Journal: Frontiers in Neuroscience

Article Title: Reimplantable Microdrive for Long-Term Chronic Extracellular Recordings in Freely Moving Rats

doi: 10.3389/fnins.2019.00128

Figure Lengend Snippet: Exploded view of the microdrive proposed. (1) Electrode shuttle system, (2a) nut-screw linear motion system, (2b) piezoelectric motor, (3) Hall-effect sensor, (4) housing element, (5) EIB-18, (6) EIB-18 cover, (7) electrode cover, (8) baseplate, (9) fixing screw of the motor or nut, (10) EIB cover-housing fixing screw (×2), (11) electrode cover-housing fixing screws (×3), (12) posterior housing-baseplate fixing screws (×2), (13) anterior housing-baseplate fixing screw, (14) baseplate-skull fixing screws (×4).

Article Snippet: Also, the same manuscript shows the steps for assembling a commercially available microdrive (Versa Drive 4, Neuralynx) based on a Mill-Max commercial connector and containing four drive screws ( ).

Techniques:

Journal: Frontiers in Neuroscience

Article Title: Reimplantable Microdrive for Long-Term Chronic Extracellular Recordings in Freely Moving Rats

doi: 10.3389/fnins.2019.00128

Figure Lengend Snippet: Reimplantable microdrive assembly. (A) Polyimide tube in the guide cannula. (B) Guide cannula fixed to the piston. (C) A magnet placed in the piston. (D) Compression spring placed concentrically to the piston rod. (E) Piston placed concentrically and aligned to the bushing. (F) Electrode shuttle system assembled with the housing element. (G) Electrodes introduced through the polyimide tube. (H) Electrodes introduced through the conduits. (I) Nut-screw and EIB placed in the housing element. (J) Piezoelectric actuator placed in the housing element for the automated configuration. (K) Final assembly with the two covers and the housing fixing screws. (L) Illustrative picture of a rat implanted with a reimplantable microdrive.

Article Snippet: Also, the same manuscript shows the steps for assembling a commercially available microdrive (Versa Drive 4, Neuralynx) based on a Mill-Max commercial connector and containing four drive screws ( ).

Techniques:

Journal: Frontiers in Neuroscience

Article Title: Reimplantable Microdrive for Long-Term Chronic Extracellular Recordings in Freely Moving Rats

doi: 10.3389/fnins.2019.00128

Figure Lengend Snippet: Microdrive implantation procedure. (A) The baseplate is located on the cranium of the rat according to the recording site and fixed using four screws. (B) The microdrive holder allows a smooth and precise mounting of the microdrive, which is fixed to the baseplate using three screws. (C) After the ground wire fixation, the microdrive is released from the holder and ready to use. (D) Microdrive firmly attached on the baseplate.

Article Snippet: Also, the same manuscript shows the steps for assembling a commercially available microdrive (Versa Drive 4, Neuralynx) based on a Mill-Max commercial connector and containing four drive screws ( ).

Techniques:

Journal: Frontiers in Neuroscience

Article Title: Reimplantable Microdrive for Long-Term Chronic Extracellular Recordings in Freely Moving Rats

doi: 10.3389/fnins.2019.00128

Figure Lengend Snippet: In the same animals, we recorded a similar proportion of lick-modulated NAcSh neurons in the first and second microdrive implant. (A) Action potentials (dots) of two single-neurons recorded in the same channel (yellow and green, respectively) within a 1 h freely licking behavioral session. Values are plotted in a three-dimensional space built with the first two principal components (PCs) of the voltage signals vs. time. Inset: Depicts the time-voltage window showing the mean ± SEM of action potential waveforms. These neurons were recorded from the “first” implant. (B) Histogram depicting the number of single neurons recorded in the first and second implant across sessions. (C) Number of daily sessions where single-unit activity was recorded in the first and second implant. (D) The population activity (normalized to z-score) of neurons that were either Lick-Active (red) or Lick-Inactive (blue) around the initiation of licking (vertical line at time = 0 s). The baseline level of neuronal activity (z-score = 0) is indicated by a horizontal dashed line and was taken from –1.5 to –0.5 s relative to the lick onset. (E) Histograms of the percentage of Lick-Active and Lick-Inactive neurons found in the NAcSh using the first and the second implant of the microdrive and the proportion of the lick modulated neurons reported in a study published elsewhere . The proportions of neurons were not statistically different relative to data from (chi-square test; Lick-Active neurons of the first and second implants vs. Tellez, χ 2 = 0.004, and χ 2 = 0.005, respectively; Lick-Inactive of the first and second implants vs. Tellez, χ 2 = 0.017 and χ 2 = 0.003, respectively; all p’ s > 0.05).

Article Snippet: Also, the same manuscript shows the steps for assembling a commercially available microdrive (Versa Drive 4, Neuralynx) based on a Mill-Max commercial connector and containing four drive screws ( ).

Techniques: Activity Assay

Journal: Frontiers in Neuroscience

Article Title: Reimplantable Microdrive for Long-Term Chronic Extracellular Recordings in Freely Moving Rats

doi: 10.3389/fnins.2019.00128

Figure Lengend Snippet: Long-term stable recordings of NAcc neurons in freely behaving rats. (A) Left: X-ray of the head of the rat showing location of the microdrive implant. Right: Histological reconstruction of the location of electrode tips in NAc of the ventral striatum. (B) Left top: Superimposed waveforms from two different units (green and yellow) recorded simultaneously in the same electrode and separated from noise (gray). Grid: 400 μV, 800 μs. Left bottom: Interspike interval histogram of the two units. Right: Offline sorting of two units using voltage-time threshold, principal component time-space surface (top) and 3D (bottom). (C) Freely behaving rats pressed a lever to obtain a food pellet, in a fixed ratio 1 reinforcement schedule. (D) Raster plot (top) and peri-event time histogram (bottom) for a neuron exhibiting an increase in firing rate after lever pressing (time = 0 s; the waveform of this neuron is shown in yellow in panel B ). In the raster, a black tick indicates one action potential; the bin size was 100 ms. Arrowheads (▾) indicate the time of lever pressing (time = 0 s). (E) We tested the stability of recordings during spontaneous activity sessions in another freely behaving Wistar rat. Top: Waveforms of two separate neurons (yellow and green) recorded from the same single electrode for over a month (40 days). For visualization purposes, only waveforms in days 1, 3, 7, and 40 are shown. Bottom: Verification of long-term stable single-unit recordings using principal component space cylinders. A straight cylinder indicates that the same single unit was recorded in different sessions across time (days).

Article Snippet: Also, the same manuscript shows the steps for assembling a commercially available microdrive (Versa Drive 4, Neuralynx) based on a Mill-Max commercial connector and containing four drive screws ( ).

Techniques: Activity Assay