Boi, F. | Search bioRxiv

bioRxiv2026

Experience Reorganizes Coordinated Population Dynamics Across Hippocampal Circuits

Hippocampal function relies on structured patterns of population activity that reflect the intrinsic organization of the circuit. Although experience is known to influence synaptic properties and local activity features, whether prolonged experience reshapes the large-scale organization of population dynamics across hippocampal subfields in the intact brain has remained unclear. Progress on this question has been limited by the lack of measurements that capture circuit-wide activity simultaneously while preserving spatial circuit structure. Here, we combined prolonged environmental experience with large-scale, simultaneous multi-shank recordings spanning CA1, CA3, and dentate gyrus in the mouse hippocampus to examine experience-dependent changes in circuit dynamics. We find that long-term experience reorganizes the basal operating state of the hippocampus, altering the statistical structure of field potentials, population spiking, and sharp-wave ripple activity in a coordinated manner across subfields. These changes are not confined to specific regions but instead reflect a circuit-wide reconfiguration of functional interactions that extends over larger spatial scales. At the population level, experience shifts hippocampal dynamics into a more coordinated dynamical regime, characterized by shared low-dimensional structure across hippocampal subfields. Together, these findings demonstrate that long-term experience reorganizes coordinated population dynamics across hippocampal circuits, establishing an intrinsic activity organization that reflects the experiential history of a memory network.

neuroscience↗

bioRxiv2019

Multi-shanks SiNAPS Active Pixel Sensor CMOSprobe: 1024 simultaneously recording channels for high-density intracortical brain mapping

The advent of implantable active dense CMOS neural probes opened a new era for electrophysiology in neuroscience. These single shank electrode arrays, and the emerging tailored analysis tools, provide for the first time to neuroscientists the neurotechnology means to spatiotemporally resolve the activity of hundreds of different single-neurons in multiple vertically aligned brain structures. However, while these unprecedented experimental capabilities to study columnar brain properties are a big leap forward in neuroscience, there is the need to spatially distribute electrodes also horizontally. Closely spacing and consistently placing in well-defined geometrical arrangement multiple isolated single-shank probes is methodologically and economically impractical. Here, we present the first high-density CMOS neural probe with multiple shanks integrating thousands of closely spaced and simultaneously recording microelectrodes to map neural activity across 2D lattice. Taking advantage from the high-modularity of our electrode-pixels-based SiNAPS technology, we realized a four shanks active dense probe with 256 electrode-pixels/shank and a pitch of 28 {micro}m, for a total of 1024 simultaneously recording channels. The achieved performances allow for full-band, whole-array read-outs at 25 kHz/channel, show a measured input referred noise in the action potential band (300-7000 Hz) of 6.5 {+/-} 2.1{micro}VRMS, and a power consumption <6 {micro}W/electrode-pixel. Preliminary recordings in awake behaving mice demonstrated the capability of multi-shanks SiNAPS probes to simultaneously record neural activity (both LFPs and spikes) from a brain area >6 mm2, spanning cortical, hippocampal and thalamic regions. High-density 2D array enables combining large population unit recording across distributed networks with precise intra- and interlaminar/nuclear mapping of the oscillatory dynamics. These results pave the way to a new generation of high-density and extremely compact multi-shanks CMOS-probes with tunable layouts for electrophysiological mapping of brain activity at the single-neurons resolution.

bioengineering↗