Biology subjects

D'Esposito, M.

Publications and source records attributed to D'Esposito, M..

At least 19 recordsLinked to original sources

bioRxiv2026

Enhancing working memories using repetitive TMS

Working memory, the ability to retain and manipulate information no longer present in the environment, is fundamental for goal-directed behavior (Baddeley, 2012; Baddeley & Hitch, 1974; D'Esposito, 2007; D'Esposito & Postle, 2015). Alpha oscillations (~8-12 Hz) have two apparently contradictory roles in working memory. Alpha activity gates irrelevant information through inhibition, a role causally supported by rhythmic transcranial magnetic stimulation (TMS) of parietal cortex at alpha frequency when a retrospective cue renders a memory item irrelevant (Bonnefond & Jensen, 2012; Riddle et al., 2020). Yet alpha activity also tracks the content of memory and binds the features of memorized objects during maintenance (Foster et al., 2016; Pagnotta et al., 2026). Whether alpha oscillations causally support the fidelity of memory representations during maintenance is untested. Here, 24 participants received short trains of repetitive TMS (rTMS) at theta (6 Hz) or alpha frequency (10 Hz), or in an arrhythmic control pattern, during the second half of the delay of a color working memory task, over the left posterior inferior frontal sulcus or the left intraparietal sulcus. A mixture model separated memory precision from swap errors and guesses. Alpha stimulation of the intraparietal sulcus specifically increased memory precision, whereas rhythmic stimulation of either site reduced response error, guesses and swaps irrespective of frequency. These results provide causal evidence that alpha oscillations support the fidelity of working memory representations during maintenance, and show that rhythmic stimulation at the appropriate frequency, site and time can enhance human working memory.

neuroscience↗

bioRxiv2026

Ongoing brain state dynamics shape spontaneous awake reactivation and its relationship with memory

Memory reactivation is thought to support memory consolidation, but how ongoing brain states shape awake reactivation and its relationship to memory remain poorly understood. Here, we asked whether spontaneous hippocampal-cortical reactivation during awake rest is embedded in ongoing brain state dynamics by examining its coupling with whole-brain activity patterns and infra-slow global signal (GS) fluctuations, and whether these dynamics shape its relationship to memory retention. Reactivation preferentially occurred during an internally oriented brain state characterized by default mode network activation and dorsal attention network suppression, as well as states that reinstated encoding-related visual activity. Reactivation also clustered around the peak of infra-slow GS fluctuations and in high GS amplitude time windows, features previously associated with lower arousal. Importantly, the relationship between reactivation and memory depended on the ongoing brain state: distinct whole-brain activity patterns expressed during reactivation were associated with opposing memory outcomes, while reactivation during high GS amplitude windows was positively associated with retention. Together, these findings show that awake memory reactivation is embedded in dynamic whole-brain states that may influence its memory outcome, suggesting that recurring brain states may provide favorable windows for awake memory consolidation.

neuroscience↗

bioRxiv2026

Functional brain organization is stable within individuals across years

Brain regions exhibit dynamic yet highly coordinated activity patterns that form large-scale functional networks measurable through resting-state correlations. While their association with fluctuating activity may intuitively suggest functional networks to be temporally transient and dependent on state, a growing body of literature suggests that they are person-specific and stable across days. If truly person-specific, then functional networks should preserve unique characteristics over extended periods. To test this hypothesis, we collected longitudinal precision fMRI data ([≥]60 minutes per participant per time point) from 10 healthy young adults across 1-3 year intervals, as well as three adults over 8-13 years. We further replicated findings in the MyConnectome dataset and its 10-year follow-up. Functional network organization--when sufficient per-participant data were collected-- remained largely stable within individuals over prolonged periods of up to 13 years, suggesting that individualized brain organization constitutes persistent features of personal identity that may be supported by homeostatic mechanisms. SIGNIFICANCEWhile many aspects of brain function are portrayed as dynamic and malleable, our study provides evidence for the long-term preservation of functional organization of the healthy young adult brain. Whole-brain functional organization exhibited unique individual characteristics that were preserved for years, even over a decade. The stability of such individualized neural architecture suggests that the brain encodes features of personhood that may be invariant across contexts and temporal fluctuations. This observation reframes our understanding of brain resilience and plasticity by offering new insights into the extent that homeostatic mechanisms of brain organization can withstand stressors and environmental changes through time to maintain a constant functional organization. These insights pave the way for a more comprehensive understanding of the neural mechanisms behind this stability, with the possibility of pinpointing critical markers of healthy brain function and its disruptions.

