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PubMed1978

[Spatio-temporal analysis of contraction dependent surface movements in Physarum polycephalum (author's transl)].

Plasmodial veins of Physarum polycephalum were investigated by combining cinematographical and tensiometrical methods. Veins remaining on their original growing substrate show characteristic surface movements resulting from an intrinsic contraction automaticity. Radial and longitudinal components of surface movements were registered simultaneously. Both contraction activities show identical frequencies, in contrast to results derived from experiments with isolated veins. There is only one genuine frequency and therefore one has not necessarily to suppose the existence of a cooperation of two oscillating systems underlying the rhythmic contraction phenomena. The results are discussed in respect to the basis of the contraction phenomena: the cytoplasmic actomyosin fibrils of Physarum and their function in motive force generation for protoplasmic streaming.

Actomyosin↗

PubMed1979

Modifications of the pattern-evoked potential (PEP) in relation to the stimulated part of the visual field (clues for the most probable origin of each component).

A spatio-temporal analysis of the successive and simultaneous components of the pattern-evoked potential recorded on the scalp, and of their modifications according to which part of the visual field is stimulated, was carried out with 20 'normal' subjects, in order to shed some light on their most probable sites of origin. The stimulus consisted in the onset of a 20 degree checkerboard presented in runs of 75 stimuli each. Its duration was 750 msec and its frequency of occurrence was random (about 1 every 1500 msec). Twelve different visual field situations were recorded: whole field, half fields and quadrants and stimuli limited to the fovea, to the macula and to extramacular areas. Data were collected from 9 active electrodes (in line, forming a cross montage), and various reference electrodes (ear lobes, Fz, non-cephalic). Eye movements were simultaneously recorded. The electrophysiological data were digitized on line and processed by computer in the form of averaged spatio-temporal maps. In addition to the classical posterior components which peak on the midline (N 60, N 140, and P 200) or less than 4 cm away on both sides (P 90), a late negative wave (LN 210) was differentiated which peaked lower than the inion and more than 8 cm away from the midline on both hemispheres. The large inter-individual variability of the spatio-temporal organization of these components under the same conditions, as well as its very good intra-individual reproducibility, were emphasized. Interpreted on the basis of a simple dipole sheet model of the visual cortex, the changes observed for each component in the 12 experimental situations led to the following suggestions: only the first component N 60 could reflect the activity of the part of area 17 emerging on the convexity, whereas P 90 (Jeffreys' CI) is more likely to originate in area 19 and the midline components N 140 and P 200 in area 18. The topography and reactivity of LN 210 could fit with the hypothesis that it reflects activity of the infero-temporal cortex.

Adult↗

PubMed2026

Estimating the impact of parvovirus B19 outbreaks on congenital anomalies and fetal outcomes in Wales.

OBJECTIVES: Parvovirus B19 (B19V) is a common infection that can cause complications in pregnancy. Outbreaks of B19V in Europe and the UK were recorded in 2024. We aimed to describe the epidemiology of maternal parvovirus in Wales and to investigate associated fetal outcomes widely and in 2024 specifically. STUDY DESIGN: A retrospective observational study. METHODS: All cases of maternal B19V reported to the Congenital Anomaly Register Information Service (CARIS) were analysed. Maternal risk factors included gestational age at the time of infection and maternal age. Spatio-temporal analysis was performed to look for clusters. Poisson regression was used to model incidence of maternal B19V over time. Fetal outcomes were tested for association with risk factors using linear regression and Fisher's exact test. Outcomes and congenital anomalies were descriptively analysed. RESULTS: Between 1998 and 2025, there were 79 cases of maternal B19V across 81 fetuses, mostly reported in South Wales (74/81, 91.3%). There were 24 (29.6%) cases of at least one confirmed congenital anomaly and 57 (70.3%) cases reporting no anomalies; 53 (93%) of these cases had a positive outcome. Congenital anomalies were associated with worse fetal outcomes. Excluding terminations, the overall fetal survival rate was 88%. No association between maternal risk factors and fetal outcome was identified. There was an increase in cases in 2024 with an increase in fetal losses. CONCLUSIONS: The 2024 European B19V outbreak led to an increase in maternal cases and negative fetal outcomes in Wales.

Humans↗

PubMed2026

Spatiotemporal genomic analysis and risk assessment of the plasmids carrying blaOXA-48-like genes based on a large-scale international dataset.

