scholarly journals Robust neurophysiological correlates of the rubber hand illusion emerge at early latencies but are unrelated to changes in skin conductance accompanying the illusion

2021 ◽  
Author(s):  
Placido Sciortino ◽  
Christoph Kayser
Keyword(s):  
Skin Conductance ◽  
Spatial Arrangement ◽  
Confounding Factors ◽  
Evoked Responses ◽  
Rubber Hand ◽  
Artificial Limb ◽  
Cross Classification ◽  
Evoked Activity ◽  
Sensory Evoked

AbstractThe neurophysiological processes reflecting the illusory ownership over an artificial limb remain debated. We used multivariate (cross-)classification of evoked EEG responses to probe for signatures of the illusion that robustly generalize across a number of confounding factors identified based on previous studies: the spatial arrangement of limbs, controls involving either a misaligned artificial object or participant’s own hand, and which provide evidence of illusory ownership directly within an experimental trial. Our results show that sensory-evoked responses differ between illusion and non-illusion epochs from early latencies on. While these responses exhibit distinct sensitivity to the experimental factors at distinct times, around 140 ms the evoked activity reflects the illusory state robustly across experimental manipulations. This neurophysiological signature of illusory ownership was not correlated with increases in skin conductance accompanying the illusion, suggesting that neurophysiological and bodily signals reflect distinct processes related to the embodiment of an artificial limb.

scholarly journals Quantitative Analysis and Biophysically Realistic Neural Modeling of the MEG Mu Rhythm: Rhythmogenesis and Modulation of Sensory-Evoked Responses

2009 ◽  
Vol 102 (6) ◽  
pp. 3554-3572 ◽  
Author(s):  
Stephanie R. Jones ◽  
Dominique L. Pritchett ◽  
Michael A. Sikora ◽  
Steven M. Stufflebeam ◽  
Matti Hämäläinen ◽  
...  
Keyword(s):  
Neural Model ◽  
Evoked Responses ◽  
Mu Rhythm ◽  
Thalamic Nuclei ◽  
Localized Source ◽  
Cortical Oscillations ◽  
Alpha 7 ◽  
Evoked Activity ◽  
Sensory Evoked ◽  
The Impact

Variations in cortical oscillations in the alpha (7–14 Hz) and beta (15–29 Hz) range have been correlated with attention, working memory, and stimulus detection. The mu rhythm recorded with magnetoencephalography (MEG) is a prominent oscillation generated by Rolandic cortex containing alpha and beta bands. Despite its prominence, the neural mechanisms regulating mu are unknown. We characterized the ongoing MEG mu rhythm from a localized source in the finger representation of primary somatosensory (SI) cortex. Subjects showed variation in the relative expression of mu-alpha or mu-beta, which were nonoverlapping for roughly 50% of their respective durations on single trials. To delineate the origins of this rhythm, a biophysically principled computational neural model of SI was developed, with distinct laminae, inhibitory and excitatory neurons, and feedforward (FF, representative of lemniscal thalamic drive) and feedback (FB, representative of higher-order cortical drive or input from nonlemniscal thalamic nuclei) inputs defined by the laminar location of their postsynaptic effects. The mu-alpha component was accurately modeled by rhythmic FF input at approximately 10-Hz. The mu-beta component was accurately modeled by the addition of approximately 10-Hz FB input that was nearly synchronous with the FF input. The relative dominance of these two frequencies depended on the delay between FF and FB drives, their relative input strengths, and stochastic changes in these variables. The model also reproduced key features of the impact of high prestimulus mu power on peaks in SI-evoked activity. For stimuli presented during high mu power, the model predicted enhancement in an initial evoked peak and decreased subsequent deflections. In agreement, the MEG-evoked responses showed an enhanced initial peak and a trend to smaller subsequent peaks. These data provide new information on the dynamics of the mu rhythm in humans and the model provides a novel mechanistic interpretation of this rhythm and its functional significance.

scholarly journals Spatiotemporal structure of sensory-evoked and spontaneous activity revealed by mesoscale imaging in anesthetized and awake mice

2020 ◽  
Author(s):  
Navvab Afrashteh ◽  
Samsoon Inayat ◽  
Edgar Bermudez Contreras ◽  
Artur Luczak ◽  
Bruce L. McNaughton ◽  
...  
Keyword(s):  
Spontaneous Activity ◽  
Brain Activity ◽  
Activity Patterns ◽  
Sensory Stimulation ◽  
Wide Field ◽  
Evoked Responses ◽  
Evoked Activity ◽  
Cortical Regions ◽  
The One ◽  
Sensory Evoked

