scholarly journals Multi-Channel Whole-Head OPM-MEG: Helmet Design and a Comparison with a Conventional System

2020 ◽  
Author(s):  
Ryan M. Hill ◽  
Elena Boto ◽  
Molly Rea ◽  
Niall Holmes ◽  
James Leggett ◽  
...  
Keyword(s):  
Functional Neuroimaging ◽  
Gamma Oscillations ◽  
Brain Regions ◽  
Quality Data ◽  
List Type ◽  
Viable Systems ◽  
Fundamental Limitations ◽  
Comparable Performance ◽  
Alpha Beta ◽  
Neuronal Current

ABSTRACTMagnetoencephalography (MEG) is a powerful technique for functional neuroimaging, offering a non-invasive window on brain electrophysiology. MEG systems have traditionally been based on cryogenic sensors which detect the small extracranial magnetic fields generated by synchronised current in neuronal assemblies, however such systems have fundamental limitations. In recent years quantum-enabled devices, called optically-pumped magnetometers (OPMs), have promised to lift those restrictions, offering an adaptable, motion-robust MEG device, with improved data quality, at reduced cost. However, OPM-MEG remains a nascent technology, and whilst viable systems exist, most employ small numbers of sensors sited above targeted brain regions. Here, building on previous work, we construct a wearable OPM-MEG system with ‘whole-head’ coverage based upon commercially available OPMs, and test its capabilities to measure alpha, beta and gamma oscillations. We design two methods for OPM mounting; a flexible (EEG-like) cap and rigid (additively-manufactured) helmet. Whilst both designs allow for high quality data to be collected, we argue that the rigid helmet offers a more robust option with significant advantages for reconstruction of field data into 3D images of changes in neuronal current. Using repeat measurements in two participants, we show signal detection for our device to be highly robust. Moreover, via application of source-space modelling, we show that, despite having 5 times fewer sensors, our system exhibits comparable performance to an established cryogenic MEG device. While significant challenges still remain, these developments provide further evidence that OPM-MEG is likely to facilitate a step change for functional neuroimaging.HIGHLIGHTSA 49-channel whole-head OPM-MEG system is constructedSystem evaluated via repeat measurements of alpha, beta and gamma oscillationsTwo OPM-helmet designs are contrasted, a flexible (EEG-like) cap and a rigid helmetThe rigid helmet offers significant advantages for a viable OPM-MEG device49-channel OPM-MEG offers performance comparable to established cryogenic devices

Hyporesponsive Reward Anticipation in the Basal Ganglia following Severe Institutional Deprivation Early in Life

2010 ◽  
Vol 22 (10) ◽  
pp. 2316-2325 ◽  
Author(s):  
Mitul A. Mehta ◽  
Emma Gore-Langton ◽  
Nicole Golembo ◽  
Emma Colvert ◽  
Steven C. R. Williams ◽  
...  
Keyword(s):  
Basal Ganglia ◽  
Functional Neuroimaging ◽  
Imaging Study ◽  
Brain Regions ◽  
Reward Processing ◽  
Reward Anticipation ◽  
Functional Imaging Study ◽  
Comparable Performance ◽  
And Behavior ◽  
First Time

Severe deprivation in the first few years of life is associated with multiple difficulties in cognition and behavior. However, the brain basis for these difficulties is poorly understood. Structural and functional neuroimaging studies have implicated limbic system structures as dysfunctional, and one functional imaging study in a heterogeneous group of maltreated individuals has confirmed the presence of abnormalities in the basal ganglia. Based on these studies and known dopaminergic abnormalities from studies in experimental animals using social isolation, we used a task of monetary reward anticipation to examine the functional integrity of brain regions previously shown to be implicated in reward processing. Our sample included a group of adolescents (n = 12) who had experienced global deprivation early in their lives in Romania prior to adoption into UK families. In contrast to a nonadopted comparison group (n = 11), the adoptees did not recruit the striatum during reward anticipation despite comparable performance accuracy and latency. These results show, for the first time, an association between early institutional deprivation and brain reward systems in humans and highlight potential neural vulnerabilities resulting from such exposures.

scholarly journals From cognitive to neural models of working memory

2007 ◽  
Vol 362 (1481) ◽  
pp. 761-772 ◽  
Author(s):  
Mark D'Esposito
Keyword(s):  
Working Memory ◽  
Functional Neuroimaging ◽  
Empirical Studies ◽  
Brain Regions ◽  
Cognitive Models ◽  
Neural Mechanisms ◽  
Long Term Memory ◽  
Cognitive Mechanisms ◽  
Internal Representations ◽  
Active Maintenance