neuroscience↗

bioRxiv2026

Prenatal Maternal Inflammation Is Associated with Altered Offspring Mesolimbic White Matter Circuitry Observed in Late Midlife

BackgroundExposure to prenatal maternal inflammation (PNMI) has been linked to neurodevelopmental alterations in human offspring. Preclinical studies suggest that PNMI disrupts reward circuitry, particularly within mesolimbic circuits. However, the effects of PNMI on mesolimbic circuits (i.e, ventral tegmental area (VTA) projections to the hippocampus (VTA-H) and limbic striatum (VTA-LS)) in humans are not yet known. MethodsData for PNMI biomarkers [interleukin (IL)-6, IL-8, IL-1 receptor antagonist (IL-1ra), soluble TNF receptor-II (sTNF-RII)] from first trimester (T1) and second trimester (T2) maternal sera, and offspring MRI brain scans in late midlife (aged 57-63 years), were available for 89 mother-offspring dyads. Probabilistic tractography delineated bilateral VTA-H and VTA-LS tracts. Macrostructural tract measures were examined using hierarchical linear regressions. Microstructural integrity was assessed using neurite orientation dispersion and density imaging, and permutation-based cluster analyses. ResultsHigher T2 IL-1ra was associated with increased macrostructure (left VTA-H tract), whereas higher T2 sTNF-RII was associated with reduced macrostructure (right VTA-H and VTA-LS tracts) and higher T2 IL-8 (bilateral VTA-LS tracts). Microstructurally, higher T2 IL-6 was associated with increased neurite density (distal cluster, right VTA-H tract), while higher T1 IL-8 was associated with reduced neurite density (near the hippocampus in the left VTA-H tract, near the VTA in bilateral VTA-LS tracts). ConclusionsPNMI was associated with altered mesolimbic reward circuitry in offspring. This suggests that prenatal inflammation may contribute to affective and motivational disorders in offspring via alterations in mesolimbic circuitry.

neuroscience↗

bioRxiv2025

Temporal fMRI Dynamics Map Dopamine Physiology

Spatial variations in dopamine function are linked to cognition and substance use disorders but are challenging to characterize with current methods. Because dopamine influences blood vessel dilation, we hypothesized that hemodynamic latency, which reflects BOLD signal timing, could serve as an indirect marker of dopamine physiology. Across four datasets, we found a topography of hemodynamic latencies that precisely distinguished the nucleus accumbens, a dopaminergic region implicated in motivation and substance abuse, from other striatal regions. Using PET, genetics, and pharmacology, we found that hemodynamic latencies are robustly related to dopamine function and dopamine-linked behavior. In individuals with cocaine use disorder, we observed a spatial gradient of altered hemodynamic latencies in the striatum. This pattern independently predicted nicotine use, revealing a conserved physiological profile associated with addictive substance use. Hemodynamic latencies map regional, individual, and pathological differences linked to dopamine, opening new avenues for indirectly assessing the role of dopamine in healthy cognition and disease.

neuroscience↗

bioRxiv2024

Decreased hippocampal neurite density in middle-aged/aging adults following prenatal exposure to higher levels of maternal inflammation