BACKGROUND: The spread of OXA-48-like carbapenemases represents a major public health challenge. Although previous studies have investigated OXA-48-like carbapenemases risk factors, nosocomial dissemination, and plasmid dynamics, an integrated plasmid-centered framework combining complete plasmid mining, transmission-unit analysis, phylogenetic reconstruction, and machine learning-based risk assessment remains limited. METHODS: We systematically collected 747 complete plasmid sequences carrying blaOXA-48-like genes from the NCBI database, establishing the largest collections of complete plasmid sequences to date. Using an integrative framework of population genomics, phylogenetic dating, and machine learning, this study aimed to characterize the dissemination patterns, plasmid replicon diversity, transmission units, mobile genetic elements, co-resistance profiles, and risk classification of these plasmid. RESULTS: Plasmids carrying blaOXA-48-like genes were detected across 50 countries on six continents, with blaOXA-48 predominating in Europe, blaOXA-181 in South Asia, and blaOXA-232 largely in Asia. IncL and ColKP3/IncX3 replicons, together with Tn1999.2 and other MGEs, were central drivers of plasmid maintenance and spread. Sixteen transmission units were defined, with AA068_Cluster3 estimated to have originated in the Netherlands around 2005 before expanding to Europe, the Middle East, Asia, and North America. Co-resistance analyses revealed frequent modules involving aminoglycoside and quinolone resistance, with qnrS1 and aph(3'')-Ib most prevalent. Notably, high-risk transposon structures were often identified in non-clinical environments, underscoring their cross-ecological transmission potential. Machine learning-based classification models showed good internal performance for predefined composite-risk categories, with plasmid mobility, clinical/non-clinical source composition, and host background contributing to the classification results. CONCLUSIONS: This study provides a large-scale plasmid-centered genomic analysis of publicly available complete plasmid sequences carrying blaOXA-48-like genes, integrating transmission-unit inference, phylogeographic reconstruction, mobile genetic element and co-resistance profiling, and composite genomic risk stratification. This gene-centered framework may support future One Health-oriented antimicrobial resistance surveillance and prioritization of plasmids with higher dissemination and resistance potential.

Plasmids↗

PubMed2026

GenOT: generative optimal transport enables spatiotemporal interpolation and generation in cross-platform spatial transcriptomics.

Spatial transcriptomics technologies have revolutionized the analysis of spatial gene expression, yet integrating spatial information and generating data across heterogeneous samples remain challenging. We present GenOT, a generative framework combining multi-scale graph self-supervised contrastive learning with optimal transport barycenter theory for efficient cross-slice and cross-platform spatiotemporal interpolation. The core innovation of GenOT lies in introducing an optimal transport barycenter-based interpolation algorithm, which mathematically models spatial distribution differences across heterogeneous samples to reconstruct spatiotemporal gene expression dynamics. Extensive evaluations demonstrate that GenOT consistently outperforms existing approaches in spatial domain identification, cross-platform interpolation, and developmental trajectory reconstruction.

Spatial Transcriptomics↗

PubMed2025

Unveiling the Dynamics of SARS-CoV-2 Gamma and Delta Waves in Paraná, Brazil - Delta Displacing a Persistent Gamma Through Alternative Routes of Dispersal.

The Gamma and Delta variants of concern (VOCs) of SARS-CoV-2 drove the second and third wave in Brazil and significantly intensified the number of cases and deaths. In this study, we investigate the timeline and origins of the Gamma and Delta variants using a spatiotemporal analysis based on 1508 genomes collected between March and September 2021 from health administrative regions in Paraná state, Brazil. Our findings indicate that community transmission of Gamma-P.1 began in late 2020, with substantial contributions from the Northeast and North regions. In contrast, our analysis of the Delta-AY.101 genomes underscored the crucial role of Paraná in national-level transmission dynamics beginning in late March 2021. At a local level, the movement estimates inferred from the monophyletic clades showed that the Curitiba health region was the primary source for Gamma-P.1, with a substantial contribution from Londrina. This health-region also emerged as an important hub for Delta-AY.101. Our phylogeographical GLM analysis demonstrates that air travel fluxes and population size at the origin of locations were the strongest predictors of shaping SARS-CoV-2 dispersal dynamics within Paraná. In addition, viral load analysis suggests that Gamma-P.1 and Delta-AY.101 may have maintained a similarly high transmissibility potential throughout the evaluated months, providing insights into the prolonged co-circulation dynamics. Our study underscores the relevance of understanding SARS-CoV-2 introductions and regional circulation contributions at the country level to enhance public health preparedness and strengthen local surveillance programs.

