Jacques Grapperon

Learn More
When subjects make an erroneous response in a choice reaction time task, an error negativity, or error-related negativity (N(E)/ERN), peaking at about 100 ms after EMG onset, has been described. This wave is often considered to be absent on correct response trials. We report a small N(E)/ERN wave on correct response trials during a choice reaction time task(More)
The error negativity, an EEG wave observed when subjects commit an error in a choice reaction time (RT) task, is often considered as a sign of error detection. Recently, reports of Ne-like waves on correct responses did challenge this interpretation. It has been proposed, however, that these Ne-like waves result either from an artifactual contamination of(More)
OBJECTIVE The involvement of the supplementary motor areas (SMAs) and primary motor areas (M1s) in motor processes was studied. METHODS A between-hand choice and a simple reaction time (RT) task were mixed in a precueing paradigm. Laplacians were estimated by the source derivation method from the electroencephalogram recorded over the SMAs and M1s. (More)
From electroencephalographic recordings, we estimated the surface Laplacian over motor areas in a Stroop-like between-hand choice reaction time task in humans. Response-locked averages showed a (negative) "motor potential" over the primary motor areas contralateral to the response. At the same time, a positive wave was observed over the primary motor areas(More)
In his seminal paper, Donders proposed that Choice reaction time (RT) tasks differ from Go/No-go RT tasks only by the insertion of a response decision operation. We evaluated this possibility by comparing the time course of Laplacian-transformed ERPs, recorded over the primary (M1s) and supplementary motor areas (SMAs) in a Choice and in a Go/No-go task.(More)
OBJECTIVE The elicitation of an evoked potential, the 'error negativity' (Ne) when subjects commit errors in speeded tasks, is often taken as an index of response monitoring processes. The presence of a Ne-like wave on purely correct trials challenges the current conceptions about the nature of such a monitoring system. Here, we evaluate the possibility(More)
The Stroop test is based on interference between reading and naming of incongruent color words. To decide whether this conflict was of perceptual or motor origin, event-related potentials were simultaneously recorded. Since the components of these potentials are dependent on the progression of information processing, their changes related with the nature of(More)
The velocities of motor and sensory nervous conduction and of neuro-muscular transmission were measured in four subjects during a simulated dive at 4.6 MPa (46 bars). The results show an increase in motor distal latency in the ulnar nerve, especially during decompression, with reversibility of the effect on return to ambient conditions. The hypothesis of an(More)
Utilization of the Stroop test with schizophrenic subjects is reviewed from 32 studies published since 1960. This test, in which subject has to name the color of color-words which are congruent or incongruent, is much used as a selective attention test. Its specific disturbance in schizophrenics would confirm the overload of consciousness with unsignificant(More)
In order to assess the central motor pathways of HIV-infected patients motor evoked potentials were recorded on the upper limbs after transcranial and cervical magnetic stimulations and compared with peripheral conduction velocities. Motor evoked potentials were measured on both sides of 28 patients, mostly at the AIDS stage. Our results showed that(More)