Biology subjects

Bringas Vega, M. L.

Publications and source records attributed to Bringas Vega, M. L..

4 recordsLinked to original sources

bioRxiv2026

Quilting the Brain: Whole-Brain iEEG Reconstruction via Incomplete Observation Linear Mixed Models

Mapping human brain function at high spatiotemporal resolution is constrained by the physical limitations of non-invasive imaging and the sparse sampling of invasive electrophysiology. While intracranial electroencephalography (iEEG) captures local eld potentials with millimeter precision, clinical implantation strategies result in a "coverage paradox" : observations are restricted to disjoint, patient-specific patches, leaving most of the cortex unobserved. This study introduces the Incomplete Observation Linear Mixed-Effect Model (IOLMM), a statistical framework that resolves this paradox by "quilting" fragmented observations into continuous, whole-brain source activity maps. Our approach integrates two innovations: (1) Sure Independence Screening (SIS) adapted from ultra-high-dimensional statistics to distinguish true physiological signals from volume-conducted "ghost sources"; (2) a hierarchical IOLMM that decouples group-level physiological fixed effects from subject-specific instrumental random effects, solving the scaling ambiguities that plague iEEG group analyses. Applied to the MNI Open iEEG Atlas, the framework is validated through sleep stage-dependent cortical source power reconstruction across Wake, N2, N3, and REM states, recovering the frontal predominance of NREM slow-wave activity and the graded electrophysiological hierarchy from fragmented recordings of 106 patients. This work establishes the first cortical surface-level normative electrophysiological atlas derived from iEEG, providing a quantitative reference for detecting and predicting epileptogenic lesions and bridging the gap between the microscopic precision of electrophysiology and the macroscopic scope of systems neuroscience. HighlightsO_LISolving the Coverage Paradox: A novel IOLMM statistical framework quilts sparse, non-overlapping iEEG data into a unified whole-brain probabilistic map. C_LIO_LIGeometric Screening: Adapts high-dimensional Sure Independence Screening (SIS) using cortical geometric eigenmodes to effectively filter out spurious ghost sources in inverse solutions. C_LIO_LIRobust Harmonization: Decouples group-level physiological fixed effects from subject-specific random effects, resolving scaling ambiguities inherent in heterogeneous multi-center recordings. C_LIO_LIBiological Validation: Validates the framework on real multi-center iEEG data by reconstructing sleep stage-dependent cortical source power maps, recovering known electrophysiological signatures of NREM and REM sleep from fragmented recordings. C_LI

neuroscience↗

bioRxiv2024

EEG Signatures of COVID-19 Survival compared to close contacts and the Cuban EEG normative database

BackgroundThe EEG constitutes a powerful neuroimaging technique for assessing functional brain impairment in COVID-19 patients. ObjectiveThe current investigation compared the EEG among COVID-19 survivors, close contacts and the Cuban EEG normative database, using semi-quantitative visual EEG inspection, quantitative and the current source density measures EEG analysis. MethodsThe resting-state EEG activity, quantitative QEEG, and VARETA inverse solution, were evaluated in 173 subjects: 87 patients confirmed cases by the positive reverse transcription polymerase chain reaction (RT-PCR), 86 close contacts (negative PCR) and the Cuban EEG normative database. All patients were physical, neurological, and clinically assessed using neurological retrospective survey and version 2.1 of the Schedules for Clinical Assessment in Neuropsychiatry (SCAN). ResultsThe GTE score showed significant differences in terms of frequency scores of backgrounds rhythmic activity, diffuse slow activity, and focal abnormality. The QEEG analysis showed a pattern of abnormality with respect to the Cuban EEG normative values, displaying an excess of alpha and beta activities in the fronto-central-parietal areas in both groups. The anomalies, of COVID-19 patients and close contacts, differs in the right fronto-centro parietal area. The COVID 19 group differed-s from the close control group in theta band of the right parieto-central. The symptomatic group of COVID-19 patients differs from asymptomatic patients in delta and theta activities of the parieto-central region. The sources of activation using VARETA showed a difference in cortical activation patterns at alpha and beta frequencies in the groups studied with respect to the normative EEG database. In beta frequency were localized in right middle temporal gyrus in both groups and right angular gyrus in Covid 19 group only. In alpha band, the regions were the left supramarginal gyrus for Covid 19 group and the left superior temporal gyrus for Control group. Greater activation was found in the right middle temporal gyrus at alpha frequency in COVID-19 patients than in their close contacts. ConclusionsBrain functions are impaired in long COVID-19 patients. QEEG and VARETA permit us to comprehend the susceptibility of particular brain regions exposed to viral illness. HighlightsO_LIBackground frequency abnormalities diffuse slow activity and focal abnormality associated with a pattern of excess oftheta, alpha and beta energies in in the right fronto-centro-parietal regions in QEEG analysis characterizedCOVID-19 patients. C_LIO_LIPatients with COVID-19 show more alpha and beta EEG activities related to normative EEG database. C_LIO_LIPatients with COVID-19 and close contacts show high cortical activation in temporo-parietal areas in alpha and beta bands compared to normative EEG database. C_LIO_LIPatients with COVID-19 (positive PCR) have high activation in the right middle frontal gyrus for alpha band related to close contacts. C_LI

