scholarly journals Neural dynamics of illusory tactile pulling sensations

2021 ◽  
Author(s):  
Jack De Havas ◽  
Sho Ito ◽  
Sven Bestmann ◽  
Hiroaki Gomi

The sensation of directional forces and their associated sensorimotor commands are inextricably intertwined, complicating the identification of brain circuits responsible for tactile pulling sensations. One hypothesis is that, like tactile frequency discrimination, pulling sensations are generated by early sensory-frontal activity. Alternatively, they may be generated later in the somatosensory association cortex. To dissociate these accounts and uncouple the pulling sensation from unrelated but correlated sensory and motor processing, we combined high-density EEG with an oddball paradigm and asymmetric vibration, which creates an illusory sensation of the hand being directionally pulled. Oddballs that created a pulling sensation in the opposite direction to common stimuli were compared to the same oddballs in the context of neutral common stimuli (symmetric vibration) and to neutral oddballs. Brain responses to having directional pulling expectations violated by directional stimuli were therefore isolated. Contrary to the sensory-frontal account, frontal N140 brain activity was actually larger for neutral than pulling oddballs. Instead, pulling sensations were associated with amplitude and latency modulations of midline P200 and P3b potentials, and specifically, to contralateral parietal lobe activity 280ms post-stimulus. The timing of this activity suggested pulling sensations involve spatial processing, such as tactile remapping between coordinate frames. Source localization showed this activity to be centered on the postcentral sulcus, superior parietal lobule and intraparietal sulcus, suggesting that pulling sensations arise via the processing of body position, tactile orientation and peripersonal space. Our results demonstrate how tactile illusions can uniquely disambiguate parietal contributions to somatosensation by removing unrelated sensory processing.

2020 ◽  
Author(s):  
Julia Moser ◽  
Franziska Schleger ◽  
Magdalene Weiss ◽  
Katrin Sippel ◽  
Lorenzo Semeia ◽  
...  

AbstractThe concept of fetal consciousness is a widely discussed topic. In this study, we applied a hierarchical rule learning paradigm to investigate the possibility of fetal conscious processing during the last trimester of pregnancy. We used fetal magnetoencephalography, to assess fetal brain activity in 56 healthy fetuses between gestational week 25 and 40, during an auditory oddball paradigm containing first- and second-order regularities. The comparison of fetal brain responses towards standard and deviant tones revealed that fetuses show signs of hierarchical rule learning, and thus the formation of a memory trace for the second-order regularity. This ability develops over the course of the last trimester of gestation, in accordance with processes in physiological brain development. On the whole, our results support the assumption that fetuses are capable of consciously processing stimuli that reach them from outside the womb.


2019 ◽  
Author(s):  
Kendra Oudyk ◽  
Iballa Burunat ◽  
Elvira Brattico ◽  
Petri Toiviainen

AbstractWhether and how personality traits explain the individual variance in neural responses to emotion in music remains unclear. The sparse studies on this topic report inconsistent findings. The present study extends previous work using regions of variance (ROVs) as regions of interest, compared with whole-brain analysis. Fifty-five subjects listened to happy, sad, and fearful music during functional Magnetic Resonance Imaging. Personality was measured with the Big Five Questionnaire. Results confirmed previous observations of Neuroticism being positively related to activation during sad music, in the left inferior parietal lobe. In an exploratory analysis, Openness was positively related to activation during Happy music in an extended cluster in auditory areas, primarily including portions of the left Heschl’s gyrus, superior and middle temporal gyri, supramarginal gyrus, and Rolandic operculum. In the whole-brain analysis, similar results were found for Neuroticism but not for Openness. In turn, we did not replicate previous findings of Extraversion associated to activity during happy music, nor Neuroticism during fearful music. These results support a trait-congruent link between personality and emotion-elicited brain activity, and further our understanding of the action-observation network during emotional music listening. This study also indicates the usefulness of the ROV method in individual-differences research.


