Jesús Poza

Universidad de Valladolid | UVA · Department of Theory of Signal and Communications and Telematic Engineering

Neuronal effects mediated by proteins related to neurodegenerative diseases are shown to tilt cortical circuits away from balanced excitation and inhibition (E/I). Crucially, these circuit-level imbalances provide diagnostic and prognostic information and offer a unique framework to make real progress in our understanding and treatment of the demen...

Our study aimed to verify the possibilities of effectively applying chronnectomics methods to reconstruct the dynamic processes of network transition between three types of brain states, namely, eyes-closed rest, eyes-open rest, and a task state. The study involved dense EEG recordings and reconstruction of the source-level time-courses of the sign...

Background and Objective: Alzheimer's disease (AD) is a neurological disorder that impairs brain functions associated with cognition, memory, and behavior. Noninvasive neurophysiological techniques like magnetoen-cephalography (MEG) and electroencephalography (EEG) have shown promise in reflecting brain changes related to AD. These techniques are u...

Our study aimed to verify the possibilities of effectively applying chronnectomics methods to reconstruct the dynamic processes of network transition between three types of brain states, namely, eyes-closed rest, eyes-open rest, and a task state. The study involved dense EEG recordings and reconstruction of the source-level time-courses of the sign...

Schizophrenia has been associated with a reduced task-related modulation of cortical activity assessed through electroencephalography (EEG). However, to the best of our knowledge, no study so far has assessed the underpinnings of this decreased EEG modulation in schizophrenia. A possible substrate of these findings could be a decreased inhibitory f...

La migraña es un trastorno neurológico que se divide en dos subtipos dependiendo de la frecuencia de los ataques al mes: migraña crónica (MC) y episódica (ME). No existen biomarcadores que permitan realizar un diagnóstico preciso. Por ello, el objetivo de este estudio es cuantificar las posibles alteraciones producidas por los subtipos de migraña e...

La actividad electroencefalográfica (EEG) espontánea es generada por el cerebro de forma natural en ausencia de estímulos específicos. El registro de la actividad EEG en estado de reposo (RS, resting-state) suele realizarse tratando de “no pensar en nada”, con lo cual se induce un estado de divagación mental (MW, mind-wandering). Sin embargo, exist...

Las hiperintesidades de materia blanca (white matter hyperintensities, WMHs) son indicios de lesiones en el tejido cerebral observables mediante resonancia magnética. Las WMHs son útiles para caracterizar cuadros patológicos tempranos y están asociadas a un incremento del riesgo de diversas dolencias. Sin embargo, el impacto que producen dichas ano...

The majority of electroencephalographic (EEG) and magnetoencephalographic (MEG) studies filter and analyse neural signals in specific frequency ranges, known as "canonical" frequency bands. However, this segmentation, is not exempt from limitations, mainly due to the lack of adaptation to the neural idiosyncrasies of each individual. In this study,...

Introduction Logically valid deductive arguments are clear examples of abstract recursive computational procedures on propositions or on probabilities. However, it is not known if the cortical time-consuming inferential processes in which logical arguments are eventually realized in the brain are in fact physically different from other kinds of inf...

Objective: Brain connectivity networks are usually characterized in terms of properties coming from the Complex Network Theory. Using new measures to summarize the attributes of functional connectivity networks can be an important step for their better understanding and characterization, as well as to comprehend the alterations associated with neu...

The majority of electroencephalographic (EEG) and magnetoencephalographic (MEG) studies filter and analyse neural signals in specific frequency ranges, known as "canonical" frequency bands. However, this segmentation, is not exempt from limitations, mainly due to the lack of adaptation to the neural idiosyncrasies of each individual. In this study,...

Objective. Previous studies have reported neurophysiological differences between chronic migraine (CM) and healthy controls (HC). The aim of the current study is to evaluate how the CM condition affects the brain activity in women using spectral measures. Methods. We have included 62 female subjects: 32 CM patients (age 34.50 (27.50, 39.00)) and 30...

La migraña puede ser clasificada en dos subtipos: migraña crónica (MC) y episódica (ME), en función de los días que se sufre dolor de cabeza al mes (más, o menos de 15 días). Estos dos subtipos de migraña requieren un tratamiento diferente, lo cual sugiere que el desarrollo de cada una también es distinta. El objetivo de este estudio es analizar la...

La magnetoencefalografía (MEG) permite registrar los campos magnéticos inducidos por la actividad neuronal. Sin embargo, los registros MEG están contaminados por señales procedentes de fuentes no neuronales. Para un posterior análisis de los datos es necesario mitigar la presencia de estos artefactos. El análisis de componentes independientes (ICA)...