In animal models, exposure to heightened maternal inflammation in utero is associated with altered offspring hippocampal development, including reduced dendritic arborization and density. However, the effects of prenatal maternal inflammation (PNMI) on offspring hippocampal microstructure in humans remains unclear. Here, we examined the relationship between exposure to PNMI and neurite density in the hippocampus and its subfields among offspring during late middle age. Participants included 72 mother-offspring dyads from the Child Health and Development Studies (CHDS) cohort. Data for four inflammatory biomarkers (IL-6, IL-8, IL-1 receptor antagonist [IL-1RA], and soluble TNF receptor-II [sTNF-RII]) were available from first and second trimester maternal sera. Neurite density in the offspring hippocampus and its subfields was estimated using microstructural modeling of offsprings diffusion-weighted Magnetic Resonance Imaging data (mean age of offspring at imaging = 59 years; 51% male). We estimated the relationship between each biomarker and region-of-interests neurite density. Higher first trimester maternal IL-1RA and IL-6 levels were associated with lower offspring hippocampal neurite density. These relationships were specific to the CA3, CA4, dentate gyrus, and subiculum subfields. In addition, higher second trimester IL-6 was associated with lower subiculum neurite density. Our findings reveal that exposure to heightened prenatal levels of maternal inflammation is linked to altered offspring hippocampal microstructure in late middle age, which could have implications for memory decreases during this period and may be relevant for understanding risk of aging-related cognitive changes. Significance StatementThe contribution of prenatal maternal inflammation (PNMI) to offspring brain microstructure in later life is well established in animal models but poorly understood in humans. Our study discovered long-lasting impacts of elevated PNMI during early mid-gestation on the structural integrity of the hippocampus in offspring during late middle age. Our findings underscore the potential role of prenatal insults in aging-related neurological and cognitive decline, as the observed degradation in hippocampal microstructure is present over half a century following exposure.

immunology↗

bioRxiv2024

Lateral prefrontal cortex controls interplay between working memory and actions

Humans must often keep multiple task goals in mind, at different levels of priority and immediacy, while also interacting with the environment. We might need to remember information for an upcoming task while engaged in more immediate actions. Consequently, actively maintained working memory (WM) content may bleed into ongoing but unrelated motor behavior. Here, we experimentally test the impact of WM maintenance on action execution, and we transcranially stimulate lateral prefrontal cortex (PFC) to parse its functional contributions to WM-motor interactions. We first created a task scenario wherein human participants (both sexes) executed cued hand movements during WM maintenance. We manipulated the compatibility between WM and movement goals at the trial level and the statistical likelihood that the two would be compatible at the block level. We found that remembering directional words (e.g., left, down) biased the trajectory and speed of hand movements that occurred during the WM delay, but the bias was dampened in blocks when WM content predictably conflicted with movement goals. Then we targeted left lateral PFC with two different transcranial magnetic stimulation (TMS) protocols before participants completed the task. We found that an intermittent theta-burst protocol, which is thought to be excitatory, dampened sensitivity to block-level control demands (i.e., proactive control), while a continuous theta-burst protocol, which is thought to be inhibitory, dampened adaptation to trial-by- trial conflict (i.e., reactive control). Therefore, lateral PFC is involved in controlling the interplay between WM content and manual action, but different PFC mechanisms may support different time-scales of adaptive control. Significance StatementWorking memory (WM) allows us to keep information active in mind to achieve our moment-to-moment goals. However, WM maintenance may sometimes unintentionally shape our externally-geared actions. This study formalizes the everyday "action slips" humans commit when we type out or say the wrong word in conversation because it was held in mind for a different goal. The results show that internally maintained content can influence ongoing hand movements, but this interplay between WM and motor behavior depends on the cortical excitability state of the lateral PFC. Neural perturbation with transcranial magnetic stimulation (TMS) shows that temporarily increasing or decreasing PFC excitability can make participants more or less susceptible to the impact of WM on actions.