2010 ◽  
Vol 24 (2) ◽  
pp. 76-82 ◽  
Author(s):  
Martin M. Monti ◽  
Adrian M. Owen

Recent evidence has suggested that functional neuroimaging may play a crucial role in assessing residual cognition and awareness in brain injury survivors. In particular, brain insults that compromise the patient’s ability to produce motor output may render standard clinical testing ineffective. Indeed, if patients were aware but unable to signal so via motor behavior, they would be impossible to distinguish, at the bedside, from vegetative patients. Considering the alarming rate with which minimally conscious patients are misdiagnosed as vegetative, and the severe medical, legal, and ethical implications of such decisions, novel tools are urgently required to complement current clinical-assessment protocols. Functional neuroimaging may be particularly suited to this aim by providing a window on brain function without requiring patients to produce any motor output. Specifically, the possibility of detecting signs of willful behavior by directly observing brain activity (i.e., “brain behavior”), rather than motoric output, allows this approach to reach beyond what is observable at the bedside with standard clinical assessments. In addition, several neuroimaging studies have already highlighted neuroimaging protocols that can distinguish automatic brain responses from willful brain activity, making it possible to employ willful brain activations as an index of awareness. Certainly, neuroimaging in patient populations faces some theoretical and experimental difficulties, but willful, task-dependent, brain activation may be the only way to discriminate the conscious, but immobile, patient from the unconscious one.


2021 ◽  
pp. 1-29
Author(s):  
Kangyu Jin ◽  
Zhe Shen ◽  
Guoxun Feng ◽  
Zhiyong Zhao ◽  
Jing Lu ◽  
...  

Abstract Objective: A few former studies suggested there are partial overlaps in abnormal brain structure and cognitive function between Hypochondriasis (HS) and schizophrenia (SZ). But their differences in brain activity and cognitive function were unclear. Methods: 21 HS patients, 23 SZ patients, and 24 healthy controls (HC) underwent Resting-state functional magnetic resonance imaging (rs-fMRI) with the regional homogeneity analysis (ReHo), subsequently exploring the relationship between ReHo value and cognitive functions. The support vector machines (SVM) were used on effectiveness evaluation of ReHo for differentiating HS from SZ. Results: Compared with HC, HS showed significantly increased ReHo values in right middle temporal gyrus (MTG), left inferior parietal lobe (IPL) and right fusiform gyrus (FG), while SZ showed increased ReHo in left insula, decreased ReHo values in right paracentral lobule. Additionally, HS showed significantly higher ReHo values in FG, MTG and left paracentral lobule but lower in insula than SZ. The higher ReHo values in insula were associated with worse performance in MCCB in HS group. SVM analysis showed a combination of the ReHo values in insula and FG was able to satisfactorily distinguish the HS and SZ patients. Conclusion: our results suggested the altered default mode network (DMN), of which abnormal spontaneous neural activity occurs in multiple brain regions, might play a key role in the pathogenesis of HS, and the resting-state alterations of insula closely related to cognitive dysfunction in HS. Furthermore, the combination of the ReHo in FG and insula was a relatively ideal indicator to distinguish HS from SZ.


2018 ◽  
Vol 314 (5) ◽  
pp. E522-E529 ◽  
Author(s):  
Renata Belfort-DeAguiar ◽  
Dongju Seo ◽  
Cheryl Lacadie ◽  
Sarita Naik ◽  
Christian Schmidt ◽  
...  

