Connecting two spinal cords as a way of sharing information between two brains

Methods

Summary

To test the hypothesis, adults Long Evan rats weighing between 250–350 g will be used. Each rat will be implanted with both brain electrodes and spinal cord electrodes. The brain electrodes will be implanted in the right M1 and left S1 areas according to the procedure described in previous works. These electrode aims to record the Local Field Potential (LFP) as well as single unit activity. The spinal cord electrode will be implanted into the epidural space of the dorsal column of thoracic vertebrae 2 (T2). As each spinal cord electrode has two leads, the connection cable will consist of two wires that will be plugged to each lead. This cable will have a switch to establish or interrupt the connection between the two spinal cords. The signal to be transmitted or shared between the two rats will be seizure activity provoked by the injection of Pentylenetetrazole.  Besides the electrical recording of LFP and single units, the seizure activity and the behavior of the animals will also be monitored using a video recording system.  After injecting the sender rat with intraperitoneal PTZ, the simultaneous LFP and video recording session of the two rats will begin. However, during the first 5 min, no connection between the two spinal cords will be made to allow a baseline recording where the sender rat will have seizure episodes and the receiver rat will not experience seizures. Following this period, the switch of the connection cable will be turned on to establish the connection between the two spinal cords. It will be created an induction period of about 23 min to allow a free communication between the two nervous system. After this time, the connection will be switched off for 5 min. After that, it will follow an ON/OFF periods of 5 min each meaning that the connection will be established during 5 min and then interrupted during 5 min. The total duration of this experiment will be 60 min counting from the beginning of the baseline recording. During the whole experiment, the seizure activity will be recorded in video, single units and LFP.