Parietal Brain Regions Research Articles

Abnormal Connectivity and Brain Structure in Patients With Visual Snow.

ObjectiveVisual snow (VS) is a distressing, life-impacting condition with persistent visual phenomena. VS patients show cerebral hypermetabolism within the visual cortex, resulting in altered neuronal excitability. We hypothesized to see disease-dependent alterations in functional connectivity and gray matter volume (GMV) in regions associated with visual perception.MethodsNineteen patients with VS and 16 sex- and age-matched controls were recruited. Functional magnetic resonance imaging (fMRI) was applied to examine resting-state functional connectivity (rsFC). Volume changes were assessed by means of voxel-based morphometry (VBM). Finally, we assessed associations between MRI indices and clinical parameters.ResultsPatients with VS showed hyperconnectivity between extrastriate visual and inferior temporal brain regions and also between prefrontal and parietal (angular cortex) brain regions (p < 0.05, corrected for age and migraine occurrence). In addition, patients showed increased GMV in the right lingual gyrus (p < 0.05 corrected). Symptom duration positively correlated with GMV in both lingual gyri (p < 0.01 corrected).ConclusionThis study found VS to be associated with both functional and structural changes in the early and higher visual cortex, as well as the temporal cortex. These brain regions are involved in visual processing, memory, spatial attention, and cognitive control. We conclude that VS is not just confined to the visual system and that both functional and structural changes arise in VS patients, be it as an epiphenomenon or a direct contributor to the pathomechanism of VS. These in vivo neuroimaging biomarkers may hold potential as objective outcome measures of this so far purely subjective condition.

Neural correlates of within-session practice effects in mild motor impairment after stroke: a preliminary investigation.

While the structural integrity of the corticospinal tract (CST) has been shown to support motor performance after stroke, the neural correlates of within-session practice effects are not known. The purpose of this preliminary investigation was to examine the structural brain correlates of within-session practice effects on a functional motor task completed with the more impaired arm after stroke. Eleven individuals with mild motor impairment (mean age 57.0 ± 9.4years, mean months post-stroke 37.0 ± 66.1, able to move ≥ 26 blocks on the Box and Blocks Test) due to left hemisphere stroke completed structural MRI and practiced a functional motor task that involved spooning beans from a start cup to three distal targets. Performance on the motor task improved with practice (p = 0.004), although response was variable. Baseline motor performance (Block 1) correlated with integrity of the CST (r = - 0.696) while within-session practice effects (change from Block 1 to Block 3) did not. Instead, practice effects correlated with degree of lesion to the superior longitudinal fasciculus (r = 0.606), a pathway that connects frontal and parietal brain regions previously shown to support motor learning. This difference between white matter tracts associated with baseline motor performance and within-session practice effects may have implications for understanding response to motor practice and the application of brain-focused intervention approaches aimed at improving hand function after stroke.

PEO-CYTOP Fluoropolymer Nanosheets as a Novel Open-Skull Window for Imaging of the Living Mouse Brain.

SummaryIn vivo two-photon deep imaging with a broad field of view has revealed functional connectivity among brain regions. Here, we developed a novel observation method that utilizes a polyethylene-oxide-coated CYTOP (PEO-CYTOP) nanosheet with a thickness of ∼130 nm that exhibited a water retention effect and a hydrophilized adhesive surface. PEO-CYTOP nanosheets firmly adhered to brain surfaces, which suppressed bleeding from superficial veins. By taking advantage of the excellent optical properties of PEO-CYTOP nanosheets, we performed in vivo deep imaging in mouse brains at high resolution. Moreover, PEO-CYTOP nanosheets enabled to prepare large cranial windows, achieving in vivo imaging of neural structure and Ca2+ elevation in a large field of view. Furthermore, the PEO-CYTOP nanosheets functioned as a sealing material, even after the removal of the dura. These results indicate that this method would be suitable for the investigation of neural functions that are composed of interactions among multiple regions.

