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Sallum, L. F.

Publications and source records attributed to Sallum, L. F..

2 recordsLinked to original sources

Classifying Calcium Imaging Dynamics with Deep Learning: Multi-Frequency Analysis through Quantile-Based Time-Series Network Representations

To address the limitations of calcium imaging data, we propose a segmentation-agnostic deep learning framework that integrates Quantile-Based Time-Series Network (QTN) representations with convolutional neural networks to classify neuronal dynamics across multiple spatial resolutions and acquisition frequencies. By transforming fluorescence traces into compact, fixed-size matrices derived from quantile transitions, the method standardizes inputs across recordings while markedly reducing dimensionality and computational cost. Several QTN variants were systematically evaluated, demonstrating strong and consistent classification performance across both whole-image and grid-based preprocessing strategies. Notably, the framework maintained high accuracy under reduced temporal resolution and controlled noise perturbations, confirming that discrimination arises from meaningful temporal patterns rather than artifacts. This study establishes a robust, scalable, and generalizable approach for analyzing calcium imaging dynamics, paving the way for efficient, segmentation-independent characterization of neuronal activity in pharmacological and systems neuroscience applications.

cell biology↗

Network Rerouting Under Ayahuasca: Temporally and Hemisphere-Resolved EEG Connectomics

Ayahuasca profoundly alters conscious experience, yet robust, time-resolved EEG markers of its network-level effects remain limited. We combined machine learning with complex-network analysis to quantify how functional connectivity reorganizes across time and hemispheres in resting-state EEG from a randomized, double-blind, placebo-controlled trial including three 5-min sessions: pre-dose (T1), 2 h post-dose (T2), and 4 h post-dose (T3). The cohort consisted of naive ayahuasca users, a population known to exhibit attenuated or more stable acute responses, making the detection of network-level changes particularly challenging. Connectivity was estimated using multiple metrics and sliding windows (10-120 s), and network features were computed and averaged to ensure statistical validity. A representation-selection step identified Spearman correlation and an intermediate temporal scale as optimal, with classification performance peaking at 60-70 s (independent-test AUC and accuracy = 0.93). Linear mixed models revealed a bilateral decrease in eigenvector centrality (weaker hub influence), increased degree heterogeneity in the right hemisphere, and reduced global efficiency in the left. Edge-level analyses localized these effects: Posterior-left connections weakened acutely (lowest at T2), whereas right temporal-central coupling transiently strengthened (highest at T2). Together, these convergent results support a mechanistic summary: as hub-centric short-cuts weaken, communication is increasingly routed through alternative, more distributed--and less efficient--pathways, with a right-lateralized expression at a later time. Methodologically, the window-optimized, hemisphere-resolved, and edge-validated pipeline extends prior EEG work and highlights temporal scale (approximately 60 s) as a biologically meaningful parameter for detecting psychedelic-induced network reorganization.

neuroscience↗