DOI: 10.5061/dryad.pk0p2ngpk
title: Multichannel ECoG and LFP from control and cuprizone mice

description: Parvalbumin-positive (PV+) γ-aminobutyric acid (GABA)
 interneurons are critically involved in producing rapid network
 oscillations and cortical microcircuit computations but the significance
 of PV+ axon myelination to the temporal features of inhibition
 remains elusive. Here using toxic and genetic models of demyelination and
 dysmyelination, respectively, we find that loss of compact myelin reduces
 PV+ interneuron presynaptic terminals, increases failures and the
 weak phasic inhibition of pyramidal neurons abolishes optogenetically
 driven gamma oscillations in vivo. Strikingly, during periods of
 quiet wakefulness selectively theta rhythms are amplified and accompanied
 by highly synchronized interictal epileptic discharges. In support of a
 causal role of impaired PV-mediated inhibition, optogenetic activation of
 myelin-deficient PV+ interneurons attenuated the power of slow
 theta rhythms and limited interictal spike occurrence. Thus, myelination
 of PV+ axons is required to consolidate fast inhibition of
 pyramidal neurons and enable behavioral state-dependent modulation of
 local circuit synchronization.
description: Chronic ECoG and LFP recordings were performed using in-house
 made electrodes of platinum iridium wire (101R-5T, 90% Pt, 10% Ir,
 complete diameter of 200 µm with 127 µm metal  diameter, Science
 Products). The perfluoroalkoxy alkanes (PFA) coated wire platinum-iridium
 wire was only exposed at the tip to record the local field potential
 (LFP). For placement of the recording electrode, animals were anesthetized
 with isoflurane (3%, flow rate 0.8 L/min with maintenance 1.5–1.8%, flow
 rate 0.6 L/min). A 1 cm midline sagittal incision was made starting above
 the interaural line and extending along the neck to create a pocket for
 subcutaneous placement of the transmitter along the dorsal flank of the
 animal. The recording electrodes in each hemi-sphere (stereotaxic
 coordinates relative to bregma: S1; –0.15 mm anterior and ± 0.30 mm
 lateral; for LFP; ventral 0.75 mm, V1; 0.40 mm anterior and ± 0.30 mm
 lateral; for LFP; ventral 0.75 mm) and ground electrode (6 mm posterior
 and 1 mm lateral) were implanted sub durally through small holes drilled
 in the skull, held in place with stainless steel screws (A2-70, Jeveka)
 and subsequently sealed with dental cement. Mice were provided with
 Metachem analgesic (0.1 mg per kg) after surgery and allowed to recover
 for 4–7 days before recordings. To obtain multiple hours recordings of
 ECoG-LFP at multiple weeks, mice remained in their home cage during an
 overnight recording session. ECoG–LFP data were collected using a
 ME2100-system (Multi channel Systems); ECoG-LFP data were acquired at a
 sampling rate of 2 kHz using the multi-channel experimenter software
 (Multi channel systems). The data was exported and saved as EDF format
 using Multichannel Datamanager 1.102.18296 (Multi channel
 systems)
description: Control Mice; M5, M9, M10, M17, M18 8
 weeks Cuprizone treated Mice: M4, M6, M7, M11, M13
   The 7 Channels detected signals as
 below: E1/E9 = ECoG_S1_right  E2/E10
 = LFP_S1_right E3/E11 = ECoG_S1_left
 E4/E12 = ECoG_V1_right E5/E13 =
 ECoG_V1_left E6/E14 = LFP_V1_left
 E7/E15 = EMG