8 shank probes  (NeuroNexus Technologies)

Journal: bioRxiv

Article Title: Spatiotemporal Patterns Differentiate Hippocampal Sharp-Wave Ripples from Interictal Epileptiform Discharges in Mice and Humans

doi: 10.1101/2025.02.06.636758

Figure Lengend Snippet: a Recording configuration of an 8-shank, 1024 channel probe (SiNAPS, Neuronexus), positioned in the dorsal hippocampus of an APP/PS1 mouse. The dimensions of the probe enable sampling of all hippocampal subfields and neighboring deep cortical layers. Inset: schematic of the pixel design of the probe – two channels per row and shank. Inter-shank distance and inter-contact distances are indicated. b Example recording from a head-fixed APP/PS1 mouse displays a SPW-R detected in the CA1 pyramidal layer. LFP traces of every 4th channel are shown and plotted on top of an average current source density map from all SPW-Rs in one recording session (n= 803 SPW-Rs). The CA layers and granule cell layer are outlined in white. c Average LFP traces (white) and wavelet spectrograms from the CA1 stratum pyramidale (pyr), CA1 stratum radiatum (rad), CA3 pyramidal layer and hilus of the dentate gyrus (DGhil). Ripples are observed only in CA1. Right: two example SPW-R events. d Histograms of the peak frequencies of CA1 SPW-Rs on the same channels as in (b). e Above: Schematic of the locations of channels used for analysis in plots c, d, g and h: CA1 - pyramidal channel, selected by the highest high-frequency power (100-500 Hz). The black rectangle shows channels within 300 µm from the CA1 pyramidal channel, defined as distance 0 in the power-spectral density plot (PSD) plot below and in (h). Below: Peri-SPW-R PSD at different depths. f Example IED event detected on a CA1 pyramidal channel, LFP traces of every 8th recording channel are plotted on top of the current source density map, calculated from IEDs in one recording session (n=7 IEDs). g Average LFP traces (white) and wavelet spectrograms of IEDs from one recording (n=13 IEDs). IEDs were detected in CA1 rad. Corresponding traces are shown from CA1 pyr, CA3 and DG hilus. Right: two example IEDs. h Peak frequency of SPW-Rs (ripples, blue) and IEDs (pink), as a function of channel distance from the CA1 pyramidal layer (distance 0, x-axis). Negative values indicate channels above the pyramidal layer (ventral, towards cortex), as shown in (e). The purple curve represents peak frequency of IEDs on band-pass filtered data (bp 100-600 Hz). i Summary of distinctive SPW-R and IED features defined from the mouse hippocampus. * indicates regions not tested in this study but reported in other rodent studies.

Article Snippet: To evaluate the spatial, temporal, and morphological features of SPW-Rs across the hippocampus, we utilized high-density recordings spanning the entire dorsal hippocampus in APP/PS1 mice using 1024 channel 8-shank probes (SiNAPS, Neuronexus, ).

Techniques: Sampling