Working memory refers to the temporary retention of information that was just experienced or just retrieved from long-term memory but no longer exists in the external environment. These internal representations are short-lived, but can be stored for longer periods of time through active maintenance or rehearsal strategies, and can be subjected to various operations that manipulate the information in such a way that makes it useful for goal-directed behaviour. Empirical studies of working memory using neuroscientific techniques, such as neuronal recordings in monkeys or functional neuroimaging in humans, have advanced our knowledge of the underlying neural mechanisms of working memory. This rich dataset can be reconciled with behavioural findings derived from investigating the cognitive mechanisms underlying working memory. In this paper, I review the progress that has been made towards this effort by illustrating how investigations of the neural mechanisms underlying working memory can be influenced by cognitive models and, in turn, how cognitive models can be shaped and modified by neuroscientific data. One conclusion that arises from this research is that working memory can be viewed as neither a unitary nor a dedicated system. A network of brain regions, including the prefrontal cortex (PFC), is critical for the active maintenance of internal representations that are necessary for goal-directed behaviour. Thus, working memory is not localized to a single brain region but probably is an emergent property of the functional interactions between the PFC and the rest of the brain.

scholarly journals Proteolytic Remodeling of Perineuronal Nets: Effects on Synaptic Plasticity and Neuronal Population Dynamics

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
P. Lorenzo Bozzelli ◽  
Seham Alaiyed ◽  
Eunyoung Kim ◽  
Sonia Villapol ◽  
Katherine Conant
Keyword(s):  
Population Dynamics ◽  
Synaptic Plasticity ◽  
Synaptic Input ◽  
Neuronal Plasticity ◽  
Population Level ◽  
Gamma Oscillations ◽  
Brain Regions ◽  
Neuronal Population ◽  
Perineuronal Nets ◽  
Perineuronal Net

The perineuronal net (PNN) represents a lattice-like structure that is prominently expressed along the soma and proximal dendrites of parvalbumin- (PV-) positive interneurons in varied brain regions including the cortex and hippocampus. It is thus apposed to sites at which PV neurons receive synaptic input. Emerging evidence suggests that changes in PNN integrity may affect glutamatergic input to PV interneurons, a population that is critical for the expression of synchronous neuronal population discharges that occur with gamma oscillations and sharp-wave ripples. The present review is focused on the composition of PNNs, posttranslation modulation of PNN components by sulfation and proteolysis, PNN alterations in disease, and potential effects of PNN remodeling on neuronal plasticity at the single-cell and population level.

scholarly journals Spatial inhibition of return is impaired in mild cognitive impairment and mild Alzheimer’s disease

2020 ◽  
Author(s):  
Xiong Jiang ◽  
James H. Howard ◽  
G. Wiliam Rebeck ◽  
R. Scott Turner
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Medial Temporal Lobe ◽  
Inhibition Of Return ◽  
Memory Performance ◽  
Brain Regions ◽  
List Type ◽  
Older Individuals

ABSTRACTSpatial inhibition of return (IOR) refers to the phenomenon by which individuals are slower to respond to stimuli appearing at a previously cued location compared to un-cued locations. Here we provide evidence supporting that spatial IOR is mildly impaired in individuals with mild cognitive impairment (MCI) or mild Alzheimer’s disease (AD), and the impairment is readily detectable using a novel double cue paradigm. Furthermore, reduced spatial IOR in high-risk healthy older individuals is associated with reduced memory and other neurocognitive task performance, suggesting that the novel double cue spatial IOR paradigm may be useful in detecting MCI and early AD.SIGNIFICANCE STATEMENTNovel double cue spatial inhibition of return (IOR) paradigm revealed a robust effect IOR deficits in individuals with mild cognitive impairment (MCI) or mild Alzheimer’s disease (AD)Spatial IOR effect correlates with memory performance in healthy older adults at a elevated risk of Alzheimer’s disease (with a family history or APOE e4 allele)The data suggests that double cue spatial IOR may be sensitive to detect early AD pathological changes, which may be linked to disease progress at the posterior brain regions (rather than the medial temporal lobe)

scholarly journals Neural arbitration between social and individual learning systems

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Andreea Oliviana Diaconescu ◽  
Madeline Stecy ◽  
Lars Kasper ◽  
Christopher J Burke ◽  
Zoltan Nagy ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Functional Neuroimaging ◽  
Learning Task ◽  
Brain Regions ◽  
Individual Learning ◽  
Learning Systems ◽  
Learning System ◽  
Relative Precision ◽  
Decision Confidence ◽  
Dorsolateral Prefrontal

