Carles Escera

Professor

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“Brain waves enclose the answer”

I graduated in Psychology at the University of Barcelona in 1987, and after completing my PhD with the thesis “Ultradian rhythms in human brain function during wakefulness: event-related brain potentials and behavior” in 1993, I had an atypical [scattered over a few years due to my teaching obligations] postdoctoral experience in Risto Näätänen’s laboratory at the University of Helsinki (1993, 1994, 1996, 1999). There I learned about the cerebral mechanisms of selective and involuntary auditory attention, as investigated with event-related brain potentials (ERPs). Good old times where I met some very good friends with whom I still have ongoing collaboration (Kimmo Alho, Erich Schröger, Istvàn Winkler, Hirooki Yabe).

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My research has focused on three separated but closely related research areas. First, we devised an experimental task to investigate the cerebral mechanisms of involuntary attention. In short, participants have to classify visual stimuli pertaining to two different categories, while ignoring concomitant (preceding!) task-irrelevant sounds. These latter, when deviant or novel, increased response time in the primary visual task, i.e., caused behavioral distraction and elicited a typical pattern in the ERPs, characterized by the mismatch negativity (MMN), a bi-phasic novelty-P3 and the Reorienting Negativity (RON)(Escera, Alho, Winkler, Näätänen, 1998). Subsequent studies manipulated distracter features, irrelevant stimulus-main task contingencies, stimulus significance, emotional context or working memory load, and were applied to investigate involuntary attention deficits in a range of clinical conditions. The major outcome of this research was that involuntary attention is modulated by top-down factors (Escera and Corral, 2007).

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On a parallel account, we devoted research to improve the usability of the MMN as an objective index of auditory discrimination deficits in a range of neurological, psychiatric and neurodevelopmental disorders. The MMN is elicited when the current stimulus does not match a neural representation of the preceding acoustic regularity, and as such, can index central sound representation and auditory discrimination. For instance, we found that persistent developmental stutterers display abnormal representation of the sounds of language (Corbera et al., 2005). Together with Risto Näätänen, and other colleagues, we have published a series of review papers on the clinical applications of the MMN (Näätänen and Escera, 2000; Näätänen et al., 2011; Näätänen et al., 2012).

More recently, and departing from the observation that certain neurons in the primary auditory cortex, the auditory thalamus or the inferior colliculus exhibit stimulus-specific adaptation (SSA), i.e., restore their firing rate to a deviant stimulus in a manner comparable to the MMN behavior, my recent research has suggested that deviance detection based on regularity encoding in a key principle of the functional organization of the auditory system. We recorded middle-latency (MLR) and complex auditory brainstem (cABR) response or run MEG or fMRI experiments to find deviance-related responses at latency ranges and anatomical level of those of the neurons exhibit SSA (Escera and Malmierca, 2014; Escera et al., 2013). This research benefited considerably for the collaborative ERANET-NEURON project from the Seventh Framework of the EU entitled “Probing the Auditory Novelty System”, which gathered together researchers from Spain (Manuel S. Malmierca), Israel (Israel Nelken) and Finalnd (Minna Huotilainen) under my coordination.

My current research interests have turned to the effects of temporal information in encoding the acoustic regularity, and particularly to the role of entrainment of neural oscillations in fostering these effects. We aimed at investigating this role at different anatomical levels –from high-order cortical areas to subcortical structures (i.e., the inferior colliculus as measured with the Frequency Following Response) and spectral components (from very low rhythms of 4.0 Hz to very high ones of circa 400 Hz).

On the Academy side, I am the Principal Investigator of the Brainlab-Cognitive Neuroscience Research Group (since 2003), I coordinated the Spanish Network in Cognitive Neuroscience (2008-2010), I was the director of the Institute for Brain Cognition and Behavior (IR3C) of the University of Barcelona (since 2009), and I received the ICREA Academia Distinguished Professorship in 2010.

My full CV is here.

Publications

Escera, C., Alho, K., Winkler, I. & Näätänen, R. (1998). Neural mechanisms of involuntary attention to acoustic novelty and change. Journal of Cognitive Neuroscience, 10, 590-604.
Escera, C., Alho, K., Schröger, E. & Winkler, I. (2000). Involuntary attention and distractibility as evaluated with event-related brain potentials. Audiology & Neuro-Otology, 5, 151-166.
Costa-Faidella, J., Baldeweg, T., Grimm, S., & Escera, C. (2011). Interactions between “what” and “when” in the auditory system: temporal predictability enhances repetition suppression. Journal of Neuroscience, 31, 18590-18597.
Slabu, L., Grimm, S., & Escera, C. (2012). Novelty detection in the human auditory brainstem. Journal of Neuroscience, 34, 1447-1452.
Escera, C. & Malmierca, M.S. (2014). The auditory novelty system: An attempt to integrate human and animal research. Psychophysiology, 51, 111-123.