Biology subjects

Alegre-Cortes, J.

Publications and source records attributed to Alegre-Cortes, J..

4 recordsLinked to original sources

bioRxiv2024

Global and local nature of cortical slow waves

Explaining the macroscopic activity of a recorded neuronal population from its known microscopic properties still poses a great challenge, not just because of the many local agents that shape the output of a circuit, but due to the impact of long-range connections from other brain regions. Here we use a computational model to explore how local and global components of a network shape the Slow Wave Activity (SWA). We performed a sensitivity analysis of multiple cellular and synaptic features in models of isolated and connected networks. This allowed us to explore how the interaction of local properties and long-range connections shape the SWA of a population and its neighbors, as well as how the sequential propagation of active "Up" states lead to the emergence of preferred modes of propagation. We described relevant features of cortical Up states that are modulated by "stiff" combinations of parameters of the local circuit as opposed to other that are sensitive to the level of excitability of the whole network and the input coming from neighbor populations. We found that while manipulations in the synaptic excitatory/inhibitory balance can create local changes, cellular components that modulate the excitability or adaptation of a population have a long-range effect that leads to changes in neighbor populations too. Additionally, our simulations guided in vivo experiments that showed how heterogeneities in excitability between cortical areas can determine the directionality of travelling waves during SWA. We expect these results to motivate future research exploring and comparing cortical circuits through the analysis of their Up states.

neuroscience↗

bioRxiv2023

Dopamine enhances multisensory responses in the dorsomedial striatum

The brain operates with simultaneous different sensory modalities in order to engage adaptive responses. However, the question of how (and where) multisensory information is integrated remains unanswered. In the dorsomedial striatum, single medium spiny neurons (MSNs) are excited by tactile and visual inputs; however, the mechanism which allows the integration of these responses and how they are shaped by dopamine is unknown. Using in vivo optopatch-clamp recordings, we study how dopamine modulates tactile, visual and simultaneous bimodal responses in identified MSNs and their spontaneous activity. Results show that dopamine enhances bimodal responses, specifically in direct pathway MSNs, through the acceleration of the visual responses. We provide anatomical and computational evidence suggesting that this relies on the disinhibition of direct MSNs by a cell-type-specific corticostriatal pathway. Altogether, our in vivo, in silico and tracing results propose a new mechanism underlying the synchronization of multimodal information mediated by dopamine.

neuroscience↗

bioRxiv2022

Callosal inputs generate side-invariant receptive fields in the barrel cortex

Barrel cortex integrates contra- and ipsilateral whiskers inputs. While contralateral inputs depend on the thalamocortical innervation, ipsilateral ones are thought to rely on callosal axons. These are more abundant in the barrel cortex region bordering with S2 and containing the row A-whiskers representation, the row lying nearest to the facial midline. Here we ask what role this callosal axonal arrangement plays in ipsilateral tactile signalling. We found that novel object exploration with ipsilateral whiskers confines c-Fos expression within the highly callosal subregion. Targeting this area with in vivo patch-clamp recordings revealed neurons with uniquely strong ipsilateral responses dependent on the corpus callosum, as assessed by tetrodotoxin silencing and by optogenetic activation of the contralateral hemisphere. Still, in this area, stimulation of contra- or ipsilateral row A-whiskers evoked an indistinguishable response in some neurons, mostly located in layers 5/6, indicating their involvement in the midline representation of the whiskers sensory space.

neuroscience↗

bioRxiv2020

Slow Wave Oscillation reveals the discrete segregation of dorsal striatum

Behavioural studies differentiate the rodent dorsal striatum (DS) into lateral and medial regions based on their particular roles; however, anatomical evidence suggest that it is a unified structure. To understand striatal dynamics and basal ganglia functions, it is essential to clarify the circuitry that supports this behavioural-based segregation. Here, we show that the mouse DS is made of two non-overlapping functional circuits divided by a sharp boundary. Combining in vivo optopatch-clamp and extracellular recordings of spontaneous activity, we demonstrate different coupling of lateral and medial striatum to the cortex together with an independent integration of the slow and fast oscillations, due to particular cortico-striatal connectivity and local properties of each region. Additionally, distinct properties between striatonigral and striatopallidal neurons were revealed along DS. These results demonstrate that the rodent DS is segregated in two neuronal circuits, in homology with the caudate and putamen nuclei of primates.

neuroscience↗