Article Figures & Data
Figures
- Figure 1.
The proposed design and exploded view of the automated microdisplacement system (OptoDrive). (1) Miniature linear actuator, (2) 4p FPC/FFC connector, (3) nut of the miniature linear actuator, (4) electrode shuttle, (5) compression spring, (6) upper support board, (7) upper bushing, (8) guide, (9) lower support board, (10) OptoDrive main body, (11) lower bushing, (12) microelectrodes, (13) optical fiber with its ferrule, (14) gold-plated electronic interface board, (15) screws, (16) gold plate pins, (17) body cover, (18) fixing nut, (19) OptoDrive baseplate, (20) fixing screw.
- Figure 2.
OptoDrive assembly process. A, OptoDrive components; B, miniature linear actuator and 4p FPC/FFC assembly; C, spring and miniature linear actuator assembly; D, electrode shuttle and upper support board assembly, fixed by the upper bushing; E, assembly of sections C and D; F, lower support board and main OptoDrive body assembly via the lower bushing; G, assembly of sections E and F with the guide; H, assembly of the EIB-16 using two screws and attachment of the electrodes to the EIB-16 board using gold-plated pins; I, assembly of the optical fiber; and J, assembly of the body cover. For the bill of materials, see Extended Data Figure 2-1, and for the development files, see Gutierrez and Caballero-Ruiz (2025) (https://doi.org/10.17605/OSF.IO/DKR42).
- Figure 3.
Accuracy of the electrode positioning system during downward movement. A, Experimental position versus expected position. B, Residual error for each displacement experiment.
- Figure 4.
Trace of OptoDrive (only electrodes) on a coronal mouse brain section. A, A 40 µm-thick coronal section 4× image montage of the OptoDrive stained with CellTracker CM-Dil. The following abbreviations are used: ARH, arcuate nucleus; DMH, dorsomedial hypothalamus; LHA, lateral hypothalamic area; VMH, ventromedial hypothalamus; TU, tuberal nucleus; ZI, zona incerta.
- Figure 5.
Representative extracellular recordings during sequential OptoDrive movements. A, Ascending the positioning system and moving the OptoDrive: The top panel shows placement in coronal brain slides, representing the positioning of electrodes during three sequential sessions of OptoDrive movements. Movements traverse three distinct brain regions: the TU, the LHA, and the ZI. The bottom panel shows single-unit extracellular waveforms from 16 channels recorded via the same electrode array. Individual waveforms are color coded (yellow, green, and red), and each row represents the recordings from a single electrode channel. B, Descending of OptoDrive. The 24 h transitions are represented by one arrow in the top panel and a solid red line in the bottom panel. Ref indicates the channel used as a digital reference.
- Figure 6.
Representative extracellular recordings from the first OptoDrive implant and a second implant. A, Representative final recording sessions for the initial OptoDrive implant are depicted. The top panel illustrates the positioning of electrodes during the final two sessions of OptoDrive electrode movements in coronal brain slides. The bottom panel presents single-unit extracellular waveforms from 16 channels recorded with the same electrode array. B, Schematic representation of stereotaxic surgery for a subsequent OptoDrive electrode implant. C, Two representative recording sessions for a second OptoDrive implant. The top panel depicts the placement of electrodes on coronal brain slides. The bottom panel displays single-unit extracellular waveforms from 16 channels recorded with the same electrode array. Individual waveforms are distinguished by color coding (yellow, green, and red), and each row corresponds to recordings from a particular electrode channel.
- Figure 7.
Optogenetic modulation of GtACR2-expressing neurons in the LH via OptoDrive. A, Histological verification of OptoDrive placement in the ventral LH. The image shows the optical fiber track (indicated by the hole in the tissue) and the fluorescent track left by the electrodes. B–H, Representative raster plots and overlapping peristimulus time histograms (PSTHs) of seven LH neurons expressing GtACR2, demonstrating diverse responses to optogenetic stimulation. Each panel shows neuronal activity during stimulation with blue light (473 nm) at various frequencies, presented in a randomized order: no stimulation (control; ctrl); 5, 10, 20, 30, 40, and 50 Hz; and continuous (cont) stimulation. Each black tick represents an action potential; blue ticks indicate laser pulses. Neuronal activity is aligned with the onset of the laser pulse (time = 0 s). Each recording session lasted for 30 min. B, Neuron 1: This neuron exhibited a brief period of inhibition followed by activation during continuous stimulation. C, Neuron 2: This neuron was inhibited during continuous stimulation. D, Neuron 3: This neuron displayed a phasic increase in the firing rate at the onset of stimulation. E, Neuron 4: This neuron showed increased activity during stimulation, followed by a period of inhibition after stimulation ceased. F, Neuron 5 exhibited a delayed peak response at ∼200 ms postlaser onset (most likely a polysynaptic response). This peak was more prominent during continuous stimulation than at other laser frequencies. G, Neuron 6: This neuron exhibited firing rate inhibition at 30, 40, and 50 Hz stimulation. Paradoxically, under continuous optostimulation, the firing rate of the same neuron increases. H, Neuron 7: This neuron exhibits a phasic spike at each laser pulse, reliably following 5, 10, 20, and 30 Hz frequencies. Then, at 40 and 50 Hz, the neuron could not follow these frequencies, reliably exhibiting some jitter. During continuous laser irradiation, neurons, after a brief phasic response, exhibited robust inhibition. See Extended Data Figure 7-1 for other recordings made in the laboratory of the neurobiology of appetite, Cinvestav.
Movies
- Movie 1.
OptoDrive moving up and down. [View online]
- Movie 2.
Mice moving with the OptoDrive. [View online]
Figure 2-1
Optodrive Bill of Materials. Download Figure 2-1, DOCX file.
Figure 7-1
Additional neurons recorded from other mice currently used in the laboratory neurobiology of appetite, Cinvestav. Download Figure 7-1, DOCX file.
In this issue
