scholarly journals Visual evoked feedforward-feedback travelling waves organize neural activity across the cortical hierarchy in mice

2021 ◽  
Author(s):  
Adeeti Aggarwal ◽  
Connor Brennan ◽  
Jennifer Luo ◽  
Helen Chung ◽  
Diego Contreras ◽  
...  
Keyword(s):  
Sensory Processing ◽  
Traveling Waves ◽  
Visual Processing ◽  
Cerebral Hemisphere ◽  
Travelling Waves ◽  
Brain Regions ◽  
Distributed Networks ◽  
Association Cortex ◽  
Cortical Hierarchy ◽  
Visual Evoked

Sensory processing is distributed among many brain regions that interact via feedforward and feedback signaling. It has been hypothesized that neuronal oscillations mediating feedforward and feedback interactions organize into travelling waves. However, stimulus evoked travelling waves of sufficient spatial scale have never been demonstrated directly. Here, we show that simple visual stimuli reliably evoke two traveling waves with spatial wavelengths that cover much of the cerebral hemisphere in awake mice. 30-50Hz feedforward waves arise in primary visual cortex (V1) and propagate rostrally, while 3-6Hz feedback waves originate in the association cortex and flow caudally. The phase of the feedback wave modulates the amplitude of the feedforward wave and synchronizes firing between V1 and parietal cortex. Altogether, these results provide direct experimental evidence that visual evoked travelling waves percolate through the cerebral cortex and coordinate neuronal activity across broadly distributed networks mediating visual processing.

scholarly journals Hierarchy in sensory processing reflected by innervation balance on cortical interneurons

2021 ◽  
Vol 7 (20) ◽  
pp. eabf5676
Author(s):  
Guofen Ma ◽  
Yanmei Liu ◽  
Lizhao Wang ◽  
Zhongyi Xiao ◽  
Kun Song ◽  
...  
Keyword(s):  
Long Range ◽  
Sensory Processing ◽  
Visual Processing ◽  
Brain Regions ◽  
Brain Areas ◽  
Local Interneurons ◽  
Cortical Interneurons ◽  
Different Types ◽  
Virus Tracing ◽  
The Brain

Sensory processing is subjected to modulation by behavioral contexts that are often mediated by long-range inputs to cortical interneurons, but their selectivity to different types of interneurons remains largely unknown. Using rabies-virus tracing and optogenetics-assisted recording, we analyzed the long-range connections to various brain regions along the hierarchy of visual processing, including primary visual cortex, medial association cortices, and frontal cortices. We found that hierarchical corticocortical and thalamocortical connectivity is reflected by the relative weights of inputs to parvalbumin-positive (PV+) and vasoactive intestinal peptide–positive (VIP+) neurons within the conserved local circuit motif, with bottom-up and top-down inputs preferring PV+ and VIP+ neurons, respectively. Our algorithms based on innervation weights for these two types of local interneurons generated testable predictions of the hierarchical position of many brain areas. These results support the notion that preferential long-range inputs to specific local interneurons are essential for the hierarchical information flow in the brain.

Compressed sensorimotor-to-transmodal hierarchical organization in schizophrenia

2021 ◽  
pp. 1-14
Author(s):  
Debo Dong ◽  
Dezhong Yao ◽  
Yulin Wang ◽  
Seok-Jun Hong ◽  
Sarah Genon ◽  
...  
Keyword(s):  
Sensory Information ◽  
Resting State Fmri ◽  
Brain Regions ◽  
High Order ◽  
Hierarchical Organization ◽  
System Level ◽  
Integrative System ◽  
Sensorimotor Region ◽  
Cortical Hierarchy ◽  
High Level

Abstract Background Schizophrenia has been primarily conceptualized as a disorder of high-order cognitive functions with deficits in executive brain regions. Yet due to the increasing reports of early sensory processing deficit, recent models focus more on the developmental effects of impaired sensory process on high-order functions. The present study examined whether this pathological interaction relates to an overarching system-level imbalance, specifically a disruption in macroscale hierarchy affecting integration and segregation of unimodal and transmodal networks. Methods We applied a novel combination of connectome gradient and stepwise connectivity analysis to resting-state fMRI to characterize the sensorimotor-to-transmodal cortical hierarchy organization (96 patients v. 122 controls). Results We demonstrated compression of the cortical hierarchy organization in schizophrenia, with a prominent compression from the sensorimotor region and a less prominent compression from the frontal−parietal region, resulting in a diminished separation between sensory and fronto-parietal cognitive systems. Further analyses suggested reduced differentiation related to atypical functional connectome transition from unimodal to transmodal brain areas. Specifically, we found hypo-connectivity within unimodal regions and hyper-connectivity between unimodal regions and fronto-parietal and ventral attention regions along the classical sensation-to-cognition continuum (voxel-level corrected, p < 0.05). Conclusions The compression of cortical hierarchy organization represents a novel and integrative system-level substrate underlying the pathological interaction of early sensory and cognitive function in schizophrenia. This abnormal cortical hierarchy organization suggests cascading impairments from the disruption of the somatosensory−motor system and inefficient integration of bottom-up sensory information with attentional demands and executive control processes partially account for high-level cognitive deficits characteristic of schizophrenia.