Brazil↗

PubMed2026

Spatiotemporal patterns of Rift Valley fever virus in Africa: a retrospective genomic epidemiology and phylodynamic modelling study.

BACKGROUND: Rift Valley fever virus (RVFV) is a mosquito-borne zoonotic pathogen causing outbreaks in humans and ruminants across Africa and the Arabian Peninsula. Originally restricted to the Great Rift Valley, RVFV has expanded geographically, prompting its classification by WHO as a pathogen of pandemic potential. We investigated the evolutionary and spatial dynamics of RVFV across Africa. METHODS: We used genomic data generated at the International Livestock Research Institute Nairobi genomic laboratory (BioProject PRJNA1106221) and combined with publicly available datasets retrieved from the National Center for Biotechnology (NCBI) GenBank nucleotide database. In retrieving RVFV genome sequences from the NCBI GenBank, we applied the search terms "Rift Valley fever virus segment L AND 6404[SLEN]", "Rift Valley fever virus segment M AND 3885[SLEN]", and "Rift Valley fever virus segment S AND 1520:1690[SLEN]" for L (Large), M (Medium), and S (Small) segments, respectively. For sequences without additional spatiotemporal information, we searched PubMed to extract the associated sequence metadata. We performed molecular clock analysis, phylogenetic inference, phylodynamic modelling (continuous phylogeographic reconstruction), and landscape phylogeography on the three RVFV genome segments (L, M, and S). We aimed to assess evolutionary rates, dispersal patterns, and environmental drivers. Focus was placed on lineage C, the most widely distributed variant. FINDINGS: The global dataset used in this study consisted of large (n=236), medium (n=237), and small (n=247), which were further filtered to exclude potential reassortants and vaccine strains. Genome sequences retrieved from NCBI GenBank database comprised large (n=180), medium (n=184), and small (n=202). The genome sequences from retrospective human and livestock isolates comprised large (n=56), medium (n=53), and small (n=45) collected in Burundi (2018), Kenya (2007, 2018, 2019, 2021, and 2022), and Rwanda (2018 and 2022). Our dataset revealed that RVFV exhibited low overall genetic diversity. Lineage C, however, showed evidence of active evolution, with substitution rates ranging from 3·58 × 10-4 to 9·76 × 10-4 substitutions per site per year. This lineage probably originated in Zimbabwe in the mid-1970s and has since expanded across eastern and southern Africa. Phylogeographic reconstructions revealed rapid spread, with diffusion coefficients exceeding 50 000 km2 per year. INTERPRETATION: Lineage C appears capable of establishing endemic transmission in new regions, with ongoing diversification observed during interepidemic periods. These observations reinforce the value of continuous genomic surveillance, particularly during cryptic transmission phases when adaptive mutations might emerge. Although further evidence is needed, observed trends in climate variability and land-use change point to the potential benefit of targeted surveillance in settings that could be at increased risk, including urban centres and wetlands. FUNDING: This work was supported by the German Federal Ministry for Economic Cooperation and Development, the Rockefeller Foundation, and the Africa Centres for Disease Control and Prevention.

Rift Valley fever virus↗

PubMed2024

Spatiotemporal and genomic analysis of carbapenem resistance elements in Enterobacterales from hospital inpatients and natural water ecosystems of an Irish city.

