Kushiro, K. | bioRxiv Science

bioRxiv2020

The effects of dynamic arm movements during prolonged whole-body tilt on the perception of gravitational direction

Additional gravitational cues generated by active body movements may play a role in the perception of gravitational space, but no experimental evidence has been shown on this. To investigate this possibility, we evaluated how arm movements made against gravity influenced the perceptual distortion of visual and postural vertical induced by prolonged whole-body tilt. In Experiment 1, participants were asked to perform static or dynamic arm movements during prolonged whole-body tilt and we assessed their effects on subjective visual vertical (SVV) at the tilt position (during-tilt session) and after tilting back to the upright position (post-tilt session). In Experiment 2, we evaluated how static or dynamic arm movements during prolonged tilt subsequently affected the subjective postural vertical (SPV). In Experiment 1, we observed that prolonged tilt induced the SVV shifts toward the side of body tilts in both sessions. The prolonged tilt-induced SVV shifts effectively decreased when performing dynamic arm movements in the during-tilt session, but not in the post-tilt session. In Experiment 2, the SPV shifted toward the side of prolonged body tilt, which was not significantly influenced by the performance of static or dynamic arm movements. Results of the during-tilt session suggest that the central nervous system utilizes additional cues generated by dynamic body movements for the perception of the visual vertical.

neuroscience↗

bioRxiv2019

Unique Cancer Motility Behaviors in Confined Spaces of Microgroove Topography with Acute Wall Angles

In recent years, many types of micro-engineered platform have been fabricated to investigate the influences of surrounding microenvironments on cell migration. Previous researches demonstrate that microgroove-based topographies can influence cell motilities of normal and cancerous cells differently. In this paper, the microgroove wall angle is altered from obtuse to acute angles and the resulting differences in the responses of normal and cancer cells are investigated to explore the geometrical characteristics that can efficiently distinguish normal and cancer cells. Interestingly, trends in cell motilities of normal and cancer cells as the wall angles are varied between 60-120{degrees} were different, and in particular, invasive cancer cells exhibit a unique, oscillatory migratory behavior. Results from the immunostaining of cell mechanotransduction components suggest that this difference stems from directional extension and adhesion behaviors of each cell type. In addition, the specific behaviors of invasive cancer cells are found to be dependent on the myosin II activity, and modulating the activity can revert cancerous behaviors to normal ones. These novel findings on the interactions of acute angle walls and cancer cell migration provide a new perspective on cancer metastasis and additional strategies via microstructure geometries for the manipulations of cell behaviors in microscale biodevices.\n\nStatement of SignificanceCancer metastasis is the leading cause of cancer patient deaths, and yet how the microstructures within the body affect this cell migration phenomenon is not well understood. In this paper, microdevices containing microgroove structures of varying geometries, in particular obtuse and acute angles, were utilized to monitor cell motilities of various cancer cells to understand the influences of the geometrical features of microstructures on cancer metastasis. Surprisingly, it was found that the acute angle geometries lowered the persistence of migration for cancer cells, which was a totally different response from non-cancerous cells. These new findings would enable the next-generation biodevices to analyze, separate and capture cancer cells, as well as shed light onto the underlying mechanisms of cancer metastasis.

cancer biology↗