AbstractBrain activity propagates across the cortex in diverse spatiotemporal patterns, both as a response to sensory stimulation and during spontaneous activity. Despite been extensively studied, the relationship between the characteristics of such patterns during spontaneous and evoked activity is not completely understood. To investigate this relationship, we compared visual, auditory, and tactile evoked activity patterns elicited with different stimulus strengths and spontaneous activity motifs in lightly anesthetized and awake mice using mesoscale wide-field voltage-sensitive dye and glutamate imaging respectively. The characteristics of cortical activity that we compared include amplitude, speed, direction, and complexity of propagation trajectories in spontaneous and evoked activity patterns. We found that the complexity of the propagation trajectories of spontaneous activity, quantified as their fractal dimension, is higher than the one from sensory evoked responses. Moreover, the speed and direction of propagation, are modulated by the amplitude during both, spontaneous and evoked activity. Finally, we found that spontaneous activity had similar amplitude and speed when compared to evoked activity elicited with low stimulus strengths. However, this similarity gradually decreased when the strength of stimuli eliciting evoked responses increased. Altogether, these findings are consistent with the fact that even primary sensory areas receive widespread inputs from other cortical regions, and that, during rest, the cortex tends to reactivate traces of complex, multi-sensory experiences that may have occurred in a range of different behavioural contexts.

scholarly journals Sodium-Calcium Exchanger Mediates Sensory-Evoked Glial Calcium Transients in the Developing Retinotectal System

2020 ◽  
Author(s):  
Nicholas J. Benfey ◽  
Vanessa J. Li ◽  
Anne Schohl ◽  
Edward S. Ruthazer
Keyword(s):  
Visual Stimulation ◽  
Activity Patterns ◽  
Sensory Stimulation ◽  
Calcium Transients ◽  
Evoked Responses ◽  
Sodium Calcium Exchanger ◽  
Sensory Stimuli ◽  
Sodium Calcium ◽  
Evoked Activity ◽  
Sensory Evoked

AbstractVarious types of sensory stimuli have been shown to induce calcium elevations in glia. However, a mechanistic understanding of the signalling pathways mediating sensory-evoked activity in glia in intact animals is still emerging. Here we demonstrate that during early development of the Xenopus laevis visual system, radial astrocytes in the optic tectum are highly responsive to sensory stimulation. Calcium transients occur spontaneously in radial astrocytes at rest and are abolished by silencing neuronal activity with tetrodotoxin. Visual stimulation drives temporally correlated increases in the activity patterns of neighbouring radial astrocytes. Following blockade of all glutamate receptors, visually-evoked calcium activity in radial astrocytes is enhanced, rather than suppressed, while the additional blockade of either glutamate transporters or sodium-calcium exchangers (NCX) fully prevents visually-evoked responses. Additionally, we demonstrate that blockade of NCX alone is sufficient to prevent visually-evoked responses in radial astrocytes, highlighting a pivotal role for NCX in glia during development.

scholarly journals Motor-evoked neural responses in auditory cortex are associated with improved sensitivity to self-generated sounds

2020 ◽  
Author(s):  
Daniel Reznik ◽  
Noa Hacohen ◽  
Batel Buaron ◽  
Elana Zion-Golumbic ◽  
Roy Mukamel
Keyword(s):  
Auditory Cortex ◽  
Auditory Processing ◽  
Internal State ◽  
Button Press ◽  
Evoked Responses ◽  
Complex Interactions ◽  
Sensory Interactions ◽  
Evoked Activity ◽  
Functional Relevance ◽  
Sensory Evoked

AbstractSensory perception is a product of complex interactions between the internal state of an organism and the physical attributes of a stimulus. One factor that modulates the internal state of the perceiving agent is voluntary movement. It has been shown across the animal kingdom that perception and sensory-evoked physiological responses are modulated depending on whether or not the stimulus is the consequence of voluntary actions. These phenomena are often attributed to motor signals sent to relevant sensory regions (efference copies), that convey information about expected upcoming sensory consequences. However, to date, there is no direct evidence in humans for efferent signals underlying these motor-sensory interactions. In the current study we recorded neurophysiological (using Magnetoencephalography) and behavioral responses from 16 healthy subjects performing an auditory detection task of faint tones. Tones were either generated by subjects’ voluntary button presses or occurred predictably following a visual cue. By introducing a constant temporal delay between button press/cue and tone delivery and applying source-level analysis we decoupled motor-evoked and auditory-evoked activity in auditory cortex. We show motor-related evoked-responses in auditory cortex following sound-triggering actions and preceding sound onset. Such evoked-responses were not found for button-presses that were not coupled with expected sounds. Furthermore, the amplitude of these evoked-responses corresponded with subsequent sound detection, suggesting their functional relevance to auditory processing. Our results provide first direct evidence for efferent signals in sensory cortex that are evoked by voluntary actions coupled with sensory consequences.

