scholarly journals Neuro-Current Response Functions: A Unified Approach to MEG Source Analysis under the Continuous Stimuli Paradigm

2019 ◽  
Author(s):  
Proloy Das ◽  
Christian Brodbeck ◽  
Jonathan Z. Simon ◽  
Behtash Babadi
Keyword(s):  
Auditory Processing ◽  
Source Analysis ◽  
High Temporal Resolution ◽  
Linear Filter ◽  
Current Response ◽  
Response Functions ◽  
Continuous Speech ◽  
Spatiotemporal Resolution ◽  
Linear Filters ◽  
Neural Processes

AbstractCharacterizing the neural dynamics underlying sensory processing is one of the central areas of investigation in systems and cognitive neuroscience. Neuroimaging techniques such as magnetoencephalography (MEG) and Electroencephalography (EEG) have provided significant insights into the neural processing of continuous stimuli, such as speech, thanks to their high temporal resolution. Existing work in the context of auditory processing suggests that certain features of speech, such as the acoustic envelope, can be used as reliable linear predictors of the neural response manifested in M/EEG. The corresponding linear filters are referred to as temporal response functions (TRFs). While the functional roles of specific components of the TRF are well-studied and linked to behavioral attributes such as attention, the cortical origins of the underlying neural processes are not as well understood. In this work, we address this issue by estimating a linear filter representation of cortical sources directly from neuroimaging data in the context of continuous speech processing. To this end, we introduce Neuro-Current Response Functions (NCRFs), a set of linear filters, spatially distributed throughout the cortex, that predict the cortical currents giving rise to the observed ongoing MEG (or EEG) data in response to continuous speech. NCRF estimation is cast within a Bayesian framework, which allows unification of the TRF and source estimation problems, and also facilitates the incorporation of prior information on the structural properties of the NCRFs. To generalize this analysis to M/EEG recordings which lack individual structural magnetic resonance (MR) scans, NCRFs are extended to free-orientation dipoles and a novel regularizing scheme is put forward to lessen reliance on fine-tuned coordinate co-registration. We present a fast estimation algorithm, which we refer to as the Champ-Lasso algorithm, by leveraging recent advances in optimization, and demonstrate its utility through application to simulated and experimentally recorded MEG data under auditory experiments. Our simulation studies reveal significant improvements over existing methods that typically operate in a two-stage fashion, in terms of spatial resolution, response function reconstruction, and recovering dipole orientations. The analysis of experimentally-recorded MEG data without MR scans corroborates existing findings, but also delineates the distinct cortical distribution of the underlying neural processes at high spatiotemporal resolution. In summary, we provide a principled modeling and estimation paradigm for MEG source analysis tailored to extracting the cortical origin of electrophysiological responses to continuous stimuli.

scholarly journals Neuro-current response functions: A unified approach to MEG source analysis under the continuous stimuli paradigm

NeuroImage ◽  
2020 ◽  
Vol 211 ◽  
pp. 116528 ◽  
Author(s):  
Proloy Das ◽  
Christian Brodbeck ◽  
Jonathan Z. Simon ◽  
Behtash Babadi
Keyword(s):  
Source Analysis ◽  
Current Response ◽  
Response Functions ◽  
Unified Approach

scholarly journals Linking the Rapid Cascade of Visuo-Attentional Processes to Successful Memory Encoding

2020 ◽  
Author(s):  
B R Geib ◽  
R Cabeza ◽  
M G Woldorff
Keyword(s):  
Visual Processing ◽  
Memory Retrieval ◽  
Current Knowledge ◽  
High Temporal Resolution ◽  
Alpha Power ◽  
Attentional Orienting ◽  
Memory Encoding ◽  
Attentional Processes ◽  
Neural Processes ◽  
Dm Effect

Abstract While it is broadly accepted that attention modulates memory, the contribution of specific rapid attentional processes to successful encoding is largely unknown. To investigate this issue, we leveraged the high temporal resolution of electroencephalographic recordings to directly link a cascade of visuo-attentional neural processes to successful encoding: namely (1) the N2pc (peaking ~200 ms), which reflects stimulus-specific attentional orienting and allocation, (2) the sustained posterior-contralateral negativity (post-N2pc), which has been associated with sustained visual processing, (3) the contralateral reduction in oscillatory alpha power (contralateral reduction in alpha > 200 ms), which has also been independently related to attentionally sustained visual processing. Each of these visuo-attentional processes was robustly predictive of successful encoding, and, moreover, each enhanced memory independently of the classic, longer-latency, conceptually related, difference-due-to memory (Dm) effect. Early latency midfrontal theta power also promoted successful encoding, with at least part of this influence being mediated by the later latency Dm effect. These findings markedly expand current knowledge by helping to elucidate the intimate relationship between attentional modulations of perceptual processing and effective encoding for later memory retrieval.

