Biology subjects

Ohata, R.

Publications and source records attributed to Ohata, R..

4 recordsLinked to original sources

bioRxiv2023

Time-dependent neural arbitration between cue associative and episodic fear memories

After traumatic events, simple cue-threat associative memories strengthen while episodic memories become fragmented. However, how the brain prioritizes cue associations over episodic coding of traumatic events remains unclear. Here, we developed a new episodic threat conditioning paradigm in which participants concurrently form two memory representations: cue associations and episodic cue sequence. We discovered that these two distinct memories compete for physiological fear expression, reorganizing overnight from an overgeneralized cue-based to a precise sequence-based expression. With multivariate fMRI, we track inter-area communication of the memory representations and demonstrate that a shift from hippocampal-dominant to prefrontal-dominant control of the fear regulatory circuit governs this memory maturation. Critically, this overnight reorganization is altered in individuals with heightened trait anxiety. Together, these findings suggest the brain prioritizes generalizable associative memories under recent traumatic stress, but resorts to selective episodic memories 24 hrs later. Time-dependent memory competition provides a unifying account for memory dysfunctions in posttraumatic stress disorders.

neuroscience↗

bioRxiv2021

Neural basis for adaptive motor behavior during car driving

Car driving is supported by motor skills trained through continuous daily practice. One of the skills unique to expert drivers is the ability to detect abrupt changes in the driving environment and then quickly adapt their operation mode to the changes. Previous functional neuroimaging studies on motor control investigated the mechanisms underlying behaviors adaptive to changes in control properties of simple experimental devices such as a computer mouse or a joystick. The switching of multiple internal models mainly engages adaptive behaviors and underlies the interplay between the cerebellum and frontoparietal network (FPN) regions as the neural process. However, it remains unclear whether the neural mechanisms identified through an experimental paradigm using such simple devices also underlie practical driving behaviors. In the current study, we measure functional magnetic resonance imaging (fMRI) activities while participants control a realistic driving simulator inside the MRI scanner. Here, the accelerator sensitivity of a virtual car is abruptly changed, requiring participants to respond to this change as quickly as possible. We first compare brain activities before and after the sensitivity change. As a result, sensorimotor areas, including the left cerebellum, increase their activities after the sensitivity change. Moreover, after the change, activity significantly increases in the inferior parietal lobe and dorsolateral prefrontal cortex, parts of the FPN regions. By contrast, the posterior cingulate cortex, a part of the default mode network, deactivates after the sensitivity change. Our results suggest that the neural bases found in previous experiments using the simpler devices can serve as the foundation of adaptive car driving. At the same time, this study also highlights the unique contribution of non-motor-related regions to addressing the high cognitive demands of driving.

neuroscience↗

bioRxiv2020

My voice therefore I spoke: sense of agency over speech enhanced in hearing self-voice

The subjective experience of causing an action is known as the sense of agency. Dysfunction in the sense of agency has been suggested as a cause of auditory hallucinations (AHs), an important diagnostic criterion for schizophrenia. However, agency over speech has not been extensively characterized in previous empirical studies. Here, we examine both implicit and explicit measures of the sense of agency and reveal bottom-up and top-down components that constitute self-agency during speech. The first is action-outcome causality, which is perceived based on a low-level sensorimotor process when hearing their own voice following their speech. The second component is self-voice identity, which is embedded in the acoustic quality of voice and dominantly influences agency over speech at the cognitive judgment level. Our findings provide profound insight into the sense of agency over speech and present an informative perspective for understanding aberrant experience in AHs.

neuroscience↗

bioRxiv2018

Self-agency built with sensorimotor processing: Decoding self-other action attribution in the human brain

A sense of agency can be defined as a subjective experience that I am the one who is causing or generating an action. Several brain regions have been proposed as neural substrates of the subjective experience; however, how the information is processed and organized by each region to achieve the sense of agency still remains unclear. In this study, we have clarified the neural representations corresponding to three processes namely, sensorimotor error, feeling of agency, and judgment of agency. Specifically, we found that the widespread sensorimotor areas represent sensorimotor error information. The right inferior parietal lobe represents the information solely on self-/other-attribution even during movements, which corresponds to the feeling of agency. Finally, the right inferior frontal gyrus shows a distinct representation between self- and other-attribution immediately before reporting the judgment on the movement attribution. These results suggest that the brain builds a sense of agency by developing distinct types of information each corresponding to the three processes with the passage of time.

neuroscience↗