Complex properties of functional connectivity networks built using source-level neural electromagnetic signals are useful to characterize the alterations of mild cognitive impairment (MCI). Source-level signals were obtained from 20 electroencephalographic and 20 magnetoencephalographic longitudinal recordings of MCI patients using a finite element...

Introduction. Logically valid deductive arguments are clear examples of abstract recursive computational procedures on propositions or on probabilities. However, it is not known if the cortical time-consuming inferential processes in which logical arguments are eventually realized in the brain are in fact physically different from other kinds of in...

Previous studies have suggested that the typical slow oscillations (SO) characteristics during sleep could be modified in the presence of pediatric obstructive sleep apnea (OSA). Here, we evaluate whether these modifications are significant and if they may reflect cognitive deficits. We recorded the overnight electroencephalogram (EEG) of 294 pedia...

Hallucinations are considered characteristic symptoms of psychosis and part of the ‘psychosis superspectrum’ of the Hierarchical Taxonomy Of Psychopathology (HiTOP) initiative. To gain insight into their psychopathological relevance, we studied their dimensional placement within a single dense transdiagnostic network constituting of basic symptoms...

Dementia is a syndrome characterised by cognitive impairments, with a loss of learning/memory abilities at the earlier stages and executive dysfunction at the later stages. However, recent studies have suggested that impairments in both learning/memory abilities and executive functioning might co-exist. Cognitive impairments have been primarily eva...

Objective: Schizophrenia is a psychiatric disorder that has been shown to disturb the dynamic top-down processing of sensory information. Various imaging techniques have revealed abnormalities in brain activity associated with this disorder, both locally and between cerebral regions. However, there is increasing interest in investigating dynamic n...

Resumen La enfermedad de Alzheimer (EA) es una enfermedad de-generativa con alta prevalencia en la sociedad actual. El diagnóstico de la misma es complejo y costoso. Por ello, se investiga en nuevas formas de caracterización de las altera-ciones que esta enfermedad provoca en la red neuronal. En el presente trabajo se pretende evaluar la robustez d...

La enfermedad de Alzheimer (EA) constituye la principal causa de demencia en los países occidentales. Para su estudio se pueden utilizar diversas técnicas neurofisiológicas y de neuroimagen, entre las que destaca la electroencefalografía (EEG) por su bajo coste, portabilidad y ser no invasivo. La EEG ha revelado diferentes alteraciones que provoca...

Pediatric obstructive sleep apnea (OSA) is a prevalent disorder that disrupts sleep and is associated with neurocognitive and behavioral negative consequences, potentially hampering the development of children for years. However, its relationships with sleep electroencephalogram (EEG) have been scarcely investigated. Here, our main objective was to...

The main objective of this study was to examine the influence that recording length, sampling frequency, and imaging modality have on the estimation and characterization of spontaneous brain meta-states during rest. To this end, a recently developed method of meta-state extraction and characterization was applied to a subset of 16 healthy elderly s...

Connectivity analyses are widely used to assess the interaction brain networks. This type of analyses is usually conducted considering the well-known classical frequency bands: delta, theta, alpha, beta, and gamma. However, this parcellation of the frequency content can bias the analyses, since it does not consider the between-subject variability o...

PICALM and CLU genes have been linked to alterations in brain biochemical processes that may have an impact on Alzheimer’s disease (AD) development and neurophysiological dynamics. The aim of this study is to analyze the relationship between the electroencephalographic (EEG) activity and the PICALM and CLU alleles described as conferring risk or pr...

A thorough and comprehensive understanding of the human brain ultimately depends on knowledge of large-scale brain organization[...].

Cerebral hypoperfusion impairs brain activity and leads to cognitive impairment. Left and right common carotid arteries (CCA) are the major source of cerebral blood supply. It remains unclear whether blood flow in both CCA contributes equally to brain activity. Here, CCA blood flow was evaluated using ultrasonography in 23 patients with cerebrovasc...

Resting-state neural oscillations are used as biomarkers for functional diseases such as dementia, epilepsy, and stroke. However, accurate interpretation of clinical outcomes requires the identification and minimisation of potential confounding factors. While several studies have indicated that the menstrual cycle also alters brain activity, most o...

Dementia due to Alzheimer’s disease (AD) is a neurological syndrome which has an increasing impact on society, provoking behavioral, cognitive, and functional impairments. AD lacks an effective pharmacological intervention; thereby, non-pharmacological treatments (NPTs) play an important role, as they have been proven to ameliorate AD symptoms. Nev...

