scholarly journals Cross-species Functional Alignment Reveals Evolutionary Hierarchy Within the Connectome

2019 ◽  
Author(s):  
Ting Xu ◽  
Karl-Heinz Nenning ◽  
Ernst Schwartz ◽  
Seok-Jun Hong ◽  
Joshua T. Vogelstein ◽  
...  
Keyword(s):  
Functional Organization ◽  
Geodesic Distance ◽  
Brain Morphology ◽  
Angular Gyrus ◽  
Default Network ◽  
Anatomical Landmarks ◽  
Functional Changes ◽  
Cortical Organization ◽  
Posterior Cingulate ◽  
Cognitive Hierarchy

AbstractEvolution provides an important window into how cortical organization shapes function and vice versa. The complex mosaic of changes in brain morphology and functional organization that have shaped the mammalian cortex during evolution, complicates attempts to chart cortical differences across species. It limits our ability to fully appreciate how evolution has shaped our brain, especially in systems associated with unique human cognitive capabilities that lack anatomical homologues in other species. Here, we demonstrate a function-based method for cross-species cortical alignment that leverages recent advances in understanding cortical organization and that enables the quantification of homologous regions across species, even when their location is decoupled from anatomical landmarks. Critically, our method establishes that cross-species similarity in cortical organization decreases with geodesic distance from unimodal systems, and culminates in the most pronounced changes in posterior regions of the default network (angular gyrus, posterior cingulate and middle temporal cortices). Our findings suggest that the establishment of the default network, as the apex of a cognitive hierarchy, as is seen in humans, is a relatively recent evolutionary adaptation. They also highlight functional changes in regions such as the posterior cingulate cortex and angular gyrus as key influences on uniquely human features of cognition.

scholarly journals Loss of function in the autism and learning disabilities associated gene Nf1 disrupts corticocortical and corticostriatal functional connectivity in human and mouse

2019 ◽  
Author(s):  
Ben Shofty ◽  
Eyal Bergmann ◽  
Gil Zur ◽  
Jad Asleh ◽  
Noam Bosak ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Functional Organization ◽  
Single Gene ◽  
Heterozygous Mutation ◽  
Default Network ◽  
Loss Of Function ◽  
Resting State Functional Connectivity ◽  
Functional Changes ◽  
Functional Connectivity Mri ◽  
Posterior Anterior

ABSTRACTChildren with the autosomal dominant single gene disorder, neurofibromatosis type 1 (NF1), display multiple structural and functional changes in the central nervous system, resulting in neuropsychological cognitive abnormalities. Here we assessed the pathological functional organization that may underlie the behavioral impairments in NF1 using resting-state functional connectivity MRI. Coherent spontaneous fluctuations in the fMRI signal across the entire brain were used to interrogate the pattern of functional organization of corticocortical and corticostriatal networks in both NF1 pediatric patients and mice with a heterozygous mutation in the Nf1 gene (Nf1+/-). Children with NF1 demonstrated abnormal organization of cortical association networks and altered posterior-anterior functional connectivity in the default network. Examining the contribution of the striatum revealed that corticostriatal functional connectivity was altered. NF1 children demonstrated reduced functional connectivity between striatum and the frontoparietal network and increased striatal functional connectivity with the limbic network. Awake passive mouse functional connectivity MRI in Nf1+/- mice similarly revealed reduced posterior-anterior connectivity along the cingulate cortex as well as disrupted corticostriatal connectivity. The striatum of Nf1+/- mice showed increased functional connectivity to somatomotor and frontal cortices and decreased functional connectivity to the auditory cortex. Collectively, these results demonstrate similar alterations across species, suggesting that NF1 pathogenesis is linked to striatal dysfunction and disrupted corticocortical connectivity in the default network.

scholarly journals Mapping the organization and dynamics of the posterior medial network during movie watching

2020 ◽  
Author(s):  
Rose A. Cooper ◽  
Kyle A. Kurkela ◽  
Simon W. Davis ◽  
Maureen Ritchey
Keyword(s):  
Functional Connectivity ◽  
Cingulate Cortex ◽  
Posterior Cingulate Cortex ◽  
Retrosplenial Cortex ◽  
Angular Gyrus ◽  
Default Network ◽  
Mediated Communication ◽  
Event Cognition ◽  
Posterior Cingulate ◽  
Parahippocampal Cortex

