Biology subjects

Deliano, M.

Publications and source records attributed to Deliano, M..

6 recordsLinked to original sources

bioRxiv2026

Dissociable thalamic oscillatory mechanisms support motor sequence learning

The ventrointermediate nucleus of the thalamus (VIM) is implicated in motor sequence learning, yet the underlying neural mechanisms remain unclear. We recorded intracranial activity from the human VIM during a serial reaction time task to determine how neural dynamics support learning. Participants responded faster during repeating than randomized sequences. Beta-to-low-gamma activity was greater during repeating sequences and elevated relative to the prestimulus baseline, consistent with emergence and stabilization of learned motor representations. In contrast, beta-phase modulation of high-frequency activity decreased progressively from rest to random to repeated sequence execution. Stronger phase-amplitude coupling was associated with faster responses, reaching significance in the random condition. These findings reveal a dissociation between power and cross-frequency coupling. Together they suggest that thalamic dynamics contribute to motor learning through multiple mechanisms: beta-band power reflects the emergence of learned motor representations, whereas beta-high-frequency coupling is enhanced when the context is less predictable.

neuroscience↗

bioRxiv2023

Ventrointermediate thalamic stimulation improves motor learning in humans

Ventrointermediate thalamic stimulation (VIM-DBS) modulates oscillatory activity in a cortical network including primary motor cortex, premotor cortex, and parietal cortex. Here we show that, beyond the beneficial effects of VIM-DBS on motor execution, this form of invasive stimulation facilitates production of sequential finger movements that follow a fixed sequence but not when the sequence is selected at random. These results highlight the role of thalamo-cortical activity in motor learning.

neuroscience↗

bioRxiv2020

Removal of the extracellular matrix biases auditory cortical layer dynamics towards supragranular corticocortical integration

In the adult vertebrate brain, enzymatic removal of the extracellular matrix (ECM) is increasingly recognized to promote learning, memory recall, and restorative plasticity. However, the underlying impact of local removal of the ECM on cortical circuit processing is still not understood. Here, we removed the ECM in the primary auditory cortex (ACx) of adult Mongolian gerbils using local injections of hyaluronidase (HYase). Using laminar current-source density (CSD) analysis, we found layer-specific changes of the spatiotemporal synaptic activity patterns. Applying multitaper spectral analysis and time-domain conditional Granger causality (GC) measures, we found increased stimulus-evoked oscillatory power in the beta band (25-36 Hz) selectively within infragranular layers Vb and enhanced supragranular synaptic activity. Our findings reveal new insights on how ECM modulation affects the sensory integration via altered translaminar cortical network dynamics with a supragranular lead of the columnar response profile.

neuroscience↗

bioRxiv2019

Task rule and choice are reflected by layer-specific processing in rodent auditory cortical microcircuits

The primary auditory cortex (A1) is an essential node in the integrative brain network that encodes the behavioral relevance of acoustic stimuli, predictions, and auditory-guided decision making. Previous studies have revealed task-related information being present at both the single-unit and population activity. However, its realization with respect to the cortical microcircuitry is less well understood. In this study, we used chronic, laminar current source density (CSD) analysis from the A1 of behaving Mongolian gerbils (Meriones unguiculatus) in order to characterize layer-specific, spatiotemporal synaptic population activity. Animals were trained to first detect and subsequently to discriminate two pure tone frequencies in consecutive training phases in a Go/NoGo shuttle-box task. We demonstrate that not only sensory but also task- and choice-related information is represented in the mesoscopic neuronal population code distributed across cortical layers. Based on a single-trial analysis using generalized linear-mixed effect models (GLMM), we found infragranular layers to be involved in auditory-guided action initiation during tone detection. Supragranular layers, particularly, are involved in the coding of choice options during tone discrimination. Further, we found that the overall columnar synaptic network activity represents the accuracy of the opted choice. Our study thereby suggests a multiplexed representation of stimulus features in dependence of the task, action selection, and the behavioral options of the animal in preparation of correct choices. The findings expand our understanding of how individual layers contribute to the integrative circuit of the A1 in order to code task-relevant information and guide sensory-based decision making.