Carbapenemase-producing Enterobacterales (CPE) is a diverse group of often multidrug-resistant organisms. Surveillance and control of infections are complicated due to the inter-species spread of carbapenemase-encoding genes (CEGs) on mobile genetic elements (MGEs), including plasmids and transposons. Due to wastewater discharges, urban water ecosystems represent a known reservoir of CPE. However, the dynamics of carbapenemase-bearing MGE dissemination between Enterobacterales in humans and environmental waters are poorly understood. We carried out whole-genome sequencing, combining short- and long-sequencing reads to enable complete characterization of CPE isolated from patients, wastewaters, and natural waters between 2018 and 2020 in Galway, Ireland. Isolates were selected based on their carriage of Class A blaKPC-2 (n = 6), Class B blaNDM-5 (n = 12), and Class D blaOXA-48 (n = 21) CEGs. CEGs were plasmid-borne in all but two isolates. OXA-48 dissemination was associated with a 64 kb IncL plasmid (62%), in a broad range of Enterobacterales isolates from both niches. Conversely, blaKPC-2 and blaNDM-5 genes were usually carried on larger and more variable multireplicon IncF plasmids in Klebsiella pneumoniae and Escherichia coli, respectively. In every isolate, each CEG was surrounded by a gene-specific common genetic environment which constituted part, or all, of a transposable element that was present in both plasmids and the bacterial chromosome. Transposons Tn1999 and Tn4401 were associated with blaOXA-48 and blaKPC-2, respectively, while blaNDM-5 was associated with variable IS26 bound composite transposons, usually containing a class 1 integron.IMPORTANCESince 2018, the Irish National Carbapenemase-Producing Enterobacterales (CPE) Reference Laboratory Service at University Hospital Galway has performed whole-genome sequencing on suspected and confirmed CPE from clinical specimens as well as patient and environmental screening isolates. Understanding the dynamics of CPE and carbapenemase-encoding gene encoding mobile genetic element (MGE) flux between human and environmental reservoirs is important for One Health surveillance of these priority organisms. We employed hybrid assembly approaches for improved resolution of CPE genomic surveillance, typing, and plasmid characterization. We analyzed a diverse collection of human (n = 17) and environmental isolates (n = 22) and found common MGE across multiple species and in different ecological niches. The conjugation ability and frequency of a subset of these plasmids were demonstrated to be affected by the presence or absence of necessary conjugation genes and by plasmid size. We characterize several MGE at play in the local dissemination of carbapenemase genes. This may facilitate their future detection in the clinical laboratory.

Humans↗

PubMed2026

Reconstructing the early spatial spread of pandemic respiratory viruses in the United States.

Understanding the geographic spread of emerging respiratory viruses is critical for pandemic preparedness, yet the early spatiotemporal dynamics of the 2009 H1N1 pandemic influenza and severe acute respiratory syndrome coronavirus 2 in the United States remain unclear. While mobility and genomic data have revealed important aspects of pandemic spatial spread, several key questions remain: Did the two pandemics follow similar spatial transmission routes? How rapidly did they spread across the United States? What role did stochastic processes play in early spatial transmission? To address these questions, we integrated high-resolution disease data with a robust, data-efficient inference framework combining air travel, commuting flows, and pathogen superspreading potentials to reconstruct their spatial spread across US metropolitan areas. The two pandemics exhibited distinct transmission pathways across locations; however, both pandemics established local circulation in most metropolitan areas within weeks, driven by several shared transmission hubs. Early spatial spread was more strongly associated with air travel than with commuting, though stochastic dynamics introduced substantial uncertainty in transmission routes, creating challenges for timely detection and control. Simulations indicate that broad wastewater surveillance coverage beyond top transmission hubs coupled with effective infection control may slow initial spatial expansion. Our findings highlight the rapid, stochastic spread of pandemic respiratory pathogens and the difficulties of early outbreak containment.

Humans↗

PubMed2025

Analysis of gene expression within individual cells reveals spatiotemporal patterns underlying Vibrio cholerae biofilm development.

Bacteria commonly exist in multicellular, surface-attached communities called biofilms. Biofilms are central to ecology, medicine, and industry. The Vibrio cholerae pathogen forms biofilms from single founder cells that, via cell division, mature into three-dimensional structures with distinct, yet reproducible, regional architectures. To define mechanisms underlying biofilm developmental transitions, we establish a single-molecule fluorescence in situ hybridization (smFISH) approach that enables accurate quantitation of spatiotemporal gene-expression patterns in biofilms at cell-scale resolution. smFISH analyses of V. cholerae biofilm regulatory and structural genes demonstrate that, as biofilms mature, overall matrix gene expression decreases, and simultaneously, a pattern emerges in which matrix gene expression becomes largely confined to peripheral biofilm cells. Both quorum sensing and c-di-GMP-signaling are required to generate the proper temporal pattern of matrix gene expression. Quorum sensing signaling is uniform across the biofilm, and thus, c-di-GMP-signaling alone sets the regional matrix gene expression pattern. The smFISH strategy provides insight into mechanisms conferring particular fates to individual biofilm cells.

Biofilms↗

PubMed1979

Excitatory synaptic ensemble properties in the visual cortex of the macaque monkey: a current source density analysis of electrically evoked potentials.

