Topic: neuronal ensembles

Events occurring close in time are often linked in memory, providing an episodic timeline and a framework for those memories. Recent studies suggest that memories acquired close in time are encoded by overlapping neuronal ensembles, but whether dendritic plasticity plays a role in linking memories is unknown. Using activity-dependent labeling and manipulation, as well as longitudinal one- and two-photon imaging of RSC somatic and dendritic compartments, we show that memory linking is not only dependent on ensemble overlap in the retrosplenial cortex, but also on branch-specific dendritic alloc

Accumulating data indicate that the brain can affect immunity, as evidenced, for example, by the effects of stress, stroke, and reward system activity on the peripheral immune system. However, our understanding of this neuroimmune interaction is still limited. Importantly, we do not know how the brain evaluates and represents the state of the immune system. In this talk, I will present our latest study from our lab, designed to test the existence of immune-related information in the brain and determine its relevance to immune regulation. We hypothesized that the InsCtx, specifically the poster

Animals constantly modify their behavior through experience. Flexible behavior is key to our ability to adapt to the ever-changing environment. My laboratory is interested in studying the activity of neuronal ensembles in behaving animals, and how it changes with learning. We have recently set up a paradigm where mice learn to associate sensory information (two different odors) to motor outputs (lick vs no-lick) under head-fixation. We combined this with two-photon calcium imaging, which can monitor the activity of a microcircuit of many tens of neurons simultaneously from a small area of the

The design of neural circuits, with large numbers of neurons interconnected in vast networks, strongly suggest that they are specifically build to generate emergent functional properties (1). To explore this hypothesis, we have developed two-photon holographic methods to selective image and manipulate the activity of neuronal populations in 3D in vivo (2). Using them we find that groups of synchronous neurons (neuronal ensembles) dominate the evoked and spontaneous activity of mouse primary visual cortex (3). Ensembles can be optogenetically imprinted for several days and some of their neurons

The analysis of neuronal ensembles often suffers from low spiking activity. As statistical analysis relies on sufficiently large samples, rare joint events in neuronal ensembles usually fail to reach statistical significance. We show that statistical power can be enhanced considerably by careful preselection of specific, separated temporal stripes distributed throughout the whole time series in which spiking is more likely to occur. In a data set of two-photon calcium imaging from the visual cortex of mice (Cleppien et al., 2024+), we identified short temporal stripes of interest from the un

Neuronal ensembles encoding a specific memory have been shown to be distributed across multiple brain regions. However, the computational principles behind the distributed nature of such memory engrams are unknown. Here we propose that distributed engrams support functional flexibility and versatility. We investigated whether distributed engrams can differentially regulate memory discrimination and generalization, opposing and complementary computations that must be balanced for adaptive memory-guided behavior. For instance, while animals need to discriminate between threat-predictive and neut