Functional Magnetic Resonance Imaging Connectivity Analyses Reveal Efference-Copy to Primary Somatosensory Area, BA2

Abstract

Some theories of motor control suggest efference-copies of motor commands reach somatosensory cortices. Here we used functional magnetic resonance imaging to test these models. We varied the amount of efference-copy signal by making participants squeeze a soft material either actively or passively. We found electromyographical recordings, an efference-copy proxy, to predict activity in primary somatosensory regions, in particular Brodmann Area (BA) 2. Partial correlation analyses confirmed that brain activity in cortical structures associated with motor control (premotor and supplementary motor cortices, the parietal area PF and the cerebellum) predicts brain activity in BA2 without being entirely mediated by activity in early somatosensory (BA3b) cortex. Our study therefore provides valuable empirical evidence for efference-copy models of motor control, and shows that signals in BA2 can indeed reflect an input from motor cortices and suggests that we should interpret activations in BA2 as evidence for somatosensory-motor rather than somatosensory coding alone.

Predicted sensory consequences of voluntary actions modulate amplitude and temporal dynamics of preceding readiness potentials

“…This suggests that the encoding of sensory consequences for self-generated actions occurs predominantly in high-order motor areas. This notion is compatible with neuroimaging studies that examined the source of sensory modulation in response to selfgenerated compared with externally-generated stimuli and pointed to high-order motor areas, such as SMA and lateral pre-motor cortex, as the source of such modulation (Christensen et al, 2007;Cui et al, 2014;Ford et al, 2014;Haggard & Whitford, 2004;Makoshi, Kroliczak, & van Donkelaar, 2011;Reznik, Ossmy, & Mukamel, 2015). Nonetheless, other studies using fMRI…”

Perceiving Hesitation requires both the Motor and Mentalizing systems

“…They were constructed as for the GLM by convolving block Thioux et al,Perceiving Hesitations 7/22 predictors with the hemodynamic response function, and included (i) the timing of the instruction, (ii) the response, (iii) the actor blocks and (iv) a final predictor capturing all the movies, irrespectively of whether the task was Target or Hesitation. This was done so that task specific activation that differentiates Target and Hesitation is not regressed out of the sequences and thus provides the main residual signal that will be tracked across the ROIs (see ref (Cui et al 2014) for a similar approach). The ICOV was then calculated as follows.…”

“…The ICOV was then calculated as follows. Assuming that the matrix of plausible connections between the ROIs is sparse, the inverse covariance method ("glasso" implementation in the R Statistical package) leverages the fact that a full set of partial correlations can be computed using the inverse of the covariance (ICOV) matrix (Friedman et al 2008;Cui et al 2014). Briefly, each variable 'i' (ROIs in this context) is represented as a general linear model (GLM) comprising of all other variables 'j', under the constraint that the sum of the absolute coefficients (Cij) of the individual regressors be less than a given constant tuning parameter P. If Cij and Cji is zero, then the ij entry of the inverse covariance matrix is zero (Meinshausen and Bühlmann 2006).…”

“…To explore how information is transferred across these networks, we used the functional connectivity methodology that has been considered most robust in comparative studies (Smith et al 2011), the ICOV method (Marrelec et al 2006;Cui et al 2014). This method calculates the partial correlation across every two nodes of interest in the brain after conditioning out the variance shared with any other nodes and the nuisance variables (see method).…”

Sensory percepts induced by microwire array and DBS microstimulation in human sensory thalamus

“…Shorter duration stimuli may also mimic subconscious motor sensations occurring during movement to help guide or direct specific aspects of motion, and may not be easily separable from motor kinematics [33, 35, 43]. The brain’s internal use of a referent control of perception [28] or more traditionally, an efference copy, are concepts which describe how intrinsic sensory patterns may be tied to motor outputs during action [14, 29, 44, 45]. For example, insertion of a patterned stimulus to indicate a “false” proprioceptive response during a movement may alter the intended trajectory or performance of a movement, but encoding appropriate proprioceptive stimuli at the single unit and field potential level to facilitate motion represents a daunting challenge for brain-machine interfaces [22, 46, 47].…”