Baseline Cortical Thickness Reductions in Clinical High Risk for Psychosis: Brain Regions Associated with Conversion to Psychosis Versus Non-Conversion as Assessed at One-Year Follow-Up in the Shanghai-At-Risk-for-Psychosis (SHARP) Study.

To assess cortical thickness (CT) and surface area (SA) of frontal, temporal, and parietal brain regions in a large clinical high risk for psychosis (CHR) sample, and to identify cortical brain abnormalities in CHR who convert to psychosis and in the whole CHR sample, compared with the healthy controls (HC). Magnetic resonance imaging, clinical, and cognitive data were acquired at baseline in 92 HC, 130 non-converters, and 22 converters (conversion assessed at 1-year follow-up). CT and SA at baseline were calculated for frontal, temporal, and parietal subregions. Correlations between regions showing group differences and clinical scores and age were also obtained. CT but not SA was significantly reduced in CHR compared with HC. Two patterns of findings emerged: (1) In converters, CT was significantly reduced relative to non-converters and controls in the banks of superior temporal sulcus, Heschl's gyrus, and pars triangularis and (2) CT in the inferior parietal and supramarginal gyrus, and at trend level in the pars opercularis, fusiform, and middle temporal gyri was significantly reduced in all high-risk individuals compared with HC. Additionally, reduced CT correlated significantly with older age in HC and in non-converters but not in converters. These results show for the first time that fronto-temporo-parietal abnormalities characterized all CHR, that is, both converters and non-converters, relative to HC, while CT abnormalities in converters relative to CHR-NC and HC were found in core auditory and language processing regions.

Decline Variability of Cortical and Subcortical Regions in Aging: A Longitudinal Study.

Describing the trajectories of age-related change for different brain structures has been of interest in many recent studies. However, our knowledge regarding these trajectories and their associations is still limited due to small sample sizes and low numbers of repeated measures. For the present study, we used a large longitudinal dataset (four measurements over 4 years) comprising anatomical data from a sample of healthy older adults (N = 231 at baseline). This dataset enables us to gain new insights about volumetric cortical and subcortical changes and their associations in the context of healthy aging. Brain structure volumes were derived from T1-weighted MRI scans using FreeSurfer segmentation tools. Brain structure trajectories were fitted using mixed models and latent growth curve models to gain information about the mean extent and variability of decline trajectories for different brain structures as well as the associations between individual trajectories. On the group level, our analyses indicate similar linear changes for frontal and parietal brain regions, while medial temporal regions showed an accelerated decline with advancing age. Regarding subcortical regions, some structures showed strong declines (e.g., hippocampus), others showed little decline (e.g., pallidum). Our data provide little evidence for sex differences regarding the aforementioned trajectories. Between-person variability of the person-specific slopes (random slopes) was largest in subcortical and medial temporal brain structures. When looking at the associations between the random slopes from each brain structure, we found that the decline is largely homogenous across the majority of cortical brain structures. In subcortical and medial temporal brain structures, however, more heterogeneity of the decline was observed, meaning that the extent of the decline in one structure is less predictive of the decline in another structure. Taken together, our study contributes to enhancing our understanding of structural brain aging by demonstrating (1) that average volumetric change differs across the brain and (2) that there are regional differences with respect to between-person variability in the slopes. Moreover, our data suggest (3) that random slopes are highly correlated across large parts of the cerebral cortex but (4) that some brain regions (i.e., medial temporal regions) deviate from this homogeneity.

Simulating a Computational Biological Model, Rather Than Reading, Elicits Changes in Brain Activity during Biological Reasoning.

The creation and analysis of models is integral to all scientific disciplines, and modeling is considered a core competency in undergraduate biology education. There remains a gap in understanding how modeling activities may support changes in students’ neural representations. The aim of this study was to evaluate the effects of simulating a model on undergraduates’ behavioral accuracy and neural response patterns when reasoning about biological systems. During brief tutorials, students (n = 30) either simulated a computer model or read expert analysis of a gene regulatory system. Subsequently, students underwent functional magnetic resonance imaging while responding to system-specific questions and system-general questions about modeling concepts. Although groups showed similar behavioral accuracy, the Simulate group showed higher levels of activation than the Read group in right cuneal and postcentral regions during the system-specific task and in the posterior insula and cingulate gyrus during the system-general task. Students’ behavioral accuracy during the system-specific task correlated with lateral prefrontal brain activity independent of instruction group. Findings highlight the sensitivity of neuroimaging methods for identifying changes in representations that may not be evident at the behavioral level. This work provides a foundation for research on how distinct pedagogical approaches may affect the neural networks students engage when reasoning about biological phenomena.

