scholarly journals Gating Patterns to Proprioceptive Stimulation in Various Cortical Areas: An MEG Study in Children and Adults using Spatial ICA

2020 ◽  
Author(s):  
Jaakko Vallinoja ◽  
Julia Jaatela ◽  
Timo Nurmi ◽  
Harri Piitulainen
Keyword(s):  
Index Finger ◽  
Primary Response ◽  
Paired Stimulus ◽  
Response Patterns ◽  
Current Dipole ◽  
Cortical Responses ◽  
Cortical Regions ◽  
Parietal Cortices ◽  
Consistent Response ◽  
Processing Network

Abstract Proprioceptive paired-stimulus paradigm was used for 30 children (10–17 years) and 21 adult (25–45 years) volunteers in magnetoencephalography (MEG). Their right index finger was moved twice with 500-ms interval every 4 ± 25 s (repeated 100 times) using a pneumatic-movement actuator. Spatial-independent component analysis (ICA) was applied to identify stimulus-related components from MEG cortical responses. Clustering was used to identify spatiotemporally consistent components across subjects. We found a consistent primary response in the primary somatosensory (SI) cortex with similar gating ratios of 0.72 and 0.69 for the children and adults, respectively. Secondary responses with similar transient gating behavior were centered bilaterally in proximity of the lateral sulcus. Delayed and prolonged responses with strong gating were found in the frontal and parietal cortices possibly corresponding to larger processing network of somatosensory afference. No significant correlation between age and gating ratio was found. We confirmed that cortical gating to proprioceptive stimuli is comparable to other somatosensory and auditory domains, and between children and adults. Gating occurred broadly beyond SI cortex. Spatial ICA revealed several consistent response patterns in various cortical regions which would have been challenging to detect with more commonly applied equivalent current dipole or distributed source estimates.

The Effects of a Communications Course for Health Professionals on Empathy Discrimination

1978 ◽  
Vol 9 (2) ◽  
pp. 46-49 ◽  
Author(s):  
Andrew V. Beale ◽  
Otto D. Payton ◽  
Ingrid G. Zachary
Keyword(s):  
Counselor Training ◽  
Health Professionals ◽  
Allied Health ◽  
Physical Therapists ◽  
Training Methods ◽  
Response Patterns ◽  
Allied Health Professionals ◽  
Communications Skills ◽  
Medical Technologists ◽  
Consistent Response

In an attempt to apply counselor training methods to new settings, empathic communications skills were taught to a group of allied health professionals including medical technologists, dietitians, and physical therapists at Virginie Commonwealth University. The results of the study demonstrated that (1) allied health professionals could be taught more effective communications skllls and (2) even relatively strong and consistent response patterns could be altered in a positive way through partlcipation in a relatively short-term training program.

scholarly journals Network-targeted, multi-site direct cortical stimulation enhances working memory by modulating phase lag of low frequency oscillations

2019 ◽  
Author(s):  
Sankaraleengam Alagapan ◽  
Justin Riddle ◽  
Wei Angel Huang ◽  
Eldad Hadar ◽  
Hae Won Shin ◽  
...  
Keyword(s):  
Working Memory ◽  
Brain Stimulation ◽  
Effective Means ◽  
Low Frequency ◽  
Brain Regions ◽  
Phase Lag ◽  
Frequency Bands ◽  
Alpha Frequency ◽  
Cortical Regions ◽  
Parietal Cortices

AbstractWorking memory, an important component of cognitive control, is supported by the coordinated activation of a network of cortical regions in the frontal and parietal cortices. Oscillations in theta and alpha frequency bands are thought to coordinate these network interactions. Thus, targeting multiple nodes of the network with brain stimulation at the frequency of interaction may be an effective means of modulating working memory. We tested this hypothesis by identifying regions that are functionally connected in theta and alpha frequency bands and intracranially stimulating both regions simultaneously in participants undergoing invasive monitoring. We found that in-phase stimulation resulted in improvement in performance compared to sham stimulation. In contrast, anti-phase stimulation did not affect performance. In-phase stimulation resulted in decreased phase lag between regions within working memory network while anti-phase stimulation resulted in increased phase lag suggesting that shorter phase lag in oscillatory connectivity may lead to better performance. The results support the idea that phase lag may play a key role in information transmission across brain regions. More broadly, brain stimulation strategies that aim to improve cognition may be better served targeting multiple nodes of brain networks.