Auditory-Somatosensory Multisensory Processing in Auditory Association Cortex: An fMRI Study

2002 ◽  
Vol 88 (1) ◽  
pp. 540-543 ◽  
Author(s):  
John J. Foxe ◽  
Glenn R. Wylie ◽  
Antigona Martinez ◽  
Charles E. Schroeder ◽  
Daniel C. Javitt ◽  
...  
Keyword(s):  
Auditory Cortex ◽  
Multisensory Integration ◽  
Multisensory Processing ◽  
Primary Auditory Cortex ◽  
Superior Temporal Gyrus ◽  
Brain Regions ◽  
Association Cortex ◽  
Convergence Region ◽  
Auditory Cortices ◽  
Auditory Association Cortex

Using high-field (3 Tesla) functional magnetic resonance imaging (fMRI), we demonstrate that auditory and somatosensory inputs converge in a subregion of human auditory cortex along the superior temporal gyrus. Further, simultaneous stimulation in both sensory modalities resulted in activity exceeding that predicted by summing the responses to the unisensory inputs, thereby showing multisensory integration in this convergence region. Recently, intracranial recordings in macaque monkeys have shown similar auditory-somatosensory convergence in a subregion of auditory cortex directly caudomedial to primary auditory cortex (area CM). The multisensory region identified in the present investigation may be the human homologue of CM. Our finding of auditory-somatosensory convergence in early auditory cortices contributes to mounting evidence for multisensory integration early in the cortical processing hierarchy, in brain regions that were previously assumed to be unisensory.

scholarly journals Increased hypothalamic–pituitary–adrenal drive is associated with decreased appetite and hypoactivation of food-motivation neurocircuitry in anorexia nervosa

2013 ◽  
Vol 169 (5) ◽  
pp. 639-647 ◽  
Author(s):  
Elizabeth A Lawson ◽  
Laura M Holsen ◽  
Rebecca DeSanti ◽  
McKale Santin ◽  
Erinne Meenaghan ◽  
...  
Keyword(s):  
Anorexia Nervosa ◽  
Visual Processing ◽  
Serum Cortisol ◽  
Brain Regions ◽  
Cross Sectional Study ◽  
Food Motivation ◽  
Cross Sectional ◽  
Hypothalamic Pituitary Adrenal ◽  
Cortisol Levels ◽  
The Relationship

ObjectiveCorticotrophin-releasing hormone (CRH)-mediated hypercortisolemia has been demonstrated in anorexia nervosa (AN), a psychiatric disorder characterized by food restriction despite low body weight. While CRH is anorexigenic, downstream cortisol stimulates hunger. Using a food-related functional magnetic resonance imaging (fMRI) paradigm, we have demonstrated hypoactivation of brain regions involved in food motivation in women with AN, even after weight recovery. The relationship between hypothalamic–pituitary–adrenal (HPA) axis dysregulation and appetite and the association with food-motivation neurocircuitry hypoactivation are unknown in AN. We investigated the relationship between HPA activity, appetite, and food-motivation neurocircuitry hypoactivation in AN.DesignCross-sectional study of 36 women (13 AN, ten weight-recovered AN (ANWR), and 13 healthy controls (HC)).MethodsPeripheral cortisol and ACTH levels were measured in a fasting state and 30, 60, and 120 min after a standardized mixed meal. The visual analog scale was used to assess homeostatic and hedonic appetite. fMRI was performed during visual processing of food and non-food stimuli to measure the brain activation pre- and post-meal.ResultsIn each group, serum cortisol levels decreased following the meal. Mean fasting, 120 min post-meal, and nadir cortisol levels were high in AN vs HC. Mean postprandial ACTH levels were high in ANWR compared with HC and AN subjects. Cortisol levels were associated with lower fasting homeostatic and hedonic appetite, independent of BMI and depressive symptoms. Cortisol levels were also associated with between-group variance in activation in the food-motivation brain regions (e.g. hypothalamus, amygdala, hippocampus, orbitofrontal cortex, and insula).ConclusionsHPA activation may contribute to the maintenance of AN by the suppression of appetitive drive.