Neural Mechanisms of Memory Enhancement and Impairment Induced by Visual Statistical Learning.

Prior research has reported that the medial temporal, parietal, and frontal brain regions are associated with visual statistical learning (VSL). However, the neural mechanisms involved in both memory enhancement and impairment induced by VSL remain unknown. In this study, we examined this issue using event-related fMRI. fMRI data from the familiarization scan showed a difference in the activation level of the superior frontal gyrus (SFG) between structured triplets, where three objects appeared in the same order, and pseudorandom triplets. More importantly, the precentral gyrus and paracentral lobule responded more strongly to Old Turkic letters inserted into the structured triplets than to those inserted into the random triplets, at the end of the familiarization scan. Furthermore, fMRI data from the recognition memory test scan, where participants were asked to decide whether the objects or letters shown were old (presented during familiarization scan) or new, indicated that the middle frontal gyrus and SFG responded more strongly to objects from the structured triplets than to those from the random triplets, which overlapped with the brain regions associated with VSL. In contrast, the response of the lingual gyrus, superior temporal gyrus, and cuneus was weaker to letters inserted into the structured triplets than to those inserted into the random triplets, which did not overlap with the brain regions associated with observing the letters during the familiarization scan. These findings suggest that different brain regions are involved in memory enhancement and impairment induced by VSL.

Direct brain recordings identify hippocampal and cortical networks that distinguish successful versus failed episodic memory retrieval

Human data collected using noninvasive imaging techniques have established the importance of parietal regions towards episodic memory retrieval, including the angular gyrus and posterior cingulate cortex. Such regions comprise part of a putative core episodic retrieval network. In free recall, comparisons between contextually appropriate and inappropriate recall events (i.e. prior list intrusions) provide the opportunity to study memory retrieval networks supporting veridical recall, and existing findings predict that differences in electrical activity in these brain regions should be identified according to the accuracy of recall. However, prior iEEG studies, utilizing principally subdural grid electrodes, have not fully characterized brain activity in parietal regions during memory retrieval and have not examined connectivity between core recollection areas and the hippocampus or prefrontal cortex. Here, we employed a data set obtained from 100 human patients implanted with stereo EEG electrodes for seizure mapping purposes as they performed a free recall task. This data set allowed us to separately analyze activity in midline versus lateral parietal brain regions, and in anterior versus posterior hippocampus, to identify areas in which retrieval-related activity predicted the recollection of a correct versus an incorrect memory. With the wide coverage afforded by the stereo EEG approach, we were also able to examine interregional connectivity. Our key findings were that differences in gamma band activity in the angular gyrus, precuneus, posterior temporal cortex, and posterior (more than anterior) hippocampus discriminated accurate versus inaccurate recall as well as active retrieval versus memory search. The left angular gyrus exhibited a significant power decrease preceding list intrusions as well as unique phase–amplitude coupling properties, whereas the prefrontal cortex was unique in exhibiting a power increase during list intrusions. Analysis of connectivity revealed significant hemispheric asymmetry, with relatively sparse left-sided functional connections compared to the right hemisphere. One exception to this finding was elevated connectivity between the prefrontal cortex and left angular gyrus. This finding is interpreted as evidence for the engagement of prefrontal cortex in memory monitoring and mnemonic decision-making.