neuroscience↗

bioRxiv2024

A dopaminergic basis of behavioral control

Both goal-directed and automatic processes shape human behavior, but these processes often conflict. Behavioral control is the decision about which process guides behavior. Despite the importance of behavioral control for adaptive decision-making, its neural mechanisms remain unclear. Critically, it is unknown if there are mechanisms for behavioral control that are distinct from those supporting the formation of goal-relevant knowledge. We performed deep phenotyping of individual dopamine system function by combining multiple PET scans, fMRI, and dopaminergic drug administration in a within-subject, double-blind, placebo-controlled design. Subjects performed a rule-based response time task, with goal-directed and automatic decision-making operationalized as model-based and model-free influences on behavior. We found a double dissociation between two aspects of ventral striatal dopamine physiology: D2/3 receptor availability and dopamine synthesis capacity. Convergent and causal evidence indicated that D2/3 receptors regulate behavioral control by enhancing model-based and blunting model-free influences on behavior but do not affect model-based knowledge formation. In contrast, dopamine synthesis capacity was linked to the formation of model-based knowledge but not behavioral control. D2/3 receptors also modulated frontostriatal functional connectivity, suggesting they regulate behavioral control by gating prefrontal inputs to the striatum. These results identify central mechanisms underlying individual and state differences in behavioral control and point to striatal D2/3 receptors as targets for interventions for improving goal-directed behavior.

neuroscience↗

bioRxiv2024

Alpha phase-coding supports feature binding during working memory maintenance

The ability to successfully retain and manipulate information in working memory (WM) requires that objects individual features are bound into cohesive representations; yet, the mechanisms supporting feature binding remain unclear. Binding (or swap) errors, where memorized features are erroneously associated with the wrong object, can provide a window into the intrinsic limits in capacity of WM that represent a key bottleneck in our cognitive ability. We tested the hypothesis that binding in WM is accomplished via neural phase synchrony and that swap errors result from perturbations in this synchrony. Using magnetoencephalography data collected from human subjects in a task designed to induce swap errors, we showed that swaps are characterized by reduced phase-locked oscillatory activity during memory retention, as predicted by an attractor model of spiking neural networks. Further, we found that this reduction arises from increased phase coding variability in the alpha-band over a distributed network of sensorimotor areas. Our findings demonstrate that feature binding in WM is accomplished through phase coding dynamics that emerge from the competition between different memories. SignificanceWe investigate the neural basis of working memory, focusing on how feature binding is accomplished and how binding or swap errors arise. Using magnetoencephalography, we found that stable phase-locking of alpha oscillations supports correct feature binding, while swap errors correlate with reduced alpha phase preservation, localized to specific brain areas. These findings align with a biologically-plausible computational model predicting that temporal synchrony in neuronal firing underpins feature binding. This work advances our understanding of the neural mechanisms of working memory, providing empirical support for theories of time-based binding and demonstrating the utility of biophysically-realistic models in human neuroimaging studies.

neuroscience↗

bioRxiv2023

Structured memory representations develop at multiple time scales in hippocampal-cortical networks

Influential views of systems memory consolidation posit that the hippocampus rapidly forms representations of specific events, while neocortical networks extract regularities across events, forming the basis of schemas and semantic knowledge. Neocortical extraction of schematic memory representations is thought to occur on a protracted timescale of months, especially for information that is unrelated to prior knowledge. However, this theorized evolution of memory representations across extended timescales, and differences in the temporal dynamics of consolidation across brain regions, lack reliable empirical support. To examine the temporal dynamics of memory representations, we repeatedly exposed human participants to structured information via sequences of fractals, while undergoing longitudinal fMRI for three months. Sequence-specific activation patterns emerged in the hippocampus during the first 1-2 weeks of learning, followed one week later by high-level visual cortex, and subsequently the medial prefrontal and parietal cortices. Schematic, sequence-general representations emerged in the prefrontal cortex after 3 weeks of learning, followed by the medial temporal lobe and anterior temporal cortex. Moreover, hippocampal and most neocortical representations showed sustained rather than time-limited dynamics, suggesting that representations tend to persist across learning. These results show that specific hippocampal representations emerge early, followed by both specific and schematic representations at a gradient of timescales across hippocampal-cortical networks as learning unfolds. Thus, memory representations do not exist only in specific brain regions at a given point in time, but are simultaneously present at multiple levels of abstraction across hippocampal-cortical networks.

