Impaired thalamic burst firing in Fragile X syndrome

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 28, 2025

Abstract The thalamus performs a critical role in sensory processing by gating the flow of information to neocortex and directing sensory-driven behaviors; functions which are disrupted people with autism spectrum disorders (ASD). We have identified cellular changes thalamic neurons mouse model Fragile X syndrome (FX), leading monogenic cause ASD, that alter how transmits neocortical circuits. In awake animals, relay cells gate input shifting between two firing modes: burst tonic. Relay FX mice, however, do not shift these modes instead operate primarily tonic mode. demonstrate lack mode is caused voltage sensitivity for Ca 2+ -dependent low threshold spike, underlies normal firing.

Language: Английский

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Environmental context influences visual processing in thalamus

Current Biology, Journal Year: 2025, Volume and Issue: unknown

Published: March 1, 2025

Language: Английский

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A mechanism for deviance detection and contextual routing in the thalamus: a review and theoretical proposal

Frontiers in Neuroscience, Journal Year: 2024, Volume and Issue: 18

Published: Feb. 29, 2024

Predictive processing theories conceptualize neocortical feedback as conveying expectations and contextual attention signals derived from internal cortical models, playing an essential role in the perception interpretation of sensory information. However, few predictive frameworks outline concrete mechanistic roles for corticothalamic (CT) layer 6 (L6), despite fact that number CT axons is order magnitude greater than feedforward thalamocortical (TC) axons. Here we review functional architecture circuits propose a mechanism through which L6 could regulate thalamic firing modes (burst, tonic) to detect unexpected inputs. Using simulations model TC cell, show how support prediction-based input discrimination cells by promoting burst firing. This type control can enable circuit implement spatial context selective mechanisms. The proposed generates specific experimentally testable hypotheses. We suggest allows thalamus deviance predictions thereby supporting routing operations, far more powerful traditionally assumed.

Language: Английский

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Visual Corticotectal Neurons in Awake Rabbits: Receptive Fields and Driving Monosynaptic Thalamocortical Inputs

Journal of Neuroscience, Journal Year: 2024, Volume and Issue: 44(19), P. e1945232024 - e1945232024

Published: March 14, 2024

The superior colliculus receives powerful synaptic inputs from corticotectal neurons in the visual cortex. function of these remains largely unknown due to a limited understanding their response properties and connectivity. Here, we use antidromic methods identify awake male female rabbits, measure axonal conduction times, thalamic receptive field properties. All responded sinusoidal drifting gratings with nonlinear (nonsinusoidal) increase mean firing rate but showed pronounced differences ON–OFF structures that classified into three groups, Cx, S2, S1. Cx fields had highly overlapping ON OFF subfields as classical complex cells, S2 separated simple S1 single or subfield. Thus, all are homogeneous spatial summation very heterogeneous integration inputs. type fastest conducting axons, highest spontaneous activity, strongest responses. orientation selectivity, slowest axons. Moreover, our cross-correlation analyses found subpopulation fast axons high rates (largely “Cx” type) monosynaptic input retinotopically aligned neurons. This previously unrecognized fast-conducting thalamic-mediated pathway may provide specialized information prime recipient for subsequent retinal input.

Language: Английский

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More than expected: extracellular waveforms and functional responses in monkey LGN

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2023, Volume and Issue: unknown

Published: Nov. 23, 2023

Abstract Unlike the exhaustive determination of cell types in retina, key populations lateral geniculate nucleus thalamus (LGN) may have been missed. Here, we begun to characterize full range extracellular neuronal responses LGN awake monkeys using multi-electrodes during presentation colored noise visual stimuli identify any previously overlooked signals. Extracellular spike waveforms single units were classified into seven distinct classes, revealing unrecognized diversity: four negative-dominant classes that narrow or broad, one triphasic class, and two positive-dominant classes. Based on their mapped receptive field (RF), these further categorized either magnocellular ( M ), parvocellular P koniocellular K non-RF N ). We found correlations between shape RF response characteristics, with negative spiking waveform predominantly associated RFs, positive mostly linked RFs. Responses from exhibited shorter latencies, larger sizes, eccentricities than other Additionally, cells, those without an estimated RF, consistently responsive visually presented mapping stimulus at a lower more sustained rate RF. These findings suggest population be diverse believed. Significance statement This study uncovers evidence for intricate diversity within (LGN), challenging conventional classifications populations. By characterizing revising classifications, provide novel insights function. Our significant implications understanding early processing mechanisms interpreting signals neural circuits. Furthermore, non-receptive units, prompting exploration functional roles broader non-visual computations. not only advances our organization but also highlights importance considering recording biases electrophysiological studies. Overall, work opens new avenues interdisciplinary research contributes advancing knowledge dynamics system.

Language: Английский

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Effects of eye closure on the spiking activity of human lateral geniculate neurons

Research Square (Research Square), Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 16, 2024

We recorded spiking activity in the human lateral geniculate nucleus (LGN), which links retina with primary visual cortex. The cells had receptive-field properties resembling those of monkeys. Responses were largely monocular and closure one eye decreased spontaneous neurons broader spikes preferring this increased narrower spikes, suggesting that interneurons might gate LGN during closure.

Language: Английский

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