Decision making requires integrating knowledge gathered from personal experiences with advice from others. The neural underpinnings of the process of arbitrating between information sources has not been fully elucidated. In this study, we formalized arbitration as the relative precision of predictions, afforded by each learning system, using hierarchical Bayesian modeling. In a probabilistic learning task, participants predicted the outcome of a lottery using recommendations from a more informed advisor and/or self-sampled outcomes. Decision confidence, as measured by the number of points participants wagered on their predictions, varied with our definition of arbitration as a ratio of precisions. Functional neuroimaging demonstrated that arbitration signals were independent of decision confidence and involved modality-specific brain regions. Arbitrating in favor of self-gathered information activated the dorsolateral prefrontal cortex and the midbrain, whereas arbitrating in favor of social information engaged the ventromedial prefrontal cortex and the amygdala. These findings indicate that relative precision captures arbitration between social and individual learning systems at both behavioral and neural levels.

Reward-Associated Gamma Oscillations in Ventral Striatum Are Regionally Differentiated and Modulate Local Firing Activity

2010 ◽  
Vol 103 (3) ◽  
pp. 1658-1672 ◽  
Author(s):  
Tobias Kalenscher ◽  
Carien S. Lansink ◽  
Jan V. Lankelma ◽  
Cyriel M. A. Pennartz
Keyword(s):  
Ventral Striatum ◽  
Phase Locking ◽  
Gamma Oscillations ◽  
Brain Regions ◽  
Reward Processing ◽  
Temporal Organization ◽  
Gamma Activity ◽  
Neural Ensembles ◽  
Gamma Range ◽  
Gamma Power

Oscillations of local field potentials (LFPs) in the gamma range are found in many brain regions and are supposed to support the temporal organization of cognitive, perceptual, and motor functions. Even though gamma oscillations have also been observed in ventral striatum, one of the brain's most important structures for motivated behavior and reward processing, their specific function during ongoing behavior is unknown. Using a movable tetrode array, we recorded LFPs and activity of neural ensembles in the ventral striatum of rats performing a reward-collection task. Rats were running along a triangle track and in each round collected one of three different types of rewards. The gamma power of LFPs on subsets of tetrodes was modulated by reward-site visits, discriminated between reward types, between baitedness of reward locations and was different before versus after arrival at a reward site. Many single units in ventral striatum phase-locked their discharge pattern to the gamma oscillations of the LFPs. Phase-locking occurred more often in reward-related than in reward-unrelated neurons and LFPs. A substantial number of simultaneously recorded LFPs correlated poorly with each other in terms of gamma rhythmicity, indicating that the expression of gamma activity was heterogeneous and regionally differentiated. The orchestration of LFPs and single-unit activity by way of gamma rhythmicity sheds light on the functional architecture of the ventral striatum and the temporal coordination of ventral striatal activity for modulating downstream areas and regulating synaptic plasticity.

scholarly journals A Meta-analysis of Functional Neuroimaging Studies of Self- and Other Judgments Reveals a Spatial Gradient for Mentalizing in Medial Prefrontal Cortex

2012 ◽  
Vol 24 (8) ◽  
pp. 1742-1752 ◽  
Author(s):  
Bryan T. Denny ◽  
Hedy Kober ◽  
Tor D. Wager ◽  
Kevin N. Ochsner
Keyword(s):  
Functional Organization ◽  
Functional Neuroimaging ◽  
Meta Analysis ◽  
Brain Regions ◽  
The Self ◽  
Spatial Gradient ◽  
Self And Other ◽  
Neuroimaging Data ◽  
Medial Pfc ◽  
Meta Analyses

The distinction between processes used to perceive and understand the self and others has received considerable attention in psychology and neuroscience. Brain findings highlight a role for various regions, in particular the medial PFC (mPFC), in supporting judgments about both the self and others. We performed a meta-analysis of 107 neuroimaging studies of self- and other-related judgments using multilevel kernel density analysis [Kober, H., & Wager, T. D. Meta-analyses of neuroimaging data. Wiley Interdisciplinary Reviews, 1, 293–300, 2010]. We sought to determine what brain regions are reliably involved in each judgment type and, in particular, what the spatial and functional organization of mPFC is with respect to them. Relative to nonmentalizing judgments, both self- and other judgments were associated with activity in mPFC, ranging from ventral to dorsal extents, as well as common activation of the left TPJ and posterior cingulate. A direct comparison between self- and other judgments revealed that ventral mPFC as well as left ventrolateral PFC and left insula were more frequently activated by self-related judgments, whereas dorsal mPFC, in addition to bilateral TPJ and cuneus, was more frequently activated by other-related judgments. Logistic regression analyses revealed that ventral and dorsal mPFC lay at opposite ends of a functional gradient: The z coordinates reported in individual studies predicted whether the study involved self- or other-related judgments, which were associated with increasingly ventral or dorsal portions of mPFC, respectively. These results argue for a distributed rather than localizationist account of mPFC organization and support an emerging view on the functional heterogeneity of mPFC.