scholarly journals Synaptic propagation in neuronal networks with finite-support space dependent coupling

2020 ◽  
Author(s):  
Ricardo Erazo Toscano ◽  
Remus Osan
Keyword(s):  
Time Constant ◽  
Sensory Processing ◽  
Traveling Waves ◽  
Traveling Wave ◽  
Neuronal Networks ◽  
Evolution Equations ◽  
Network Connectivity ◽  
Space Constant ◽  
The Stability ◽  
The Brain

1AbstractTraveling waves of electrical activity are ubiquitous in biological neuronal networks. Traveling waves in the brain are associated with sensory processing, phase coding, and sleep. The neuron and network parameters that determine traveling waves’ evolution are synaptic space constant, synaptic conductance, membrane time constant, and synaptic decay time constant. We used an abstract neuron model to investigate the propagation characteristics of traveling wave activity. We formulated a set of evolution equations based on the network connectivity parameters. We numerically investigated the stability of the traveling wave propagation with a series of perturbations with biological relevance.

scholarly journals Parallel Distributed Networks Resolved at High Resolution Reveal Close Juxtaposition of Distinct Regions

2018 ◽  
Author(s):  
Rodrigo M. Braga ◽  
Koene R. A. Van Dijk ◽  
Jonathan R. Polimeni ◽  
Mark C. Eldaief ◽  
Randy L. Buckner
Keyword(s):  
High Resolution ◽  
Large Scale ◽  
Spatial Separation ◽  
Distributed Networks ◽  
Association Cortex ◽  
Default Network ◽  
Network Organization ◽  
Parahippocampal Cortex ◽  
The Individual ◽  
Insight Into

Examination of large-scale distributed networks within the individual reveals details of cortical network organization that are absent in group-averaged studies. One recent discovery is that a distributed transmodal network, often referred to as the ‘default network’, is comprised of two separate but closely interdigitated networks, only one of which is coupled to posterior parahippocampal cortex. Not all studies of individuals have identified the same networks and questions remain about the degree to which the two networks are separate, particularly within regions hypothesized to be interconnected hubs. Here we replicate the observation of network separation across analytical (seed-based connectivity and parcellation) and data projection (volume and surface) methods in 2 individuals each scanned 31 times. Additionally, 3 individuals were examined with high-resolution fMRI to gain further insight into the anatomical details. The two networks were identified with separate regions localized to adjacent portions of the cortical ribbon, sometimes inside the same sulcus. Midline regions previously implicated as hubs revealed near complete spatial separation of the two networks, displaying a complex spatial topography in the posterior cingulate and precuneus. The network coupled to parahippocampal cortex also revealed a separate region directly within the hippocampus at or near the subiculum. These collective results support that the default network is composed of at least two spatially juxtaposed networks. Fine spatial details and juxta-positions of the two networks can be identified within individuals at high resolution, providing insight into the network organization of association cortex and placing further constraints on interpretation of group-averaged neuroimaging data.

scholarly journals A nested cortical hierarchy of neural states underlies event segmentation in the human brain

2021 ◽  
Author(s):  
Linda Geerligs ◽  
Marcel van Gerven ◽  
Karen L. Campbell ◽  
Umut Güçlü
Keyword(s):  
Brain Regions ◽  
Data Driven ◽  
Fundamental Aspect ◽  
Segmentation Method ◽  
Discrete Events ◽  
Event Segmentation ◽  
Temporal Pole ◽  
Cortical Hierarchy ◽  
State Boundaries ◽  
Anterior Temporal Pole

AbstractA fundamental aspect of human experience is that it is segmented into discrete events. This may be underpinned by transitions between distinct neural states. Using an innovative data-driven state segmentation method, we investigate how neural states are organized across the cortical hierarchy and where in cortex neural state and perceived event boundaries overlap. Our results show that neural state boundaries are organized in a temporal cortical hierarchy, with short states in primary sensory regions and long states in anterior temporal pole and lateral and medial prefrontal cortex. Neural state boundaries overlap with event boundaries across large parts of this hierarchy. State boundaries are shared within and between groups of brain regions that resemble well known functional networks, such as the default mode network that fractionates into two subnetworks – one fast, one slow. Together these findings suggest that a nested cortical hierarchy of neural states forms the basis of event segmentation.

scholarly journals Going beyond rote auditory learning: Neural patterns of generalized auditory learning