neuroscience↗

bioRxiv2022

Task learning is subserved by a domain-general brain network

One of the most important human faculties is the ability to acquire not just new memories but the capacity to perform entirely new tasks. However, little is known about the brain mechanisms underlying the learning of novel tasks. Specifically, it is unclear to what extent learning of different tasks depends on domain-general and/or domain-specific brain mechanisms. Here human subjects (N=45) learned to perform six new tasks while undergoing functional MRI. The different tasks required the engagement of perceptual, motor, and various cognitive processes (attention, expectation, speed-accuracy tradeoff, and metacognition). We found that a bilateral frontoparietal network was more active during the initial compared to the later stages of task learning, and that this effect was stronger for task variants requiring more new learning. Critically, the same frontoparietal network was engaged by all six tasks, demonstrating its domain generality. Finally, although task learning decreased the overall activity in the frontoparietal network, it increased the connectivity strength between the different nodes of that network. These results demonstrate the existence of a domain-general brain network whose activity and connectivity reflect learning for a wide variety of new tasks, and thus may underlie the human capacity for acquiring new abilities.

neuroscience↗

bioRxiv2022

Striatal dopamine synthesis and cognitive flexibility differ between hormonal contraceptive users and non-users

In rodents and nonhuman primates, sex hormones are powerful modulators of dopamine neurotransmission. Yet little is known about hormonal regulation of the dopamine system in the human brain. Using Positron Emission Tomography (PET), we address this gap by comparing hormonal contraceptive users and non-users across multiple aspects of dopamine function: dopamine synthesis capacity via the PET radioligand 6-[18F]fluoro-m-tyrosine ([18F]FMT), baseline D2/3 receptor binding potential using [11C]raclopride, and dopamine release using methylphenidate-paired [11C]raclopride. Participants consisted of 36 healthy women (n=21 naturally cycling; n=15 hormonal contraceptive users), and men (n=20) as a comparison group. A behavioral index of cognitive flexibility was assessed prior to PET imaging. Hormonal contraceptive users exhibited greater dopamine synthesis capacity than naturally cycling participants, particularly in dorsal caudate, and greater cognitive flexibility. Further, across individuals the magnitude of striatal DA synthesis capacity was associated with cognitive flexibility. No group differences were observed in D2/3 receptor binding or dopamine release. Analyses by sex alone may obscure underlying differences in DA synthesis tied to womens hormone status. Hormonal contraception (in the form of pill, shot, implant, ring or IUD) is used by ~400 million women worldwide, yet few studies have examined whether chronic hormonal manipulations impact basic properties of the dopamine system. Findings from this study begin to address this critical gap in womens health.

neuroscience↗

bioRxiv2022

Cerebral perfusion in post-stroke aphasia and its relation to residual language abilities

Stroke alters blood flow to the brain resulting in damaged tissue and cell death. Moreover, the disruption of cerebral blood flow (perfusion) can be observed in areas surrounding and distal to the lesion. These structurally preserved but sub-optimally perfused regions may also affect recovery. Thus, to better understand aphasia recovery the relationship between cerebral perfusion and language needs to be systematically examined. In the current study, we aimed to evaluate 1) how stroke affects perfusion outside of lesioned areas in chronic aphasia, and 2) how perfusion in specific cortical areas and perilesional tissue relates to language outcomes in aphasia. We analyzed perfusion data from a large sample of participants with chronic aphasia due to left hemisphere stroke (n=43) and age-matched healthy controls (n=25). We used anatomically-defined regions of interest that covered the frontal, parietal, and temporal areas of the perisylvian cortex in both hemispheres, areas typically known to support language, along with several control regions not implicated in language processing. For the aphasia group we also looked at three regions of interest in the perilesional tissue. We compared perfusion levels between the two groups and investigated the relationship between perfusion levels and language subtest scores while controlling for demographic and lesion variables. First, we observed that perfusion levels outside the lesioned areas were significantly reduced in frontal and parietal regions in the left hemisphere in people with aphasia compared to the control group, while no differences were observed for the right hemisphere regions. Second, we found that perfusion in the left temporal lobe (and most strongly in the posterior part of both superior and middle temporal gyri) and inferior parietal areas (supramarginal gyrus) was significantly related to residual expressive and receptive language abilities. In contrast, perfusion in the frontal regions did not show such a relationship; no relationship with language was also observed for perfusion levels in control areas and all right hemisphere regions. Third, perilesional perfusion was only marginally related to language production abilities. Cumulatively, the current findings demonstrate that blood flow is reduced beyond the lesion site in chronic aphasia and that hypoperfused neural tissue in critical temporoparietal language areas has a negative impact on behavioral outcomes. These results, using perfusion imaging, underscore the critical and general role that left hemisphere posterior temporal regions play in various expressive and receptive language abilities. Overall, the study highlights the importance of exploring perfusion measures in stroke.