scholarly journals Electro-plasmonic nanoantenna: A nonfluorescent optical probe for ultrasensitive label-free detection of electrophysiological signals

2019 ◽  
Vol 5 (10) ◽  
pp. eaav9786 ◽  
Author(s):  
Ahsan Habib ◽  
Xiangchao Zhu ◽  
Uryan I. Can ◽  
Maverick L. McLanahan ◽  
Pinar Zorlutuna ◽  
...  
Keyword(s):  
Electric Field ◽  
Field Measurements ◽  
Optical Probe ◽  
Optical Recording ◽  
High Temporal Resolution ◽  
Label Free ◽  
Spatiotemporal Resolution ◽  
Photon Count ◽  
Label Free Detection ◽  
Electrophysiological Signals

Harnessing the unprecedented spatiotemporal resolution capability of light to detect electrophysiological signals has been the goal of scientists for nearly 50 years. Yet, progress toward that goal remains elusive due to lack of electro-optic translators that can efficiently convert electrical activity to high photon count optical signals. Here, we introduce an ultrasensitive and extremely bright nanoscale electric-field probe overcoming the low photon count limitations of existing optical field reporters. Our electro-plasmonic nanoantennas with drastically enhanced cross sections (~104 nm2 compared to typical values of ~10−2 nm2 for voltage-sensitive fluorescence dyes and ~1 nm2 for quantum dots) offer reliable detection of local electric-field dynamics with remarkably high sensitivities and signal–to–shot noise ratios (~60 to 220) from diffraction-limited spots. In our electro-optics experiments, we demonstrate high-temporal resolution electric-field measurements at kilohertz frequencies and achieved label-free optical recording of network-level electrogenic activity of cardiomyocyte cells with low-intensity light (11 mW/mm2).

Neurocomputational Models of Voice and Speech Perception

2018 ◽  
pp. 742-756
Author(s):  
Bernd J. Kröger
Keyword(s):  
Speech Perception ◽  
Auditory Processing ◽  
Computational Models ◽  
Affective State ◽  
Facial Perception ◽  
Neural Processes ◽  
Neurophysiological Data ◽  
Paralinguistic Information ◽  
Sound Features ◽  
Voice And Speech

This chapter outlines a comprehensive neurocomputational model of voice and speech perception based on (i) already established computational models, as well as on (ii) neurophysiological data of the underlying neural processes. Neurocomputational models of speech perception comprise auditory as well as cognitive modules, in order to extract sound features as well as linguistic information (linguistic content). A model of voice and speech perception in addition needs to process paralinguistic information like gender, age, emotional or affective state of speaker, etc. It is argued here that modules of a neurocomputational model of voice and speech perception need to interact with modules which go beyond unimodal auditory processing because, for example, processing of paralinguistic information is closely related to such as visual facial perception. Thus, this chapter describes neural modelling of voice and speech perception in relation to general communication and social-interaction processes, which makes it necessary to develop a hypermodal processing approach.

scholarly journals Propagation of Strong Rainfall Events from Southeastern South America to the Central Andes

2015 ◽  
Vol 28 (19) ◽  
pp. 7641-7658 ◽  
Author(s):  
Niklas Boers ◽  
Henrique M. J. Barbosa ◽  
Bodo Bookhagen ◽  
José A. Marengo ◽  
Norbert Marwan ◽  
...  
Keyword(s):  
South America ◽  
Wave Train ◽  
Monsoon Season ◽  
Central Andes ◽  
High Temporal Resolution ◽  
Spatiotemporal Resolution ◽  
Rainfall Events ◽  
Low Level ◽  
Societal Relevance ◽  
The Tropics

