Richard Kempter

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A correlation-based ~‘‘Hebbian’’! learning rule at a spike level with millisecond resolution is formulated, mathematically analyzed, and compared with learning in a firing-rate description. The relative timing of presynaptic and postsynaptic spikes influences synaptic weights via an asymmetric ‘‘learning window.’’ A differential equation for the learning(More)
We study analytically a model of long-term synaptic plasticity where synaptic changes are triggered by presynaptic spikes, postsynaptic spikes, and the time differences between presynaptic and postsynaptic spikes. The changes due to correlated input and output spikes are quantified by means of a learning window. We show that plasticity can lead to an(More)
Neuronal oscillations allow for temporal segmentation of neuronal spikes. Interdependent oscillators can integrate multiple layers of information. We examined phase-phase coupling of theta and gamma oscillators in the CA1 region of rat hippocampus during maze exploration and rapid eye movement sleep. Hippocampal theta waves were asymmetric, and estimation(More)
Mariano A. Belluscio,1 Kenji Mizuseki,1 Robert Schmidt,2,3 Richard Kempter,2,3 and György Buzsáki1 1Center for Molecular and Behavioral Neuroscience, Rutgers, The State University of New Jersey, Newark, New Jersey 07102, 2Institute for Theoretical Biology, Department of Biology, Humboldt University of Berlin, 10115 Berlin, Germany, and 3Bernstein Center for(More)
High-frequency hippocampal network oscillations, or "ripples," are thought to be involved in episodic memory. According to current theories, memory traces are represented by assemblies of principal neurons that are activated during ripple-associated network states. Here we performed in vivo and in vitro experiments to investigate the synaptic mechanisms(More)
How does a neuron vary its mean output firing rate if the input changes from random to oscillatory coherent but noisy activity? What are the critical parameters of the neuronal dynamics and input statistics? To answer these questions, we investigate the coincidence-detection properties of an integrate-and-fire neuron. We derive an expression indicating how(More)
Chronic tinnitus is often accompanied by a hearing impairment, but it is still unknown whether hearing loss can actually cause tinnitus. The association between the pitch of the tinnitus sensation and the audiogram edge in patients with high-frequency hearing loss suggests a functional relation, but a large fraction of patients with hearing loss does not(More)
Tinnitus, the perception of a sound in the absence of acoustic stimulation, is often associated with hearing loss. Animal studies indicate that hearing loss through cochlear damage can lead to behavioral signs of tinnitus that are correlated with pathologically increased spontaneous firing rates, or hyperactivity, of neurons in the auditory pathway.(More)
Acoustic stimulation with hearing aids or noise devices is frequently used in tinnitus therapy. However, such behind-the-ear devices are limited in their high-frequency output with an upper cut-off frequency of approximately 5-6 kHz. Theoretical modeling suggests that acoustic stimulation treatments with these devices might be most effective when the(More)
A temporal-feature map is a topographic neuronal representation of temporal attributes of phenomena or objects that occur in the outside world. We explain the evolution of such maps by means of a spike-based Hebbian learning rule in conjunction with a presynaptically unspecific contribution in that, if a synapse changes, then all other synapses connected to(More)