Complementary Correlational Profiles between Slow Wave Brain Oscillations and Working Memory Capacity

Working memory involves a range of functions, including maintenance of information and processing that information undisturbed by distraction. Neuroscientific studies have observed critical contributions from frontal and parietal brain regions during processing of cognitive demanding tasks. However, less is known about individual differences in the resting state and their association with working memory capacity. In this study, electrophysiological recordings were taken from thirty volunteers in eyes closed and eyes open conditions after completing the automated version of the operation span task. The results reveal two clusters of correlations: a midline-theta cluster and a parieto-temporal alpha cluster. The theta and alpha clusters have a negative and a positive correlation with operation span performance, respectively. These results are interpreted as individual differences in cognitive preparedness, with the centro-parietal region being critical in switching between outward and inward attention, with the balance of theta and alpha spectral power at Pz indicating to where cognitive resources are directed.

The Importance of Cursive Handwriting Over Typewriting for Learning in the Classroom: A High-Density EEG Study of 12-Year-Old Children and Young Adults.

To write by hand, to type, or to draw – which of these strategies is the most efficient for optimal learning in the classroom? As digital devices are increasingly replacing traditional writing by hand, it is crucial to examine the long-term implications of this practice. High-density electroencephalogram (HD EEG) was used in 12 young adults and 12, 12-year-old children to study brain electrical activity as they were writing in cursive by hand, typewriting, or drawing visually presented words that were varying in difficulty. Analyses of temporal spectral evolution (TSE, i.e., time-dependent amplitude changes) were performed on EEG data recorded with a 256-channel sensor array. For young adults, we found that when writing by hand using a digital pen on a touchscreen, brain areas in the parietal and central regions showed event-related synchronized activity in the theta range. Existing literature suggests that such oscillatory neuronal activity in these particular brain areas is important for memory and for the encoding of new information and, therefore, provides the brain with optimal conditions for learning. When drawing, we found similar activation patterns in the parietal areas, in addition to event-related desynchronization in the alpha/beta range, suggesting both similarities but also slight differences in activation patterns when drawing and writing by hand. When typewriting on a keyboard, we found event-related desynchronized activity in the theta range and, to a lesser extent, in the alpha range in parietal and central brain regions. However, as this activity was desynchronized and differed from when writing by hand and drawing, its relation to learning remains unclear. For 12-year-old children, the same activation patterns were found, but to a lesser extent. We suggest that children, from an early age, must be exposed to handwriting and drawing activities in school to establish the neuronal oscillation patterns that are beneficial for learning. We conclude that because of the benefits of sensory-motor integration due to the larger involvement of the senses as well as fine and precisely controlled hand movements when writing by hand and when drawing, it is vital to maintain both activities in a learning environment to facilitate and optimize learning.

Impact of network-targeted multichannel transcranial direct current stimulation on intrinsic and network-to-network functional connectivity.

Dynamics within and between functional resting-state networks have a crucial role in determining both healthy and pathological brain functioning in humans. The possibility to noninvasively interact and selectively modulate the activity of networks would open to relevant applications in neuroscience. Here we tested a novel approach for multichannel, network-targeted transcranial direct current stimulation (net-tDCS), optimized to increase excitability of the sensorimotor network (SMN) while inducing cathodal inhibitory modulation over prefrontal and parietal brain regions negatively correlated with the SMN. Using an MRI-compatible multichannel transcranial electrical stimulation (tES) device, 20 healthy participants underwent real and sham tDCS while at rest in the MRI scanner. Changes in functional connectivity (FC) during and after stimulation were evaluated, looking at the intrinsic FC of the SMN and the strength of the negative connectivity between SMN and the rest of the brain. Standard, bifocal tDCS targeting left motor cortex (electrode ~C3) and right frontopolar (~Fp2) regions was tested as a control condition in a separate sample of healthy subjects to investigate network specificity of multichannel stimulation effects. Net-tDCS induced greater FC increase over the SMN compared to bifocal tDCS, during and after stimulation. Moreover, exploratory analysis of the impact of net-tDCS on negatively correlated networks showed an increase in the negative connectivity between SMN and prefrontal/parietal areas targeted by cathodal stimulation both during and after real net-tDCS. Results suggest preliminary evidence of the possibility of manipulating distributed network connectivity patterns through net-tDCS, with potential relevance for the development of cognitive enhancement and therapeutic tES solutions.

