scholarly journals Cortico-motor control dynamics orchestrates visual sampling

2020 ◽  
Author(s):  
Alice Tomassini ◽  
Eric Maris ◽  
Pauline Hilt ◽  
Luciano Fadiga ◽  
Alessandro D’Ausilio

AbstractMovements overtly sample sensory information, making sensory analysis an active-sensing process. In this study, we show that visual information sampling is not just locked to the (overt) movement dynamics, but it is structured by the internal (covert) dynamics of cortico-motor control. We asked human participants to perform an isometric motor task – based on proprioceptive feedback – while detecting unrelated near-threshold visual stimuli. The motor output (Force) shows zero-lag coherence with brain activity (recorded via electroencephalography) in the beta-band, as previously reported. In contrast, cortical rhythms in the alpha-band systematically forerun the motor output by 200ms. Importantly, visual detection is facilitated when cortico-motor alpha (not beta) synchronization is enhanced immediately before stimulus onset, namely at the optimal phase relationship for sensorimotor communication. These findings demonstrate an automatic gating of visual inputs by the ongoing motor control processes, providing evidence of an internal and alpha-cycling visuomotor loop.

2020 ◽  
Author(s):  
Mireia Torralba ◽  
Alice Drew ◽  
Alba Sabaté San José ◽  
Luis Morís Fernández ◽  
Salvador Soto-Faraco

AbstractEndogenous brain processes play a paramount role in shaping up perceptual phenomenology, as illustrated by the alternations experienced by humans (and other animals) when watching perceptually ambiguous, static images. Here, we hypothesised that endogenous alpha fluctuations in the visual cortex pace the accumulation of sensory information leading to perceptual outcomes. We addressed this hypothesis using binocular rivalry combined with visual entrainment and electroencephalography in humans (42 female, 40 male). The results revealed a correlation between the individual frequency of alpha oscillations in the occipital cortex and perceptual alternation rates experienced during binocular rivalry. In subsequent experiments we show that regulating endogenous brain activity via entrainment produced corresponding changes in perceptual alternation rate, which were observed only in the alpha range but not at lower entrainment frequencies. Overall, rhythmic alpha stimulation resulted in faster perceptual alternation rates, compared to arrhythmic or no stimulation. These findings support the notion that visual information is accumulated via alpha cycles to promote the emergence of conscious perceptual representations. We suggest that models of binocular rivalry incorporating posterior alpha as a pacemaker can provide an important advance in the comprehension of the dynamics of visual awareness.Significance statementMainstream theories in cognitive neuroscience agree that endogenous brain processes play a paramount role in shaping our perceptual experience of sensory inputs. In vision, endogenous fluctuations in the alpha rhythm have been pointed out to regulate visual inputs to perception. In support of this hypothesis, here we used EEG recordings and visual entrainment to demonstrate that inter-individual differences in the speed of endogenous alpha fluctuations in the brain are causally related to the accrual of visual information to awareness. These findings provide, for the first time, evidence for alpha-gated regulation of the dynamics of alternations in conscious visual perception.


Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2461
Author(s):  
Alexander Kuc ◽  
Vadim V. Grubov ◽  
Vladimir A. Maksimenko ◽  
Natalia Shusharina ◽  
Alexander N. Pisarchik ◽  
...  

Perceptual decision-making requires transforming sensory information into decisions. An ambiguity of sensory input affects perceptual decisions inducing specific time-frequency patterns on EEG (electroencephalogram) signals. This paper uses a wavelet-based method to analyze how ambiguity affects EEG features during a perceptual decision-making task. We observe that parietal and temporal beta-band wavelet power monotonically increases throughout the perceptual process. Ambiguity induces high frontal beta-band power at 0.3–0.6 s post-stimulus onset. It may reflect the increasing reliance on the top-down mechanisms to facilitate accumulating decision-relevant sensory features. Finally, this study analyzes the perceptual process using mixed within-trial and within-subject design. First, we found significant percept-related changes in each subject and then test their significance at the group level. Thus, observed beta-band biomarkers are pronounced in single EEG trials and may serve as control commands for brain-computer interface (BCI).


2021 ◽  
Author(s):  
Robert Law ◽  
Sarah Pugliese ◽  
Hyeyoung Shin ◽  
Danielle D. Sliva ◽  
Shane Lee ◽  
...  