Blood glucose levels influence brain regulation of food intake. This study assessed the effect of mild physiological hyperglycemia on brain response to food cues in individuals with obesity (OB) versus normal weight individuals (NW). Brain responses in 10 OB and 10 NW nondiabetic healthy adults [body mass index: 34 (3) vs. 23 (2) kg/m2, means (SD), P < 0.0001] were measured with functional MRI (blood oxygen level-dependent contrast) in combination with a two-step normoglycemic-hyperglycemic clamp. Participants were shown food and nonfood images during normoglycemia (~95 mg/dl) and hyperglycemia (~130 mg/dl). Plasma glucose levels were comparable in both groups during the two-step clamp ( P = not significant). Insulin and leptin levels were higher in the OB group compared with NW, whereas ghrelin levels were lower (all P < 0.05). During hyperglycemia, insula activity showed a group-by-glucose level effect. When compared with normoglycemia, hyperglycemia resulted in decreased activity in the hypothalamus and putamen in response to food images ( P < 0.001) in the NW group, whereas the OB group exhibited increased activity in insula, putamen, and anterior and dorsolateral prefrontal cortex (aPFC/dlPFC; P < 0.001). These data suggest that OB, compared with NW, appears to have disruption of brain responses to food cues during hyperglycemia, with reduced insula response in NW but increased insula response in OB, an area involved in food perception and interoception. In a post hoc analysis, brain activity in obesity appears to be associated with dysregulated motivation (striatum) and inappropriate self-control (aPFC/dlPFC) to food cues during hyperglycemia. Hyperstimulation for food and insensitivity to internal homeostatic signals may favor food consumption to possibly play a role in the pathogenesis of obesity.


2020 ◽  
Author(s):  
Matthew F. Singh ◽  
Anxu Wang ◽  
Michael Cole ◽  
ShiNung Ching ◽  
Todd S. Braver

AbstractBrain responses recorded during fMRI are thought to reflect both rapid, stimulus-evoked activity and the propagation of spontaneous activity through brain networks. In the current work we describe a method to improve the estimation of task-evoked brain activity by first “filtering-out” the intrinsic propagation of pre-event activity from the BOLD signal. We do so using Mesoscale Individualized NeuroDynamic (MINDy; [1]) models built from individualized resting-state data (MINDy-based Filtering). After filtering, time-series are analyzed using conventional techniques. Results demonstrate that this simple operation significantly improves the statistical power and temporal precision of estimated group-level effects. Moreover, estimates based upon our technique better generalize between tasks measuring the same construct (cognitive control) and better predict individual differences in behavior. Thus, by subtracting the propagation of previous activity, we obtain better estimates of task-related neural activity.


2003 ◽  
Vol 90 (2) ◽  
pp. 1279-1294 ◽  
Author(s):  
Ralph M. Siegel ◽  
Milena Raffi ◽  
Raymond E. Phinney ◽  
Jessica A. Turner ◽  
Gábor Jandó

In the behaving monkey, inferior parietal lobe cortical neurons combine visual information with eye position signals. However, an organized topographic map of these neurons' properties has never been demonstrated. Intrinsic optical imaging revealed a functional architecture for the effect of eye position on the visual response to radial optic flow. The map was distributed across two subdivisions of the inferior parietal lobule, area 7a and the dorsal prelunate area, DP. Area 7a contains a representation of the lower eye position gain fields while area DP represents the upper eye position gain fields. Horizontal eye position is represented orthogonal to the vertical eye position across the medial lateral extents of the cortices. Similar topographies were found in three hemispheres of two monkeys; the horizontal and vertical gain field representations were not isotropic with a greater modulation found with the vertical. Monte Carlo methods demonstrated the significance of the maps, and they were verified in part using multiunit recordings. The novel topographic organization of this association cortex area provides a substrate for constructing representations of surrounding space for perception and the guidance of motor behaviors.


1992 ◽  
Vol 12 (4) ◽  
pp. 546-553 ◽  
Author(s):  
Steven Warach ◽  
Ruben C. Gur ◽  
Raquel E. Gur ◽  
Brett E. Skolnick ◽  
Walter D. Obrist ◽  
...  

