Implanta​çã​o da t​é​cnica de registro de c​é​lulas de lugar utilizando microdrives de tetrodos m​ó​veis em ratos

Abstract

The formation of spatial maps depends on the hippocampus and associated structures. Electrophysiological activity in the CA1 region of the hippocampus encodes spatial representations through increases in the firing rate of pyramidal neurons, known as place cells. The present work aimed the implementation of hippocampal electrophysiological recording technique through the use of microdrives of multiple movable tetrodes. For this, we developed a microdrive prototype and performed stereotaxic surgeries in rats for bilateral chronic implant. The new prototype microdrive contained 16 movable tetrodes and allowed the individual progressive positioning of the tetrodes in the pyramidal layer of CA1 region of the dorsal hippocampus. After the surgical recovery of the animals, we recorded the extracellular electrophysiological activity of the CA1 region while rats searched for water reward at the ends of a linear track. The waveforms of recorded action potentials were then classified as individual neural units by semi-automatic classification algorithms. Each firing of a given neuron was then associated with the instantaneous position of the rat on the linear track, and thus we detected place fields of the place cells. Thus, we validated the microdrive prototype developed and, thereby, provide an important methodological basis for future studies aiming to understand the spatial encoding of the environment and the formation of spatial memories.