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Synapses are fundamental to the function of the central nervous system and are implicated in a number of brain disorders. Despite their pivotal role, a comprehensive imaging resource detailing the distribution of synapses in the human brain has been lacking until now. Here, we employ high-resolution PET neuroimaging in healthy humans (17F/16M) to create a 3D atlas of the synaptic marker Synaptic Vesicle glycoprotein 2A (SV2A). Calibration to absolute density values (pmol/ml) was achieved by leveraging postmortem human brain autoradiography data. The atlas unveils distinctive cortical and subcortical gradients of synapse density that reflect functional topography and hierarchical order from core sensory to higher-order integrative areas-a distribution that diverges from SV2A mRNA patterns. Furthermore, we found a positive association between IQ and SV2A density in several higher-order cortical areas. This new resource will help advance our understanding of brain physiology and the pathogenesis of brain disorders, serving as a pivotal tool for future neuroscience research. [ABSTRACT FROM AUTHOR]

Neural systems have evolved to process sensory stimuli in a way that allows for efficient and adaptive behavior in a complex environment. Recent technological advances enable us to investigate sensory processing in animal models by simultaneously recording the activity of large populations of neurons with singlecell resolution, yielding high-dimensional datasets. In this review, we discuss concepts and approaches for assessing the population-level representation of sensory stimuli in the form of a representational map. In such a map, not only are the identities of stimuli distinctly represented, but their relational similarity is also mapped onto the space of neuronal activity. We highlight example studies in which the structure of representational maps in the brain are estimated from recordings in humans as well as animals and compare their methodological approaches. Finally, we integrate these aspects and provide an outlook for how the concept of representational maps could be applied to various fields in basic and clinical neuroscience. [ABSTRACT FROM AUTHOR]

Catatonia is featured by complex symptoms combining motor, affective and behavioral phenomena as well as by its syndrome character with trans-diagnostic occurrence. It paradigmatically shows the limits of current forms of psychopathology like affective and cognitive approaches with respect to both clinical symptoms and brain mechanisms. We therefore suggest Spatiotemporal Psychopathology (STPP) which, as recently introduced, is here developed further following the latest findings in both clinical psychiatry and neuroscience. STPP is characterized by two core features: (i) an experience-based approach that accounts for symptoms primarily in terms of first-person experience of time-space as distinct from third-person observation of specific functions and related behavior; (ii) an integrated brain-mind approach where the brain's neural topography and dynamic, e.g., inner time and space, are shared by the mind's mental topography and dynamic, e.g., time-space experience, as their "common currency". We demonstrate how these two features can well account for both symptom complexity and trans-diagnostic nature of catatonia. In conclusion, catatonia can serve as paradigmatic example for the need to develop a more comprehensive psychopathological approach in psychiatry. This is provided by STPP that allows integrating subjective experience, clinical symptoms and the brain's neural activity in terms of their inner space-time, e.g., topography and dynamic. [ABSTRACT FROM AUTHOR]

Phase change cooling garments (PCCGs) utilize phase change materials to store and release thermal energy, which can be used to reduce thermal sensation in hot environments. This study aims to investigate the effects of PCCGs on thermal comfort and electroencephalography (EEG) signals for laborers in hot conditions. Experiments were conducted in a climate chamber at 33 °C with 50 % relative humidity, with subjects having a metabolic rate of 2.7 met. EEG signals from 20 participants were recorded using a 32-channel EEG system after completing laboring task wearing the PCCGs or normal garment (NG), and the mean power of EEG and topological features of the brain network were analyzed. The results indicate that the use of PCCGs significantly reduce the mean power of the EEG signals, with notable changes in the θ, α, and β-bands. Additionally, wearing PCCGs alters the topological structure of the brain network, and the inter-regional information exchange was enhanced, as evidenced by the increased clustering coefficient, global efficiency, local efficiency, and decreased characteristic path length of the brain network. In this study, the effects of PCCGs on thermal comfort, EEG activity and brain network of laborers in hot environment were explored, which provides a possible indicator for assessing the improvement of thermal comfort by PCCGs. • Subjects' total brain power was significantly decreased after using PCCGs. • With PCCGs, the average power of θ,α, β band was significantly decreased in the EEG signals. • Number of edges in the α and β-bands was significantly increased after wearing PCCGs. • Using PCCGs increased clustering coefficients anddecreased characteristic path lengths in the α and β-bands. [ABSTRACT FROM AUTHOR]