AbstractBrain regions within a posterior medial network (PMN) are characterized by sensitivity to episodic tasks, and they also demonstrate strong functional connectivity as part of the default network. Despite its cohesive structure, delineating the intranetwork organization and functional diversity of the PMN is crucial for understanding its contributions to multidimensional event cognition. Here, we probed functional connectivity of the PMN during movie watching to identify its pattern of connections and subnetwork functions in a split-sample replication of 136 participants. Consistent with prior findings of default network fractionation, we identified distinct PMN subsystems: a Ventral PM subsystem (retrosplenial cortex, parahippocampal cortex, posterior angular gyrus) and a Dorsal PM subsystem (medial prefrontal cortex, hippocampus, precuneus, posterior cingulate cortex, anterior angular gyrus). These subsystems were anchored by two complementary regions: Retrosplenial cortex mediated communication between parahippocampal cortex and the Dorsal PM system, and posterior cingulate cortex mediated communication among Dorsal PM regions. Finally, the distinction between PMN subsystems is functionally relevant: whereas both Dorsal and Ventral PM connectivity tracked the movie content, only Ventral PM connections increased in strength at event transitions and appeared sensitive to episodic memory. Overall, these findings provide a model of PMN pathways and reveal distinct functional roles of intranetwork subsystems associated with event cognition.

scholarly journals MODERN CONCEPTION AS TO THE FUNCTIONAL MORPHOLOGY OF THE OLFACTORY SYSTEM AND ITS CHANGES UNDER THE INFLUENCE OF SOME EXOGENOUS POLLUTANTS

2019 ◽  
Vol 23 (3-4) ◽  
pp. 37-40
Author(s):  
A.D. Shkodina ◽  
R.M. Hrinko ◽  
I.I. Starchenko
Keyword(s):  
Environmental Factors ◽  
Olfactory Epithelium ◽  
Functional Organization ◽  
Morphological Changes ◽  
Human Life ◽  
Experimental Studies ◽  
Experimental Models ◽  
Functional Changes ◽  
Olfactory Analyzer ◽  
Long Time

The interaction between a body and an environment provides the main aspects of human life. The study of the functional structure of the olfactory analyzer plays an important role both in clinical and in experimental studies, but the question of its features in humans needs detailed research. The paper presents the modern data of the structural and functional organization of the olfactory analyzer. Particular attention is paid to the structural organization of olfactory bulbs as most complicated and least studied component of the olfactory analyzer. The morphological and functional changes of the olfactory analyzer are developing in some diseases and in action of adverse environmental factors are described while the accentuation is placed on the differences of the mechanism in the pathogenesis of damage to the olfactory analyzer, depending on the nature of the influence of pathogenic factors. In this way as the result of short-term intense effects of the pollutant, irreversible atrophic changes are primarily affected to the olfactory epithelium, thus, to some extent, preventing the spread of the toxin to other analyzer structures. Conversely, a long-term exposure to low doses usually retains the functional activity of the olfactory epithelium, while harmful substances penetrate the central unit of the olfactory analyzer. In such cases, the olfactory dysfunction can be diagnosed after a long time after the start of the cohort with certain pollutants. Currently, studies of the influence of exogenous toxins on various parts of the olfactory analyzer on animal experimental models are quite active. At the same time, the issue of functional and morphological changes in various structural components of the human olfactory analyzer under the influence of negative environmental factors remains poorly understood and requires further morphological and biochemical studies, in order to be able to further develop effective therapeutic and prophylactic means.

scholarly journals Neural Correlates of Gender Face Perception in Transgender People

2020 ◽  
Vol 9 (6) ◽  
pp. 1731
Author(s):  
Alessandra Daphne Fisher ◽  
Jiska Ristori ◽  
Giovanni Castellini ◽  
Carlotta Cocchetti ◽  
Emanuele Cassioli ◽  
...  
Keyword(s):  
Neural Development ◽  
Gender Discrimination ◽  
Group Analysis ◽  
Blood Oxygenation ◽  
Angular Gyrus ◽  
Cingulate Gyrus ◽  
Transgender People ◽  
Posterior Cingulate ◽  
Posterior Cingulate Gyrus ◽  
Oxygenation Level

