Neural correlates of partial transmission of sensorimotor information in the cerebral cortex

Using single neuron recordings in monkey primary motor (MI) cortex, two series of experiments were conducted in order to know whether response preparation can begin before perceptual processing finishes, thus providing evidence for a temporal overlap of perceptual and motor processes.

In Experiment 1, a “left/right, Go/No-Go” reaction time (RT) task was used. One monkey was trained to perform wrist flexion/extension movements to align a pointer with visual targets. The visual display was organized to provide a two-dimensional stimulus: side (an easy discrimination between left and right targets) which determined movement direction, and distance (a difficult discrimination between distal and proximal targets) which determined whether or not the movement was to be made. Changes in neuronal activity, when they were time-locked to the stimulus, were almost similar in the Go and No-Go trials, and when they were time-locked to movement onset, were markedly reduced in No-Go as compared to Go trials.

In Experiment 2, a stimulus-response compatibility (SRC) task was used. Two monkeys were trained to align a pointer with visual targets, on either left or right. In the spatially “compatible” trials, they had to point at the stimulus position, whereas in the “incompatible” trials, they had to point at the target located in the opposite side. For 12.5% of neurons, changes in activity associated with incompatible trials looked like changes in activity associated with movements performed in the opposite direction during compatible trials, thus suggesting the hypothesis of an automatic activation of the congruent, but incorrect response.

Results of both experiments provide evidence for a partial transmission of information from visual to motor cortical areas: that is, in the No-Go trials of the first task, information about movement direction, before the decision to perform or not this movement was made, and, in the incompatible trials of the SRC task, information about the congruent, but incorrect response, before the incongruent, but correct response was programmed.     

Weaving the fabric of social interaction: Articulating developmental psychology and cognitive neuroscience in the domain of motor cognition

In this article, we bring together recent findings from developmental science and cognitive neuroscience to argue that perception-action coupling constitutes the fundamental mechanism of motor cognition. A variety of empirical evidence suggests that observed and executed actions are coded in a common cognitive and neural framework, enabling individuals to construct shared representations of self and other actions. We review work to suggest that such shared representations support action anticipation, organization, and imitation. These processes, along with additional computational mechanisms for determining a sense of agency and behavioral regulation, form the fabric of social interaction. In addition, humans possess the capacity to move beyond these basic aspects of action analysis to interpret behavior at a deeper level, an ability that may be outside the scope of the mirror system. Understanding the nature of shared representations from the vantage point of developmental and cognitive science and neuroscience has the potential to inform a range of motor and social processes. This perspective also elucidates intriguing new directions and research questions and generates specific hypotheses regarding the impact of early disorders (e.g., developmental movement disorders) on subsequent action processing.