Biology subjects

Emmerzaal, J.

Publications and source records attributed to Emmerzaal, J..

2 recordsLinked to original sources

bioRxiv2022

Beta band rhythms influence reaction times

Despite their involvement in many cognitive functions, beta oscillations are among the least understood brain rhythms. Reports on whether the functional role of beta is primarily inhibitory or excitatory have been contradictory. Our framework attempts to reconcile these findings and proposes that several beta rhythms co-exist at different frequencies. Beta frequency shifts and their potential influence on behavior have thus far received little attention. In this magnetoencephalography experiment, we asked whether changes in beta power or frequency in auditory cortex and motor cortex influence behavior (reaction times) during an auditory sweep discrimination task. We found that in motor cortex, increased beta power slowed down responses, while in auditory cortex, increased beta frequency slowed down responses. We further characterized beta as transient burst events with distinct spectro-temporal profiles influencing reaction times. Finally, we found that increased motor-to-auditory beta connectivity also slowed down responses. In sum, beta power, frequency, bursting properties, cortical focus, and connectivity profile all influenced behavioral outcomes. Our results imply that the study of beta oscillations requires caution as beta dynamics are multifaceted phenomena, and that several dynamics must be taken into account to reconcile mixed findings in the literature.

neuroscience↗

bioRxiv2020

No behavioral evidence for rhythmic facilitation of perceptual discrimination

It has been hypothesized that internal oscillations can synchronize (i.e., entrain) to external environmental rhythms, thereby facilitating perception and behavior. To date, evidence for the link between the phase of neural oscillations and behavior has been scarce and contradictory; moreover, it remains an open question whether the brain can use this tentative mechanism for active temporal prediction. In our present study, we conducted a series of auditory pitch discrimination tasks with 181 healthy participants in an effort to shed light on the proposed behavioral benefits of rhythmic cueing and entrainment. In the three versions of our task, we observed no perceptual benefit of purported entrainment: targets occurring in-phase with a rhythmic cue provided no perceptual benefits in terms of discrimination accuracy or reaction time when compared with targets occurring out-of-phase or targets occurring randomly, nor did we find performance differences for targets preceded by rhythmic vs. random cues. However, we found a surprising effect of cueing frequency on reaction time, in which participants showed faster responses to cue rhythms presented at higher frequencies. We therefore provide no evidence of entrainment, but instead a tentative effect of covert active sensing in which a faster external rhythm leads to a faster communication rate between motor and sensory cortices, allowing for sensory inputs to be sampled earlier in time.

neuroscience↗