Our research efforts have been devoted to two main areas of interest. One of these areas, with increasing dedication at present, is that of the neural mechanisms of involuntary attention. Broadly speaking, we are interested in the cerebral mechanisms of distraction, that is, in the cerebral regions involved, in their temporal dynamics of activation, in pathological distraction, i.e., that resulting from brain injury or mental, neurological or developmental disease, and in the individual differences on distraction, specifically those resulting from particular genetic profiles.

We have developed a laboratory task to induce distraction under controlled conditions (Escera et al., 1998). Briefly, subjects are instructed to press a response button according to visual stimulus category, while ignoring concomitant sounds, these being a repeating tone, but occasionally a deviant tone or a unique environmental “novel” sound. We have shown repeatedly that deviant tones and novel sounds increase response time to subsequent visual stimuli, i.e., they induce distraction during subject’s task performance (e.g., Alho et al., 1997, Escera et al., 1998, 2000, 2001, Yago et al., 2001a, 2001b, 2003). The event-related brain potential (ERP) recording during distraction results in a three-phases waveform, including MMN/N1, Novelty-P3 or P3a, and Reorienting Negativity (RON) components, these indexing, respectively, capture, orienting and reorienting of attention. The use of this “Distraction Potential” (DP) has allowed us to show, for instance, that orienting of attention towards significant stimuli takes place before semantic analysis of the eliciting stimulus (Escera et al., 2003), or that the common complain of increased distractibility in chronic alcoholics may be explained by an abnormal activation of their cerebral network controlling attention to irrelevant stimuli (Polo et al., 2003). Nevertheless, this distractor effect can be modulated by top-down processes, referred to the so-called cognitive set (the ongoing task demands). We are currently investigating how an emotional context or different working memory loads in a task can modify this involuntary attentional capture (bottom-up processes).

We have also been interested in the clinical applications of mismatch negativity (MMN), an ERP elicited to auditory stimulus changes. Mostly with the support of an European Union contract (BIOMED-2, IV Framework Programme), our studies have dealt with the individual replicability of MMN (see Escera & Grau, 1996, Escera et al., 2000), the development of new MMN paradigms, specifically to test auditory sensory memory (e.g., Grau et al., 1998), the application of these paradigms to chronic alcoholism (Polo et al., 1999; Grau et al., 2001), and the relationships of MMN with conscious perception of sound changes (e.g., Amenedo & Escera, 2000). In this area of research, we are currently working in the development of protocols to assess central sound representation, and in their application to various developmental disorders, such as stuttering and dyslexia. Moreover, we are now working, with the MMN, on the brain mechanisms of abstract acoustic object formation, and on the interaction between the auditory and visual modalities in auditory perception.

See the individual pages of lab members for further details and current projects!