Alzheimer’s disease (AD) is a neurodegenerative disorder which has become an outstanding social problem. The main objective of this study was to evaluate the alterations that dementia due to AD elicits in the distribution of functional network weights. Functional connectivity networks were obtained using the orthogonalized Amplitude Envelope Correl...

Objective: Nested into slow oscillations (SO) and modulated by their up-states, spindles are electrophysiological hallmarks of N2 sleep stage that present a complex hierarchical architecture. However, most studies have only described spindles in basic statistical terms, which were limited to the spindle itself without analyzing the characteristics...

The characterization of the distinct dynamic functional connectivity (dFC) patterns that activate in the brain during rest can help to understand the underlying time-varying network organization. The presence and behavior of these patterns (known as meta-states) have been widely studied by means of functional magnetic resonance imaging (fMRI). Howe...

Background: Dementia due to Alzheimer's disease (AD) is a complex neurodegenerative disorder, which much of heritability remains unexplained. At the clinical level, one of the most common physiological alterations is the slowing of oscillatory brain activity, measurable by electroencephalography (EEG). Relative power (RP) at the conventional frequ...

Objective: The aim of this study was to solve one of the current limitations for the characterization of the brain network in the Alzheimer's disease (AD) continuum. Nowadays, frequency-dependent approaches have reached contradictory results depending on the frequency band under study, tangling the possible clinical interpretations. Approach: To...

Dementia is a progressive cognitive syndrome, with few effective pharmacological treatments that can slow its progress. Hence, non-pharmacological treatments (NPTs) play an important role in improving patient symptoms and quality of life. Designing the optimal personalised NPT strategy relies on objectively and quantitatively predicting the treatme...

La demencia debida a enfermedad de Alzheimer (EA) es el tipo de demencia más habitual en los países occidentales. Caracterizar la red neuronal desde puntos de vista novedosos puede ser de gran interés para conocer las dinámicas subyacentes a la progresión de esta enfermedad. En este estudio, se pretende evaluar la robustez de la red neuronal constr...

Dos de los métodos más utilizados para estudiar la actividad electroencefalográfica (EEG) consisten en estimar la densidad espectral de potencia (PSD) para cuantificar los patrones de activación local y en realizar un análisis de red que resuma los patrones de sincronización entre diferentes regiones cerebrales. Ambas aproximaciones se han empleado...

Brain waves, measured by electroencephalography (EEG), are a powerful tool in the investigation of neurophysiological traits and a noninvasive and cost-effective alternative in the diagnostic of some neurological diseases. In order to identify novel Quantitative Trait Loci (QTLs) for brain wave relative power (RP), we collected resting state EEG da...

La enfermedad de Alzheimer (EA) es el tipo de demencia más común y con mayor impacto en los países occidentales. Esta patología presenta diversos factores que condicionan su evolución, como son la edad, el sexo o la genética. Con el objetivo de explorar las complejas relaciones entre los diversos factores que inciden en la progresión de la EA, se h...

Objective: Although magnetoencephalography and electroencephalography (M/EEG) signals at sensor level are robust and reliable, they suffer from different degrees of distortion due to changes in brain tissue conductivities, known as field spread and volume conduction effects. To estimate original neural generators from M/EEG activity acquired at se...

The aim of this study was to characterize the EEG alterations in inter-band interactions along the Alzheimer's disease (AD) continuum. For this purpose, EEG background activity from 51 healthy control subjects, 51 mild cognitive impairment patients, 50 mild AD patients, 50 moderate AD patients, and 50 severe AD patients was analyzed by means of bis...

Alzheimer’s disease (AD) is the most prevalent cause of dementia, being considered a major health problem, especially in developed countries. Late-onset AD is the most common form of the disease, with symptoms appearing after 65 years old. Genetic determinants of AD risk are vastly unknown, though, ε 4 allele of the ApoE gene has been reported as t...

This study had two main objectives: (i) to study the effects of volume conduction on different connectivity metrics (Amplitude Envelope Correlation AEC, Phase Lag Index PLI, and Magnitude Squared Coherence MSCOH), comparing the coupling patterns at electrode- and sensor-level; and (ii) to characterize spontaneous EEG activity during different stage...

Spatial and frequency characterization of sleep spindles have been extensively addressed using M/EEG or fMRI recordings. However, its intraindividual variability across time has not been addressed. Here we propose to assess the intraindividual variability of sleep spindles in a time-resolved way by means of a trial-to-trial-variability (TTV) measur...