Non-Linear Interactions in Cortical Responses to Bilateral vs Unilateral Visual Field Stimulation

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 62-62
Author(s):  
S P Ahlfors ◽  
J J Foxe ◽  
R J Ilmoniemi ◽  
G V Simpson
Keyword(s):  
Visual Field ◽  
Evoked Potentials ◽  
Normal Subjects ◽  
Stimulus Onset ◽  
Current Dipole ◽  
Field Patterns ◽  
Cortical Responses ◽  
Bilateral Case ◽  
Multichannel Recordings ◽  
Onset Asynchrony

Stimuli in different parts of the visual field can be perceived as independent entities and as conjoined wholes. It is of interest to determine whether there are cortical representations of the left and right hemifields which remain as independent entities when both hemifields are stimulated simultaneously and/or whether they interact to form a conjoined representation. We examined whether cortical processing of visual stimuli depends on whether they occur in isolation in one hemifield (unilaterally) or simultaneously in both hemifields (bilaterally). Visual evoked potentials of six normal subjects were recorded from 128 scalp sites. Wedge-shaped chequerboard stimuli, extending 1 – 4 deg eccentricity, were presented to quadrants of the visual field. Stimulus duration was 250 ms; the stimulus onset asynchrony was random, 500 – 750 ms. The evoked potentials revealed multiple peaks of activity with different surface topography. Prominent deflections occurred around 80, 120 – 180, and 230 ms. The response to bilateral stimuli was compared with the sum of the responses to unilateral stimuli. On the basis of the multichannel recordings, nonlinear interactions were characterised as either (a) modulations (same generators, but different amplitude) or (b) interactions originating from different generators. Modulation occurred at 230 ms, the response being suppressed for the bilateral case. At 120 – 180 ms, the field patterns suggested that at least some of the sources of the interaction effect are different from the source of the bilateral response. Underlying generators of the evoked responses and the interaction effects were further explored with the use of an equivalent current dipole model.

Effects of Cold on Evoked Cortical Potentials in the Rat

1957 ◽  
Vol 191 (2) ◽  
pp. 209-212 ◽  
Author(s):  
Arthur F. Battista
Keyword(s):  
Motor Cortex ◽  
Sciatic Nerve ◽  
Brain Temperature ◽  
Maximum Amplitude ◽  
Cortical Activity ◽  
Primary Response ◽  
Normal Value ◽  
Cortical Responses ◽  
Evoked Cortical Potentials ◽  
Stimulation Of

In the rat anesthetized with Nembutal, stimulation of the sciatic nerve elicited two cortical responses from the sensori-motor cortex. The characteristics of these effects were similar to the ‘primary response’ and the ‘secondary discharge’ recorded by others from the sensori-motor cortex of the cat when the sciatic nerve was stimulated. As the rat was cooled, the primary response increased in size, and the maximum amplitude of two to three times the normal value was found at the calculated brain temperature of 26° to 20°C. Although, no spontaneous electrical cortical activity was present at the calculated brain temperature of 18° to 16°C, the primary response always could be evoked down to a temperature of 15° to 13°C. On warming the animal, the primary response reappeared at 18° to 25°C.

scholarly journals Optical Intrinsic Signal Imaging Responses Are Modulated in Rodent Somatosensory Cortex during Simultaneous Whisker and Forelimb Stimulation

1998 ◽  
Vol 18 (9) ◽  
pp. 968-977 ◽  
Author(s):  
Anne J. Blood ◽  
Arthur W. Toga
Keyword(s):  
Evoked Potentials ◽  
Barrel Cortex ◽  
Response Magnitude ◽  
Response Patterns ◽  
Response Modulation ◽  
Intrinsic Signal ◽  
Optical Intrinsic Signal ◽  
Individual Trial ◽  
Cortical Responses ◽  
Different Response

Optical intrinsic signal imaging(OIS) was used to investigate physiologic interactions between spatially and functionally distinct cortical somatosensory systems. The OIS response magnitude was evaluated after simultaneous stimulation of single whiskers and forelimb digits. Whisker C1 was deflected at a frequency of 10 Hz for 2 seconds while low- or high-intensity vibratory stimuli were applied to forelimb digits. The OIS responses to simultaneous whisker and forelimb stimulation were compared with lone whisker stimulated controls. Overall, addition of a second stimulus caused decreases in barrel cortex response magnitude. Three different response patterns were detected within individual trial sets. Modulation of barrel cortex evoked potentials provided evidence that changes in OIS responses observed here may be partially influenced by vascular responses to changes in neuronal activity. However, OIS responses in the barrel region during lone forelimb stimulation that were unaccompanied by evoked potentials suggested the possibility of independent vascular dynamic influences on response modulation. This study demonstrates that cortical responses at the level of primary sensory processing may be significantly influenced by activity in adjacent regions. Furthermore, it reveals that vascular and neuronal characteristics of interregional modulation do not co-localize and may produce responses in which one component increases while the other decreases.