scholarly journals Barrel cortex plasticity after photothrombotic stroke involves potentiating responses of pre-existing circuits but not functional remapping to new circuits

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
William A. Zeiger ◽  
Máté Marosi ◽  
Satvir Saggi ◽  
Natalie Noble ◽  
Isa Samad ◽  
...  
Keyword(s):  
Calcium Imaging ◽  
Barrel Cortex ◽  
Evoked Responses ◽  
Baseline Levels ◽  
Photothrombotic Stroke ◽  
Adaptive Circuit ◽  
Evoked Activity ◽  
Sensory Evoked ◽  
In Vivo Calcium Imaging

AbstractRecovery after stroke is thought to be mediated by adaptive circuit plasticity, whereby surviving neurons assume the roles of those that died. However, definitive longitudinal evidence of neurons changing their response selectivity after stroke is lacking. We sought to directly test whether such functional “remapping” occurs within mouse primary somatosensory cortex after a stroke that destroys the C1 barrel. Using in vivo calcium imaging to longitudinally record sensory-evoked activity under light anesthesia, we did not find any increase in the number of C1 whisker-responsive neurons in the adjacent, spared D3 barrel after stroke. To promote plasticity after stroke, we also plucked all whiskers except C1 (forced use therapy). This led to an increase in the reliability of sensory-evoked responses in C1 whisker-responsive neurons but did not increase the number of C1 whisker-responsive neurons in spared surround barrels over baseline levels. Our results argue against remapping of functionality after barrel cortex stroke, but support a circuit-based mechanism for how rehabilitation may improve recovery.

scholarly journals Clinical Validation of the Champagne Algorithm for Evoked Response Source Localization in Magnetoencephalography

2021 ◽  
Author(s):  
Abhishek S. Bhutada ◽  
Chang Cai ◽  
Danielle Mizuiri ◽  
Anne Findlay ◽  
Jessie Chen ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Source Localization ◽  
Clinical Population ◽  
Evoked Responses ◽  
Localization Algorithm ◽  
Equivalent Current Dipole ◽  
Current Dipole ◽  
Tumor Patients ◽  
Equivalent Current ◽  
Sensory Evoked

AbstractMagnetoencephalography (MEG) is a robust method for non-invasive functional brain mapping of sensory cortices due to its exceptional spatial and temporal resolution. The clinical standard for MEG source localization of functional landmarks from sensory evoked responses is the equivalent current dipole (ECD) localization algorithm, known to be sensitive to initialization, noise, and manual choice of the number of dipoles. Recently many automated and robust algorithms have been developed, including the Champagne algorithm, an empirical Bayesian algorithm, with powerful abilities for MEG source reconstruction and time course estimation (Wipf et al. 2010; Owen et al. 2012). Here, we evaluate automated Champagne performance in a clinical population of tumor patients where there was minimal failure in localizing sensory evoked responses using the clinical standard, ECD localization algorithm. MEG data of auditory evoked potentials and somatosensory evoked potentials from 21 brain tumor patients were analyzed using Champagne, and these results were compared with equivalent current dipole (ECD) fit. Across both somatosensory and auditory evoked field localization, we found there was a strong agreement between Champagne and ECD localizations in all cases. Given resolution of 8mm voxel size, peak source localizations from Champagne were below 10mm of ECD peak source localization. The Champagne algorithm provides a robust and automated alternative to manual ECD fits for clinical localization of sensory evoked potentials and can contribute to improved clinical MEG data processing workflows.

Sensory Evoked Responses in Head Injury

1985 ◽  
Vol 2 (3) ◽  
pp. 187-206 ◽  
Author(s):  
JUDY R. MACKEY-HARGADINE ◽  
JAMES W. HALL
Keyword(s):  
Head Injury ◽  
Evoked Responses ◽  
Sensory Evoked

System for Cross-Classification of Small Group Studies

1968 ◽  
Vol 23 (3_suppl) ◽  
pp. 1295-1304
Author(s):  
Richard Heslin ◽  
Dexter Dunphy
Keyword(s):  
Small Group ◽  
Classification System ◽  
Sufficient Information ◽  
Coding System ◽  
Similar System ◽  
Cross Classification

The article describes a method for placing information into a classification system that maximizes the flexibility in retrieval at a later time. It uses (1) a stack of edge-punched cards containing information of interest that has been punched according to (2) a coding system developed by the users. The authors have developed a classification system for the small-group field which is depicted and described in detail. It allows for coding a study on about 50 dimensions to (1) locate an article, (2) give an over-all description of the article, and (3) indicate the variables measured or discussed. Examples of uses and discussion of special features are provided to give the reader sufficient information to establish and use the system or a similar system for his own purposes.

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