Simultaneity of responses in a hierarchical visual network

The pattern of anatomical connections between areas of the primate visual s ystem is organized hierarchically. However, onset latencies in parietal and occipital stations are often simultaneous, and this seems to contradict hi erarchical organization in its simplest interpretation, as serial organizat ion. To understand the reasons for this contradiction, we simulated the cor tical network for which there is onset data, including the network's hierar chical structure, The network's dynamics reproduced the simultaneous onset latencies reported in several dorsal areas. These results show that a stric tly hierarchical visual system is compatible with much more complex dynamic s than serial processing, and that hodological and biophysical properties, are more closely related to onset dynamics than is hierarchical organisatio n NeuroReport 12:2753-2759 (C) 2001 Lippincott Williams & Wilkins.