Biology subjects

Carrillo-Reid, L.

Publications and source records attributed to Carrillo-Reid, L..

5 recordsLinked to original sources

bioRxiv2025

Encoding visual stimuli by striatal neurons

To move through the world, animals extract visual features from objects. Although visual object encoding is considered a cortical attribute, subcortical areas also contain visual processing circuits. Using electrophysiological recordings of spiny projection neurons (SPNs) located in a target region of the primary visual cortex, we identified striatal modules that process basic visual features. SPNs from the direct and indirect pathways exhibited high orientation selectivity in the absence of behavioral contingencies. SPNs population activity reliably predicted different visual features. Pathway-specific silencing of SPNs revealed that high orientation selectivity depends on intra-striatal connectivity. Thus, specialized striatal modules are active participants in visual feature extraction. These findings indicate parallel visual information processing in basal ganglia circuits, expanding current models of visual perception beyond cortical networks.

neuroscience↗

bioRxiv2021

Optical and computational dissection of emergent prefrontal rewiring to encode fear memory

Associative learning is crucial for adapting to environmental changes. The encoding of associative learning involves the dorso-medial prefrontal cortex (dmPFC), and is underpinned by interactions within the resident neuronal population. However, the nature of this population coding is poorly understood. Here we developed a pipeline for computational dissection and longitudinal two-photon imaging of neural population activities in the mouse dmPFC during fear-conditioning procedures, enabling us to detect learning-dependent changes in the dmPFC topology. Through regularized regression methods and graphical modeling, we found fear conditioning organized neuronal ensembles encoding conditioned responses (CR), with enhancing their coactivity, functional connectivity, and association with conditioned stimuli (CS). This suggests that fear conditioning drives dmPFC reorganization to generate novel associative circuits for CS-to-CR transformation. Importantly, neurons strongly responding to unconditioned stimuli (US) during conditioning anterogradely became a hub of the CR ensemble. Altogether, we demonstrate learning-dependent dynamic modulation of population coding structured on an activity-dependent hub-network formation within the dmPFC. TeaserOptical and computational dissection uncovered how prefrontal cortical networks are rewired to encode new associative memory Significance statementAnimals learn to adapt to changing environments. Associative learning is one of the simplest types of learning that has been intensively studied over the past century. Recent development in molecular, genetic, and optogenetic methods has enabled the identification of a neural population encoding the associative memory in the brain. However, it remains unclear how information is stored and processed by the neural population to encode and retrieve the associative memory. To investigate the nature of this population coding, we developed an optical and computational dissection method, demonstrating how associative learning drives reorganization of the neural network in the dorso-medial prefrontal cortex and generates novel circuits for associative memory and signal transformation.

neuroscience↗

bioRxiv2018

Triggering visually-guided behavior by holographic activation of pattern completion neurons in cortical ensembles

Neuronal ensembles are building blocks of cortical activity yet it is unclear if they have any causal role in behavior. Here we tested if the precise activation of neuronal ensembles with two-photon holographic optogenetics in mouse primary visual cortex alters behavioral performance in a visual task. Disruption of behaviorally relevant cortical ensembles by activation of non-selective neurons decreased behavioral performance whereas optogenetic targeting of as few as two neurons with pattern completion capability from behaviorally relevant ensembles improved task performance by reliably recalling the whole ensemble. Moreover, in some cases, activation of two pattern completion neurons, in the absence of visual stimulus, triggered correct behavioral responses. Our results demonstrate a causal role of neuronal ensembles in a visually guided behavior and suggest that ensembles could represent perceptual states.

neuroscience↗

bioRxiv2017

Identification and Targeting of Cortical Ensembles

Breaking the neural code requires the characterization of physiological and behavioral correlates of neuronal ensemble activity. To understand how the emergent properties of neuronal ensembles allow an internal representation of the external world, it is necessary to generate empirically grounded models that fully capture ensemble dynamics. We used machine learning techniques, often applied in big data pattern recognition, to identify and target cortical ensembles from mouse primary visual cortex in vivo leveraging recent developments in optical techniques that allowed the simultaneous recording and manipulation of neuronal ensembles with single-cell precision. Conditional random fields (CRFs) allowed us not only to identify cortical ensembles representing visual stimuli, but also to individually target neurons that are functionally key for pattern completion. These results represent the proof-of-principle that machine learning techniques could be used to design close-loop behavioral experiments that involve the precise manipulation of functional cortical ensembles.

neuroscience↗

bioRxiv2017

Three-Dimensional Two-Photon Optogenetics And Imaging Of Neural Circuits In Vivo

We demonstrate a holographic system for simultaneous three-dimensional (3D) two-photon stimulation and imaging of neural activity in the mouse neocortex in vivo with cellular resolution. Dual two-photon excitation paths are implemented with independent 3D targeting for calcium imaging and precision optogenetics. We validate the usefulness of the microscope by photoactivating local pools of interneurons in awake mice visual cortex in 3D, which suppress the nearby pyramidal neurons response to visual stimuli.

neuroscience↗