To date, MRI studies focused on brain sexual dimorphism have not explored the presence of specific neural patterns in gender dysphoria (GD) using gender discrimination tasks. Considering the central role of body image in GD, the present study aims to evaluate brain activation patterns with 3T-scanner functional MRI (fMRI) during gender face discrimination task in a sample of 20 hormone-naïve transgender and 20 cisgender individuals. Additionally, participants were asked to complete psychometric measures. The between-group analysis of average blood oxygenation level dependent (BOLD) activations of female vs. male face contrast showed a significant positive cluster in the bilateral precuneus in transmen when compared to the ciswomen. In addition, the transwomen group compared to the cismen showed higher activations also in the precuneus, as well as in the posterior cingulate gyrus, the angular gyrus and the lateral occipital cortices. Moreover, the activation of precuneus, angular gyrus, lateral occipital cortices and posterior cingulate gyrus was significantly associated with higher levels of body uneasiness. These results show for the first time the existence of a possible specific GD-neural pattern. However, it remains unclear if the differences in brain phenotype of transgender people may be the result of a sex-atypical neural development or of a lifelong experience of gender non-conformity.

scholarly journals Differential Functional Connectivity along the Long Axis of the Hippocampus Aligns with Differential Role in Memory Specificity and Generalization

2019 ◽  
Vol 31 (12) ◽  
pp. 1958-1975 ◽  
Author(s):  
Lea E. Frank ◽  
Caitlin R. Bowman ◽  
Dagmar Zeithamova
Keyword(s):  
Functional Connectivity ◽  
Functional Organization ◽  
Inferior Frontal Gyrus ◽  
Longitudinal Axis ◽  
Task Engagement ◽  
Angular Gyrus ◽  
Memory Specificity ◽  
Fmri Session ◽  
Passive Viewing ◽  
Generalized Knowledge

The hippocampus contributes to both remembering specific events and generalization across events. Recent work suggests that information may be represented along the longitudinal axis of the hippocampus at varied levels of specificity: detailed representations in the posterior hippocampus and generalized representations in the anterior hippocampus. Similar distinctions are thought to exist within neocortex, with lateral prefrontal and lateral parietal regions supporting memory specificity and ventromedial prefrontal and lateral temporal cortices supporting generalized memory. Here, we tested whether functional connectivity of anterior and posterior hippocampus with cortical memory regions is consistent with these proposed dissociations. We predicted greater connectivity of anterior hippocampus with putative generalization regions and posterior hippocampus with putative memory specificity regions. Furthermore, we tested whether differences in connectivity are stable under varying levels of task engagement. Participants learned to categorize a set of stimuli outside the scanner, followed by an fMRI session that included a rest scan, passive viewing runs, and category generalization task runs. Analyses revealed stronger connectivity of ventromedial pFC to anterior hippocampus and of angular gyrus and inferior frontal gyrus to posterior hippocampus. These differences remained relatively stable across the three phases (rest, passive viewing, category generalization). Whole-brain analyses further revealed widespread cortical connectivity with both anterior and posterior hippocampus, with relatively little overlap. These results contribute to our understanding of functional organization along the long axis of the hippocampus and suggest that distinct hippocampal–cortical connections are one mechanism by which the hippocampus represents both individual experiences and generalized knowledge.

scholarly journals Hippocampal atrophy and intrinsic brain network dysfunction relate to alterations in mind wandering in neurodegeneration

2019 ◽  
Vol 116 (8) ◽  
pp. 3316-3321 ◽  
Author(s):  
Claire O’Callaghan ◽  
James M. Shine ◽  
John R. Hodges ◽  
Jessica R. Andrews-Hanna ◽  
Muireann Irish
Keyword(s):  
Cognitive Processes ◽  
Neurodegenerative Disorders ◽  
Mind Wandering ◽  
Brain Network ◽  
Clinical Population ◽  
Default Network ◽  
Resting State Functional Connectivity ◽  
Functional Changes ◽  
Thought Sampling ◽  
Patient Groups

Mind wandering represents the human capacity for internally focused thought and relies upon the brain’s default network and its interactions with attentional networks. Studies have characterized mind wandering in healthy people, yet there is limited understanding of how this capacity is affected in clinical populations. This paper used a validated thought-sampling task to probe mind wandering capacity in two neurodegenerative disorders: behavioral variant frontotemporal dementia [(bvFTD); n = 35] and Alzheimer’s disease [(AD); n = 24], compared with older controls (n = 37). These patient groups were selected due to canonical structural and functional changes across sites of the default and frontoparietal networks and well-defined impairments in cognitive processes that support mind wandering. Relative to the controls, bvFTD patients displayed significantly reduced mind wandering capacity, offset by a significant increase in stimulus-bound thought. In contrast, AD patients demonstrated comparable levels of mind wandering to controls, in the context of a relatively subtle shift toward stimulus-/task-related forms of thought. In the patient groups, mind wandering was associated with gray matter integrity in the hippocampus/parahippocampus, striatum, insula, and orbitofrontal cortex. Resting-state functional connectivity revealed associations between mind wandering capacity and connectivity within and between regions of the frontoparietal and default networks with distinct patterns evident in patients vs. controls. These findings support a relationship between altered mind wandering capacity in neurodegenerative disorders and structural and functional integrity of the default and frontoparietal networks. This paper highlights a dimension of cognitive dysfunction not well documented in neurodegenerative disorders and validates current models of mind wandering in a clinical population.

