A Matlab based tool for cortical layer activation order detection through latency calculation in local field potentials recorded from rat barrel cortex by brain-chip interface

Rodents explore the environment, perform object localization, texture and shape discriminations precisely through whisking. Microcircuits in the corresponding barrel columns get activated to segregate and integrate the tactile information generated during whisking through the information processing pathway. While the sensory signals propagate, different layers of the cortex get activated at different times, thus having precise information about the order of layer activation is desired to better understand this pathway. To have precise timing information about the activations, accurate calculation of signal propagation latencies is required. Moreover, available multisite and multichannel neuronal probes can record a huge amount of data which require an automated method capable of batch processing to determine the cortical layer activation order (CLAO). In this work we propose an automated and easy to implement method to determine the CLAO using calculated latencies from the recorded LFPs at different cortical depths and the Current Source Density profile obtained from the LFPs. The method is found accurate after performing extensive tests on LFPs recorded using Electrolyte-Oxide-Semiconductor Field Effect Transistor (EOSFET) based neuronal probes from S1 barrel cortex.