Using kinematic analysis of movement to predict the time occurrence of an evoked potential associated with a motor command.

This article presents an exploratory study investigating the possibility of predicting the time occurrence of a motor event related potential (ERP) from a kinematic analysis of human movements. Although the response-locked motor potential may link the ERP components to the recorded response, to our knowledge no previous attempt has been made to predict a priori (i.e. before any contact with the electroencephalographic data) the time occurrence of an ERP component based only on the modeling of an overt response. The proposed analysis relies on the delta-lognormal modeling of velocity, as proposed by the kinematic theory of rapid human movement used in several studies of motor control. Although some methodological aspects of this technique still need to be fine-tuned, the initial results showed that the model-based kinematic analysis allowed the prediction of the time occurrence of a motor command ERP in most participants in the experiment. The average map of the motor command ERPs showed that this signal was stronger in electrodes close to the contra-lateral motor area (Fz, FCz, FC1, and FC3). These results seem to support the claims made by the kinematic theory that a motor command is emitted at time t(0), the time reference parameter of the model. This article proposes a new time marker directly associated with a cerebral event (i.e. the emission of a motor command) that can be used for the development of new data analysis methodologies and for the elaboration of new experimental protocols based on ERP.

The error negativity in nonmedicated and medicated patients with Parkinson's disease.

OBJECTIVE: It has been hypothesized that the error negativity (Ne or ERN) is modulated by the midbrain dopaminergic system. Thus, in a depleted dopaminergic system as seen in patients with Parkinson's disease (PD) one would expect an attenuated Ne. However, studies investigating the error negativities in medicated patients with PD have produced contradictory results and the present study was designed to explore this relationship further. METHODS: Using the event-related potential technique and an Eriksen flanker paradigm, we examined error negativities in nonmedicated (drug naive) and medicated PD patients and compared them to those of healthy controls. RESULTS: (a) The error negativities of the nonmedicated and medicated PD patients were attenuated compared to those of healthy elderly controls at frontocentral scalp sites; and (b) nonmedicated and medicated PD patients produced error negativities similar to each other. CONCLUSIONS: PD results in diminished error negativities both in the early stage nonmedicated patients and in the later stage medicated patients. SIGNIFICANCE: Because both patient groups have reduced dopaminergic functioning compared to healthy controls, these findings are consistent with Ne amplitude being sensitive to modulations in that system.

Activation of the human sensorimotor cortex during error-related processing: a magnetoencephalography study.

We studied error-related processing using magnetoencephalography (MEG). Previous event-related potential studies have documented error negativity or error-related negativity after incorrect responses, with a suggested source in the anterior cingulate cortex or supplementary motor area. We compared activation elicited by correct and incorrect trials using auditory and visual choice-reaction time tasks. Source areas showing different activation patterns in correct and error conditions were mainly located in sensorimotor areas, both ipsi- and contralateral to the response, suggesting that activation of sensorimotor circuits accompanies error processing. Additional activation at various other locations suggests a distributed network of brain regions active during error-related processing. Activation specific to incorrect trials tended to occur later in MEG than EEG data, possibly indicating that EEG and MEG detect different neural networks involved in error-related processes.

Error detection in patients with lesions to the medial prefrontal cortex: an ERP study.

When people detect their own errors in a discrimination task, a negative-going waveform can be observed in scalp-recorded EEG that has been coined the error-related negativity (Ne/ERN). Generation of the Ne/ERN has been associated with structures in the prefrontal cortex, especially the anterior cingulate region, but also the supplementary motor cortex and subcortical structures. There is some controversy as to whether the Ne/ERN is a necessary concomitant to error detection. We examined the Ne/ERN in five patients with damage to the medial prefrontal cortex, including the anterior cingulate region. Our findings support the implication of the rostral anterior cingulate in Ne/ERN production, but they also show that subjects can be aware of errors and yet not produce an Ne/ERN. Thus, error detection leads to the Ne/ERN process and damage to the anterior cingulate region may interrupt this relay, suggesting that error detection may be supported by circuits outside the anterior cingulate region.