Departmental Papers (BE)

Document Type

Conference Paper

Date of this Version

May 2004


This paper describes a neuromorphic implementation of the orientation hypercolumns found in the mammalian primary visual cortex. A hypercolumn contains a group of neurons that respond to the same retinal location, but with different orientation preferences. The system consists of a single silicon retina feeding multiple orientation selective chips, each of which contains neurons tuned to the same orientation, but with different receptive field centers and spatial phases. All chips operate in continuous time, and communicate with each other using spikes transmitted by the asynchronous digital Address Event Representation communication protocol. This enables us to implement recurrent interactions between neurons within one hypercolumn, even though they are located on different chips. We demonstrate this by measuring shifts in orientation selectivity due to changes in the feedback.


Copyright 2004 IEEE. Reprinted from Proceedings of the 2004 International Symposium on Circuits and Systems (ISCAS 2004), Volume 3, pages 13-16.
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neurophysiology, recurrent neural nets, visual perception, asynchronous digital address event representation, communication protocol, cortical orientation hypercolumns, mammalian primary visual cortex, multichip implementation, multiple orientation selective chips, neuromorphic implementation, orientation selectivity, receptive field centers, recurrent neuron interaction, retinal location, silicon retina, spatial phases



Date Posted: 09 November 2004

This document has been peer reviewed.