
- Distance-time, but not distance-theta phase, compression was altered
Cooling of Medial Septum Reveals Theta Phase Lag Coordination of Hippocampal Cell Assemblies Peter Christian Petersen, György Buzsáki. Neuron, June 2020. [PDF] [Link]
Description of the data content
Thermometer implanted in Medial Septum together with a thermal perturbation probe in freely awake Long Evans rats. 2000 single cells spike sorted, up to 150 bilateral simultaneous cells recorded from CA1, all sessions with behavior. All spike sorted sessions processed with CellExplorer.
– Circular track: up to 180 alternation trials, always with 40 control trials
– Linear track
– Wheel running
Most sessions were recorded with Optitrack, a 3D tracking system (120Hz), and a ceiling-mounted video camera recorded at 10Hz. The animal’s positional data was determined with Optitrack.
Globus will give the most reliable data transfer and should be very fast as well. Data is organized by subjectName / sessionName. Using Globus you are also able to download all data or a subset of sessions in one go.
The data follow the Buzsaki lab’s format and standard of CellExplorer. All files below are described on the CellExplorer’s website
. The various included files are:
- basename.dat: binary raw file, typically sampled at 20KHz. (Neurosuite standard)
- basename.lfp: A low-pass filtered and downsampled lfp file (1250Hz)
- basename.xml: parameter file used by Neuroscope. to visualize the files above
- basename.session.mat : session metadata as described on the CellExplorers website
- basename.animal.behavior.mat : behavioral data
- basename.trials.behavior.mat : trial-wise data
- basename.spikes.cellinfo.mat : spike data
- basename.mono_res.cellinfo.mat : monosynaptic connections
- basename.cell_metrics.cellinfo.mat.: cell metrics, including putative Cell types
- basename.temperature.timeseries.mat : time series containing the temperature recording from the Medial Septal region
- basename.cooling.manipulation.mat : info about time windows of the cooling manipulation
- basename.ripples.events.mat : Detection of ripples.
- basename.deepSuperficialfromRipple.channelinfo.mat : deep superficial determination using the average ripple/sharp-wave: https://cellexplorer.org/tutorials/deep-superficial-tutorial/
- Some session also contains scoring of brain state: basename.eegstates.mat
There are many other derived files in the data folder. Most sessions were recorded with Optitrack, a 3D tracking system (120Hz), and a ceiling-mounted video camera recorded at 10Hz. The animal’s positional data was determined with Optitrack. Most sessions are on the alternation track, but there are also linear track sessions (about 2 meters long) and wheel running sessions (A square box with a running wheel attached). The probe implant information is available here
and with above tabs.