Biology subjects

Hagura, N.

Publications and source records attributed to Hagura, N..

5 recordsLinked to original sources

bioRxiv2023

Intestelligence: A pharmacological neural network using intestine data

A neural network is a machine learning algorithm that can learn and make predictions by adjusting the strength of the connections between nodes. The sigmoid function is commonly used as an activation function in these nodes. This study explores the potential applicability of biological materials in the development of alternative activation functions. Inspired by the fact that acetylcholine induces intestinal contractions that follow a sigmoid function, we used pharmacological data obtained from guinea pig ilea in a layered neural network for image classification tasks. We found that the intestinal data-based neural network with the same structure as a conventional three-layer perceptron achieved an impressive classification accuracy of 85.7% {+/-} 0.6% based on the MNIST handwritten digit dataset (chance = 10%). Additionally, the neural network was trained to determine whether objects in photographs collected from the internet were digestible, achieving an accuracy of 88.5% {+/-} 0.9% (chance = 50%). Our approach highlights the potential applicability of intestine data in neural computations based on pharmacological mechanisms.

bioengineering↗

bioRxiv2023

Decision uncertainty as a context for motor memory

The current view of perceptual decision-making suggests that once the decision is made, a single motor program associated with the decision is carried out, irrespective of the degree of uncertainty involved in the decision-making process. As opposed to this view, we show that different levels of decision uncertainty contextualize actions differently, allowing the brain to form different motor memories based on each context. The match between decision uncertainty during learning and retrieval is critical for successful motor memory retrieval. The same movement trajectory can be associated with different motor memories if each memory is linked to a different level of decision uncertainty. Encoding motor memories based on decision contexts may enhance the robustness of control during the varying neural activities induced by different cognitive states.

neuroscience↗

bioRxiv2022

Neurofeedback training for improving motor performance in healthy adults: A systematic review and meta-analysis

Neurofeedback training (NFT) refers to a training where the participants voluntarily aim to manipulate their own brain activity using the sensory feedback abstracted from their brain activity. NFT has attracted attention in the field of motor learning for its potential to become an alternative or additional training method for general physical training. In this study, a systematic review of NFT studies for motor performance improvements in healthy adults and a meta-analysis on the effectiveness of NFT were conducted. To identify relevant studies published between January 1st, 1990 to August 3rd, 2021, a computerized search was performed using the databases, Web of Science, Scopus, PubMed, JDreamIII, and Ichushi-Web. Thirty-two studies were identified for the qualitative synthesis and 13 randomized controlled trials (286 subjects) for the meta-analysis. The meta-analysis revealed significant effects of NFT for motor performance improvement examined at the timing after the last NFT session (standardized mean difference = 0.96, 95% CI = 0.40-1.53), but with the existence of publication biases and substantial heterogeneity among the trials. Subsequent subgroup meta-analysis demonstrated reliable benefits when the NFT is performed longer than 1 week. The effectiveness of NFT for each motor performance measurement (e.g., speed, accuracy, and hand dexterity) remains unclear because of high heterogeneity or due to small sample size. Further accumulation of empirical NFT studies for motor performance improvement will be necessary to provide reliable evidence about the NFT effects on specific motor skills and to safely incorporate NFT into real-world scenarios.

neuroscience↗

bioRxiv2021

Intermanual transfer of visuomotor learning is facilitated by a cognitive strategy

Humans continuously adapt their movement to a novel environment by recalibrating their sensorimotor system. Recent evidence, however, shows that explicit planning to compensate for external changes, i.e. a cognitive strategy, can also aid performance. If such a strategy is indeed planned in external space, it should improve performance in an effector independent manner. We tested this hypothesis by examining whether promoting a cognitive strategy during a visual-force adaptation task performed in one hand can facilitate learning for the opposite hand. Participants rapidly adjusted the height of visual bar on screen to a target level by isometrically exerting force on a handle using their right hand. Visuomotor gain increased during the task and participants learned the increased gain. Visual feedback was continuously provided for one group, while for another group only the endpoint of the force trajectory was presented. The latter has been reported to promote cognitive strategy use. We found that endpoint feedback produced stronger intermanual transfer of learning and slower response times than continuous feedback. In a separate experiment, we confirmed that the aftereffect is indeed reduced when only endpoint feedback is provided, a finding that has been consistently observed when cognitive strategies are used. The results suggest that intermanual transfer can be facilitated by a cognitive strategy. This indicates that the behavioral observation of intermanual transfer can be achieved either by forming an effector-independent motor representation, or by sharing an effector-independent cognitive strategy between the hands. New and noteworthyThe causes and consequences of cognitive strategy use for motor learning are poorly understood. We tested whether a visuomotor task learned using a strategy generalizes across effectors. Visual feedback was manipulated to enhance the use of a cognitive strategy. Learning using a cognitive strategy for one hand transferred to the task performed by the un-learned hand. Our result suggests that intermanual transfer can also result from a common cognitive strategy used to control both hands.

neuroscience↗

bioRxiv2020

Touch inhibits touch: sanshool-induced paradoxical tingling reveals perceptual interference between somatosensory submodalities

Human perception of touch is mediated by inputs from multiple channels. Classical theories postulate independent contributions of each channel to each tactile feature, with little or no interaction between channels. In contrast to this view, we show that inputs from two sub-modalities of mechanical input channels interact to determine tactile perception. The flutter-range vibration channel was activated anomalously using hydroxy--sanshool, a bioactive compound of Szechuan pepper, which chemically induces tingling sensations. We tested whether this tingling sensation on the lips was modulated by sustained mechanical pressure. Across four experiments, we show that sustained touch inhibits sanshool tingling sensations in a location-specific, pressure-level and time-dependent manner. Additional experiments ruled out mediation of nociceptive or affective (C-tactile) channels underlying this interaction. These results reveal novel inhibitory influence from steady-pressure onto flutter-range tactile perceptual channels, consistent with early-stage interactions between mechanoreceptor inputs within the somatosensory pathway.

neuroscience↗