Potencial de disparidad (mismatch negativity): características y aplicaciones

El Potencial de Disparidad, o mismatch negativity (MMN), es un potencial evocado auditivo endógeno que se obtiene cuando se escuchan pasivamente estímulos sonoros extraños (de baja probabilidad) entremezclados aleatoriamente en una secuencia de estímulos repetitivos. A diferencia de otros componentes endógenos de los potenciales evocados, como PSOO, entre las principales características de MMN destacan que su obtención no depende del nivel atencional del sujeto, siendo de especial interés para la exploración funciona1 de la patología auditiva y cerebral en sujetos que no pueden -o no quieren- colaborar, y que se han localizado con precisión sus generadores cerebrales, en la corteza temporal y frontal. Se proponen en el texto algunas sugerencias para la estandarización del paradigma de obtención de MMN, y se revisan los aspectos más relevantes de la teoria de este componente: su independencia de la atención, su endogeneidad, su implicación en la memoria sensorial, su significado funcional, y la localización cerebral de sus generadores neuroeléctricos. Finalmente, se discuten las aplicaciones clínicas más prometedoras que se esperan para este potencial evocado en 10s próximos años. Palabras clave: Potenciales evocados endógenos, memoria sensorial, conmutación de atención, discriminación automática, audición, N I , MMN

Potencia de disparidad (mismatch negativity): características y aplicaciones

The Mismatch Negativity (MMN) is an endogenous auditory eventrelated potential (ERP) licited by low-probability (deviant) auditory stimuli, randomly replacing repetitive stimuli in a series of sounds, while the subject is not actively attending to the auditory sequence. Unlike other cognitive components of rhe ERPs, such as the P300, the main features of MMN are its independence of subjects' attention -being of special interest to study the auditory and cerebral pathology in subjects unable or unwilling to cooperate, and the well-establisehd localization of its neural generators in the temporal and frontal cortex. Several suggestions in order to standardize MMN recordings are proposed in the text. Besides this, the most relevant aspects in MMN theory, such as its irdependence of attention, its endogeneity, its implication in sensory memory, iits functional meaning, and the localization of its cerebral sources, are reviewed. Finally, the most promising clinical applications for the next years are discussed.El Potencial de Disparidad, o mismatch negativity (MMN), es un potencial evocado auditivo endógeno que se obtiene cuando se escuchan pasivamente estímulos sonoros extraños (de baja probabilidad) entremezclados aleatoriamente en una secuencia de estímulos repetitivos. A diferencia de otros componentes endógenos de los potenciales evocados, como P300, entre las principales características de MMN destacan que su obtención no depende del nivel atencional del sujeto, siendo de especial interés para la exploración funcional de la patología auditiva y cerebral en sujetos que no pueden -o no quieren- colaborar, y que se han localizado con precisión sus generadores cerebrales, en la corteza temporal y frontal. Se proponen en el texto algunas sugerencias para la estandarización del paradigma de obtención de MMN, y se revisan los aspectos más relevantes de la teoria de este componente: su independencia de la atención, su endogeneidad, su implicación en la memoria sensorial, su significado funcional, y la localización cerebral de sus generadores neuroeléctricos. Finalmente, se discuten las aplicaciones clínicas más prometedoras que se esperan para este potencial evocado en los próximos años

Potencia de disparidad (mismatch negativity): características y aplicaciones

The Mismatch Negativity (MMN) is an endogenous auditory eventrelated potential (ERP) licited by low-probability (deviant) auditory stimuli, randomly replacing repetitive stimuli in a series of sounds, while the subject is not actively attending to the auditory sequence. Unlike other cognitive components of rhe ERPs, such as the P300, the main features of MMN are its independence of subjects' attention -being of special interest to study the auditory and cerebral pathology in subjects unable or unwilling to cooperate, and the well-establisehd localization of its neural generators in the temporal and frontal cortex. Several suggestions in order to standardize MMN recordings are proposed in the text. Besides this, the most relevant aspects in MMN theory, such as its irdependence of attention, its endogeneity, its implication in sensory memory, iits functional meaning, and the localization of its cerebral sources, are reviewed. Finally, the most promising clinical applications for the next years are discussed.El Potencial de Disparidad, o mismatch negativity (MMN), es un potencial evocado auditivo endógeno que se obtiene cuando se escuchan pasivamente estímulos sonoros extraños (de baja probabilidad) entremezclados aleatoriamente en una secuencia de estímulos repetitivos. A diferencia de otros componentes endógenos de los potenciales evocados, como P300, entre las principales características de MMN destacan que su obtención no depende del nivel atencional del sujeto, siendo de especial interés para la exploración funcional de la patología auditiva y cerebral en sujetos que no pueden -o no quieren- colaborar, y que se han localizado con precisión sus generadores cerebrales, en la corteza temporal y frontal. Se proponen en el texto algunas sugerencias para la estandarización del paradigma de obtención de MMN, y se revisan los aspectos más relevantes de la teoria de este componente: su independencia de la atención, su endogeneidad, su implicación en la memoria sensorial, su significado funcional, y la localización cerebral de sus generadores neuroeléctricos. Finalmente, se discuten las aplicaciones clínicas más prometedoras que se esperan para este potencial evocado en los próximos años

