Hippocampal synaptic depression following spatial learning in a complex maze.
Activity-dependent alteration in synaptic efficacy is referred to as synaptic plasticity and is the believed hallmark of any learning process. Here we employed a recently validated complex maze for spatial training and investigated the impact of repeated and extensive training on basal synaptic transmission of the hippocampal Schaffer collateral-CA1 synaptic connection in vitro. In the present experiments, male CD-1 mice were trained in a complex maze for eight consecutive days five times a day. Subsequently, input-output functions of field excitatory postsynaptic potentials (fEPSPs) recorded in the CA1 area following stimulation of the Schaffer collateral-commissural fiber pathway were analyzed in acute hippocampal slices. We found a marked right shift of the fEPSP response in trained compared to untrained animals while fiber volley size remained unchanged. The findings provide evidence for a direct implication of homosynaptic hippocampal long-term depression in a spatial learning paradigm.
Lange-Asschenfeldt
Christian
C
Department of Psychiatry and Psychotherapy, University of Düsseldorf, Düsseldorf, Germany.
Lohmann
Peter
P
Riepe
Matthias W
MW
D000818:Animals; D004594:Electrophysiology; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D006624:Hippocampus / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D018782:Maze Learning / Q000502:physiology*; D051379:Mice; D009412:Nerve Fibers / Q000502:physiology; D009434:Neural Pathways / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology; D013569:Synapses / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology