Banca de QUALIFICAÇÃO: JAIME BRUNO CIRNE DE OLIVEIRA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : JAIME BRUNO CIRNE DE OLIVEIRA
DATE: 30/06/2026
TIME: 09:00
LOCAL: Sala de reunião, pav.1 ICe
TITLE:

NECTA: Neural Connectivity Time-resolved Analysis

KEY WORDS:

Dynamic Functional Connectivity; Electrophysiology; High-Performance Com- puting; Partial Directed Coherence; Visual Cortex.

PAGES: 42
BIG AREA: Ciências Biológicas
AREA: Biologia Geral
SUMMARY:

Traditional analysis of brain functional connectivity often collapses the temporal dimension, generating static graphs that obscure the dynamic evolution of neural networks. Further- more, extracting time-resolved networks from high-density electrophysiology (LFP) is heavily hindered by the physical phenomenon of volume conduction and the computational bottleneck associated with stochastic Big Data processing. This qualifying thesis presents NECTA (Neural Connectivity Time-resolved Analysis), an interactive high-performance computational framework designed to explore the dynamic mesoconnectome. NECTA employs a Dask-based parallel architecture and cloud-native Zarr-optimized storage to orchestrate large-scale stochastic simulations, multidimensional tensor slicing, and topo- logical null models, linearly overcoming the critical RAM (Out-Of-Memory) limitations of traditional analytical pipelines. The framework actively mitigates volume conduction artifacts (zero-phase lag) through Hilbert analytical signal processing, utilizing phase- based complex estimators such as the Weighted Phase Lag Index (wPLI) and Imaginary Coherence (iCoh). For strict causal inference, Partial Directed Coherence (PDC) was implemented within a module dynamically auto-optimized by the Bayesian Information Criterion (BIC), controlling complexity penalties in multivariate autoregressive regressions (MVAR). The system was validated in silico (against synthetic noise and modeled con- duction) and empirically applied to a 48-channel dataset from the feline primary visual cortex (Area 17, Area 18, and the Transition Zone), recorded under general anesthesia and paralysis (isolating intrinsic oscillations from top-down cognitive modulations). In vivo results demonstrated that the visual cortex exhibits intense and active high-frequency topological fluctuations, reaching transient peaks in Small-Worldness efficiency precisely coordinated during visual stimulation by moving gratings. Directed analysis in the Low Gamma band (30-59 Hz) established Area 17 as a persistent Driver node (Source) and Area 18 as a stable Sink, while the Transition Zone acted as a robust dynamic modulator of interhemispheric flow, alternating its causal directionality upon stimulation. NECTA strives to facilitate advanced neuroinformatics analyses, delivering a reproducible, Open Science-oriented interactive ecosystem (Dash/Cytoscape) that aims to streamline the translation of raw electrophysiological signals into chronological connectomic discoveries.

COMMITTEE MEMBERS:
Interno - 3086031 - DANIEL YASUMASA TAKAHASHI
Presidente - 1871878 - KERSTIN ERIKA SCHMIDT
Interno - 3884005 - PATRICK CESAR ALVES TERREMATTE