scholarly journals A probabilistic map of the human ventral sensorimotor cortex using electrical stimulation

2015 ◽  
Vol 123 (2) ◽  
pp. 340-349 ◽  
Author(s):  
Jonathan D. Breshears ◽  
Annette M. Molinaro ◽  
Edward F. Chang
Keyword(s):  
Electrical Stimulation ◽  
Sensorimotor Cortex ◽  
Functional Organization ◽  
Anatomical Landmarks ◽  
Single Individual ◽  
Precentral Gyrus ◽  
Probabilistic Maps ◽  
Sensory Responses ◽  
Intraoperative Electrical Stimulation ◽  
Stimulation Of

OBJECT The human ventral sensorimotor cortex (vSMC) is involved in facial expression, mastication, and swallowing, as well as the dynamic and highly coordinated movements of human speech production. However, vSMC organization remains poorly understood, and previously published population-driven maps of its somatotopy do not accurately reflect the variability across individuals in a quantitative, probabilistic fashion. The goal of this study was to describe the responses to electrical stimulation of the vSMC, generate probabilistic maps of function in the vSMC, and quantify the variability across individuals. METHODS Photographic, video, and stereotactic MRI data of intraoperative electrical stimulation of the vSMC were collected for 33 patients undergoing awake craniotomy. Stimulation sites were converted to a 2D coordinate system based on anatomical landmarks. Motor, sensory, and speech stimulation responses were reviewed and classified. Probabilistic maps of stimulation responses were generated, and spatial variance was quantified. RESULTS In 33 patients, the authors identified 194 motor, 212 sensory, 61 speech-arrest, and 27 mixed responses. Responses were complex, stereotyped, and mostly nonphysiological movements, involving hand, orofacial, and laryngeal musculature. Within individuals, the presence of oral movement representations varied; however, the dorsal-ventral order was always preserved. The most robust motor responses were jaw (probability 0.85), tongue (0.64), lips (0.58), and throat (0.52). Vocalizations were seen in 6 patients (0.18), more dorsally near lip and dorsal throat areas. Sensory responses were spatially dispersed; however, patients' subjective reports were highly precise in localization within the mouth. The most robust responses included tongue (0.82) and lips (0.42). The probability of speech arrest was 0.85, highest 15–20 mm anterior to the central sulcus and just dorsal to the sylvian fissure, in the anterior precentral gyrus or pars opercularis. CONCLUSIONS The authors report probabilistic maps of function in the human vSMC based on intraoperative cortical electrical stimulation. These results define the expected range of mapping outcomes in the vSMC of a single individual and shed light on the functional organization of the vSMC supporting speech motor control and nonspeech functions.

scholarly journals In vivo Visualization of Pig Vagus Nerve “Vagotopy” Using Ultrasound

2021 ◽  
Vol 15 ◽  
Author(s):  
Megan L. Settell ◽  
Aaron C. Skubal ◽  
Rex C. H. Chen ◽  
Maïsha Kasole ◽  
Bruce E. Knudsen ◽  
...  
Keyword(s):  
Side Effects ◽  
Vagus Nerve ◽  
Surgical Procedure ◽  
Functional Organization ◽  
Electrode Placement ◽  
Patient Specific ◽  
Therapeutic Effects ◽  
Ultrasound Images ◽  
Anatomical Landmarks ◽  
Nodose Ganglia