neuroscience↗

bioRxiv2022

Long-term learning transforms prefrontal cortex selectivity during working memory

The lateral prefrontal cortex (lPFC) is reliably active during working memory (WM) across human and animal models, but the role of lPFC in successful WM is under debate. For instance, non-human primate (NHP) electrophysiology research finds that lPFC circuitry stores WM representations. Human neuroimaging instead suggests that lPFC plays a control function over WM content that is stored in sensory cortices. These seemingly incompatible WM accounts are often confounded by differences in the amount of task training and stimulus exposure across studies (i.e., NHPs tend to be trained extensively). Here, we test the possibility that such long-term training may alter the role of lPFC in WM maintenance. We densely sampled WM-related activity across learning, in three human participants, using a longitudinal functional MRI (fMRI) protocol. Over three months, participants trained on (1) a serial reaction time (SRT) task, wherein complex fractal stimuli were embedded within probabilistic sequences, and (2) a delayed recognition task probing WM for trained or novel stimuli. Participants were scanned frequently throughout training, to track how WM activity patterns change with repeated stimulus exposure and long-term associative learning. WM task performance improved for trained (but not novel) fractals and, neurally, delay activity significantly increased in distributed lPFC voxels across learning. Pattern similarity analyses also found that item-level WM representations became detectable within lPFC, but not in sensory cortices, and lPFC delay activity increasingly reflected sequence relationships from the SRT task, even though that information was task-irrelevant for WM. These findings demonstrate that human lPFC can show stimulus-selective WM responses with learning and WM representations are shaped by long-term experience. Therefore, influences from training and long-term memory may reconcile competing accounts of lPFC function during WM.

neuroscience↗

bioRxiv2021

Evaluating the reliability, validity, and utility of overlapping networks: Implications for cognitive control

Brain network definitions typically assume non- or minimal overlap, ignoring regions connections to multiple networks. However, new methods are emerging that emphasize network overlap. Here, we investigated the reliability and validity of one assignment method, the mixed membership algorithm, and explored its potential utility for identifying gaps in existing network models of cognition. We first assessed between-sample reliability of overlapping assignment with a split-half design; a bootstrapped Dice similarity analysis demonstrated good agreement between the networks from the two subgroups. Next, we assessed whether overlapping networks captured expected nonoverlapping topographies; overlapping networks captured portions of one to three nonoverlapping topographies, which aligned with canonical network definitions. Following this, a relative entropy analysis showed that a majority of regions participated in more than one network, as is seen biologically, and many regions did not show preferential connection to any one network. Finally, we explored overlapping network membership in regions of the Dual-Networks model of cognitive control, showing that almost every region was a member of multiple networks. Thus, the mixed membership algorithm produces consistent and biologically plausible networks, which presumably will allow for the development of more complete network models of cognition.

neuroscience↗

bioRxiv2021

Emotional context sculpts action goal representations in the lateral frontal pole

