1) In the hippocampus, activity-dependent synaptic plasticity (i.e. LTP) plays a crucial role in certain types of learning. Therefore, the physiological saturation of synaptic weights should disrupt the encoding of new memories. Researchers defined saturation of an intrinsic pathway as “a neural state in which no further potentiation is feasible, at least for a period of time, at any site in the pathway.” In this experiment, researchers were testing if saturation of hippocampal long-term potentiation (LTP) can lead to impairments in learning. 2) In this experiment, rats (with one hippocampus lessoned) received a multielectrode implant that stimulated array across and into the angular bundle afferent to the other hippocampus; the electrode array was designed to “straddle” the afferent pathway. They also received a stimulation protocol
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Two weeks later, the rats received three bipolar stimulating electrodes and one recording electrode implant in the non-lessoned part of their brain; the field potentials were measured by an electrode in the hilar zone of the ipsilateral denate gyrus.
A third electrode was placed between the other two near the center of the perforant path; this served as a low-frequency test electrode and a tetanization test electrode. After receiving the implants, the rats were given two weeks to recover from the acute effects the surgery.
High-frequency tetanization was conducted on day 28 through a cathode on one side of the bundle and an anode on the other side. After the baseline responses had been recorded, the rats received five rounds of cross-bundle tetanization (0, 1.5, 3, 4.5, and 6 hours periods). Low-frequency control rats received the same cathode and anode stimulation, but they only received single pulses at each
Two weeks later, the rats received three bipolar stimulating electrodes and one recording electrode implant in the non-lessoned part of their brain; the field potentials were measured by an electrode in the hilar zone of the ipsilateral denate gyrus.
A third electrode was placed between the other two near the center of the perforant path; this served as a low-frequency test electrode and a tetanization test electrode. After receiving the implants, the rats were given two weeks to recover from the acute effects the surgery.
High-frequency tetanization was conducted on day 28 through a cathode on one side of the bundle and an anode on the other side. After the baseline responses had been recorded, the rats received five rounds of cross-bundle tetanization (0, 1.5, 3, 4.5, and 6 hours periods). Low-frequency control rats received the same cathode and anode stimulation, but they only received single pulses at each