The spatio-temporal distributions of excitatory synaptic ensemble activities in A17 and A18 of the visual cortex of the macaque monkey have been investigated. The synaptic activities were elicited by electrical stimulation of the primary efferents and were localized by applying the current source density analysis to the intracortically recorded field potentials. The principal results are as follows: 1. In A17, two groups of activity, evoked by fast and slow afferents, respectively, were distinguishable. 2. The fast afferents induced monosynaptic activity in layer IV C alpha and layer VI, disynaptic activity in layer IV C alpha and in the supragranular layers and trisynaptic activity in layer IV B. 3. The slow efferents induced monosynaptic activity in lower layers IV C beta and layer VI, disynaptic activity via strong connections in upper layer IV C beta, further disynaptic activity in layers III and IV B and trisynaptic activity in layers V A and II. 4. With the exception that the CSD data reveal more polysynaptic activity within layer IV, there is good agreement between the spatio-temporal distribution of synaptic activities and the cortical circuit diagrams proposed in anatomical studies. 5. In A18, activities from the slow and fast conducting afferent systems are revealed in layer IV, both most likely mediated by the monosynaptically activated target cells of A17. These activities are passed on to the supra-and infragranular layers. 6. In the lateral geniculate nucleus the safety factor of transmission is higher for activity conveyed by slow-than by fast-conducting retinal afferents. 7. The spatial distribution of monocularly evoked surface potentials failed to reveal the ocular dominance columns. 8. Comparison with the cat indicates that, with respect to the intracortical circuitry and LHN-transmission, there are more similarities between the fast-group activity in the monkey and the y-system in the cat and between the slow-group activity in the monkey and the x-system in the cat than vice versa.

Animals↗

PubMedDate not supplied

[Space-time organization of recruitment in rabbit cerebral cortex].

The spatio-temporal organization of the recruiting responses in the cerebral cortex was studied in an acute experiment on alert rabbits. Local low-frequency stimulation of the thalamic central medial nucleus leads to the appearance of both "generalized" and "local" spindles. Temporal shifts of 0.1--2 sec. occur in the appearance of the "generalized" spindles. The performed analysis permits the assumption that under local stimulation the spatio-temporal dynamics of the recruiting response is connected with the appearance of several spindle pacemakers which differ in their characteristics, e. g. in the speed of the excitability recovery and in their interrelations.

Animals↗

PubMed1978

A polygraphic study of bioelectrical brain maturation in preterm infants.

Bioelectrical brain maturation was studied in 26 low-risk preterm infants by serial polygraphic recordings. A modified method of visual EEG analysis was used, based on Parmelee's coding system, which allowed quantification. It gave the following results: (1) The main characteristics of EEG maturation in preterm infants were a progressive spatio-temporal differentiation, with an increase of rhythmic activities and a decrease of discontinuity. (2) A strong relationship was found between post-menstrual age of the infants and EEG maturity, but there were exceptions to this rule. (3) longer duration of extra-uterine life had a small accelerating influence on EEG maturation. (4) Certain basic types of EEG patterns were closely related to behavioural states, whereas EEG maturity was not state-dependent. (5) The relationship between EEG pattern types and behavioural states becomes more stable with increasing age.

Electroencephalography↗

PubMed2026

Dynamic metabolic modelling of ATP allocation during viral infection.

Viral pathogens, like SARS-CoV-2, hijack the host's macromolecular production machinery, imposing an energetic burden that is distributed across cellular metabolism. To explore the dynamic metabolic tension between the host's survival and viral replication, we developed a computational framework that uses genome-scale models to perform dynamic flux balance analysis of human cell metabolism during virus infections. Relative to previous models, our framework addresses the physiology of viral infections of non-proliferating host cells through two new features. First, by incorporating the lipid content of SARS-CoV-2 biomass, we discovered activation of previously overlooked pathways giving rise to new predictions of possible drug targets. Furthermore, we introduce a dynamic model that simulates the partitioning of resources between the virus and the host cell, capturing the extent to which the competition depletes the human cells from essential ATP. By incorporating viral dynamics into our COMETS framework for spatio-temporal modelling of metabolism, we provide a mechanistic, dynamic and generalizable starting point for bridging systems biology modelling with viral pathogenesis. This framework could be extended to broadly incorporate phage dynamics in microbial systems and ecosystems.

Humans↗

PubMed2026

Scalable, open-access and multidisciplinary data integration pipeline for climate-sensitive diseases.

