Gustav Bernroider1, Franz Ritt2 and Edward W. N. Bernroider2
1Institute of Zoology, University of Salzburg, A-5020 Salzburg, Austria
2Institute of Computer Science, University of Salzburg, A-5020 Salzburg, Austria
(Received October 25, 1995; Accepted January 10, 1996)
Keywords: Keywords: Neural Coding, Neurodynamics, Cortical Neurons
Abstract. Neural ensemble processing involves a spatial and a temporal component of the underlaying neural code. The spatial dimension can plausibly be verified at the level of place coding along the topography of cortical maps. The temporal component, facilitating plastic cooperativity among distributed neuronal responses and thereby ellaborating unique response constellations, remains a matter of controversy. It has not been possible to coherently relate time-correlated ensemble activities, such as synchronous or phase-locked firing to the time-resolved stimulus response of single units. Here we propose a neurophysical concept that addresses scale-invariant neuronal charge propagation from the view of an electrodynamic perturbation problem. In contrast to classical neurodynamics (e.g. spin models), this view follows the charges along continuous world lines, rather than the locations of cells and their connectivities. This naturally links the spatio-temporal lay-out of post-synaptic charges along dendritic trees to an action-potential phase-time code. The composition of these signals to a large-scale dynamic complex finally provides 'time-advanced' population codes operative at the milli-second time-scale as can be observed within the response characteristics of awake cortical ensembles.