GCaMP6f

In nature, humans and animals are constantly bombarded with sensory information, which needs to be promptly contextualized to elicit the appropriate motor sequences through a process known as sensorimotor transformation. While we begin to understand how sensory information is transformed into motor action, it is still unclear in what way contextual information can modify a given sensorimotor plan. In this project, we investigate this phenomenon by training water restricted mice in a context-dependent multisensory detection task. We developed a behavioural paradigm in which mice are required to

…We expressed the GCaMP6f calcium sensor in the ventral tegment

Calcium is a key intracellular messenger that regulates many vital cellular processes. Calcium signals in oligodendrocytes, the myelinating glia of the CNS, are known to translate environmental information to cellular processes such as proliferation, differentiation and myelination. Myelination is an adaptive process that depends on neuronal activity. We recently demonstrated that neuronal activity in vivo enhances remyelination in demyelinated lesions (Ortiz et al., 2019, JCI Insight). Here, we investigate whether calcium singal in oligodendroglia play a role in remyelination and whether beha

A major challenge in studying spatial memory is understanding whether and how different navigational strategies influence hippocampal spatial representations of the environment.We designed a spatial recency memory task with two variants: one requiring allocentric representations of location, the other entailing egocentric representations. 10 freely-moving rats were trained over 34 daily sessions; each day, rats learned and then recalled the position of a food reward among six locations. Each trial, animals entered the arena from one of four start locations, generating distinct origin-goal traj

Alzheimer's Disease (AD) is the primary cause of dementia, characterized by irreversible neurodegeneration resulting in memory loss and cognitive decline. Growing evidence suggests that neuroinflammation plays a pivotal role in AD, with extracellular ATP (eATP) as one of the key players in this process. Our project aims at investigating whether eATP influences microglia activation, AD-associated neuroinflammation and neuronal Ca2+ excitability in an AD mouse model (B6.152H) expressing human PS2-N141I and APP Swedish mutations. We conducted experiments at various disease stages: pre- and post-A

A primary goal of cortical physiology is to explain how the cortex transforms incoming information to generate precise output behaviour. A recent work from our group show that cortical astrocytes are crucial to set the threshold detection of neuronal circuities across cortical layers to compute specific sensory modalities. But how can astrocyte help to set the sensibility of neurons in a modality-specific manner? By using in vivo electrophysiology and sensory experiments in fosTRAP2 mice, we show that disruption of cortical astrocyte activity impairs the transfer of information across the feed

Noradrenergic (NA) neurons in the locus coeruleus (LC) play a critical role in behavior by supplying norepinephrine to the brain. Understanding how LC-NA neurons are regulated is essential to understanding the role of the LC-NA system in behavior. Since previous studies have identified a population of inhibitory pre-LC neurons that regulate LC-NA neurons, this study investigates whether there are excitatory pre-LC neurons responsible for the regulation of LC-NA neurons. We infused AAVs into the LC of TH-Cre crossed with vGluT2-FLP mice expressing wheat germ agglutinin (WGA) and eYFP in a Cre-

Learning a new task is accompanied by changes at multiple levels in the brain. At the neuronal population level, learning requires coordinated adaptations to achieve optimal sensory processing and appropriate behavioral output. To understand how learning shapes high-dimensional neuronal dynamics across cortical areas, we simultaneously imaged the activity of neuronal populations in mouse somatosensory (S1) cortex and posterior parietal cortex (PPC) while mice were learning a multisensory texture discrimination task. Mice were trained to discriminate two textures, each preceded by a distinct au

Recent studies have revealed an essential contribution of cortical astrocyte calcium activity in regulation of sleep depth and state transitions (Bojarskaite et al., 2020, Nat Comms; Vaidyanathan et al., 2021, Nat Comms). However, astrocytic activity is highly heterogeneous across brain regions, and it is unclear if astrocytes mediate sleep transitions in a brain region specific manner. A region of utmost interest to investigate astrocytic activity during sleep is the hippocampus, which not only display high astrocytic heterogeneity (Viana et al., 2023, Glia), but also shows sleep-specific pat

…We expressed the calcium indicator GCaMP6f in the medial PFC (mPFC) of C57BL/6N mice and implanted a GRIN lens t

…calcium signals by expressing GCaMP6f under the control of gfaABC1D promoter and implanted optic fiber into the sublaterodorsal tegmental nucleus (SLD). Also, we simultaneously acquired cortical electroe

Ischemic stroke results from neural tissue death due to a decrease in blood supply, and is a major cause of death and motor disabilities worldwide. Although it is established that the tissue immediately surrounding the stroke core undergoes spontaneous functional reorganization, partially taking over lost functionality, the role of the healthy contralesional cortex remains unclear. Adaptions in neuronal activity on the contralesional side have been reported both in humans and in rodent stroke models, but it remains elusive whether such modifications represent spontaneous functional re-mapping

In the cerebral cortex, activity dynamics measured at a mesoscopic (0.1 to 1 mm) scale are characterized by both spontaneous and task-related dynamical waves of synchronized neuronal activity ranging from spreading stationary depolarizations (blobs) to traveling waves that can follow complex trajectories throughout the cortical network. These waves are thought to participate in information propagation and processing, but remain poorly understood. To test whether cortical waves can be actively generated and their trajectory controlled, we have implemented a goal-directed task for head-fixed mic

…alongside calcium activity via GCaMP6F in cortical neurons in triple-transgenic animals or in hippocampal astrocytes via viral transduction are brought to bear to reveal hitherto inaccessible and under-appreciated a

Odors evoke distinct patterns of neural activity across different concentrations, both at the input level of olfactory sensory neurons (OSN) and glomeruli, as well as the next level, mitral/tufted cells (MTCs). What features of these patterns carry invariant information about odor identity and what are the neural mechanisms defining these features? To address this question, we designed an all-optical system to monitor the activity of many glomeruli and MT cells with high temporal resolution and developed an optogenetic method for establishing functional connectivity between glomeruli and MTCs.

The superior colliculus (SC) is a major recipient of visual input in the mouse and controls innate approach and avoidance behaviours. Neurons in the superficial SC (sSC), which receives direct input from the retina, do not only process visual stimuli, but are also modulated by the animal’s running speed and pupil-linked arousal, similar to modulations observed in the primary visual cortex. While these observations were made during passive viewing of visual stimuli, a major purpose of vision is to guide behaviour. We therefore asked whether, in the context of a behavioural task, visual activity