Climate-sensitive infectious diseases pose an important challenge for human, animal and environmental health and it has been estimated that over half of known human pathogenic diseases can be aggravated by climate change. While climatic and weather conditions are important drivers of transmission of vector-borne diseases, socio-economic, behavioural, and land-use factors as well as the interactions among them impact transmission dynamics. Analysis of drivers of climate-sensitive diseases require rapid integration of interdisciplinary data to be jointly analysed with epidemiological (including genomic and clinical) data. Current tools for the integration of multiple data sources are often limited to one data type or rely on proprietary data and software. To address this gap, we develop a scalable and open-access pipeline for the integration of multiple spatio-temporal datasets that requires only the declaration of the country and temporal range and resolution of the study. The tool is locally deployable and can easily be integrated into existing climate-disease-modelling applications. We demonstrate the utility of the tool for dengue modelling in Vietnam where epidemiological data are legally required to remain local. We include a pipeline for bias correction of climate data to enhance their quality for downstream modelling tasks. The Dengue Advanced Readiness Tools-Pipeline empowers users by simplifying complex download, correction, and aggregation steps, fostering data-driven discovery of relationships between infectious diseases and their drivers in space and time, and enhancing reproducibility in research. Additional modules and datasets can be added to the existing ones to make the pipeline extendable to use cases other than the ones presented here.

automated workflows↗

PubMed1977

[Automatic analysis of gastrographies by means of optical digital equipment (author's transl)].

The present paper is concerned with problems of automatic analysis of radiograms, specially cinegastrographies. This study is connected with the utilisation of an interactive system including optical digitizer with its units of control and visualization. This system can explore the radiologic film in its current size of 30 X 40 cm. The particular interest of this application is extracting several parameters characterizing the size and the shape of the stomach. A middle axis can be extracted by computing, from this one a spatio-temporal diagram can be obtained. From this methodology of representation, several states of gastric motility could be characterized.

Analog-Digital Conversion↗

PubMed1979

A model for processing of movement in the visual system.

Processing of spatio-temporal information in the human visual system has been investigated thoroughly during the past decade, but is still far from being properly understood. Moreover, the theory of separation of information by means of sustained and transient channels already at the retinal level is not satisfactory, as experimental results indicate that these two types of channels span a continuum of temporal characteristics. It is however obvious, that the process of pattern recognition and velocity perception calls for their separation at some level of the hierarchy. In this communication, we extend our model of three-dimensional spatio-temporal frequency expansion in the visual system (Gafni and Zeevi, 1977) to show how velocity-information extraction channels, sensitive to direction and velocity exclusively, can be formed by simple summation of signals from well-defined sets of channels representing points in the frequency space. Correspondence of these channels to characteristics of the cortical neurons is discussed.

Depth Perception↗

PubMed1976

Spatio-temporal organization of EEG in premature infants and full-term new-borns.

Inter- and intrahemispheric EEG relationships were studied as a function of maturation in new-born infants. The spatio-temporal organization of EEG activity obtained during the two stages of sleep described in new-born infants - quiet sleep and active sleep - was analysed in 9 full-term new-born infants and 5 prematures (6 records). EEGs were recorded through transverse parietal montage made up of six bipolar derivations. Two epochs of 1.5 min each - successively obtained in both stages of sleep - were digitized, filtered in three frequency bands (beta, theta and delta) and computer-processed according to two methods, factor analysis and rhythms averaging. 1. The following EEG characteristics were found in both groups: (a) Instability of frequency within each frequency band (beta, theta and delta). However, theta activity was the most stable of the three, especially in quiet sleep. (b) Variability of topographical organization (i.e., localization of maxima of potentials) from one moment to another in both stages of sleep and in the three frequency bands. In spite of this intra-individual variability some sort of "average structure" was found in all infants; it was characterized by usually lateral and often symmetrical positions of the maxima of potential on the two hemispheres. For the same infant this structure was the same in the three frequency bands. (c) Poor interhemispheric relationships under all conditions, as well as poor interregional links in one hemisphere. 2. Some EEG characteristics differentiated the two groups and thus seemed to be related to maturation. Compared to full-term newborns the premature group showed: better stability for all three activities, especially for beta activity; higher frequency and larger amplitude of beta activity; better inter- and intrahemispheric relationships; fewer differences related to sleep stages. These results are discussed in terms of organization of the underlying cortical generators. The authors suggest that the active areas would increase in number and in surface with maturation, whereas the links between these different separate areas would remain very poor in the human full-term new-borns as well on one hemisphere as across hemispheres. This last finding would argue against the hypothesis that the corpus callosum which, as is well known, matures early, plays an important role in the establishment of interhemispheric links.

Age Factors↗