Emotional states provide an ever-present source of contextual information that should inform behavioral goals. Despite the ubiquity of emotional signals in our environment, the neural mechanisms underlying their influence on goal-directed action remains unclear. Prior work suggests that the lateral frontal pole (FPl) is uniquely positioned to integrate affective information into cognitive control representations. We used pattern similarity analysis to examine the content of representations in FPl and interconnected mid-lateral prefrontal and amygdala circuitry. Healthy participants (n=37; n=21 females) were scanned while undergoing an event-related Affective Go/No-Go task, which requires goal-oriented action selection during emotional processing. We found that FPl contained conjunctive emotion-action goal representations that were related to successful cognitive control during emotional processing. These representations differed from conjunctive emotion-action goal representations found in the basolateral amygdala. While robust action goal representations were present in mid-lateral prefrontal cortex, they were not modulated by emotional valence. Finally, converging results from functional connectivity and multivoxel pattern analyses indicated that FPls emotional valence signals likely originated from interconnected subgenual ACC (BA25), which was in turn functionally coupled with the amygdala. Thus, our results identify a key pathway by which internal emotional states influence goal-directed behavior. Significance statementOptimal functioning in everyday life requires behavioral regulation that flexibly adapts to dynamically changing emotional states. However, precisely how emotional states influence goal-directed action remains unclear. Unveiling the neural architecture that supports emotion-goal integration is critical for our understanding of disorders such as psychopathy, which is characterized by deficits in incorporating emotional cues into goals, as well as mood and anxiety disorders, which are characterized by impaired goal-based emotion regulation. Our study identifies a key circuit through which emotional states influence goal-directed behavior. This circuitry comprised the lateral frontal pole (FPl), which represented integrated emotion-goal information, as well as interconnected amygdala and subgenual ACC, which conveyed emotional signals to FPl.

neuroscience↗

bioRxiv2021

Consciousness is supported by near-critical cortical electrodynamics

Mounting evidence suggests that during conscious states, the electrodynamics of the cortex are poised near a critical point or phase transition, and that this near-critical behavior supports the vast flow of information through cortical networks during conscious states. Here, for the first time, we empirically identify the specific critical point near which conscious cortical dynamics operate as the edge-of-chaos critical point, or the boundary between periodicity/stability and chaos/instability. We do so by applying the recently developed modified 0-1 chaos test to electrocorticography (ECoG) and magne-toencephalography (MEG) recordings from the cortices of humans and macaques across normal waking, generalized seizure, GABAergic anesthesia, and psychedelic states. Our evidence suggests that cortical information processing is disrupted during unconscious states because of a transition of cortical dynamics away from this critical point; conversely, we show that psychedelics may increase the information-richness of cortical activity by tuning cortical electrodynamics closer to this critical point. Finally, we analyze clinical electroencephalography (EEG) recordings from patients with disorders of consciousness (DOC), and show that assessing the proximity of cortical electrodynamics to the edge-of-chaos critical point may be clinically useful as a new biomarker of consciousness. Significance StatementWhat changes in the brain when we lose consciousness? One possibility is that the loss of consciousness corresponds to a transition of the brains electric activity away from edge-of-chaos criticality, or the knifes edge in between stability and chaos. Recent mathematical developments have produced novel tools for testing this hypothesis, which we apply for the first time to cortical recordings from diverse brain states. We show that the electric activity of the cortex is indeed poised near the boundary between stability and chaos during conscious states and transitions away from this boundary during unconsciousness, and that this transition disrupts cortical information processing.

neuroscience↗

bioRxiv2020

Early Alpine human occupation backdates westward human migration in Late Glacial Europe

The end of the Last Glacial Maximum (LGM) in Europe (~16.5 ka ago) set in motion major changes in human culture and population structure1. In Southern Europe, Early Epigravettian material culture was replaced by Late Epigravettian art and technology about 18-17 ka ago at the beginning of southern Alpine deglaciation, although available genetic evidence from individuals who lived ~14 ka ago2-5 opened up questions on the impact of migrations on this cultural transition only after that date. Here we generate new genomic data from a human mandible uncovered at the Late Epigravettian site of Riparo Tagliente (Veneto, Italy), that we directly dated to 16,980-16,510 cal BP (2{sigma}). This individual, affected by a low-prevalence dental pathology named focal osseous dysplasia, attests that the very emergence of Late Epigravettian material culture in Italy was already associated with migration and genetic replacement of the Gravettian-related ancestry. In doing so, we push back by at least 3,000 years the date of the diffusion in Southern Europe of a genetic component linked to Balkan/Anatolian refugia, previously believed to have spread during the later Bolling/Allerod warming event (~14 ka ago4,6). Our results suggest that demic diffusion from a genetically diverse population may have substantially contributed to cultural changes in LGM and post-LGM Southern Europe, independently from abrupt shifts to warmer and more favourable conditions.

genomics↗