Biology subjects

Haruki, Y.

Publications and source records attributed to Haruki, Y..

3 recordsLinked to original sources

bioRxiv2023

Neural substrates of top-down processing during perceptual duration-based timing and beat-based timing

Temporal context is a crucial factor in timing. Previous studies have revealed that the timing of regular stimuli, such as isochronous beats or rhythmic sequences (termed beat-based timing), activated the basal ganglia, whereas the timing of single intervals or irregular stimuli (termed duration-based timing) activated the cerebellum. We conducted a functional magnetic resonance imaging (fMRI) experiment to determine whether top-down processing of perceptual duration-based and beat-based timings affected brain activation patterns. Our participants listened to auditory sequences containing both single intervals and isochronous beats and judged either the duration of the intervals or the tempo of the beats. Whole-brain analysis revealed that both duration judgments and tempo judgments activated similar areas, including the basal ganglia and cerebellum, with no significant difference in the activated regions between the two conditions. In addition, an analysis of the regions of interest revealed no significant differences between the activation levels measured for the two tasks in the basal ganglia as well as the cerebellum. These results suggested that a set of common brain areas were involved in top-down processing of both duration judgments and tempo judgments. Our findings indicate that perceptual duration-based timing and beat-based timing are driven by stimulus regularity irrespective of top-down processing.

neuroscience↗

bioRxiv2022

Supramodal representation of the sense of body ownership in the human parieto-premotor and extrastriate cortices

The sense of body ownership, defined as the sensation that ones body belongs to oneself, is a fundamental component of bodily self-consciousness. Several studies have shown the importance of multisensory integration for the emergence of the sense of body ownership, together with the involvement of the parieto-premotor and extrastriate cortices in bodily awareness. However, whether the sense of body ownership elicited by different sources of signal, especially visuotactile and visuomotor inputs, is represented by common neural patterns remains to be elucidated. We used functional magnetic resonance imaging (fMRI) to investigate the existence of neural correlates of the sense of body ownership independent of the sensory modalities. Participants received tactile stimulation or executed finger movements while given synchronous and asynchronous visual feedback of their hand. We used multi-voxel patterns analysis (MVPA) to decode the synchronous and asynchronous conditions with cross-classification between two modalities: the classifier was first trained in the visuotactile sessions and then tested in the visuomotor sessions and vice versa. Regions of interest-based and searchlight analyses revealed significant above-chance cross-classification accuracies in the bilateral intraparietal sulcus (IPS), the bilateral ventral premotor cortex (PMv), and the left extrastriate body area (EBA). Moreover, we observed a significant positive correlation between the cross-classification accuracy in the left PMv and the difference in subjective ratings of the sense of body ownership between the synchronous and asynchronous conditions. Our findings revealed the neural representations of the sense of body ownership in the IPS, PMv, and EBA that is invariant to the sensory modalities. Significance StatementPrevious studies have shown neural correlates of the sense of body ownership in parieto-premotor and extrastriate cortices. However, whether the sense of body ownership induced by different sensory inputs is represented in common neural patterns remains unelucidated. Using functional magnetic resonance imaging (fMRI) with multi-voxel pattern analysis (MVPA), we investigated neural representations of the sense of body ownership invariant to modalities. Decoding neural patterns for visuotactile and visuomotor modalities revealed successful cross-classification accuracies in intraparietal sulcus (IPS), ventral premotor cortex (PMv), and extrastriate body area (EBA). Furthermore, cross-classification accuracy in PMv was positively correlated with subjective ratings of the sense of body ownership. These findings demonstrate that supramodal representations in parieto-premotor and extrastriate cortices underlie the sense of body ownership.

neuroscience↗

bioRxiv2022

Cardiac and gastric interoception have distinct neural substrates

Interoception, or an awareness of the internal body state, guides agents in adaptive behavior by informing them of ongoing bodily signals, such as heart rate or energy status. However, it is still unclear whether the human brain represents the differences in the subjective experience of interoception differently. Hence, we directly compared the neural activation for cardiac (awareness related to heartbeats) and gastric (awareness related to the stomach) interoception in the same population (healthy human, N = 31). Participants were asked to focus on their heart and stomach sensations to be aware of interoception in a magnetic resonance imaging scanner. The results indicated that neural activation underlying gastric interoception encompassed larger brain regions, including the occipitotemporal visual cortices, bilateral primary motor cortex, primary somatosensory cortex, left orbitofrontal cortex, and bilateral hippocampal regions. Cardiac interoception, however, selectively activated the right anterior insula extending to the frontal operculum more compared to gastric interoception. Moreover, our detailed analyses focusing on the insula, the most relevant region for interoception, revealed that the left dorsal middle insula encoded cardiac and gastric interoception in different activation patterns but not the posterior insula. Our results demonstrate that cardiac and gastric interoception have distinct neural substrates; in particular, the selective brain activation may reflect differences in the functional roles of cardiac and gastric interoception. Significance statementInteroception, subjective senses that arise from within the body, plays a critical role in maintaining adaptive behavior by informing of the ongoing bodily states, such as heart rate and energy status. Although interoception has various characteristics depending on its source signals, previous neuroimaging studies have extensively used cardiac interoception (senses related to heartbeats), making it unclear whether the brain differently encodes diverse experiences of interoception. Here, we demonstrate that cardiac interoception and gastric interoception (senses related to the stomach) have distinct neural substrates by combining mass-univariate analysis with multivoxel pattern analysis for fMRI data. Our findings suggest that the selective brain activation may reflect differences in the functional roles of cardiac and gastric interoception.

neuroscience↗