Research On Local Cortical Circuits Based On Multi-channel Patch Clamp Technolog

In addition to long-range projection neural circuits,connections within local neural circuits play a critical role in the investigation of neural networks,particularly in the study of information processing in the neocortex,which is essential for learning,cognitive computation,and behavioral processing.The processing and integration of information by local neocortical circuits underpin human higher cognition.As a result,exploring the connectivity of local neocortical circuits is vital for a deeper understanding of cortical circuit architecture and information processing mechanisms.At present,research on local cortical circuits is relatively scarce,with a predominant focus on synaptic connections across brain regions and their associated long-range projection neural circuits.In our study,we concentrate on neuronal connections within local circuits,employing multiple whole-cell patch-clamp recording techniques to simultaneously perform whole-cell patch-clamp experiments on various neurons in the somatosensory cortex.This approach allows us to examine local connections within the cortex,primarily encompassing the following aspects:(1)We have developed a multiple whole-cell patch-clamp recording protocol for juvenile mice and standardized the preparation of high-quality brain slices and the multiple whole-cell patch-clamp procedure.The brain slices obtained using this protocol exhibit well-preserved neuronal integrity,enabling more prolonged participation in multiple whole-cell patch-clamp recording experiments.This experimental workflow substantially enhances the efficiency of multi-channel recordings.(2)We conducted a preliminary exploration of the morphological and electrophysiological diversity of neurons in layers 2 and 3(L2/3)of the somatosensory cortex.We reconstructed the morphology of 74 neurons and classified the pyramidal neurons into 5 groups based on their dendritic complexity.We further corroborated the validity of this classification using Sholl analysis.Additionally,we assessed the intrinsic electrophysiological properties of 126 neurons to evaluate their diversity.(3)We obtained 73 sets of multi-channel data,incorporating a total of 256 neurons in our analysis.Among these data sets,12 exhibited connections.Further examination of connection patterns revealed that inhibitory neurons markedly increased the complexity of connection architecture,while connection patterns among excitatory neurons remained relatively simplistic.We also observed that,within the same neural network structure,the initial connection strength and latency differed between various neurons,resulting in the information flow propagating in diverse directions.In conclusion,our study provided a comprehensive understanding of the morphology,electrophysiology,and synaptic connections of L2/3 neurons in the somatosensory cortex.We thoroughly investigated the relationships between neuron types and connections,fundamental connection architecture patterns,and connection complexity analysis.Moreover,we delved into the intricacy of cortical local circuit connections and signal transmission,considering the disparities in information transmission within the same architecture.This research deepened our comprehension of connection preferences and information transmission differences in cortical local circuits,laying a solid foundation for future investigations into more complex cortical local circuit connections.