Single granule cells reliably discharge targets in the hippocampal CA3 network in vivo.
Processing of neuronal information depends on interactions between the anatomical connectivity and cellular properties of single cells. We examined how these computational building blocks work together in the intact rat hippocampus. Single spikes in dentate granule cells, controlled intracellularly, generally failed to discharge either interneurons or CA3 pyramidal cells. In contrast, trains of spikes effectively discharged both CA3 cell types. Increasing the discharge rate of the granule cell increased the discharge probability of its target neuron and decreased the delay between the onset of a granule cell train and evoked firing in postsynaptic targets. Thus, we conclude that the granule cell to CA3 synapses are 'conditional detonators,' dependent on granule cell firing pattern. In addition, we suggest that information in single granule cells is converted into a temporal delay code in target CA3 pyramidal cells and interneurons. These data demonstrate how a neural circuit of the CNS may process information.
Center for Molecular and Behavioral Neuroscience, Rutgers University, The State University of New Jersey, 197 University Avenue, Newark, New Jersey 07102, USA.
Darrell A
DA
Henze
Lucia
L
Wittner
György
G
Buzsáki
D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D004558:Electric Stimulation; D004567:Electrodes, Implanted; D006624:Hippocampus / Q000166:cytology / Q000502:physiology*; D007395:Interneurons / Q000502:physiology; D008839:Microelectrodes; D009415:Nerve Net / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D017966:Pyramidal Cells / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000502:physiology; D009435:Synaptic Transmission / Q000502:physiology*