Dissociable neural mechanisms underlie currently-relevant, future-relevant, and discarded working memory representations

In daily life, we use visual working memory (WM) to guide our actions. While attending to currently-relevant information, we must simultaneously maintain future-relevant information, and discard information that is no longer relevant. However, the neural mechanisms by which unattended, but future-relevant, information is maintained in working memory, and future-irrelevant information is discarded, are not well understood. Here, we investigated representations of these different information types, using functional magnetic resonance imaging in combination with multivoxel pattern analysis and computational modeling based on inverted encoding model simulations. We found that currently-relevant WM information in the focus of attention was maintained through representations in visual, parietal and posterior frontal brain regions,whereas deliberate forgetting led to suppression of the discarded representations in early visual cortex. In contrast, future-relevant information was neither inhibited nor actively maintained in these areas. These findings suggest that different neural mechanisms underlie the WM representation of currently- and future-relevant information, as compared to information that is discarded from WM.

Variability of clinical syndromes and cerebral glucose metabolism in symptomatic frontotemporal lobar degeneration associated with progranulin mutations

Objective: The aims of our study were to describe the clinical phenotype and to characterize the cerebral glucose metabolism patterns as measured with fluordesoxyglucose-positron emission tomography (FDG-PET) in symptomatic FTLD-patients with different GRN variants. Methods: For this study, data were included from all patients (n = 10) of a single-center FTLD registry study who had a pathogenic GRN variant and who had undergone a cerebral FDG-PET scan. Results: An overt variability of clinical phenotypes was identified with half of the cases being not unambiguously classifiable into one of the clinical FTLD subtypes. Furthermore, GRN + patients showed a considerable inter-individual variability of FDG uptake pattern. In half of the GRN + patients, metabolic changes expanded from frontal and temporal brain regions to parietal brain regions including the posterior cingulate cortex. Striking asymmetry without a preference for either hemisphere was overt in half of GRN + cases. Conclusion: We conclude that GRN mutations cause variable patterns of neurodegeneration that often exceed the anatomical boundaries of the frontotemporal brain regions and produce clinical syndromes that cannot clearly be classified into one of the subtypes as defined by the diagnostic criteria.

Sleep spindles are resilient to extensive white matter deterioration.

Sleep spindles are an essential part of non-rapid eye movement sleep, notably involved in sleep consolidation, cognition, learning and memory. These oscillatory waves depend on an interaction loop between the thalamus and the cortex, which relies on a structural backbone of thalamo-cortical white matter tracts. It is still largely unknown if the brain can properly produce sleep spindles when it underwent extensive white matter deterioration in these tracts, and we hypothesized that it would affect sleep spindle generation and morphology. We tested this hypothesis with chronic moderate to severe traumatic brain injury (n = 23; 30.5 ± 11.1 years old; 17 m/6f), a unique human model of extensive white matter deterioration, and a healthy control group (n = 27; 30.3 ± 13.4 years old; 21m/6f). Sleep spindles were analysed on a full night of polysomnography over the frontal, central and parietal brain regions, and we measured their density, morphology and sigma-band power. White matter deterioration was quantified using diffusion-weighted MRI, with which we performed both whole-brain voxel-wise analysis (Tract-Based Spatial Statistics) and probabilistic tractography (with High Angular Resolution Diffusion Imaging) to target the thalamo-cortical tracts. Group differences were assessed for all variables and correlations were performed separately in each group, corrected for age and multiple comparisons. Surprisingly, although extensive white matter damage across the brain including all thalamo-cortical tracts was evident in the brain-injured group, sleep spindles remained completely undisrupted when compared to a healthy control group. In addition, almost all sleep spindle characteristics were not associated with the degree of white matter deterioration in the brain-injured group, except that more white matter deterioration correlated with lower spindle frequency over the frontal regions. This study highlights the resilience of sleep spindles to the deterioration of all white matter tracts critical to their existence, as they conserve normal density during non-rapid eye movement sleep with mostly unaltered morphology. We show that even with such a severe traumatic event, the brain has the ability to adapt or to withstand alterations in order to conserve normal sleep spindles.