The effects of foreknowledge and task-set shifting as mirrored in cue- and target-locked event-related potentials

The present study examined the use of foreknowledge in a task-cueing protocol while manipulating sensory updating and executive control in both, informatively and non-informatively pre-cued trials. Foreknowledge, sensory updating (cue switch effects) and task-switching were orthogonally manipulated in order to address the question of whether, and to which extent, the sensory processing of cue changes can partly or totally explain the final task switch costs. Participants responded faster when they could prepare for the upcoming task and if no task-set updating was necessary. Sensory cue switches influenced cue-locked ERPs only when they contained conceptual information about the upcoming task: frontal P2 amplitudes were modulated by task-relevant cue changes, mid-parietal P3 amplitudes by the anticipatory updating of stimulus-response mappings, and P3 peak latencies were modulated by task switching. Task preparation was advantageous for efficient stimulus-response re-mapping at target-onset as mirrored in target N2 amplitudes. However, N2 peak latencies indicate that this process is faster for all repeat trials. The results provide evidence to support a very fast detection of task-relevance in sensory (cue) changes and argue against the view of task repetition benefits as secondary to purely perceptual repetition priming. Advanced preparation may have a stronger influence on behavioral performance and target-locked brain activity than the local effect of repeating or switching the task-set in the current trial

Psychology Meets Archaeology: Psychoarchaeoacoustics for Understanding Ancient Minds and Their Relationship to the Sacred

How important is the influence of spatial acoustics on our mental processes related to sound perception and cognition? There is a large body of research in fields encompassing architecture, musicology, and psychology that analyzes human response, both subjective and objective, to different soundscapes. But what if we want to understand how acoustic environments influenced the human experience of sound in sacred ritual practices in premodern societies? Archaeoacoustics is the research field that investigates sound in the past. One of its branches delves into how sound was used in specific landscapes and at sites with rock art, and why past societies endowed a special significance to places with specific acoustical properties. Taking advantage of the advances made in sound recording and reproduction technologies, researchers are now exploring how ancient social and sacred ceremonies and practices related to the acoustic properties of their sound environment. Here, we advocate for the emergence of a new and innovative discipline, experimental psychoarchaeoacoustics. We also review underlying methodological approaches and discuss the limitations, challenges, and future directions for this new field

Detection of simple and pattern regularity violations occurs at different levels of the auditory hierarchy

Auditory deviance detection in humans is indexed by the mismatch negativity (MMN), a component of the auditory evoked potential (AEP) of the electroencephalogram (EEG) occurring at a latency of 100-250 ms after stimulus onset. However, by using classic oddball paradigms, differential responses to regularity violations of simple auditory features have been found at the level of the middle latency response (MLR) of the AEP occurring within the first 50 ms after stimulus (deviation) onset. These findings suggest the existence of fast deviance detection mechanisms for simple feature changes, but it is not clear whether deviance detection among more complex acoustic regularities could be observed at such early latencies. To test this, we examined the pre-attentive processing of rare stimulus repetitions in a sequence of tones alternating in frequency in both long and middle latency ranges. Additionally, we introduced occasional changes in the interaural time difference (ITD), so that a simple-feature regularity could be examined in the same paradigm. MMN was obtained for both repetition and ITD deviants, occurring at 150 ms and 100 ms after stimulus onset respectively. At the level of the MLR, a difference was observed between standards and ITD deviants at the Na component (20-30 ms after stimulus onset), for 800 Hz tones, but not for repetition deviants. These findings suggest that detection mechanisms for deviants to simple regularities, but not to more complex regularities, are already activated in the MLR range, supporting the view that the auditory deviance detection system is organized in a hierarchical manner

