Biology subjects

Moya, M. V.

Publications and source records attributed to Moya, M. V..

6 recordsLinked to original sources

bioRxiv2026

Distinct cell-type contributions and network topography of theta-nested gamma oscillations in the medial entorhinal cortex

Theta-nested gamma oscillations in the medial entorhinal cortex (mEC) are essential for spatial coding and memory, but the underlying cellular mechanisms remain unclear. We combined optogenetics, whole-cell electrophysiology, intracellular voltage imaging, and local field potential (LFP) recordings in acute slices from CaMKII-ChR2 mice to investigate how excitation and inhibition shape theta-gamma coupling in layer II/III mEC. During theta-frequency stimulation, fast-spiking interneurons received strong gamma-frequency excitation and fired rhythmic bursts, whereas stellate and pyramidal neurons fired more sparsely and were dominated by gamma-frequency inhibition. This sparse firing could support the selective firing of grid cells. Excitatory post-synaptic currents in interneurons preceded inhibitory currents and LFP gamma by [~]3 ms, supporting a pyramidal-interneuron network gamma (PING) mechanism. Pyramidal neurons fired on the descending phase of the gamma cycle, whereas stellate cells and fast-spiking interneurons fired before and after the trough, respectively. Intracellular voltage imaging revealed network gamma synchronization among excitatory neurons at a population level, with topographic clustering of subthreshold membrane potentials, but not spike timing, while individual neurons often skipped gamma cycles. These findings identify the dominant role of reciprocal E-I interactions in generating theta-nested gamma oscillations and highlight distinct cell-type contributions to the temporal dynamics of the mEC. Further, a biophysically realistic computational model predicted gamma cycle skipping in stellate cells and burst firing in fast-spiking interneurons during PING. Our experimental and computational results provide mechanistic insight into how the intrinsic properties of mEC cell types generate oscillatory activity in a manner that could support grid cell function and spatial computation. Significance StatementTheta-nested gamma oscillations in the medial entorhinal cortex (mEC) are essential for spatial navigation and memory, yet the underlying circuit mechanisms remain incompletely understood. Using optogenetics, voltage imaging, electrophysiology, and biophysically realistic computational modeling, we show that reciprocal interactions between excitatory neurons and fast-spiking interneurons generate robust gamma oscillations through a pyramidal-interneuron network gamma (PING) mechanism. We reveal cell-type specific differences in gamma phase-locking and demonstrate that principal neurons synchronize at the population-level across large laminar distances (up to 800 {micro}m). Further, the voltage activity, but not spike timing, of principal neurons exhibited topographic clustering. These findings clarify how local circuits in mEC generate temporal dynamics critical for grid cell coding and further constrain computational models of spatial representation.

neuroscience↗

bioRxiv2025

A scalable, all-optical method for mapping synaptic connectivity with cell-type specificity

Single-cell transcriptomics has uncovered the vast heterogeneity of cell types that compose each region of the mammalian brain, but describing how such diverse types connect to form functional circuits has remained challenging. Current methods for measuring the presence and strength of synaptic connections principally rely on low-throughput whole-cell recording approaches. However, the development of optical tools for perturbing and observing neural activity--now notably including genetically encoded voltage indicators--presents an exciting opportunity to vastly increase the throughput of physiological connectivity mapping. Here, we combine massively parallel optical measurements of synaptic strength with a novel pipeline for thick-tissue spatial transcriptomics to assay synaptic connectivity motifs with high sensitivity, high throughput, and cell-type specificity. We apply this approach in the motor cortex to describe new cell-type-specific synaptic innervation patterns for long-range thalamic and contralateral input onto more than 1000 motor cortical neurons.

neuroscience↗

bioRxiv2023

Large-scale deep tissue voltage imaging with targeted illumination confocal microscopy

Voltage imaging with cellular specificity has been made possible by the tremendous advances in genetically encoded voltage indicators (GEVIs). However, the kilohertz rates required for voltage imaging lead to weak signals. Moreover, out-of-focus fluorescence and tissue scattering produce background that both undermines signal-to-noise ratio (SNR) and induces crosstalk between cells, making reliable in vivo imaging in densely labeled tissue highly challenging. We describe a microscope that combines the distinct advantages of targeted illumination and confocal gating, while also maximizing signal detection efficiency. The resulting benefits in SNR and crosstalk reduction are quantified experimentally and theoretically. Our microscope provides a versatile solution for enabling high-fidelity in vivo voltage imaging at large scales and penetration depths, which we demonstrate across a wide range of imaging conditions and different GEVI classes.

neuroscience↗

bioRxiv2021

High-speed, multi-Z confocal microscopy for voltage imaging in densely labeled neuronal populations

Genetically encoded voltage indicators (GEVIs) hold great promise for monitoring neuronal population activity, but GEVI imaging in dense neuronal populations remains difficult due to a lack of contrast and/or speed. To address this challenge, we developed a novel confocal microscope that allows simultaneous multiplane imaging with high-contrast at near-kHz rates. This approach enables high signal-to-noise ratio voltage imaging in densely labeled populations and minimizes optical crosstalk during concurrent optogenetic photostimulation.

neuroscience↗

bioRxiv2021

Sensitivity optimization of a rhodopsin-based fluorescent voltage indicator

The ability to optically image cellular transmembrane voltage at millisecond-timescale resolution can offer unprecedented insight into the function of living brains in behaving animals. The chemigenetic voltage indicator Voltron is bright and photostable, making it a favorable choice for long in vivo imaging of neuronal populations at cellular resolution. Improving the voltage sensitivity of Voltron would allow better detection of spiking and subthreshold voltage signals. We performed site saturation mutagenesis at 40 positions in Voltron and screened for increased {Delta}F/F0 in response to action potentials (APs) in neurons. Using a fully automated patch-clamp system, we discovered a Voltron variant (Voltron.A122D) that increased the sensitivity to a single AP by 65% compared to Voltron. This variant (named Voltron2) also exhibited approximately 3-fold higher sensitivity in response to sub-threshold membrane potential changes. Voltron2 retained the sub-millisecond kinetics and photostability of its predecessor, with lower baseline fluorescence. Introducing the same A122D substitution to other Ace2 opsin-based voltage sensors similarly increased their sensitivity. We show that Voltron2 enables improved sensitivity voltage imaging in mice, zebrafish and fruit flies. Overall, we have discovered a generalizable mutation that significantly increases the sensitivity of Ace2 rhodopsin-based sensors, improving their voltage reporting capability.

neuroscience↗

bioRxiv2021

Unique molecular features and cellular responses differentiate two populations of motor cortical layer 5b neurons in a preclinical model of ALS.

Many neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS), lead to the selective degeneration of discrete cell types in the CNS despite the ubiquitous expression of many genes linked to disease. Therapeutic advancement depends on understanding unique cellular adaptations that underlie pathology of vulnerable cells in the context of disease-causing mutations. Here, we employ bacTRAP molecular profiling to elucidate cell type specific molecular responses of cortical upper motor neurons in a preclinical ALS model. Using two bacTRAP mouse lines that label distinct vulnerable or resilient projection neuron populations in motor cortex, we show that the regulation of oxidative phosphorylation (Oxphos) pathways is a common response in both cell types. However, differences in the baseline expression of genes involved in Oxphos and the handling of reactive oxygen species likely lead to the selective degeneration of the vulnerable cells. These results provide a framework to identify cell type-specific processes in neurodegenerative disease.

neuroscience↗