Multiscale entropy analysis to quantify the dynamics of motor movement signals with fist or feet movement using topographic maps.

Brain neural activity is measured using electroencephalography (EEG) recording from the scalp. The EEG motor/imagery tasks help disabled people to communicate with the external environment. In this paper, robust multiscale sample entropy (MSE) and wavelet entropy measures are employed using topographic maps' analysis and tabulated form to quantify the dynamics of EEG motor movements tasks with actual and imagery opening and closing of fist or feet movements. To distinguish these conditions, we used the topographic maps which visually show the significance level of the brain regions and probes for dominant activities. The paired t-test and Posthoc Tukey test are used to find the significance levels. The topographic maps results obtained using MSE reveal that maximum electrodes show the significance in frontpolar, frontal, and few frontal and parietal brain regions at temporal scales 3, 4, 6 and 7. Moreover, it was also observed that the distribution of significance is from frontoparietal brain regions. Using wavelet entropy, the significant results are obtained at frontpolar, frontal, and few electrodes in right hemisphere. The highest significance is obtained at frontpolar electrodes followed by frontal and few central and parietal electrodes.

T183. LOW LEVELS OF VITAMIN D ARE ASSOCIATED WITH REDUCED CORTICAL THICKNESS AND SURFACE AREA IN FRONTAL, TEMPORAL AND OCCIPITAL REGIONS IN FIRST-EPISODE PSYCHOSIS PATIENTS

BackgroundVitamin D is a neuro-steroid hormone important in brain development, maturation and function as it modulates the production of numerous brain growth factors. Indeed insufficient levels seem to compromise brain development and confer an increased risk of developing schizophrenia later on in life. Finally patients with first-episode psychosis tend to have lower levels of vitamin D than healthy controls. We aimed to explore: 1) The association between vitamin levels and brain structure (i.e. cortical thickness and surface area) in FEP individuals; 2) Differences in brain structure (i.e. cortical thickness and surface area) between FEP individuals with optimal and sub-optimal levels of Vitamin D.MethodsSample: 49 patients with first episode of psychosis (mean age: 27.8 SD ± 9.1 years) part of the BRC Psychosis Theme study on Genetics and Psychosis (GAP). Vitamin D: Vitamin D (serum 25-hydroxyvitamin D) levels were determined by immunoassay. Patients were considered to have sub-optimal levels if vitamin D concentration was below 20 ng/ml, with higher concentrations deemed optimal. Twenty patients had sub-optimal levels of Vitamin D whereas 29 had optimal Vitamin D concentration. Brain Structure: 3T MRI scan were used to evaluate the cortical thickness and the surface area in 49 FEP patients. FreeSurfer 5.3.0 was used to correlate Vitamin D levels with both cortical thickness and surface area in a vertex-by-vertex analysis. afterwards differences in cortical thickness and surface area between FEP participants with both optimal and sub-optimal Vitamin D levels were examined using a vertex-by-vertex General Linear Model analysis in FreeSurfer 5.3.0. Results were corrected for multiples comparison with Montecarlo simulation.ResultsVitamin D levels positively correlated with cortical thickness in the left superior-frontal gyrus and surface area in the right peri-calcarine and right inferior-parietal gyrus (all p<0.05 FWE corrected).FEP patients with sub-optimal levels of Vitamin D (below 20 ng/ml) had reduced cortical thickness in the right medial-orbitofrontal gyrus and lingual gyrus compared to those with optimal levels of Vitamin D (all p<0.05 FWE corrected). Additionally, FEP patients with sub-optimal levels of Vitamin D had smaller surface areas in the cuneus, latero-orbitofrontal gyrus, pre- and post central gyri, superio-frontal gyrus, and inferio parietal gyrus in the right hemisphere than those with optimal levels (all p<0.05 FWE corrected).DiscussionVitamin D levels are associated with reduced cortical thickness and smaller surface area in frontal, temporal, parietal and occipital brain regions in individuals with FEP. Interestingly, these areas complete their maturation well into late adolescence, thus potentially being exposed to low Vitamin D levels over a long period of time may contribute to specific brain structure in adulthood. The identification of a specific brain conformation associated to low levels of Vitamin D would promote greater understanding of the interface between physical and mental illness fostering the development of precision psychiatry.

