A Computational Theory for the Emergence of Grammatical Categories in Cortical Dynamics

DEMATTIES, DARIO; RIZZI, SILVIO; THIRUVATHUKAL, GEORGE K.; PÉREZ, MAURICIO DAVID; WAINSELBOIM, ALEJANDRO; ZANUTTO, B. SILVANO

Frontiers in Neural Circuits

Qian-Quan Sun

Año: 2020 vol. 14 p. 1 - 69

ORIGINAL RESEARCH ARTICLEFront. Neural Circuits, 16 April 2020 | https://doi.org/10.3389/fncir.2020.00012A Computational Theory for the Emergence of Grammatical Categories in Cortical Dynamics Dario Dematties1*, Silvio Rizzi2, George K. Thiruvathukal2,3, Mauricio David Pérez4, Alejandro Wainselboim5 and B. Silvano Zanutto1,6?1Universidad de Buenos Aires, Facultad de Ingeniería, Instituto de Ingeniería Biomédica, Buenos Aires, Argentina?2Argonne National Laboratory, Lemont, IL, United States?3Computer Science Department, Loyola University Chicago, Chicago, IL, United States?4Microwaves in Medical Engineering Group, Division of Solid-State Electronics, Department of Electrical Engineering, Uppsala University, Uppsala, Sweden?5Centro Científico Tecnológico Conicet Mendoza, Instituto de Ciencias Humanas, Sociales y Ambientales, Mendoza, Argentina?6Instituto de Biología y Medicina Experimental-CONICET, Buenos Aires, ArgentinaA general agreement in psycholinguistics claims that syntax and meaning are unified precisely and very quickly during online sentence processing. Although several theories have advanced arguments regarding the neurocomputational bases of this phenomenon, we argue that these theories could potentially benefit by including neurophysiological data concerning cortical dynamics constraints in brain tissue. In addition, some theories promote the integration of complex optimization methods in neural tissue. In this paper we attempt to fill these gaps introducing a computational model inspired in the dynamics of cortical tissue. In our modeling approach, proximal afferent dendrites produce stochastic cellular activations, while distal dendritic branches?on the other hand?contribute independently to somatic depolarization by means of dendritic spikes, and finally, prediction failures produce massive firing events preventing formation of sparse distributed representations. The model presented in this paper combines semantic and coarse-grained syntactic constraints for each word in a sentence context until grammatically related word function discrimination emerges spontaneously by the sole correlation of lexical information from different sources without applying complex optimization methods. By means of support vector machine techniques, we show that the sparse activation features returned by our approach are well suited?bootstrapping from the features returned by Word Embedding mechanisms?to accomplish grammatical function classification of individual words in a sentence. In this way we develop a biologically guided computational explanation for linguistically relevant unification processes in cortex which connects psycholinguistics to neurobiological accounts of language. We also claim that the computational hypotheses established in this research could foster future work on biologically-inspired learning algorithms for natural language processing applications.