The electroencephalogram amplitude spectra at 11 fixed frequencies of intermittent photic stimulation of 3 to 24 Hz were combined into driving "profiles" for 14 scalp points in 8 male and 7 female normal subjects aged 9 to 17 years. The driving response varied over frequency and was detected in 70 to 100% of cases in the occipital areas (maximum) and in 27 to 77% of cases in the frontal areas (minimum) using as a criterion peak amplitude 20% higher than those of the neighbors. Each subject responded, on average, to 9.7 ± 1.15 intermittent photic stimulation frequencies in the right occipital area and to 6.8 ± 1.97 frequencies in the right frontal area. Most of the driving responses (in relation to the previous background) were significant according to the spectral F-test (a = 0.05), which also detected changes in some cases of low amplitude responses not revealed by the peak criterion. The profiles had two maxima in the alpha and theta bands in all leads. The latter was not present in the background spectra in the posterior areas and was less pronounced in the anterior ones. The weight of the profile theta maximum increased towards the frontal areas where the two maxima were similar, while the profile amplitudes decreased. The profiles repeated the shape of the background spectra, except for the theta band. The interhemispheric correlation between profiles was high. The theta driving detected in all areas recorded suggests a generalized influence of the theta generators in prepubertal and pubertal subjects.

In order to quantify the visual reactivity of EEC to opening the eyes, the topography of EEG power spectra in a sample of 72 healthy subjects aged from 7-15 years, was studied. The EEGs were recorder at 14 scalp sites under eyes closed (ECL) and eyes open (EOP). It has been established that the absolute powers in total and in alpha band were significant- ly higher in all derivations under ECL as compared with EOP condition. Except for the frontal derivations, absolute power in theta band under ECL condition was significantly higher than that under EOP condition. Changes in delta and beta powers were seldom significant. In beta 2 band no EEG blocking was noticed in anterior area. Opening the eyes significantly influenced the values of asymmetry index in alpha band and total power. In all frequency bands and under both conditions, the differences of powers between the hemi spheres were found mainly in the prefrontal and laterofrontal areas. The results showed that the visual blocking of EEG was mostly due to a higher degree of EEG desynchronization after opening the eyes.

Organization of resting state cortical networks is of fundamental importance for the phenomenon of awareness, which is altered in the first part of hypnagogic period (Hori stages 1–4). Our aim was to investigate the change in brain topography pattern of EEG alpha attractor correlation dimension ( CD ) in the period of transition from Hori stage 1 to 4. EEG of ten healthy adult individuals was recorded in the wake and drowsy states, using a 14 channel average reference montage, from which 91 bipolar channels were derived and filtered in the wider alpha (6–14 Hz) range. Sixty 1 s long epochs of each state and individual were subjected to CD calculation according to the Grassberger–Procaccia method. For such a collection of signals, two embedding dimensions, d = {5, 10}, and 22 time delays τ = 2–23 samples were explored. Optimal values were d = 10 and τ = 18, where both saturation and second zero crossing of the autocorrelation function occurred. Bipolar channel CD underwent a significant decrease during the transition and showed a positive linear correlation with electrode distance, stronger in the wake individuals. Topographic distribution of bipolar channels with above median CD changed from longitudinal anterior–posterior pattern (awake) to a more diagonal pattern, with localization in posterior regions (drowsiness). Our data are in line with the literature reporting functional segregation of neuronal assemblies in anterior and posterior regions during this transition. Our results should contribute to understanding of complex reorganization of the cortical part of alpha generators during the wake/drowsy transition. [ABSTRACT FROM AUTHOR]

Intracortical microstimulation and single cell recordings in non-human primates showed that both, muscles and movements are represented in primary motor cortex (M1). This was also suggested in humans using electrophysiological and neuroimaging techniques. Transcranial magnetic stimulation (TMS) thus far was used to study motor cortical muscle representations, but data on movement representations in man are scarce. Therefore, we used TMS of M1 to evoke directional (flexion, extension) thumb movements and generated topographic movement maps (TMS-mov-map) in fourteen healthy individuals. TMS-mov-maps were related to the individual voluntary motor output (Vol-mov, directional thumb acceleration). Conventional TMS-motor evoked potentials (TMS-MEP) were simultaneously recorded from the prime movers (flexor and extensor pollicis brevis) and also compared to the voluntary motor output. Remarkably stable topographic maps were generated with both, thumb flexion and extension being multiply represented, overlapped and interspersed. Thumb Flexion was usually more robust than extension. TMS-mov-maps rather than TMS-MEP-maps seemed to better reflect the individual voluntary motor output. The findings emphasize existing models of multiple, overlapping finger movement representations in human M1, and indicate that this model also adapts to antagonistic thumb movements. The results suggest that investigating topographic movement maps may be an interesting adjunct in studying human motor cortical topography and its relevance for motor control. [ABSTRACT FROM AUTHOR]