neuroscience↗

bioRxiv2019

ERP sources in middle cingulate and precuneus differentiate Parkinson's patients from healthy controls and lingual gyri sources reflect human recombinant EPO effects in a Flanker task

We used EEG source analysis to identify which cortical areas were involved in the automatic and controlled processes of inhibitory control on a flanker task and compared the potential efficacy of recombinant-human erythropoietin (rHuEPO) on the performance of Parkinson s Disease patients. The samples were 18 medicated PD patients (nine of them received rHuEPO in addition to their usual anti-PD medication through random allocation and the other nine patients were on their regular anti-PD medication only) and 9 age and education-matched healthy controls (HCs) who completed the flanker task with simultaneous EEG recordings. N1 and N2 event-related potential (ERP) components were identified and a low-resolution tomography (LORETA) inverse solution was employed to localize the neural generators. Reaction times and errors were increased for the incongruent flankers for PD patients compared to controls. EEG source analysis identified an effect of rHuEPO on the lingual gyri for the early N1 component. N2-related sources in middle cingulate and precuneus were associated with the inhibition of automatic responses evoked by incongruent stimuli differentiated PD and HCs. From our results rHuEPO, seems to mediate an effect on N1 sources in lingual gyri but not on behavioural performance. N2-related sources in middle cingulate and precuneus evoked by incongruent stimuli differentiated PD and HCs.

neuroscience↗

bioRxiv2019

Impact of early childhood malnutrition on the adult brain function: an ERP study

According to the World Health Organization, 45% of deaths among children under five years of age are caused by malnutrition, which impacts more than 224 million children globally. The Barbados Nutrition Study (BNS) is a 50+ year longitudinal study on a Barbadian cohort with histories of moderate to severe protein-energy malnutrition (PEM) limited to the first year of life and a healthy comparison group. We have previously used quantitative electroencephalography (EEG) to highlight differences in brain function during childhood (lower alpha1 activity and higher theta, alpha2 and beta activity) between participants who suffered from early PEM and controls. In order to determine whether similar differences between the PEM and control groups persisted into adulthood, our current study used recordings obtained during a Go-No-Go task in a subsample of the original BNS cohort (N=53) at ages 45-51 years. We found that previously malnourished adults (n=24) had a higher rate of omission errors on the task relative to controls (n=29). Evoked-Related Potentials (ERP) were significantly different in participants with histories of early PEM, who presented with lower N2 amplitudes (p<0.05). These findings are typically associated with impaired conflict monitoring and/or attention deficits and may therefore be linked to the attentional and executive function deficits that have been previously reported in this cohort in childhood and again in middle-adulthood. HighlightsO_LIChildhood malnutrition increases risk of brain function alterations. C_LIO_LIThere is a need to investigate the evolution of those outcomes later in life. C_LIO_LIAdults who suffered childhood malnutrition undertook a Go-No-Go task during EEG. C_LIO_LITask performance and N2 amplitude were reduced in malnutrition group (vs control). C_LIO_LIFirst evidence of adult brain function alteration following childhood malnutrition. C_LI

neuroscience↗