La potencial utilidad de Forbrain ® en la tartamudez: estudio de caso único

We present a single-case study on the potential clinical relevance of a new altered auditory feedback (AAF) device (Forbrain® ) in stuttering. One adult who stutter was tested in an appropriately-controlled single-case time-series (A-B-A) study. On each of six consecutive working days, the stuttering adult was instructed to read aloud during three different experimental phases: Baseline, Test and Post-test, while wearing a Forbrain® headset. During the Test phase the device was turned on, whereas it was off during Baseline and Post-test phases. This way the transient effects of Forbrain® could be analyzed. Six quantitative measures of voice quality were retrieved from the participant’s voice recordings during his readings over each phase of the experiment. Data was statistically analyzed through the single-case d-statistic. A clear transient effect of Forbrain® , when turned on, was observed on voice quality, supported by significant differences between Baseline and Test, and Test and Post-test in the tilt of the trendline of the long term average spectrum (tLTAS) of the voice. The present single-case study support the effectiveness of Forbrain® in modifying the voice during stuttering, supporting its role as an AAF device.Presentamos un estudio de caso único sobre la potencial relevancia clínica de un nuevo dispositivo de realimentación auditiva retardada (Forbrain® ) en la tartamudez. Se examinó un adulto con tartamudez mediante un diseño de series temporales de caso único (A-B-A) adecuadamente controlado. En cada uno de 6 días consecutivos se dieron instrucciones al sujeto para leer en voz alta durante las 3 fases del estudio: línea base, test y post-test, mientras llevaba colocado un dispositivo Forbrain®. Durante las fases línea base y post-test, el aparato estaba apagado, mientras que este se conectó durante la fase de test. De esta manera se pudieron analizar los efectos transitorios de Forbrain®. Se obtuvieron 6 parámetros cuantitativos de la calidad de la voz durante la lectura a partir de los registros de esta durante cada una de las fases del experimento. Los datos se analizaron estadísticamente mediante el estadístico d para casos únicos. Se observó un claro efecto de Forbrain® en la calidad de la voz al conectar el dispositivo, según revelaron los contrastes significativos ente la línea base y el test, y el test con el post-test en el parámetro tLTAS de la voz. El presente estudio de caso único sugiere la efectividad de Forbrain® para modificar la voz durante el tartamudeo, y da apoyo a la funcionalidad de este como dispositivo de realimentación auditiva retardada

Phonological Task Enhances the Frequency-Following Response to Deviant Task-Irrelevant Speech Sounds

In electroencephalography (EEG) measurements, processing of periodic sounds in the ascending auditory pathway generates the frequency-following response (FFR) phase-locked to the fundamental frequency (F0) and its harmonics of a sound. We measured FFRs to the steady-state (vowel) part of syllables /ba/ and /aw/ occurring in binaural rapid streams of speech sounds as frequently repeating standard syllables or as infrequent (p = 0.2) deviant syllables among standard /wa/ syllables. Our aim was to study whether concurrent active phonological processing affects early processing of irrelevant speech sounds reflected by FFRs to these sounds. To this end, during syllable delivery, our healthy adult participants performed tasks involving written letters delivered on a computer screen in a rapid stream. The stream consisted of vowel letters written in red, infrequently occurring consonant letters written in the same color, and infrequently occurring vowel letters written in blue. In the phonological task, the participants were instructed to press a response key to the consonant letters differing phonologically but not in color from the frequently occurring red vowels, whereas in the non-phonological task, they were instructed to respond to the vowel letters written in blue differing only in color from the frequently occurring red vowels. We observed that the phonological task enhanced responses to deviant /ba/ syllables but not responses to deviant /aw/ syllables. This suggests that active phonological task performance may enhance processing of such small changes in irrelevant speech sounds as the 30-ms difference in the initial formant-transition time between the otherwise identical syllables /ba/ and /wa/ used in the present study

Potenciales evocados cerebrales en el contexto de la investigación psicológica: una actualización

Event-related brain potentials (ERPS) are presented in the context of the psychological research. Firstly, aspects such as how un ERP is obtained, their characteristic features, the way in which they are classified, or their main advantages with respect to another type of measures usually used in Psychology, are presented. Then, two cognitive processes that have been extensively investigated with this technique are briejly reviewed, concretely, attention and language, and the recent research in the study of emotional processes is also commented. The main ERPs that have been used to study these psychological processes are discussed

Binaural Beat: A Failure to Enhance EEG Power and Emotional Arousal

When two pure tones of slightly different frequencies are delivered simultaneously to the two ears, is generated a beat whose frequency corresponds to the frequency difference between them. That beat is known as acoustic beat. If these two tones are presented one to each ear, they still produce the sensation of the same beat, although no physical combination of the tones occurs outside the auditory system. This phenomenon is called binaural beat. In the present study, we explored the potential contribution of binaural beats to the enhancement of specific electroencephalographic (EEG) bands, as previous studies suggest the potential usefulness of binaural beats as a brainwave entrainment tool. Additionally, we analyzed the effects of binaural-beat stimulation on two psychophysiological measures related to emotional arousal: heart rate and skin conductance. Beats of five different frequencies (4.53 Hz -theta-, 8.97 Hz -alpha-, 17.93 Hz -beta-, 34.49 Hz -gamma-or 57.3 Hz -upper-gamma) were presented binaurally and acoustically for epochs of 3 min (Beat epochs), preceded and followed by pink noise epochs of 90 s (Baseline and Post epochs, respectively). In each of these epochs, we analyzed the EEG spectral power, as well as calculated the heart rate and skin conductance response (SCR). For all the beat frequencies used for stimulation, no significant changes between Baseline and Beat epochs were observed within the corresponding EEG bands, neither with binaural or with acoustic beats. Additional analysis of spectral EEG topographies yielded negative results for the effect of binaural beats in the scalp distribution of EEG spectral power. In the psychophysiological measures, no changes in heart rate and skin conductance were observed for any of the beat frequencies presented. Our results do not support binaural-beat stimulation as a potential tool for the enhancement of EEG oscillatory activity, nor to induce changes in emotional arousal