Categorization of perceptually similar stimuli in monkeys: a neural network model.

S.E. LEW, D.A. GUTNISKY, B.S. ZANUTTO

San Diego - USA

Congreso; 34th Annual Meeting of the Society for Neuroscience; 2004

Society For Neuroscience

Abstract View CATEGORIZATION OF PERCEPTUALLY SIMILAR STIMULI IN MONKEYS: A NEURAL NETWORK MODEL S.E.Lew1; D.A.Gutnisky1; B.S.Zanutto1,2* 1. IIBM-FI, Univ. Buenos Aires, Buenos Aires, Argentina 2. IBYME, CONICET, Buenos Aires, Argentina In this work we present a biologically plausible neural network model to explain the neuronal processes involved in the categorization of perceptually similar stimuli. The model simulates the role of the areas 46 and 8 of the prefrontal cortex (PFC) involved in the learning of rules and the sacadic movements. Also, the role of the orbital prefrontal cortex (PFC-O) in working memory, and the role of the inferotemporal and the posterior parietal cortex (ITC, PPC) are simulated. In the model, the ventral tegmental area and sustantia nigra pars compacta, predict the appearance of the unconditioned stimulus (Schultz et al., 1997). They control the hebbian or anti-hebbian plasticity in PFC-46 and ITC neurons by comparing the prediction with a threshold. This model predicts experimental and behavioral data, such as: acquisition on delayed matching and delayed nonmatching to sample, reversal (Asaad et al., 1998), stimuli selectivity on PFC-46 (Asaad et al., 1998), categorization of perceptually similar stimuli (Freedman et al., 2001), response latency on PFC-46 neurons (Asaad et al., 1998), effects of cooling PFC and ITC neurons (Fuster et al., 1981; Quinatana et al., 1989; Chafee and Goldman Rakic, 2000), dissociation of the composed stimulus (color-position) (Iversen, 1997) and the neural activity on PFC after the subject reaches criterion (Miller and Cohen, 2001). As Sheinberg and Logothetis (2001) showed, the ITC can act as a modulator of the activity in V4 neurons. In the model, the receptive field of the target in ITC produces an inhibition of the wrong comparison stimulus in V4 neurons. This mechanism allows the model to simulate the learning of logical categorization responding correctly when it is tested under identity, simetry and transitivity tests (Sidman, 1994). Citation:S.E. Lew, D.A. Gutnisky, B.S. Zanutto. CATEGORIZATION OF PERCEPTUALLY SIMILAR STIMULI IN MONKEYS: A NEURAL NETWORK MODEL Program No. 82.13. 2004 Abstract Viewer/Itinerary Planner. Washington, DC: Society for Neuroscience, 2004. Online.   2004 Copyright by the Society for Neuroscience all rights reserved. Permission to republish any abstract or part of any abstract in any form must be obtained in writing from the SfN office prior to publication