scholarly journals Topology-preserving smoothing of retinotopic maps

2021 ◽  
Vol 17 (8) ◽  
pp. e1009216
Author(s):  
Yanshuai Tu ◽  
Duyan Ta ◽  
Zhong-Lin Lu ◽  
Yalin Wang
Keyword(s):  
Signal To Noise Ratio ◽  
Accurate Analysis ◽  
Visual Neuroscience ◽  
Retinotopic Mapping ◽  
Retinotopic Maps ◽  
Topological Condition ◽  
Visual Inputs ◽  
Human Connectome Project ◽  
Cortical Responses ◽  
Cortical Regions

Retinotopic mapping, i.e., the mapping between visual inputs on the retina and neuronal activations in cortical visual areas, is one of the central topics in visual neuroscience. For human observers, the mapping is obtained by analyzing functional magnetic resonance imaging (fMRI) signals of cortical responses to slowly moving visual stimuli on the retina. Although it is well known from neurophysiology that the mapping is topological (i.e., the topology of neighborhood connectivity is preserved) within each visual area, retinotopic maps derived from the state-of-the-art methods are often not topological because of the low signal-to-noise ratio and spatial resolution of fMRI. The violation of topological condition is most severe in cortical regions corresponding to the neighborhood of the fovea (e.g., < 1 degree eccentricity in the Human Connectome Project (HCP) dataset), significantly impeding accurate analysis of retinotopic maps. This study aims to directly model the topological condition and generate topology-preserving and smooth retinotopic maps. Specifically, we adopted the Beltrami coefficient, a metric of quasiconformal mapping, to define the topological condition, developed a mathematical model to quantify topological smoothing as a constrained optimization problem, and elaborated an efficient numerical method to solve the problem. The method was then applied to V1, V2, and V3 simultaneously in the HCP dataset. Experiments with both simulated and real retinotopy data demonstrated that the proposed method could generate topological and smooth retinotopic maps.

scholarly journals Functional dissociation of stimulus intensity encoding and predictive coding of pain in the insula

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Stephan Geuter ◽  
Sabrina Boll ◽  
Falk Eippert ◽  
Christian Büchel
Keyword(s):  
Stimulus Intensity ◽  
Pain Perception ◽  
Predictive Coding ◽  
Pain Processing ◽  
Prediction Errors ◽  
Response Patterns ◽  
Unified Framework ◽  
Posterior Insula ◽  
Cortical Regions ◽  
Pain Stimuli

The computational principles by which the brain creates a painful experience from nociception are still unknown. Classic theories suggest that cortical regions either reflect stimulus intensity or additive effects of intensity and expectations, respectively. By contrast, predictive coding theories provide a unified framework explaining how perception is shaped by the integration of beliefs about the world with mismatches resulting from the comparison of these beliefs against sensory input. Using functional magnetic resonance imaging during a probabilistic heat pain paradigm, we investigated which computations underlie pain perception. Skin conductance, pupil dilation, and anterior insula responses to cued pain stimuli strictly followed the response patterns hypothesized by the predictive coding model, whereas posterior insula encoded stimulus intensity. This novel functional dissociation of pain processing within the insula together with previously observed alterations in chronic pain offer a novel interpretation of aberrant pain processing as disturbed weighting of predictions and prediction errors.

scholarly journals Heartbeat evokes a dynamically changing cortical theta-synchronized network in the resting state

2019 ◽  
Author(s):  
Jaejoong Kim ◽  
Bumseok Jeong
Keyword(s):  
Resting State ◽  
Phase Synchronization ◽  
Human Subjects ◽  
Predictive Coding ◽  
Regional Level ◽  
Human Connectome Project ◽  
Cortical Responses ◽  
Theta Frequency ◽  
Theta Phase ◽  
Cortical Regions

