Biomedical subjects

Jesse Goldberg

Publications and source records attributed to Jesse Goldberg.

2 recordsLinked to original sources

PubMed2002

Calcium oscillations in neocortical astrocytes under epileptiform conditions.

Morphological and functional alterations in astrocytic glia are often found in epileptic syndromes, although the exact role of astrocytes in epilepsy is poorly understood. During calcium imaging of epileptiform events in juvenile neocortical slices we previously discovered cells with spontaneous oscillations in their intracellular free calcium concentration ([Ca(2+)](i)). We have now characterized these oscillations using two in vitro models of epilepsy and find that they are produced by astrocytes. Astrocytic oscillations are widespread throughout the imaged territories, are remarkably regular and have long periods, averaging 100 s, which become shorter during development. Astrocytic oscillations are uncorrelated among themselves and with epileptiform events, are blocked by internal release antagonists and are stimulated by caffeine. Astrocytic calcium oscillations could mediate reactive astrogliosis, contribute to the pathogenesis of chronic epileptic syndromes, and be used as a diagnostic test for epileptic tissue.

Animals↗

PubMed2002

A problem with Hebb and local spikes.

Although our understanding of the cellular properties of mammalian neurons is increasing rapidly, the computational function of their elaborate dendritic trees is still mysterious. In recent years, experiments have shown that, in pyramidal cells, individual dendritic compartments sustain local excitation spikes.. These dendrites also support Hebbian synaptic plasticity, which depends on the precise temporal relationship between pre- and postsynaptic spikes. In this review we discuss what we consider to be a problem with Hebbian (i.e., spike-timing-dependent) plasticity. We argue that most of the spikes that occur in dendrites are not back-propagating action potentials but but local spikes, and that Hebbian plasticity caused by local spikes can undermine the functional integrity of the geometrically complex dendritic tree. We propose that the inverted Hebbian plasticity of synapses involved in local spikes, and/or local dendritic homeostatic plasticity, could prevent an unbalanced distribution of synaptic weights on the dendritic tree.

Animals↗