Abstract Based on high-spatiotemporal-resolution data, the authors perform a climatological study of strong rainfall events propagating from southeastern South America to the eastern slopes of the central Andes during the monsoon season. These events account for up to 70% of total seasonal rainfall in these areas. They are of societal relevance because of associated natural hazards in the form of floods and landslides, and they form an intriguing climatic phenomenon, because they propagate against the direction of the low-level moisture flow from the tropics. The responsible synoptic mechanism is analyzed using suitable composites of the relevant atmospheric variables with high temporal resolution. The results suggest that the low-level inflow from the tropics, while important for maintaining sufficient moisture in the area of rainfall, does not initiate the formation of rainfall clusters. Instead, alternating low and high pressure anomalies in midlatitudes, which are associated with an eastward-moving Rossby wave train, in combination with the northwestern Argentinean low, create favorable pressure and wind conditions for frontogenesis and subsequent precipitation events propagating from southeastern South America toward the Bolivian Andes.

scholarly journals Creativity comes in waves: An EEG-focused exploration of the creative brain.

2019 ◽  
Author(s):  
Carl E. Stevens ◽  
Darya Zabelina
Keyword(s):  
Creative Process ◽  
Creative Thinking ◽  
Divergent Thinking ◽  
Empirical Work ◽  
High Temporal Resolution ◽  
Alpha Band ◽  
Creative Cognition ◽  
Creativity Research ◽  
Neural Processes ◽  
Band Activity

Electroencephalographic (EEG) methodology in creativity research has been remarkably fruitful, establishing the potential of EEG to illuminate complex and transient creativity-related neural processes. Here we synthesize recent advances in the field, highlighting empirical work on creativity as divergent thinking, remote associations, musical creativity, and visual imagery. There is a general consensus that alpha-band activity plays a key role in the creative process, though other frequency bands, such as theta and gamma also serve critical functions. We further discuss evidence for electrical stimulation (tDCS and tACS) as a tool for improvements in creative thinking. EEG’s high temporal resolution is supremely suitable for studying creative cognition, and studies continuing to yield new and exciting evidence regarding the local and global neural processes underlying creativity.

scholarly journals Dynamic FRET-FLIM based screening of signal transduction pathways

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rolf Harkes ◽  
Olga Kukk ◽  
Sravasti Mukherjee ◽  
Jeffrey Klarenbeek ◽  
Bram van den Broek ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Hela Cells ◽  
Source Analysis ◽  
High Temporal Resolution ◽  
Fluorescence Lifetime Imaging ◽  
Decay Kinetics ◽  
Specific Expression ◽  
Breakdown Rates ◽  
Dynamic Screening ◽  
Camp Levels

AbstractFluorescence Lifetime Imaging (FLIM) is an intrinsically quantitative method to screen for protein–protein interactions and is frequently used to record the outcome of signal transduction events. With new highly sensitive and photon efficient FLIM instrumentation, the technique also becomes attractive to screen, with high temporal resolution, for fast changes in Förster Resonance Energy Transfer (FRET), such as those occurring upon activation of cell signaling. The second messenger cyclic adenosine monophosphate (cAMP) is rapidly formed following activation of certain cell surface receptors. cAMP is subsequently degraded by a set of phosphodiesterases (PDEs) which display cell-type specific expression and may also affect baseline levels of the messenger. To study which specific PDEs contribute most to cAMP regulation, we knocked down individual PDEs and recorded breakdown rates of cAMP levels following transient stimulation in HeLa cells stably expressing the FRET/FLIM sensor, Epac-SH189. Many hundreds of cells were recorded at 5 s intervals for each condition. FLIM time traces were calculated for every cell, and decay kinetics were obtained. cAMP clearance was significantly slower when PDE3A and, to a lesser amount, PDE10A were knocked down, identifying these isoforms as dominant in HeLa cells. However, taking advantage of the quantitative FLIM data, we found that knockdown of individual PDEs has a very limited effect on baseline cAMP levels. By combining photon-efficient FLIM instrumentation with optimized sensors, systematic gene knockdown and an automated open-source analysis pipeline, our study demonstrates that dynamic screening of transient cell signals has become feasible. The quantitative platform described here provides detailed kinetic analysis of cellular signals in individual cells with unprecedented throughput.

scholarly journals In vivo volumetric imaging of calcium and glutamate activity at synapses with high spatiotemporal resolution

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Wei Chen ◽  
Ryan G. Natan ◽  
Yuhan Yang ◽  
Shih-Wei Chou ◽  
Qinrong Zhang ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Temporal Resolution ◽  
Simultaneous Recording ◽  
High Temporal Resolution ◽  
Spatiotemporal Resolution ◽  
Volumetric Imaging ◽  
High Spatiotemporal Resolution ◽  
Mouse Cortex ◽  
Two Photon Fluorescence

