Egocentric processing of items in spines, dendrites, and somas in the retrosplenial cortex
Egocentric representations of external items are essential for spatial navigation and memory. Here, we explored the neural mechanisms underlying egocentric processing in the retrosplenial cortex (RSC), a pivotal area for memory and navigation. Using one-photon and two-photon calcium imaging, we identified egocentric tuning for environment boundaries in dendrites, spines, and somas of RSC neurons (egocentric boundary cells) in the open-field task. Dendrites with egocentric tuning tended to have similarly tuned spines. We further identified egocentric neurons representing landmarks in a virtual navigation task or remembered cue location in a goal-oriented task, respectively. These neurons formed an independent population with egocentric boundary cells, suggesting that dedicated neurons with microscopic clustering of functional inputs shaped egocentric boundary processing in RSC and that RSC adopted a labeled line code with distinct classes of egocentric neurons responsible for representing different items in specific behavioral contexts, which could lead to efficient and flexible computation.
Imaging Microglia Surveillance during Sleep-wake Cycles in Freely Behaving Mice
We used miniature two-photon microscopy (mTPM) to acquire time-lapse high-resolution microglia images of the somatosensory cortex, along with EEG/EMG recordings and behavioral video, in freely-behaving mice. We uncovered fast and robust brain state-dependent changes in microglia surveillance, occurring in parallel with sleep dynamics and early-onset phagocytic microglial contraction during sleep deprivation stress.
A nociceptive neuronal ensemble in the dorsomedial prefrontal cortex underlies pain chronicity
Here we identify a nociceptive neuronal ensemble in the dorsomedial prefrontal cortex (dmPFC), which shows prominent reactivity to nociceptive stimuli. We observed that this ensemble shows distinct molecular characteristics and is densely connected to pain-related regions including basolateral amygdala (BLA) and lateral parabrachial nuclei (LPB).
Encoding of social novelty by sparse GABAergic neural ensembles in the prelimbic cortex
Although the prelimbic (PrL) area is associated with social behaviors, the neural ensembles that regulate social preference toward novelty or familiarity remain unknown. Using miniature two-photon microscopy (mTPM) to visualize social behavior–associated neuronal activity within the PrL in freely behaving mice, we found that the Ca2+ transients of GABAergic neurons were more highly correlated with social behaviors than those of glutamatergic neurons. Chemogenetic suppression of social behavior–activated GABAergic neurons in the PrL disrupts social novelty behaviors. Restoring the MeCP2 level in PrL GABAergic neurons in MECP2 transgenic (MECP2-TG) mice rescues the social novelty deficits. Moreover, we identified and characterized sparsely distributed NewPNs and OldPNs of GABAergic interneurons in the PrL preferentially responsible for new and old mouse exploration, respectively. Together, we propose that social novelty information may be encoded by the responses of NewPNs and OldPNs in the PrL area, possibly via synergistic actions on both sides of the seesaw.
Visualizing Seizure Propagation in Freely-moving Mice via Miniature Two-photon Microscopy
Due to the tight and precise associations between behaviors and neural activities, the investigation of neuronal activity in freely-moving and behaving animals is a major unaccomplished goal in neuroscience. Epileptiform seizures, characterized by hyper-synchronized discharges and hyper-excitation in neuronal networks, are one of the most common neurological disorders. However, the underlying mechanisms remain only partially understood. Characterizing the processes of their initiation and propagation is critical in understanding the pathophysiology of seizures.
Dynamics of a disinhibitory prefrontal microcircuit in controlling social competition
How the dorsomedial prefrontal cortex (dmPFC) computes complex information in social competition within its local network is unclear. Here, Zhang et al. reveal a dynamic disinhibitory microcircuit, involving dmPFCVIP+, PV+, and pyramidal neurons, that controls social competition in the dominance tube test.
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