A deficit in task-related functional connectivity modulation from electroencephalogram (EEG) has been described in schizophrenia. The use of measures of neuronal connectivity as an intermediate phenotype may allow identifying genetic factors involved in these deficits, and therefore, establishing underlying pathophysiological mechanisms. Genes invo...

Objective: Mild cognitive impairment (MCI) and dementia due to Alzheimer's disease (AD) have been shown to induce perturbations to normal neuronal behavior and disrupt neuronal networks. Recent work suggests that the dynamic properties of resting-state neuronal activity could be affected by MCI and AD-induced neurodegeneration. The aim of the stud...

Early detection of and intervention in psychoses prior to their first episode is presently based on the symptomatic ultra-high risk and the basic symptom criteria. Current models of symptom development assume that basic symptoms develop first, followed by attenuated and, finally, frank psychotic symptoms, though interrelations of these symptoms are...

La enfermedad de Alzheimer (EA) tiene un gran impacto en nuestra sociedad, especialmente en los países occidentales. Existen muchos factores que condicionan su progresión, tales como la edad, el sexo, la genética o la reserva cognitiva (RC). La influencia de la RC no ha sido apenas estudiada, por lo que en este estudio se explora su influencia en l...

El objetivo de este trabajo es estudiar el efecto de la conducción de volumen en varias medidas de conectividad funcional: la coherencia sin retardo de fase (lagCOH), la correlación de la envolvente de la amplitud (AEC), y el índice de retardo de fase (PLI). Estas medidas se han aplicado a: (i) un conjunto de señales sintéticas generadas con un mod...

The aim of this project is the development of a bioinformatics tool to aid in the diagnosis of Alzheimer's disease, allowing an early detection and a better characterization of its different stages. This tool will combine genetic data and brain activity. The tool will base its accuracy on the correlation between the genetic information and the elec...

Alzheimer’s Disease (AD) has a high economical, social, and clinical impact in our society, especially in most developed world. It has been proven that its progression is influenced by many factors such as age, gender, genetics or cognitive reserve (CR). In the case of the latter, its influence in neural signals during AD progression has been scarc...

One major risk of paediatric sleep apnoea-hypopnoea syndrome (SAHS) is the development of cognitive impairments among affected children. Electroencephalography (EEG) is ordinarily used as part of polysomnography, the standard diagnostic test for SAHS. However, how SAHS changes overnight EEG, and its relationships with cognitive performance, remains...

Objective: The aim of this study was to evaluate the effect of electroencephalographic (EEG) volume conduction in different measures of functional connectivity and to characterize the EEG coupling alterations at the different stages of dementia due to Alzheimer's disease (AD). Approach: Magnitude Squared Coherence (MSCOH), imaginary part of Cohe...

The aim of this study was to evaluate the effect of volume conduction on different connectivity metrics: Amplitude Envelope Correlation (AEC), Phase Lag Index (PLI), and Magnitude Squared Coherence (MSCOH). These measures were applied to: (i) a synthetic model of 64 coupled oscillators; and (ii) a resting-state EEG database of 72 patients with deme...

In this study, a new automated noise rejection algorithm, the SOurce-estimate-Utilizing Noise-Discarding algorithm (SOUND), was evaluated on magnetoencephalographic (MEG) resting-state signals in order to select its optimal configuration parameters. Different values of the epoch length and the regularization parameter λ0 were assessed in three scen...

Background The study of cerebral underpinnings of schizophrenia may benefit from the high temporal resolution of electromagnetic techniques, but its spatial resolution is low. However, source imaging approaches such as low-resolution brain electromagnetic tomography (LORETA) allow for an acceptable compromise between spatial and temporal resolution...

Alzheimer’s disease (AD) is a neurodegenerative disorder with high prevalence, known for its highly disabling symptoms. The aim of this study was to characterize the alterations in the irregularity and the complexity of the brain activity along the AD continuum. Both irregularity and complexity can be studied applying entropy-based measures through...

Objective: The characterization of brain functional connectivity is a helpful tool in the study of the neuronal substrates and mechanisms that are altered in Azheimer's Disease (AD) and mild cognitive impairment (MCI). Recently, there has been a shift towards the characterization of dynamic functional connectivity (dFC), discarding the assumption...

RATIONALE. Obstructive sleep apnea (OSA) in children is a highly prevalent disease that hampers their cognitive development while also increasing the risk of behavioral disturbances. Sleep fragmentation and intermittent hypoxia have been implicated in these adverse outcomes. Even though EEG is used to evaluate sleep architecture during polysomnogra...