Rhythm In Perception Research Articles

Visual brain: The role of EEG alpha rhythm in perception, attention and vigilance

Visual brain: The role of EEG alpha rhythm in perception, attention and vigilance

The relevance of alpha phase in human perception

Neural oscillations in the low frequencies, roughly in the alpha band (α, 5–15 Hz), have been suggested to act as a gateway from sensation to perception. This hypothesis assumes discrete perception. In particular, the amplitude and the phase of the low frequency rhythm entails a cortical mechanism which paces the access of sensory information into the cognitive system. Evidence supporting this idea includes correlations between the phase of neural oscillations and behavioral performance in perception, spatial attention and working memory. Despite a widespread confidence in the theory, these findings have been mostly based on a varied range of exploratory approaches and inferential group statistics. Here, we aimed at validating the involvement of low frequency cortical rhythm in perception and at providing a clear-cut EEG analysis pipeline. Such an analytical pipeline should support the adoption of a hypothesis-driven framework for future replications and applications. The design, the analyses and the statistical power of the present experiment were based on prior studies in which phase opposition was successfully found. However, our results provide evidence for the involvement of pre-stimulus oscillatory alpha amplitude but not phase in perception. We discuss the null findings from the present study within the existing literature.

Speech Entrainment: Rhythmic Predictions Carried by Neural Oscillations

It has been hypothesized that stimulus-aligned brain rhythms reflect predictions about upcoming input. New research shows that these rhythms bias subsequent speech perception, in line with a mechanism of prediction.

The Rhythm of Perception

Acoustic rhythms are pervasive in speech, music, and environmental sounds. Recent evidence for neural codes representing periodic information suggests that they may be a neural basis for the ability to detect rhythm. Further, rhythmic information has been found to modulate auditory-system excitability, which provides a potential mechanism for parsing the acoustic stream. Here, we explored the effects of a rhythmic stimulus on subsequent auditory perception. We found that a low-frequency (3 Hz), amplitude-modulated signal induces a subsequent oscillation of the perceptual detectability of a brief nonperiodic acoustic stimulus (1-kHz tone); the frequency but not the phase of the perceptual oscillation matches the entrained stimulus-driven rhythmic oscillation. This provides evidence that rhythmic contexts have a direct influence on subsequent auditory perception of discrete acoustic events. Rhythm coding is likely a fundamental feature of auditory-system design that predates the development of explicit human enjoyment of rhythm in music or poetry.

Attention and Rhythm in Perception

Attention and Rhythm in Perception

Consonant duration in speech production and perception of adults and children

A method of adjustment to internal criterion was used to investigate the perception of consonant duration. Three adults and two children, 5 and 7 years old, adjusted the durations of /s/ and /t/ in the synthesised words say, tay, stay, and stray. The words were presented in two synthesised sentences, in both an adult male and a child's voice. The perceptual data were compared with speech produced by the same and different subjects. The just noticeable difference (jnd) for consonant segment duration was of the order of 25 msec; but the internal criterion for “acceptable” durations can shift over time by more than the jnd at any one time. Durations of /s,t/ in perception and production were strongly associated within and between subjects, but there were some interesting adult—child differences. Compared with adults, children appeared to lack sensitivity to differences between sentence contexts in the same speaker voice, but to differentiate more between /s,t/ durations they required for the child versus the adult speaker.The differences required in perception for the child speaker did not always mirror the child listener's own production durations. These data are interpreted with respect to possible processes governing the regulation of segmental timing and rhythm in perception and production. [Supported by SRC, Great Britian.]