neuroscience↗

bioRxiv2019

Ketamine anesthesia induces gain enhancement via recurrent excitation in granular input layers of the auditory cortex

The N-methyl-D-aspartate (NMDA) receptor antagonist, ketamine, is commonly used as an anesthetic agent and has more recently gained attention as an antidepressant. Ketamine has been linked to increased stimulus-locked excitability, inhibition of interneurons, and modulation of intrinsic neuronal oscillations. However, the functional network mechanisms are still elusive. A better understanding of these anesthetic network effects may improve upon previous interpretations of seminal studies conducted under anesthesia and have widespread relevance for neuroscience with awake and anesthetized subjects as well as in medicine. Here, we investigated the effects of anesthetic doses of ketamine (15mg kg-1/h i.p.) on the network activity after pure tone stimulation within the auditory cortex of male Mongolian gerbils (Meriones unguiculatus). We used laminar current source density (CSD) analysis and subsequent layer-specific continuous wavelet analysis to investigate spatiotemporal response dynamics on cortical columnar processing in awake and ketamine-anesthetized animals. We found thalamocortical input processing within granular layers III/IV to be significantly increased under ketamine. This effect on early thalamocortical input processing was not due to changes in cross-trial phase coherence. Rather, the layer-dependent gain enhancement under ketamine was attributed to a broadband increase in amplitude reflecting an increase in recurrent excitation. The time-frequency analysis is further indicative of a prolonged period of stimulus-induced excitation possibly due to a reduced coupling of excitation and inhibition in granular input circuits--in line with the common hypothesis of cortical disinhibition via NMDA-mediated suppression of GABAergic interneurons.\n\nStatement of significanceKetamine is a common anesthetic agent and is known to alter excitability and neuronal synchronicity in the cortex. We reveal here that anesthetic doses of ketamine increase recurrent excitation of thalamic input in the granular layers of the auditory cortex of Mongolian gerbils. This leads to a layer-specific gain enhancement of the time-locked response to external stimuli. Analysis of tone-evoked amplitudes and cross-trial variability of cortical current sources and sinks indicate a mechanism of cortical disinhibition via NMDA-mediated suppression of GABAergic interneurons. Our findings might help to understand the functional mechanisms of the clinical effects of ketamine promoting the development of new therapeutic agents with lower side effects.

neuroscience↗

bioRxiv2019

The VTA modulates a frequency-specific gain of thalamocortical inputs in infragranular layers of the gerbil auditory cortex

BackgroundReward associations during auditory learning induce cortical plasticity in the primary auditory cortex. A prominent source of such influence is the ventral tegmental area (VTA), which conveys a dopaminergic teaching signal to the primary auditory cortex. It is currently unknown, however, how the VTA circuitry thereby influences cortical frequency information processing and spectral integration. In this study, we therefore investigated the temporal effects of direct optogenetic stimulation of the VTA onto spectral integration in the auditory cortex on a synaptic circuit level by current-source-density analysis in anesthetized Mongolian gerbils.\n\nResultsWhile auditory lemniscal input predominantly terminates in the granular input layers III/IV, we found that VTA-mediated modulation of spectral processing is relayed by a different circuit, namely enhanced thalamic inputs to the infragranular layers Vb/VIa. Activation of this circuit yields a frequency-specific gain amplification of local sensory input and enhances corticocortical information transfer, especially in supragranular layers I/II. This effects further persisted over more than 30 minutes after VTA stimulation.\n\nConclusionsAltogether, we demonstrate that the VTA exhibits a long-lasting influence on sensory cortical processing via infragranular layers transcending the signaling of a mere reward-prediction error. Our findings thereby demonstrate a cellular and circuit substrate for the influence of reinforcement-evaluating brain systems on sensory processing in the auditory cortex.

neuroscience↗