Background: Placement of the clinical vagus nerve stimulating cuff is a standard surgical procedure based on anatomical landmarks, with limited patient specificity in terms of fascicular organization or vagal anatomy. As such, the therapeutic effects are generally limited by unwanted side effects of neck muscle contractions, demonstrated by previous studies to result from stimulation of (1) motor fibers near the cuff in the superior laryngeal and (2) motor fibers within the cuff projecting to the recurrent laryngeal.Objective: Conventional non-invasive ultrasound, where the transducer is placed on the surface of the skin, has been previously used to visualize the vagus with respect to other landmarks such as the carotid and internal jugular vein. However, it lacks sufficient resolution to provide details about the vagus fascicular organization, or detail about smaller neural structures such as the recurrent and superior laryngeal branch responsible for therapy limiting side effects. Here, we characterize the use of ultrasound with the transducer placed in the surgical pocket to improve resolution without adding significant additional risk to the surgical procedure in the pig model.Methods: Ultrasound images were obtained from a point of known functional organization at the nodose ganglia to the point of placement of stimulating electrodes within the surgical window. Naïve volunteers with minimal training were then asked to use these ultrasound videos to trace afferent groupings of fascicles from the nodose to their location within the surgical window where a stimulating cuff would normally be placed. Volunteers were asked to select a location for epineural electrode placement away from the fascicles containing efferent motor nerves responsible for therapy limiting side effects. 2-D and 3-D reconstructions of the ultrasound were directly compared to post-mortem histology in the same animals.Results: High-resolution ultrasound from the surgical pocket enabled 2-D and 3-D reconstruction of the cervical vagus and surrounding structures that accurately depicted the functional vagotopy of the pig vagus nerve as confirmed via histology. Although resolution was not sufficient to match specific fascicles between ultrasound and histology 1 to 1, it was sufficient to trace fascicle groupings from a point of known functional organization at the nodose ganglia to their locations within the surgical window at stimulating electrode placement. Naïve volunteers were able place an electrode proximal to the sensory afferent grouping of fascicles and away from the motor nerve efferent grouping of fascicles in each subject (n = 3).Conclusion: The surgical pocket itself provides a unique opportunity to obtain higher resolution ultrasound images of neural targets responsible for intended therapeutic effect and limiting off-target effects. We demonstrate the increase in resolution is sufficient to aid patient-specific electrode placement to optimize outcomes. This simple technique could be easily adopted for multiple neuromodulation targets to better understand how patient specific anatomy impacts functional outcomes.

scholarly journals Changes in spinal cord hemodynamic reflect modulation of spinal network with different parameters of epidural stimulation

2019 ◽  
Author(s):  
Shanshan Tang ◽  
Carlos A. Cuellar ◽  
Pengfei Song ◽  
Riazul Islam ◽  
Chengwu Huang ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Electrical Stimulation ◽  
Functional Organization ◽  
Hemodynamic Response ◽  
Epidural Stimulation ◽  
Functional Changes ◽  
Spinal Circuitry ◽  
Cord Injury ◽  
First Time

AbstractIn this study functional ultrasound (fUS) imaging has been implemented to explore the local hemodynamic response induced by electrical epidural stimulation and to study real-time in vivo functional changes of the spinal cord, taking advantage of the superior spatiotemporal resolution provided by fUS. By quantifying the hemodynamic and electromyographic response features, we tested the hypothesis that the transient hemodynamic response of the spinal cord to electrical epidural stimulation could reflect modulation of the spinal circuitry and accordingly respond to the changes in parameters of electrical stimulation. The results of this study for the first time demonstrate that the hemodynamic response to electrical stimulation could reflect functional organization of the spinal cord. Response in the dorsal areas to epidural stimulation was significantly higher and faster compared to the response in ventral spinal cord. Positive relation between the hemodynamic and the EMG responses was observed at the lower frequencies of epidural stimulation (20 and 40 Hz), which according to our previous findings can facilitate spinal circuitry after spinal cord injury, compared to higher frequencies (200 and 500 Hz). These findings suggest that different mechanisms could be involved in spinal cord hemodynamic changes during different parameters of electrical stimulation and for the first time provide the evidence that functional organization of the spinal cord circuitry could be related to specific organization of spinal cord vasculature and hemodynamic.Significance StatementElectrical epidural stimulation (EES) has been successfully applied to control chronic refractory pain and was evolved to alleviate motor impairment after spinal cord injury, in Parkinson’s disease, and other neurological conditions. The mechanisms underlying the EES remain unclear, and current methods for monitoring EES are limited in sensitivity and spatiotemporal resolutions to evaluate functional changes in response to EES. We tested the hypothesis that the transient hemodynamic response of the spinal cord to EES could reflect modulation of the spinal cord circuitry and accordingly respond to the changes in parameters of EES. The proposed methodology opens a new direction for quantitative evaluation of the spinal cord hemodynamic in understanding the mechanisms of spinal cord functional organization and effect of neuromodulation.

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