Transient neocortical events with high spectral power in the 15-29Hz beta band are among the most reliable predictors of sensory perception. Prestimulus beta event rates in primary somatosensory cortex correlate with sensory suppression, most effectively 100-300ms before stimulus onset. However, the neural mechanisms underlying this perceptual association are unknown. We combined human magnetoencephalography (MEG) measurements with biophysical neural modeling to test potential cellular and circuit mechanisms that underlie observed correlations between prestimulus beta events and tactile detection. Extending prior studies, we found that simulated bursts from higher-order, non-lemniscal thalamus were sufficient to drive beta event generation and to recruit slow supragranular inhibition acting on a 300ms time scale to suppress sensory information. Further analysis showed that the same beta generating mechanism can lead to facilitated perception for a brief period when beta events occur simultaneously with tactile stimulation before inhibition is recruited. These findings were supported by close agreement between model-derived predictions and empirical MEG data. The post-event suppressive mechanism explains an array of studies that associate beta with decreased processing, while the during-event faciliatory mechanism may demand a reinterpretation of the role of beta events in the context of coincident timing.


2019 ◽  
Author(s):  
Mohamed Abdelhack ◽  
Yukiyasu Kamitani

AbstractVisual recognition involves integrating visual information with other sensory information and prior knowledge. In accord with Bayesian inference under conditions of unreliable visual input, the brain relies on the prior as a source of information to achieve the inference process. This drives a top-down process to improve the neural representation of visual input. However, the extent to which non-stimulus-driven top-down information affects processing in the ventral stream is still unclear. We conducted a perceptual decision-making task using blurred images, while conducting functional magnetic resonance imaging. We then transformed brain activity into deep neural network features to distinguish bottom-up and top-down signals. We found that top-down information unrelated to the stimulus had a minimal effect on lower-level visual processes. The neural representations of degraded stimuli that were misrecognized were still correlated with the correct object category in the lower levels of processing. In contrast, activity in the higher cognitive areas was more strongly correlated with recognition reported by the subjects. The results indicated a discrepancy between the results of processing at the lower and higher levels, indicating the existence of a stimulus-independent top-down signal flowing back down the hierarchy. These findings suggest that integration between bottom-up and top-down information takes the form of competing evidence in higher visual areas between prior-driven top-down and stimulus-driven bottom-up signals. These findings could provide important insight into the different modes of integration of neural signals in the visual cortex that contribute to the visual inference process.


2020 ◽  
Author(s):  
Leila Reddy ◽  
Radoslaw Martin Cichy ◽  
Rufin VanRullen

AbstractNumerous theories propose a key role for brain oscillations in visual perception. Most of these theories postulate that sensory information is encoded in specific oscillatory components (e.g., power or phase) of specific frequency bands. These theories are often tested with whole-brain recording methods of low spatial resolution (EEG or MEG), or depth recordings that provide a local, incomplete view of the brain. Opportunities to bridge the gap between local neural populations and whole-brain signals are rare. Here, using representational similarity analysis we ask which MEG oscillatory components (power and phase, across various frequency bands) correspond to low or high-level visual object representations, using brain representations from fMRI, or layer-wise representations in Deep Neural Networks (DNNs) as a template for low/high-level object representations. The results showed that around stimulus onset and offset, most transient oscillatory signals correlated with low-level brain patterns (V1). During stimulus presentation, sustained beta (∼20Hz) and gamma (>60Hz) power best correlated with V1, while oscillatory phase components correlated with IT representations. Surprisingly, this pattern of results did not always correspond to low- or high-level DNN layer activity. In particular, sustained beta-band oscillatory power reflected high-level DNN layers, suggestive of a feed-back component. These results begin to bridge the gap between whole-brain oscillatory signals and object representations supported by local neuronal activations.


2020 ◽  
Vol 8 (4_suppl3) ◽  
pp. 2325967120S0018
Author(s):  
Jed A. Diekfuss ◽  
Dustin R. Grooms ◽  
Robert C. Coghill ◽  
Katharine S. Nissen ◽  
Anna J. Saltman ◽  
...  

Background: Patellofemoral pain (PFP) is a chronic knee condition that affects over 1 in 4 physically-active girls. PFP symptomology contributes to dysfunctional motor control and heightened kinesiophobia (i.e., fear of pain/movement). Both chronic pain and kinesiophobia induce substantial changes throughout the central nervous system (CNS) in many populations who experience pain (e.g., low back pain), but such relationships have not been explored in pediatric patients with PFP. As current treatment approaches for PFP generally fail to provide complete symptom mitigation, identifying the mechanisms by which kinesiophobia exacerbate PFP and disrupt the CNS could provide mechanistic neural pathways to guide novel, brain-based treatments for pain relief. Hypothesis/Purpose: The purpose of this study was to determine the relationship between kinesiophobia and brain functional activation during a knee motor control task in pediatric patients with PFP. Methods: Girls clinically diagnosed with PFP ( n = 15; 14.3 ± 3.2 yrs) were positioned supine in a 3 Tesla magnetic resonance imaging (MRI) scanner and completed a series of unilateral 45° knee extension/flexion movements during functional MRI (fMRI). Patients completed this open kinetic chain movement at a frequency of 1.2 Hz (Figure 1.1). Patients also completed the Tampa Scale of Kinesiophobia (TSK; scores range from 0 – 68, with scores greater than 37 indicating high kinesiophobia). Correlation analyses were performed to determine whether kinesiophobia was associated with brain activity during the motor task. Statistical corrections were made to account for multiple, voxel-wise comparisons. Results: Study patients exhibited high kinesiophobia, with a mean TSK score of 38.27 (SD = 5.79). Neuroimaging analyses revealed that greater kinesiophobia was directly associated with increased brain activity in a cluster located within the occipital pole/cuneus, supracalcarine cortex, and intracalcarine cortex (p < .001, z-max = 4.30; Figure 1). Conclusion: The results revealed that the degree of kinesiophobia was related to the magnitude of visual-related brain activity for knee motor control. As perceived fear of movement increases, patients with PFP may recruit additional visual resources to compensate for pain-disrupted somatosensory processing. Future interventions that promote sensorimotor engagement and reduce visual feedback for motor control (i.e., dynamic movements with occluded vision) may be beneficial to reorganize neural processes, decrease kinesiophobia, and restore an active lifestyle in young girls with PFP. Tables/Figures: [Figure: see text]


2020 ◽  
Author(s):  
Nicola Meda ◽  
Giulio M. Menti ◽  
Aram Megighian ◽  
Mauro A. Zordan

ABSTRACTAnimals rely on multiple sensory information systems to make decisions. The integration of information stemming from these systems is believed to result in a precise behavioural output. To what degree a single sensory system may override the others is unknown. Evidence for a hierarchical use of different systems to guide navigation is lacking. We used Drosophila melanogaster to investigate whether, in order to relieve an unpleasant stimulation, fruit flies employed an idiothetically-based local search strategy before making use of visual information, or viceversa. Fruit flies appear to initially resort to idiothetic information and only later, if the first strategy proves unsuccessful to relieve the unpleasant stimulation, make use of other information, such as visual cues. By leveraging on this innate preference for a hierarchical use of one strategy over another, we believe that in vivo recordings of brain activity during the navigation of fruit flies could provide mechanistic insights into how simultaneous information from multiple sensory modalities is evaluated, integrated, and motor responses elicited, thus shedding new light on the neural basis of decision-making.


2021 ◽  
Vol 7 (13) ◽  
pp. eabe8212
Author(s):  
Sage E. P. Boettcher ◽  
Daniela Gresch ◽  
Anna C. Nobre ◽  
Freek van Ede

Working memory serves as the buffer between past sensations and future behavior, making it vital to understand not only how we encode and retain sensory information in memory but also how we plan for its upcoming use. We ask when prospective action goals emerge alongside the encoding and retention of visual information in working memory. We show that prospective action plans do not emerge gradually during memory delays but are brought into memory early, in tandem with sensory encoding. This action encoding (i) precedes a second stage of action preparation that adapts to the time of expected memory utilization, (ii) occurs even ahead of an intervening motor task, and (iii) predicts visual memory–guided behavior several seconds later. By bringing prospective action plans into working memory at an early stage, the brain creates a dual (visual-motor) memory code that can make memories more effective and robust for serving ensuing behavior.


2021 ◽  
Vol 15 ◽  
Author(s):  
Charidimos Tzagarakis ◽  
Sarah West ◽  
Giuseppe Pellizzer

Visual information about the location of an upcoming target can be used to prepare an appropriate motor response and reduce its reaction time. Here, we investigated the brain mechanisms associated with the reliability of directional information used for motor preparation. We recorded brain activity using magnetoencephalography (MEG) during a delayed reaching task in which a visual cue provided valid information about the location of the upcoming target with 50, 75, or 100% reliability. We found that reaction time increased as cue reliability decreased and that trials with invalid cues had longer reaction times than trials with valid cues. MEG channel analysis showed that during the late cue period the power of the beta-band from left mid-anterior channels, contralateral to the responding hand, correlated with the reliability of the cue. This effect was source localized over a large motor-related cortical and subcortical network. In addition, during invalid-cue trials there was a phasic increase of theta-band power following target onset from left posterior channels, localized to the left occipito-parietal cortex. Furthermore, the theta-beta cross-frequency coupling between left mid-occipital and motor cortex transiently increased before responses to invalid-cue trials. In conclusion, beta-band power in motor-related areas reflected the reliability of directional information used during motor preparation, whereas phasic theta-band activity may have signaled whether the target was at the expected location or not. These results elucidate mechanisms of interaction between attentional and motor processes.


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.


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