AbstractStudying neuronal activity at synapses requires high spatiotemporal resolution. For high spatial resolution in vivo imaging at depth, adaptive optics (AO) is required to correct sample-induced aberrations. To improve temporal resolution, Bessel focus has been combined with two-photon fluorescence microscopy (2PFM) for fast volumetric imaging at subcellular lateral resolution. To achieve both high-spatial and high-temporal resolution at depth, we develop an efficient AO method that corrects the distorted wavefront of Bessel focus at the objective focal plane and recovers diffraction-limited imaging performance. Applying AO Bessel focus scanning 2PFM to volumetric imaging of zebrafish larval and mouse brains down to 500 µm depth, we demonstrate substantial improvements in the sensitivity and resolution of structural and functional measurements of synapses in vivo. This enables volumetric measurements of synaptic calcium and glutamate activity at high accuracy, including the simultaneous recording of glutamate activity of apical and basal dendritic spines in the mouse cortex.

scholarly journals High temporal resolution reveals simultaneous plasma membrane recruitment of the TPLATE complex subunits

2020 ◽  
Author(s):  
Jie Wang ◽  
Evelien Mylle ◽  
Alexander Johnson ◽  
Nienke Besbrugge ◽  
Geert De Jaeger ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Temporal Resolution ◽  
Live Cell Imaging ◽  
Adaptor Protein ◽  
High Temporal Resolution ◽  
Spatiotemporal Resolution ◽  
Membrane Recruitment ◽  
Localization Analysis ◽  
Dynamic Assembly ◽  
Protein Recruitment

AbstractThe TPLATE complex (TPC) is a key endocytic adaptor protein complex in plants. TPC contains six evolutionary conserved subunits and two plant specific subunits, AtEH1/Pan1 and AtEH2/Pan1, which are not associated with the hexameric subcomplex in the cytoplasm. To investigate the dynamic assembly of the octameric TPC at the plasma membrane (PM), we performed state-of-the-art dual-color live cell imaging at physiological and a lowered temperature. Our data show that lowering the temperature slows down endocytosis and thereby enhances the temporal resolution of the differential recruitment of endocytic components. Under both normal and lowered temperature conditions, the core TPC subunit TPLATE, and the AtEH/Pan1 proteins, exhibited simultaneous recruitment at the PM. These results, together with our co-localization analysis of different TPC subunits, allow us to conclude that in plant cells, TPC is not recruited to the PM sequentially but as an octameric complex.One sentence summaryLowering the temperature increases spatiotemporal resolution of protein recruitment at the plasma membrane.

scholarly journals Modular preprocessing pipelines can reintroduce artifacts into fMRI data

2018 ◽  
Author(s):  
Martin A. Lindquist ◽  
Stephan Geuter ◽  
Tor D. Wager ◽  
Brian S. Caffo
Keyword(s):  
Fmri Data ◽  
Linear Filter ◽  
Linear Filtering ◽  
Linear Filters ◽  
Data Set ◽  
Temporal Filtering ◽  
Global Signal ◽  
In Series ◽  
Band Pass ◽  
Fmri Analysis

AbstractThe preprocessing pipelines typically used in both task and restingstate fMRI (rs-fMRI) analysis are modular in nature: They are composed of a number of separate filtering/regression steps, including removal of head motion covariates and band-pass filtering, performed sequentially and in a flexible order. In this paper we illustrate the shortcomings of this approach, as we show how later preprocessing steps can reintroduce artifacts previously removed from the data in prior preprocessing steps. We show that each regression step is a geometric projection of data onto a subspace, and that performing a sequence of projections can move the data into subspaces no longer orthogonal to those previously removed, reintroducing signal related to nuisance covariates. Thus, linear filtering operations are not commutative, and the order in which the preprocessing steps are performed is critical. These issues can arise in practice when any combination of standard preprocessing steps—including motion regression, scrubbing, component-based correction, global signal regression, and temporal filtering—are performed sequentially. In this work we focus primarily on rs-fMRI. We illustrate the problem both theoretically and empirically through application to a test-retest rs-fMRI data set, and suggest remedies. These include (a) combining all steps into a single linear filter, or (b) sequential orthogonalization of covariates/linear filters performed in series.

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