AbstractIn the resting state, heartbeats evoke cortical responses called heartbeat-evoked responses (HERs). While previous studies reported regional level HERs, researchers have not determined how heartbeat is processed at the cortical network level. Using resting-state magnetoencephalography data from 87 human subjects of both genders provided by the Human Connectome Project, we first showed that heartbeat increases the phase synchronization between cortical regions in the theta frequency, which forms a network structure, and we called this network a heartbeat-evoked network (HEN). The HEN was not an artefactual increase in phase synchronization. The HEN was partitioned into three modules with connector hubs in each module. The first module contained major interoception-related regions and thus was called a visceromotor-interoceptive network (VIN) displaying the strongest synchronization among modules, suggesting a major role for the VIN in processing heartbeat information. Two modules contained regions involved in the default mode network (DMN). The HEN structure was not fixed, but dynamically changed. The most prominent change was observed at approximately 200 ms after R-peak of the electrocardiogram, which was quantified based on the ‘flexibility’ of the network. Furthermore, the strongest synchronization within VIN was observed before heartbeat stimulated the cortex, which might be related to the prediction of an afferent heartbeat signal, thus supporting an interoceptive coding framework. Based on our results, the heartbeat is processed at the network level, and this result provides a useful framework that may potentially explain previous results of the regional level HER modulation through network-level processing.Significance statementThe resting-state network is composed of several networks supporting different functions. However, although the heartbeat is processed in the cortical regions, even in the resting state, the network supporting this function is unknown. Thus, we identified and investigated the heartbeat-evoked network (HEN), a network composed of significantly increased theta-phase synchronization between cortical regions after a heartbeat. The HEN comprised three modules. In particularly, the visceromotor-interoceptive network was likely to play a major role in network-level heartbeat processing and displayed the strongest synchronization immediately before the heartbeat enters the CNS, which supports an interoceptive predictive coding framework. These results provide a novel framework that may improve our understanding of cortical heartbeat processing from a network perspective.

scholarly journals Parcellation of motor sequence representations in the human neocortex

2018 ◽  
Author(s):  
Atsushi Yokoi ◽  
Jörn Diedrichsen
Keyword(s):  
Activity Patterns ◽  
Motor Sequence ◽  
Finger Movements ◽  
Unique Representation ◽  
Human Neocortex ◽  
Model Free ◽  
Sequence Production ◽  
Cortical Regions ◽  
Parietal Cortices

AbstractWhile previous studies have revealed an extended network of cortical regions associated with motor sequence production, the specific role of each of these areas is still elusive. To address this issue, we designed a novel behavioural paradigm that allowed us to experimentally manipulate the structure of motor sequences representations in individual participants. We then conducted fMRI while participants executed 8 trained sequences to examine how this structure is reflected in the associated activity patterns. Both model-based and model-free approaches revealed a clear distinction between primary and non-primary motor cortices in their representational contents, with M1 specifically representing individual finger movements, and premotor and parietal cortices showing a mixture of chunk, sequence and finger transition representations. Using model-free representational parcellation, we could divide these non-primary motor cortices into separate clusters, each with a unique representation along the stimulus-to-action gradient. These results provide new insights into how human neocortex organizes movement sequences.

scholarly journals Oscillatory Characteristics of Nociceptive Responses in the SII Cortex

2008 ◽  
Vol 35 (5) ◽  
pp. 630-637 ◽  
Author(s):  
Fu-Jung Hsiao ◽  
Wei-Ta Chen ◽  
Kwong-Kum Liao ◽  
Zin-An Wu ◽  
Low-Tone Ho ◽  
...  
Keyword(s):  
Statistical Power ◽  
Stimulus Onset ◽  
Pain Level ◽  
Thulium Laser ◽  
Current Dipole ◽  
Left Hand ◽  
Power Difference ◽  
Nociceptive Responses ◽  
Cortical Responses ◽  
Pain Stimuli

Objective:This study is aimed to explore the frequency characteristics of pain-evoked neuromagnetic responses in the secondary somatosensory (SII) cortices.Methods:Thulium-laser nociceptive stimuli to the left hand dorsum of 10 right-handed healthy adults. The pain stimuli were rated as mild, moderate, and severe levels according to subjects' reports on a 10-point visual analog scale. We analyzed their cortical responses with wavelet-based frequency analyses and equivalent current dipole (ECD) modeling.Results:For each pain level, we found an increase of theta (4-8 Hz) and alpha (8-13 Hz) power in bilateral SII areas at 180-210 ms after stimulus onset. The power was larger for the moderate than for the mild pain level (p < 0.05), but there was no statistical power difference of these oscillations between moderate and severe pain stimulus conditions (p = 0.7). Within the SII area, we did not observe particular difference in theta and alpha ECD locations between varying pain level conditions.Conclusions:The 4-13 Hz activities, peaking from 180 to 210 ms, are oscillatory correlates of SII activation in response to nociceptive stimulation, but their power may code the magnitude of pain stimuli only up to moderate level, as rated subjectively. This measure could be potentially used to evaluate SII activation in further pain studies.

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