An investigation of Hebbian phase sequences as assembly graphs

Autor(es)

Almeida-Filho, Daniel G. ^[1] ; Lopes-dos-Santos, Vitor ^[1] ; Vasconcelos, Nivaldo A. P. ^{[2, 3]} ; Miranda, Jose G. V. ^[4] ; Tort, Adriano B. L. ^[1] ; Ribeiro, Sidarta ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Rio Grande do Norte, Inst Brain, BR-59056450 Natal, RN - Brazil

^[2] Circuit Dynam & Computat Lab, Champalimaud Neurosci Programme, Lisbon - Portugal

^[3] Univ Ctr Rio Grande Norte, Natal, RN - Brazil

^[4] Univ Fed Bahia, Dept Phys, Salvador, BA - Brazil

• Tipo de documento: Artigo Científico
• Fonte: FRONTIERS IN NEURAL CIRCUITS; v. 8, APR 8 2014.
• Citações Web of Science: 8

Resumo

Hebb proposed that synapses between neurons that fire synchronously are strengthened, forming cell assemblies and phasese quences. The former, on a shorter scale,are ensembles of synchronized cells that function transiently as a closed processing system; the latter, on a larger scale, correspond to the sequential activation of cell assemblies able to represent percepts and behaviors. Nowadays, the recording of large neuronal populations allows for the detection of multiple cell assemblies. With in Hebb's theory, the next logical step is the analysis of phase sequences. Here we detected phase sequences as consecutive assembly activation patterns, and then analyzed their graph attributes in relation to behavior. We investigated action potentials recorded from the adult rat hippocampus and neocortex before, during and after novel object exploration(experimental periods). With in assembly graphs, each assembly corresponded to a node,and each edge corresponded to the temporal sequence of consecutive node activations. The sum of all assembly activations was proportional to firing rates, but the activity of individual assemblies was not. Assembly repertoire was stable across experimental periods, suggesting that novel experience does not create new assemblies in the adult rat. Assembly graph attributes, on the other hand, varied significantly across behavioral states and experimental periods, and were separable enough to correctly classify experimental period (Nave Bayes classifier; maximum AUROC sranging from 0.55 to 0.99) and behavioral states (waking, slow wave sleep, and rapid eye movement sleep; maximum AUROCs ranging from 0.64 to 0.98). Our findings agree with Hebb's view that assemblies correspond to primitive building blocks of representation, nearly unchanged in the adult, while phase sequences are labile across behavioral states and change after novel experience. The results are compatible with a role for phase sequences in behavior and cognition. (AU)

• Processo FAPESP: 13/07699-0 - Centro de Pesquisa, Inovação e Difusão em Neuromatemática - NeuroMat
• Beneficiário: Jefferson Antonio Galves
• Linha de fomento: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs