Actual and Imagined Movements Reveal a Dual Role of the Insular Cortex for Motor Control

2020 ◽  
Author(s):  
Célia Rousseau ◽  
Marie Barbiero ◽  
Thierry Pozzo ◽  
Charalambos Papaxanthis ◽  
Olivier White
Keyword(s):  
Brain Area ◽  
Posterior Part ◽  
Internal Representation ◽  
Insular Cortex ◽  
Mental Simulation ◽  
Psychophysical Experiment ◽  
Vertical Movements ◽  
Feedback Mechanisms ◽  
Conceptual Link

Abstract Movements rely on a mixture of feedforward and feedback mechanisms. With experience, the brain builds internal representations of actions in different contexts. Many factors are taken into account in this process among which is the immutable presence of gravity. Any displacement of a massive body in the gravitational field generates forces and torques that must be predicted and compensated by appropriate motor commands. The insular cortex is a key brain area for graviception. However, no attempt has been made to address whether the same internal representation of gravity is shared between feedforward and feedback mechanisms. Here, participants either mentally simulated (only feedforward) or performed (feedforward and feedback) vertical movements of the hand. We found that the posterior part of the insular cortex was engaged when feedback was processed. The anterior insula, however, was activated only in mental simulation of the action. A psychophysical experiment demonstrates participants’ ability to integrate the effects of gravity. Our results point toward a dual internal representation of gravity within the insula. We discuss the conceptual link between these two dualities.

scholarly journals Gravity highlights a dual role of the insula in internal models

2019 ◽  
Author(s):  
Célia Rousseau ◽  
Marie Barbiero ◽  
Thierry Pozzo ◽  
Charalambos Papaxanthis ◽  
Olivier White
Keyword(s):  
Brain Area ◽  
Posterior Part ◽  
Internal Representation ◽  
Insular Cortex ◽  
Mental Simulation ◽  
Anterior Insula ◽  
Psychophysical Experiment ◽  
Vertical Movements ◽  
The Brain

AbstractMovements rely on a mixture of predictive and reactive mechanisms. With experience, the brain builds internal representations of actions in different contexts. Many factors are taken into account in this process among which the immutable presence of gravity. Any displacement of a massive body in the gravitational field generates forces and torques that must be predicted and compensated by appropriate motor commands. Studies have shown that the insular cortex is a key brain area for graviception. However, none attempted to address whether the same internal representation of gravity is shared between reactive and predictive mechanisms. Here, participants either mentally simulated (only predictive) or performed (predictive and reactive) vertical movements of the hand. We found that the posterior part of the insular cortex was engaged when feedback was processed. The anterior insula, however, was activated only in mental simulation of the action. A psychophysical experiment shows participants’ ability to integrate the effects of gravity. Our results demonstrate a dual internal representation of gravity within the insula and discuss how they can conceptually be linked.

Réponses évoquées par les mouvements oculaires d'exploration (réponse lambda): Rôle des afférences intervenant à divers moments du processus oculo-moteur

Perception ◽  
1972 ◽  
Vol 1 (2) ◽  
pp. 167-175 ◽  
Author(s):  
Nicole Lesèvre ◽  
A Rémond
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Visual Effects ◽  
Experimental Conditions ◽  
Initial Portion ◽  
Vertical Movements ◽  
Black Field ◽  
Fixation Points ◽  
Lambda Response

Experiments are reported the aim of which was to elucidate the cause of each of the components of the lambda response, and particularly to evaluate the role of ‘on’ and ‘off’ visual effects which appear at various times during the oculomotor process and also the possible influence of non-visual mechanisms. Eight subjects with normal sight were studied under the following conditions: (i) horizontal eye movements of 12° were guided by fixation points placed on a dimly-lit uniform black field of 20°; a checkerboard of 6° aperture was placed in this field so as to be integrated into the oculomotor process at different times—at the beginning, during and at the end of the eye movement; (ii) successive horizontal eye movements of 3°, 7° and 11° scanned a checkerboard of 20°, each square of which had a 40′ aperture; (iii) the checkerboard was moved with an amplitude and period similar to those of the eye movements in (ii), but this time with gaze fixed. Horizontal and vertical movements of both eyes were recorded with an EOG. An EEG of the parieto-occipital regions was obtained using eight linked bipolar derivations in line on two montages, median longitudinal and right-left transverse. The EEG and EOG data were digitalized and a numerical programme of waveform recognition was used to identify the beginning of the saccade which triggers the averaging out of the EEG before (100 ms) and after (500 ms) the eye movement. A discussion of the results, taking into account the latency of the different components and their reinforcements or inhibition depending on experimental conditions, suggests that the two initial components of lambda response (including the initial portion of the classical lambda wave) might be due to visual effects (‘off effect’) that arise at the start of the movement or slightly before it at the time that the saccadic suppression begins. The later components could be attributed to visual effects brought into play towards the end of the movement (‘on effect’), when perception becomes normal again. It is, however, difficult to explain some of the results related to the amplitude of lambda components without bringing in a mechanism of non-visual origin (corollary discharge).

The human cortical autonomic network and volitional exercise in health and disease

2018 ◽  
Vol 43 (11) ◽  
pp. 1122-1130 ◽  
Author(s):  
Baraa K. Al-Khazraji ◽  
J. Kevin Shoemaker
Keyword(s):  
Current Knowledge ◽  
Insular Cortex ◽  
Cardiovascular Control ◽  
Anterior Cingulate ◽  
Disease States ◽  
Autonomic Activation ◽  
Imaging Research ◽  
Health And Disease ◽  
Cortical Regions

The autonomic nervous system elicits continuous beat-by-beat homeostatic adjustments to cardiovascular control. These modifications are mediated by sensory inputs (e.g., baroreceptors, metaboreceptors, pulmonary, thermoreceptors, and chemoreceptors afferents), integration at the brainstem control centres (i.e., medulla), and efferent autonomic neural outputs (e.g., spinal, preganglionic, and postganglionic pathways). However, extensive electrical stimulation and functional imaging research show that the brain’s higher cortical regions (e.g., insular cortex, medial prefrontal cortex, anterior cingulate cortex) partake in homeostatic regulation of the cardiovascular system at rest and during exercise. We now appreciate that these cortical areas form a network, namely the “cortical autonomic network” (CAN), which operate as part of a larger central autonomic network comprising 2-way communication of cortical and subcortical areas to exert autonomic influence. Interestingly, differential patterns of CAN activity and ensuing cardiovascular control are present in disease states, thereby highlighting the importance of considering the role of CAN as an integral aspect of cardiovascular regulation in health and disease. This review discusses current knowledge on human cortical autonomic activation during volitional exercise, and the role of exercise training on this activation in both health and disease.

Hedgehog organises the pattern and polarity of epidermal cells in the Drosophila abdomen

Development ◽  
1997 ◽  
Vol 124 (11) ◽  
pp. 2143-2154 ◽  
Author(s):  
G. Struhl ◽  
D.A. Barbash ◽  
P.A. Lawrence
Keyword(s):  
Anterior Part ◽  
Posterior Part ◽  
Cell Types ◽  
Epidermal Cells ◽  
Concentration Gradients ◽  
Cell Pattern ◽  
Different Cell Types ◽  
Adult Drosophila

The abdomen of adult Drosophila, like that of other insects, is formed by a continuous epithelium spanning several segments. Each segment is subdivided into an anterior (A) and posterior (P) compartment, distinguished by activity of the selector gene engrailed (en) in P but not A compartment cells. Here we provide evidence that Hedgehog (Hh), a protein secreted by P compartment cells, spreads into each A compartment across the anterior and the posterior boundaries to form opposing concentration gradients that organize cell pattern and polarity. We find that anteriorly and posteriorly situated cells within the A compartment respond in distinct ways to Hh: they express different combinations of genes and form different cell types. They also form polarised structures that, in the anterior part, point down the Hh gradient and, in the posterior part, point up the gradient - therefore all structures point posteriorly. Finally, we show that ectopic Hh can induce cells in the middle of each A compartment to activate en. Where this happens, A compartment cells are transformed into an ectopic P compartment and reorganise pattern and polarity both within and around the transformed tissue. Many of these results are unexpected and lead us to reassess the role of gradients and compartments in patterning insect segments.

The role of mental simulation in food attractiveness

2021 ◽  
Author(s):  
Laura Jane Speed ◽  
Esther K. Papies ◽  
Asifa Majid
Keyword(s):  
Sensory Experience ◽  
Mental Simulation ◽  
Healthy Food ◽  
Unhealthy Food ◽  
Important Food ◽  
Everyday Cognition ◽  
Perceptual Modalities ◽  
Goal Directed Behavior ◽  
The Relationship

Concepts are grounded in sensorimotor simulations, but what role these simulations play in everyday cognition is unknown. We investigate one domain where the senses are especially important: food. Unhealthy food is typically considered tastier than healthy food, and is therefore more attractive. We explored to what extent sensory associations differ between healthy and unhealthy foods, and whether these differences affect food attractiveness. In Study 1, using existing sensorimotor norms (Lynott, Connell, Brysbaert, Brand, & Carney, 2020) we found that unhealthy food is more strongly associated with taste, smell, and interoception than healthy food. Furthermore, these enhanced sensory associations mediated the relationship between healthiness and attractiveness. In Study 2, when participants were presented only with food words, unhealthy foods were more strongly associated with all perceptual modalities than healthy food. Again, this association mediated the relationship between healthiness and attractiveness: unhealthy food is more attractive because it is more strongly associated with sensory experience. We also found that the role of sensory associations in food attractiveness is affected by context. When participants were instructed to imagine eating the food, mediation by perceptual strength was weaker compared to receiving no instruction. Our results suggest that sensory simulation explains why unhealthy food is more attractive than healthy food, implying sensory simulation has a role in goal-directed behavior.

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