Miyamoto, N. | Search bioRxiv

bioRxiv2023

Observation of electromyogram and electrocardiogram changes with deqi for the development of an objective evaluation index of the occurrence of deqi

A unique sensation called "deqi" occurs in acupuncture, which is considered an essential variable in the study of the mechanisms and effects of acupuncture. However, an objective method for evaluating deqi is yet to be established. Therefore, we aimed to create an objective evaluation index for deqi using electromyogram (EMG) and electrocardiogram (ECG), which are expected to present characteristic changes based on the findings of previous studies. This study included 16 healthy adult male subjects. ST36 stimulation was performed three times after a one-week washout (N=48). EMG was used to calculate myopotentials, and ECG was used to calculate the heart rate (HR) immediately after stimulation. The subjects declared whether Deqi occurred, and the characteristic reactions of deqi in EMG and ECG were evaluated. In 48 trials, Deqi occurred 42 times and did not occur 6 times. Myopotentials were significantly higher when deqi occurred than when it did not. Furthermore, a positive correlation was identified between subjective sensation and the rate of change in myopotential. Deqi significantly increased the myopotential levels, indicating that it induced involuntary muscle activity. This involuntary muscle activity may be related to the stretch reflexes and nerve stimulation. For the HR immediately after stimulation, no change with deqi was identified, although a significant decrease in HR was found in cases without deqi. Deqi could induce a transient stress response and inhibit the decrease in the HR caused by acupuncture. The results of this study indicate two characteristics of deqi obtained from EMG and ECG: an increase in myopotential and an inhibition of the decrease in HR expected with acupuncture. These characteristics could provide objective evidence for the occurrence of deqi. Future studies with larger sample sizes are required toto further strengthen the objective assessment of deqi.

neuroscience↗

bioRxiv2023

Millisecond-scale behaviours of plankton quantified in situ and in vitro using the Event-based Vision Sensor (EVS)

The Event-based Vision Sensor (EVS) is a bio-inspired sensor that captures detailed motions of objects, developed with the applicability to become the eyes of machines and especially self-driving cars. Compared to conventional frame-based image sensors as employed in video cameras, EVS has an extremely fast motion capture equivalent to 10,000-fps even with standard optical settings and additionally has high dynamic ranges for brightness and also lower consumption of memory and energy. These features make the EVS an ideal method to tackle questions in biology, such as the fine-scale behavioural ecology. Here, we developed 22 characteristic features for analysing the motions of aquatic particles from the raw data of the EVS, and deployed the EVS system in both natural environments and laboratory aquariums to test its applicability to filming and analysing plankton behaviour. Our EVS monitoring in turbid water at the bottom of Lake Biwa, Japan identified several particles exhibiting distinct cumulative trajectory with periodicities in their motion (up to 16 Hz), suggesting that they were living organisms with rhythmic behaviour. We also carried out EVS monitoring in the deep sea aided by infrared lighting to minimise influence on behaviour, and observed particles with active motion and periodicities over 40 Hz. Furthermore, we used the EVS to observe laboratory cultures of six species of zooplankton and phytoplankton, confirming that they have species-specific motion periodicities of up to 41 Hz. We applied machine learning to automatically classify particles into five categories (four categories of zooplankton plus passive particles), which achieved an accuracy up to 86%. Our attempts to use the EVS for biological observations, especially focusing on its millisecond-scale temporal resolution and wide dynamic range provide a new avenue to investigate rapid and periodical motion and behaviour in small organisms. Given its compact size with low consumption of battery and memory, the EVS will likely be applicable in the near future for the automated monitoring of the behaviour of plankton by edge computing on autonomous floats, as well as quantifying rapid cellular-level activities under microscopy.

animal behavior and cognition↗