S44. NEUROBIOLOGICAL FINGERPRINTS OF COGNITIVE SUBTYPES IN RECENT ONSET PSYCHOSIS PATIENTS

BackgroundNeurocognitive impairment plays a central role in pathogenesis and course of psychotic disorders. Patients suffering from psychosis or psychosis-related diseases show general and specific neurocognitive impairments that often precede the onset of manifest symptoms. Neurocognitive impairments are frequently associated with reduced psychosocial functioning along with altered brain morphology and function. Quantifying neurocognitive heterogeneity in impairment in schizophrenia patients, cluster analytic approaches differentiated several cognitive subtypes, including a generally impaired and generally spared subgroup. An independent set of findings provided evidence that neurocognitive subgroups of cognitively spared and impaired SZ patients can also be differentiated based on their brain morphology. The current study aims to (1) subtype a first episode psychosis sample based on neurocognitive performance using cluster analysis and (2) investigate grey matter (GM) differences between the obtained cognitive subtypes and healthy volunteers.Methods121 recent onset-psychosis (ROP) patients and 201 healthy controls (HC) were recruited within the framework of the Personalized Prognostic Tool for Early Psychosis Management (PRONIA) project. Patients fulfilled DSM-IV-TR criteria of a first affective or non-affective psychotic episode in the last 3 month with onset in the last 24 months. Cognitive subtypes of the ROP patients were derived from 83 variables of 10 neurocognitive tasks using a kmeans clustering algorithm. A resampling approach implemented in R was used to assess the statistical stability of the results. Neuropsychological and clinical cluster characteristics were assessed using t tests. GM volume of the obtained patient clusters was compared by means of intracranial volume corrected t tests with age, sex and site matched HCs using SPM.ResultsThe analysis reveals a stable two-cluster solution: A higher cognitive performance cluster (HCP; N=71) and a lower cognitive performance cluster (LCP; N=39). Patients assigned to HCP performed significantly (p < 0.01) worse in 4 out of 10 neuropsychological tasks. Patients assigned to LCP performed significantly (p < 0.01) worse in 9 out of 10 neuropsychological tasks. LCP patients show significantly lower premorbid IQ (p < 0.001) and General Assessment of Functioning score (GAF; p < 0.01), lower occupational functioning (p < 0.01) and higher values on the negative component of the Positive and Negative Syndrom Scale (PANSS; p < 0.05). They show no demographical differences regarding age, sex, education years and study site. LCP patients reveal widespread GM reductions in bilateral temporal, parietal and frontal brain regions as compared to healthy controls. GM reductions of the HCP cluster are more restricted and evident in temporal, occipital regions and in the anterior cingulum.DiscussionTwo homogeneous, neurocognitive subgroups of patients suffering from a recent psychotic episode were identified and show distinctive psychopathological and neuroanatomical patterns. The obtained GM reductions in LCP go in line with the neuro-developmental origin of the disease affecting premorbid cognitive and occupational functioning as well as the STG which was reported to be decreased in the early course of the disease. Finding subgroups within early stage psychotic patients with minimal intake of antipsychotic medication, suggests different underlying patho(-physio)logical mechanisms predating manifest illness expression. This evidence offers the opportunity for personalizing interventions like neurocognitive trainings to enhance patients’ odds for recovery after psychosis.

Transient brain networks underlying interpersonal strategies during synchronized action.