Highlights: [•] We evaluated permutation entropy (PE) extracted from different electrodes in patients with typical absences (TAs) and healthy subjects. [•] In patients with TAs there was a recurrent behavior of PE topography, with electrodes from anterior regions associated to higher randomness and electrodes from posterior regions associated to lower randomness. [•] PE seems a useful tool to disclose abnormalities of cerebral electric activity not revealed by conventional EEG. [Copyright &y& Elsevier]

Abstract: Dreaming occurs during non-rapid eye movement (NREM) and rapid eye movement (REM) sleep, which both are regulated by homeostatic, ultradian, and circadian processes. However, the magnitude of how ultradian REM and NREM sleep and its EEG correlates impact onto dream recall remains fairly unknown. In this review, we address three questions: 1. Is there an ultradian NREM–REM sleep modulation in successful dream recall, which is gated by the circadian clock? 2. What are the key electrophysiological correlates that account for dream recall during NREM and REM sleep and 3. Are there age-related changes in the ultradian and circadian regulation in dream recall and its electrophysiological correlates? Knowledge on the specific frequency and topography NREM and REM sleep differences prior to dream recall may pinpoint to the cerebral correlates that account for this cognitive process, and hint to their possible physiological meaning. [Copyright &y& Elsevier]

Topographic brain mapping of evoked potentials can be used to localize abnormalities of cortical function. We evaluated the effect of sleep fragmentation on brain function by measuring the visual P300 waveform using brain mapping. Eight normal subjects (Epworth Score ± SD: 5 ± 3) underwent tone-induced sleep fragmentation and undisturbed study nights in a randomized cross-over design. Study nights were followed by topographic brain mapping using a visual information processing test and concurrent event-related potentials. Experimental sleep fragmentation did not significantly increase objective daytime sleepiness or lower cognitive performance on a battery of cognitive function tests (all P ≥ 0.1). There were no significant topographical delays in P300 latencies with sleep fragmentation (all P > 0.15). However, at sites Fz, F4, T3, C3, Cz and C4 the P300 amplitudes were reduced significantly after sleep fragmentation (all P < 0.05). A reduction in P300 amplitude has previously been interpreted as a decrease in attention. These reductions in P300 amplitudes with sleep fragmentation in frontal, central and temporal brain areas suggest that sleep fragmentation may cause a broad decrease in attention. Sleep fragmentation did not delay P300 latencies in any brain area, and so does not explain the delay in P300 latencies reported in sleep apnoeics. [ABSTRACT FROM AUTHOR]

This study aimed to finding modality-independent event-related potentials (ERP) modulations related to spatial attention by minimising several possible methodological constrains which may account for the rareness of this finding in past spatial attention ERP research. ERP were recorded while subjects performed a shifting spatial attention task of either auditory, visual or mixed (both auditory and visual) modality. Task requirements and stimulation devices were identical for either modality. Stimuli could appear (80%, valid trials) or not (invalid trials) at predicted locations, and subjects had to perform a speeded response to every stimulus. Reaction time benefits were found for valid trials. Instead of the usually found enhancement of sensory-evoked modality-specific components for valid trials, ERP showed modality-independent modulations as a function of attention. They consisted of a fronto-central activity starting 240 ms after stimulus onset and originated in the anterior cingulate gyrus, followed 40 ms later by a bilateral parietal cortex activation. These processes would be reflecting the activity, respectively, of the anterior and posterior attention systems postulated in Posner's model (Posner and Petersen 1990), which showed a higher degree of participation during invalid trials. P300-like processes were also observed for invalid trials. These results demonstrate that supramodal effects of spatial attention on ERP can be obtained. Furthermore, they extend Posner's model by indicating the timings of implication of the attention subsystems. [ABSTRACT FROM AUTHOR]