scholarly journals Methodological Considerations in Conducting an Olfactory fMRI Study

2013 ◽  
Vol 27 (3) ◽  
pp. 267-276 ◽  
Author(s):  
Faezeh Vedaei ◽  
Mohammad Fakhri ◽  
Mohammad Hossein Harirchian ◽  
Kavous Firouznia ◽  
Yones Lotfi ◽  
...  
Keyword(s):  
Functional Neuroimaging ◽  
Neurological Diseases ◽  
Brain Regions ◽  
Brain Network ◽  
Functional Brain Imaging ◽  
Behavioral Studies ◽  
Fmri Study ◽  
Methodological Considerations ◽  
Technical Principles ◽  
Review Current

The sense of smell is a complex chemosensory processing in human and animals that allows them to connect with the environment as one of their chief sensory systems. In the field of functional brain imaging, many studies have focused on locating brain regions that are involved during olfactory processing. Despite wealth of literature about brain network in different olfactory tasks, there is a paucity of data regarding task design. Moreover, considering importance of olfactory tasks for patients with variety of neurological diseases, special contemplations should be addressed for patients. In this article, we review current olfaction tasks for behavioral studies and functional neuroimaging assessments, as well as technical principles regarding utilization of these tasks in functional magnetic resonance imaging studies.

scholarly journals Reconstructing lost BOLD signal in individual participants using deep machine learning

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuxiang Yan ◽  
Louisa Dahmani ◽  
Jianxun Ren ◽  
Lunhao Shen ◽  
Xiaolong Peng ◽  
...  
Keyword(s):  
Machine Learning ◽  
Time Series ◽  
Functional Neuroimaging ◽  
Brain Regions ◽  
Specific Information ◽  
Bold Signal ◽  
Signal Loss ◽  
Brain Organization ◽  
Good Correspondence ◽  
Functional Relationships

Abstract Signal loss in blood oxygen level-dependent (BOLD) functional neuroimaging is common and can lead to misinterpretation of findings. Here, we reconstructed compromised fMRI signal using deep machine learning. We trained a model to learn principles governing BOLD activity in one dataset and reconstruct artificially compromised regions in an independent dataset, frame by frame. Intriguingly, BOLD time series extracted from reconstructed frames are correlated with the original time series, even though the frames do not independently carry any temporal information. Moreover, reconstructed functional connectivity maps exhibit good correspondence with the original connectivity maps, indicating that the model recovers functional relationships among brain regions. We replicated this result in two healthy datasets and in patients whose scans suffered signal loss due to intracortical electrodes. Critically, the reconstructions capture individual-specific information. Deep machine learning thus presents a unique opportunity to reconstruct compromised BOLD signal while capturing features of an individual’s own functional brain organization.

scholarly journals Probing the Link Between Perception and Oscillations: Lessons from Transcranial Alternating Current Stimulation

2019 ◽  
Vol 26 (1) ◽  
pp. 57-73 ◽  
Author(s):  
Yuranny Cabral-Calderin ◽  
Melanie Wilke
Keyword(s):  
Time Windows ◽  
Gamma Oscillations ◽  
Alternating Current ◽  
Brain Regions ◽  
Causal Link ◽  
Brain Oscillations ◽  
Promising Tool ◽  
Transcranial Alternating Current Stimulation ◽  
Close Time ◽  
Auditory Cortices

Brain oscillations are regarded as important for perception as they open and close time windows for neural spiking to enable the effective communication within and across brain regions. In the past, studies on perception primarily relied on the use of electrophysiological techniques for probing a correlative link between brain oscillations and perception. The emergence of noninvasive brain stimulation techniques such as transcranial alternating current stimulation (tACS) provides the possibility to study the causal contribution of specific oscillatory frequencies to perception. Here, we review the studies on visual, auditory, and somatosensory perception that employed tACS to probe the causality of brain oscillations for perception. The current literature is consistent with a causal role of alpha and gamma oscillations in parieto-occipital regions for visual perception and theta and gamma oscillations in auditory cortices for auditory perception. In addition, the sensory gating by alpha oscillations applies not only to the visual but also to the somatosensory domain. We conclude that albeit more refined perceptual paradigms and individualized stimulation practices remain to be systematically adopted, tACS is a promising tool for establishing a causal link between neural oscillations and perception.

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