Interpersonal coordination is a core part of human interaction, and its underlying mechanisms have been extensively studied using social paradigms such as joint finger-tapping. Here, individual and dyadic differences have been found to yield a range of dyadic synchronization strategies, such as mutual adaptation, leading–leading, and leading–following behaviour, but the brain mechanisms that underlie these strategies remain poorly understood. To identify individual brain mechanisms underlying emergence of these minimal social interaction strategies, we contrasted EEG-recorded brain activity in two groups of musicians exhibiting the mutual adaptation and leading–leading strategies. We found that the individuals coordinating via mutual adaptation exhibited a more frequent occurrence of phase-locked activity within a transient action–perception-related brain network in the alpha range, as compared to the leading–leading group. Furthermore, we identified parietal and temporal brain regions that changed significantly in the directionality of their within-network information flow. Our results suggest that the stronger weight on extrinsic coupling observed in computational models of mutual adaptation as compared to leading–leading might be facilitated by a higher degree of action–perception network coupling in the brain.

Multimodal assessment shows misalignment of structural and functional thalamocortical connectivity in children and adolescents born very preterm

Thalamocortical connections are altered following very preterm birth but it is unknown whether structural and functional alterations are linked and how they contribute to neurodevelopmental deficits. We used a multimodal approach in 27 very preterm and 35 term-born children and adolescents aged 10–16 years: Structural thalamocortical connectivity was quantified with two measures derived from probabilistic tractography of diffusion tensor data, namely the volume of thalamic segments with cortical connections and mean fractional anisotropy (FA) within the respective segments. High-density sleep EEG was recorded and sleep spindles were identified at each electrode. Sleep spindle density and integrated spindle activity (ISA) were calculated to quantify functional thalamocortical connectivity. In term-born participants, the volume of the global thalamic segment with cortical connections was strongly related to sleep spindles across the entire head (mean r ​= ​.53 ​± .10; range ​= ​0.35 to 0.78). Regionally, the volume of the thalamic segment connecting to frontal brain regions correlated with sleep spindle density in two clusters of electrodes over fronto-temporal brain regions (.42 ​± .06; 0.35 to 0.51 and 0.43 ​± .08; 0.35 to 0.62) and the volume of the thalamic segment connecting to parietal brain regions correlated with sleep spindle density over parietal brain regions (mean r ​= ​.43 ​± .07; 0.35 to 0.61). In very preterm participants, the volume of the thalamic segments was not associated with sleep spindles. In the very preterm group, mean FA within the global thalamic segment was negatively correlated with ISA over a cluster of frontal and temporo-occipital brain regions (mean r ​= ​−.53 ​± .07; −.41 to −.72). No association between mean FA and ISA was found in the term-born group. With this multimodal study protocol, we identified a potential misalignment between structural and functional thalamocortical connectivity in children and adolescents born very preterm. Eventually, this may shed further light on the neuronal mechanisms underlying neurodevelopmental sequelae of preterm birth.

Acute and Chronic Effects of Betel Quid Chewing on Brain Functional Connectivity.

BackgroundThe active alkaloid in Betel quid is arecoline. Consumption of betel quid is associated with both acute effects and longer-term addictive effects. Despite growing evidence that betel quid use is linked with altered brain function and connectivity, the neurobiology of this psychoactive substance in initial acute chewing, and long-term dependence, is not clear.MethodsIn this observational study, functional magnetic resonance imaging in a resting-state was performed in 24 male betel quid-dependent chewers and 28 male controls prior to and promptly after betel quid chewing. Network-based statistics were employed to determine significant differences in functional connectivity between brain networks for both acute effects and in long-term betel users versus controls. A support vector machine was employed for pattern classification analysis.ResultsBefore chewing betel quid, higher functional connectivity in betel quid-dependent chewers than in controls was found between the temporal, parietal and frontal brain regions (right medial orbitofrontal cortex, right lateral orbital frontal cortex, right angular gyrus, bilateral inferior temporal gyrus, superior parietal gyrus, and right medial superior frontal gyrus). In controls, the effect of betel quid chewing was significantly increased functional connectivity between the subcortical regions (caudate, putamen, pallidum, and thalamus), and the visual cortex (superior occipital gyrus and right middle occipital gyrus).ConclusionThese findings show that individuals who chronically use betel quid have higher functional connectivity than controls of the orbitofrontal cortex, and inferior temporal and angular gyri. Acute effects of betel quid are to increase the functional connectivity of some visual cortical areas (which may relate to the acute symptoms) and the basal ganglia and thalamus.