The influence of genetic relatedness on the similarity degree of topographical EEG parameters was studied in a sample of 26 sets of monozygotic (MZ) and 46 sets of dizygotic (DZ) twins. All 144 subjects were healthy, primary school children, aged 7–15 years, 69 boys and 75 girls. Correlation coefficients were calculated for 50 quantitative EEG parameters of paired values obtained at each of 16 active electrode sites, in four groups of paired tracings: 1. MZ twins, 2. DZ twins, 3. The autocorrelated (A) group formed by correlating the spectral parameters from the same subjects in two different analyzed sequences, 4. The random (R) control group of 1200 unrelated pairs formed from DZ twin pairs. Sets of MZ twins and A group showed the highest degrees of similarity of spectral parameters over all brain areas except for significant differences only for some background features over posterior regions. In contrast, highly significant differences in topographic parameters were evident in comparison of MZ sets with DZ sets, particularly when MZ sets were compared with DZ subsets of opposite sex. Both number and degree of significant differences increased progressively in comparisons with groups 3 vs 2,1 vs 4, and 3 vs 4. The data gave strong evidence for a complex polygenic determination of normal human EEG topography. [ABSTRACT FROM AUTHOR]

Copyright of Italian Journal of Neurological Sciences is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the present study, we investigated topographical differences between monocularly and binocularly evoked potential fields related to the retinal location and spatial frequency of grating stimuli. Electrical brain activity was recorded in 18 healthy adults using an array of 21 electrodes over the occipital areas. Vertical black-and-white grating patterns of different spatial frequencies were presented with central fixation or lateralized to the left or right hemiretina. Computation of global field power determined component latency. Topographic characteristics of the field distributions were examined at the individual component latency for each subject using statistical comparisons between experimental conditions. The strength of the potential fields was significantly larger with binocular stimuli, whereas no effects were observed when comparing component latencies. Pronounced differences occurred in the spatial distribution of electrical brain activity: with 2.5 cycles/deg, large, significant topographic differences between monocularly and binocularly evoked activity were obtained. The potential fields showed a more anterior and more lateralized component distribution with binocular than monocular stimuli. In addition, when the gratings were presented binocularly, significant topographic differences were observed when low and high spatial frequency stimuli were compared. Our results suggest that the relationship between the topography of evoked components and retinal stimulus location and spatial frequency is different for monocular and binocular stimuli, indicating that binocular information processing triggers different neuronal processes in the human visual cortex. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Neurology is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Of the three largest outputs of the cerebral cortex, two have been extensively studied and mapped. Topographic maps of cortico-thalamic and cortico-striatal functional connectivity in humans are well established. However, for the third largest cerebral output, to the pontine nuclei, which connect the cerebrum to the cerebellum, the existence of such an organized connectivity pattern in humans is unknown. Here, using high-resolution functional MRI and a large sample size, we found a topographically organized pattern of functional connectivity between the human cerebral cortex and pons. Our results indicate a rostral-caudal topography; rostral (frontal) cerebral cortex shows connectivity to the rostral pons, and the more caudal cortical areas (i.e. the sensorimotor cortices) show functional connectivity more caudally in the pons, with the occipital lobe connectivity being most caudal. While prefrontal, sensorimotor and occipital cortices have a connectivity to the medial pontine nuclei, posterior parietal cortex and temporal lobe correlate with lateral pontine nuclei. Topography is sufficiently detailed to identify distinct connectivity for leg, trunk, hand and face areas of the motor cortex. These findings reveal the existence of a topographic organization in human cortico-pontine connectivity and provide the topographic map for future studies of cortico-ponto-cerebellum pathway in a variety of disorders., (Published by Oxford University Press on behalf of the Guarantors of Brain 2022. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Morphometric investigations of brain volumes in Williams syndrome (WS) consistently show significant reductions in gray matter volume compared to controls. Cortical thickness (CT) and surface area (SA) are two constituent parts of cortical gray matter volume that are considered genetically distinguishable features of brain morphology. Yet, little is known about the independent contribution of cortical CT and SA to these volumetric differences in WS. Thus, our objectives were: (i) to evaluate whether the microdeletion in chromosome 7 associated with WS has a distinct effect on CT and SA, and (ii) to evaluate age-related variations in CT and SA within WS. We compared CT and SA values in 44 individuals with WS to 49 age- and sex-matched typically developing controls. Between-group differences in CT and SA were evaluated across two age groups: young (age range 6.6-18.9 years), and adults (age range 20.2-51.5 years). Overall, we found contrasting effects of WS on cortical thickness (increases) and surface area (decreases). With respect to brain topography, the between-group pattern of CT differences showed a scattered pattern while the between-group surface area pattern was widely distributed throughout the brain. In the adult subgroup, we observed a cluster of increases in cortical thickness in WS across the brain that was not observed in the young subgroup. Our findings suggest that extensive early reductions in surface area are the driving force for the overall reduction in brain volume in WS. The age-related cortical thickness findings might reflect delayed or even arrested development of specific brain regions in WS., (© 2016 Wiley Periodicals, Inc.)