The phase of low-frequency, rhythmic cortical activity is essential for organizing brain processes because it provides a recurrent temporal frame for information coding. However, the low-frequency cortical phase exhibits great flexibility in response to external influences. Given that brain rhythms have been found to track respiratory inputs, we hypothesized that slow breathing, commonly associated with mental regulation, could reorganize the relationship between these two rhythmic systems through the adjustment of the cortical phase to such a slow train of inputs. Based on simultaneous magnetoencephalography and respiratory measurements, we report that while participants performed paced breathing, slow relative to normal breathing modulated cortical phase activity in the alpha range across widespread brain areas. Such modulation effects were specifically locked to the middle of the inspiration stage and exhibited a well-structured pattern. At the single-subject level, the phase angles underlying the effects became more likely to be diametrically opposed across breaths, indicating unique and consistent phase adjustment to slow inspiratory inputs. Neither cardiac fluctuations nor breathing-unrelated task effects could account for the findings. We suggest that slow-paced inspiration could organize the cortical phase in a regularized phase pattern, revealing a rhythmic but dynamic neural network integrated with different neurophysiological systems through volitional control. NEW & NOTEWORTHY Breathing is more complicated than a simple gas exchange, as it is integrated with numerous cognitive and emotional functions. Controlled slow breathing has often been used to regulate mental processes. This magnetoencephalography study demonstrates that slow-paced relative to normal-paced inspiration could organize the timing of alpha rhythmic activities across breathing cycles in a structured manner over widespread brain areas. Our results reveal how a volitionally controlled change in respiratory behavior could systematically modulate cortical activity.

Facial expressions are highly dynamic signals that are rarely categorized as static, isolated displays. However, the role of sequential context in facial expression categorization is poorly understood. This study examines the fine temporal structure of expression-based categorization on a trial-to-trial basis as participants categorized a sequence of facial expressions. The results showed that the local sequential context provided by preceding facial expressions could bias the categorical judgments of current facial expressions. Two types of categorization biases were found: (a) Assimilation effects-current expressions were categorized as close to the category of the preceding expressions, and (b) contrast effects-current expressions were categorized as away from the category of the preceding expressions. The effects of such categorization biases were modulated by the relative distance between the preceding and current expressions, as well as by the different experimental contexts, possibly including the factors of face identity and the range effect. Thus, the present study suggests that facial expression categorization is not a static process. Rather, the temporal relation between the preceding and current expressions could inform categorization, revealing a more dynamic and adaptive aspect of facial expression processing.

Learning non-native phonetic categories in adulthood is an exceptionally challenging task, characterized by large interindividual differences in learning speed and outcomes. The neurobiological mechanisms underlying the interindividual differences in the learning efficacy are not fully understood. Here we examine the extent to which training-induced neural representations of non-native Mandarin tone categories in English listeners (n = 53) are increasingly similar to those of the native listeners (n = 33) who acquired these categories early in infancy. We assess the extent to which the neural similarities in representational structure between non-native learners and native listeners are robust neuromarkers of interindividual differences in learning success. Using intersubject neural representational similarity (IS-NRS) analysis and predictive modeling on two functional magnetic resonance imaging datasets, we examined the neural representational mechanisms underlying speech category learning success. Learners’ neural representations that were significantly similar to the native listeners emerged in brain regions mediating speech perception following training; the extent of the emerging neural similarities with native listeners significantly predicted the learning speed and outcome in learners. The predictive power of IS-NRS outperformed models with other neural representational measures. Furthermore, neural representations underlying successful learning were multidimensional but cost-efficient in nature. The degree of the emergent native-similar neural representations was closely related to the robustness of neural sensitivity to feedback in the frontostriatal network. These findings provide important insights into the experience-dependent representational neuroplasticity underlying successful speech learning in adulthood and could be leveraged in designing individualized feedback-based training paradigms that maximize learning efficacy.

Existing models of facial identity perception often assume that information conveyed by facial stimuli provides the sole basis for identity judgments, largely ignoring the involvement of contextual effects. Capitalizing on sequential effects, the present study investigates whether facial identity is judged relative to a context shaped by stimuli presented in previous trials. When categorizing a sequence of facial identities, our results demonstrated that participants' categorization of current faces varied according to the local sequential context provided by the immediately preceding faces and, to some extent, by the preceding stimuli presented two trials prior to the current trial. Moreover, this variation depended on the relative distance between the preceding and current faces. Notably, the nature of these identity-based sequential effects was qualitatively different between male and female participants. Female participants tended to respond to the current faces with the same category label as on the preceding faces. However, male participants responded with the same label only when the relative distance was small, but responded with a different label when the relative distance was increasingly large. The present study demonstrates that relative information between the preceding and current faces may be used as evidence to inform a judgment. However, this process is multifaceted rather than unitary and depends in part on participant gender.