Synthesis of a Liquid State Machine with Hopfield/Brody Transient Synchrony

P. Joshi

Abstract:

Understanding the mechanism of spatiotemporal integration used by our brain to perform recognition of complex temporal sequences is a challenge for current researchers in neuroscience. Recent research has proposed transient synchrony as a plausible mechanism for spatiotemporal integration. This thesis studies a biologically plausible network architecture made of simulated minicolumns that performs a temporal integration task, specifically spoken-word recognition. The network's ability to recognize a spoken word and its natural variants is independent of variations across speakers, simple masking noises and variations in system parameters. The network demonstrates inter columnar and intra columnar synchrony, which in turn leads to word recognition. The intra columnar synchrony of minicolumns acts as an event detection mechanism for events in a particular frequency band. The inter columnar transient synchrony enables the network to recognize words. Each of the minicolumns exhibit a very unique temporal signature when presented with a temporal input. These signatures looked nearly the same for similar inputs (e.g., the same word spoken by different speakers etc.) and were strikingly different for different temporal inputs (e.g., different words).



Reference: P. Joshi. Synthesis of a liquid state machine with hopfield/brody transient synchrony. Master's thesis, Center for Advanced Computer Studies, University of Louisiana, Lafayette, USA, November 2002.