We previously reported decreased mean CBF between consecutive resting conditions, ascribed to habituation. Here we address the regional specificity of habituation over three consecutive flow studies. Regional CBF (rCBF) was measured in 55 adults (12 right-handed men, 12 right-handed women, 14 left-handed men, 17 left-handed women), with the 133Xe inhalation technique, during three conditions: Resting, verbal tasks (analogies), and spatial tasks (line orientation). Changes in rCBF attributable to the cognitive tasks were eliminated by correcting these values to a resting equivalent. There was a progressive decrease in mean rCBF over time, reflecting habituation. This effect differed by region, with specificity at frontal (prefrontal, inferior frontal, midfrontal, superior frontal) and inferior parietal regions. In the inferior parietal region, habituation was more marked in the left than the right hemisphere. Right-handers showed greater habituation than did left-handers. There was no sex difference in global habituation, but males showed greater left whereas females showed greater right hemispheric habituation. The results suggest that habituation to the experimental setting has measurable effects on rCBF, which are differently lateralized for men and women. These effects are superimposed on task activation and are most pronounced in regions that have been implicated in attentional processes. Thus, regional decrement in brain activity related to habituation seems to complement attentional effects, suggesting a neural network for habituation reciprocating that for attention.


2009 ◽  
Vol 21 (10) ◽  
pp. 2007-2018 ◽  
Author(s):  
Marcus Meinzer ◽  
Tobias Flaisch ◽  
Lotte Wilser ◽  
Carsten Eulitz ◽  
Brigitte Rockstroh ◽  
...  

As we age, our ability to select and to produce words changes, yet we know little about the underlying neural substrate of word-finding difficulties in old adults. This study was designed to elucidate changes in specific frontally mediated retrieval processes involved in word-finding difficulties associated with advanced age. We implemented two overt verbal (semantic and phonemic) fluency tasks during fMRI and compared brain activity patterns of old and young adults. Performance during the phonemic task was comparable for both age groups and mirrored by strongly left-lateralized (frontal) activity patterns. On the other hand, a significant drop of performance during the semantic task in the older group was accompanied by additional right (inferior and middle) frontal activity, which was negatively correlated with performance. Moreover, the younger group recruited different subportions of the left inferior frontal gyrus for both fluency tasks, whereas the older participants failed to show this distinction. Thus, functional integrity and efficient recruitment of left frontal language areas seems to be critical for successful word retrieval in old age.


Author(s):  
Lisa Yang ◽  
Lysia Demetriou ◽  
Matthew B Wall ◽  
Edouard G Mills ◽  
Victoria C Wing ◽  
...  

Abstract Context The hormone kisspeptin has crucial and well-characterized roles in reproduction. Emerging data from animal models also suggest that kisspeptin has important metabolic effects including modulation of food intake. However, to date there have been no studies exploring the effects of kisspeptin on brain responses to food stimuli in humans. Objective This work aims to investigate the effects of kisspeptin administration on brain responses to visual food stimuli and psychometric parameters of appetite, in healthy men. Design A double-blinded, randomized, placebo-controlled, crossover study was conducted. Participants Participants included 27 healthy, right-handed, eugonadal men (mean ± SEM: age 26.5 ± 1.1 years; body mass index 23.9 ± 0.4 kg/m2). Intervention Participants received an intravenous infusion of 1 nmol/kg/h of kisspeptin or rate-matched vehicle over 75 minutes. Main Outcome Measures Measurements included change in brain activity on functional magnetic resonance imaging in response to visual food stimuli and change in psychometric parameters of appetite, during kisspeptin administration compared to vehicle. Results Kisspeptin administration at a bioactive dose did not affect brain responses to visual food stimuli or psychometric parameters of appetite compared to vehicle. Conclusions This is the first study in humans investigating the effects of kisspeptin on brain regions regulating appetite and demonstrates that peripheral administration of kisspeptin does not alter brain responses to visual food stimuli or psychometric parameters of appetite in healthy men. These data provide key translational insights to further our understanding of the interaction between reproduction and metabolism.


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