The article describes the general methods and some of the results obtained in the Psychophysiology Laboratory of the University of La Coruña. The paper covers our research on the Simon effect and accessory effect, although it is not a review of the literature. The research strategy we followed is built around the use of lateralized motor potentials recorded from scalp. These measures allow observing the way responses are selected and when they are selected, providing an invaluable tool to study response interference and to split reaction time into two halves. The research on the Simon effect concludes that interference during response selection is critical in the Simon effect but it is dubious whether this process should be considered as automatic and stimulus-driven, as is widely accepted. The experiments with the accessory effect indicate that facilitation is produced before response selection is over, which ends a long controversy about the locus of the accessory effect.

We examined the relationship between force and rate of force development aspects of movement dynamics and electroencephalogram motor components as reflected in the lateralized readiness potential (LRP). Using self-paced tasks, in Studies 1 and 3 we investigated whether differential speed and accuracy constraints in discrete and repetitive finger force production tasks influenced the LRP. These studies showed that speed tasks produced larger LRP than accuracy tasks regardless of whether the movement type was discrete or repetitive. In Studies 2 and 4 we studied four conditions with two levels of force and two levels of rate of force development. The largest LRPs were found with the greatest rate of force development. Overall, the four studies demonstrated that preparation for differential rates of force development is a major component reflected in the LRP.

Two different event-related potential (ERP) components were used to investigate the temporal processing of semantic and phonological encoding during implicit picture naming. Participants were shown pictures and carried out a dual choice go/nogo decision based on semantic information (i.e., whether the picture was of an object or an animal) and phonological information (i.e., whether the picture's name starts with a vowel or a consonant). In addition to the already established lateralized readiness potential (LRP; related to response preparation), we introduce the N200 (presumably related to response inhibition) as a tool for measuring online language processing. Both, the LRP and the N200 data indicated that semantic processing began earlier than phonological processing. The data are discussed in the context of language production models. Therein, the LRP and N200 results, taken together, favor a serial or cascaded processing model of language production in contrast to a parallel processing account.

Previous findings suggest that motoric response preparation cannot be initiated in parallel with memory scanning. In the present study, response preparation was initiated with the aid of a precue to examine whether such preparation can be maintained or continued while memory scanning is active. In Experiment 1, each trial began with a colored square indicating which hand might be needed to respond. A probe letter's memory set membership determined whether the primed response should be made or withheld. Lateralized readiness potentials were initiated by the square precue and continued to increase after letter presentation, suggesting that once response preparation had been initiated it was continued in parallel with memory scanning. Experiment 2 suggested that the difficulty of the concurrent memory search had little effect on the continuation of response preparation. The results support the view that motoric response preparation consists of at least two qualitatively distinct phases—initiation and continuation.

Effects of movement advance information were assessed on the prestimulus amplitude of the lateralized readiness potential (LRP), on the contingent negative variation (CNV), and on reaction time (RT). In a precuing paradigm with movement parameters hand, direction, and force, partial precues provided advance information about either hand alone, hand plus force, or hand plus direction, and the full precue specified all response parameters. The full precue produced the shortest RTs and the largest CNV amplitude, precuing hand and force or hand and movement direction produced somewhat slower RTs and a somewhat smaller CNV amplitude, and precuing only hand yielded slowest RTs and the smallest CNV amplitude. In contrast, the LRP amplitude was largest for the full precue and was the same for the remaining precues. The CNV appears to index the central assembling of a motor program, and the LRP represents the implementation of the program at more peripheral levels.