2021 ◽  
Author(s):  
Shannon L.M. Heald ◽  
Stephen C. Van Hedger ◽  
John Veillette ◽  
Katherine Reis ◽  
Joel S. Snyder ◽  
...  
Keyword(s):  
Speech Perception ◽  
Sensory Processing ◽  
Auditory Processing ◽  
Auditory Evoked Potentials ◽  
Brain Regions ◽  
Auditory Evoked Potential ◽  
Cortical Processing ◽  
Rote Learning ◽  
Neural Responses ◽  
Auditory Learning

AbstractThe ability to generalize rapidly across specific experiences is vital for robust recognition of new patterns, especially in speech perception considering acoustic-phonetic pattern variability. Behavioral research has demonstrated that listeners are rapidly able to generalize their experience with a talker’s speech and quickly improve understanding of a difficult-to-understand talker without prolonged practice, e.g., even after a single training session. Here, we examine the differences in neural responses to generalized versus rote learning in auditory cortical processing by training listeners to understand a novel synthetic talker using a Pretest-Posttest design with electroencephalography (EEG). Participants were trained using either (1) a large inventory of words where no words repeated across the experiment (generalized learning) or (2) a small inventory of words where words repeated (rote learning). Analysis of long-latency auditory evoked potentials at Pretest and Posttest revealed that while rote and generalized learning both produce rapid changes in auditory processing, the nature of these changes differed. In the context of adapting to a talker, generalized learning is marked by an amplitude reduction in the N1-P2 complex and by the presence of a late-negative (LN) wave in the auditory evoked potential following training. Rote learning, however, is marked only by temporally later source configuration changes. The early N1-P2 change, found only for generalized learning, suggests that generalized learning relies on the attentional system to reorganize the way acoustic features are selectively processed. This change in relatively early sensory processing (i.e. during the first 250ms) is consistent with an active processing account of speech perception, which proposes that the ability to rapidly adjust to the specific vocal characteristics of a new talker (for which rote learning is rare) relies on attentional mechanisms to adaptively tune early auditory processing sensitivity.Statement of SignificancePrevious research on perceptual learning has typically examined neural responses during rote learning: training and testing is carried out with the same stimuli. As a result, it is not clear that findings from these studies can explain learning that generalizes to novel patterns, which is critical in speech perception. Are neural responses to generalized learning in auditory processing different from neural responses to rote learning? Results indicate rote learning of a particular talker’s speech involves brain regions focused on the memory encoding and retrieving of specific learned patterns, whereas generalized learning involves brain regions involved in reorganizing attention during early sensory processing. In learning speech from a novel talker, only generalized learning is marked by changes in the N1-P2 complex (reflective of secondary auditory cortical processing). The results are consistent with the view that robust speech perception relies on the fast adjustment of attention mechanisms to adaptively tune auditory sensitivity to cope with acoustic variability.

Glutamate in the pathophysiology of schizophrenia

2020 ◽  
pp. 287-296
Author(s):  
Daniel C. Javitt
Keyword(s):  
Visual System ◽  
Visual Processing ◽  
Negative Symptoms ◽  
Glutamate Release ◽  
Critical Role ◽  
Brain Regions ◽  
Long Term Memory ◽  
Subcortical Structures ◽  
Impaired Metabolism

Glutamate theories of schizophrenia were first proposed over 30 years ago and since that time have become increasingly accepted. Theories are supported by the ability of N-methyl-D-aspartate receptor (NMDAR) antagonists such as phencyclidine (PCP) or ketamine to induce symptoms that closely resemble those of schizophrenia. Moreover, NMDAR antagonists uniquely reproduce the level of negative symptoms and cognitive deficits observed in schizophrenia, suggesting that such models may be particularly appropriate to poor outcome forms of the disorder. As opposed to dopamine, which is most prominent within frontostriatal brain regions, glutamate neurons are present throughout cortex and subcortical structures. Thus, NMDAR theories predict widespread disturbances across cortical and thalamic pathways, including sensory brain regions. In auditory cortex, NMDAR play a critical role in the generation of mismatch negativity (MMN), which may therefore serve as a translational marker of NMDAR dysfunction across species. In the visual system, NMDAR play a critical role in function of the magnocellular visual system. Deficits in both auditory and visual processing contribute to social and communication deficits, which, in turn, lead to poor functional outcome. By contrast, NMDAR dysfunction within the frontohippocampal system may contribute to well described deficits in working memory, executive processing and long-term memory formation. Deficits in NMDAR function may be driven by disturbances in presynaptic glutamate release, impaired metabolism of NMDAR modulators such as glycine or D-serine, or intrinsic abnormalities in NMDAR themselves.

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