Effect of the Antioxidant Supplement Pyrroloquinoline Quinone Disodium Salt (BioPQQ™) on Cognitive Functions.

Pyrroloquinoline quinone (PQQ) is a quinone compound first identified in 1979. It has been reported that rats fed a PQQ-supplemented diet showed better learning ability than controls, suggesting that PQQ may be useful for improving memory in humans. In the present study, a randomized, placebo-controlled, double-blinded study to examine the effect of PQQ disodium salt (BioPQQ™) on cognitive functions was conducted with 41 elderly healthy subjects. Subjects were orally given 20 mg of BioPQQ™ per day or placebo, for 12 weeks. For cognitive functions, selective attention by the Stroop and reverse Stroop test, and visual-spatial cognitive function by the laptop tablet Touch M, were evaluated. In the Stroop test, the change of Stroop interference ratios (SIs) for the PQQ group was significantly smaller than for the placebo group. In the Touch M test, the stratification analyses dividing each group into two groups showed that only in the lower group of the PQQ group (initial score<70), did the score significantly increase. Measurements of physiological parameters indicated no abnormal blood or urinary adverse events, nor adverse internal or physical examination findings at any point in the study. The preliminary experiment using near-infrared spectrometry (NIRS) suggests that cerebral blood flow in the prefrontal cortex was increased by the administration of PQQ. The results suggest that PQQ can prevent reduction of brain function in aged persons, especially in attention and working memory.

Influence of global/local processing on perceived colour transparency.

Our cognitive processing is flexible and affected by global/local dominance in prior cognitive tasks. Similar to cognitive processing, perceptual processing, especially colour perception related to global/local processing, may be affected by prior global/local dominance; however, this possibility has not yet been assessed. Here, we examined whether prior tasks involving global/local processing influenced colour perception related to global/local processing. As colour perception is related to global/local processing, we focused on perceived colour transparency, in which a transparent layer is perceived in front of a background layer, even though these stimuli are physically in the same layer. When viewing the colour transparency stimulus, we expected that the perceived colour of a specific region, when focusing on only the local region, would differ from that when focusing on the whole image. In our study, the participants completed a global or local Navon task, followed by a colour-matching task that assessed how they saw colours using colour transparency stimuli. The degree of optical illusion (i.e., perceived colour transparency) after the global Navon task was greater than that after the local Navon task. Thus, prior global/local processing, a flexible mode of cognitive processing, influenced colour perception. This study provides new insight into perceptual flexibility, especially in colour perception.

Congruency of color-sound crossmodal correspondence interacts with color and sound discrimination depending on color category.

People occasionally associate color (e.g., hue) with sound (e.g., pitch). Previous studies have reported color-sound associations, which are examples of crossmodal correspondences. However, the association between both semantic and perceptual factors with color/sound discrimination in crossmodal correspondence remains unclear. To clarify this, three psychological experiments were conducted, where Stroop tasks were used to assess automatic process on the association. We focused on the crossmodal correspondence between color (Experiment 1)/color word (Experiment 2) and sound. Participants discriminated the color/word or the sound presented simultaneously. The results showed the color-sound bidirectional enhancement/interference of the response by certain associations of the crossmodal correspondence (blue-drop and yellow-shiny) in both experiments. These results suggest that these Stroop effects were caused by the semantic factor (color category) and the perceptual factor (color appearance) was not necessary for the current results. In Experiment 3, response modulation by color labeling was investigated to clarify the influence of subjective labeling. Participants labeled a presented ambiguous color, which was a hue specification between two specific colors, by listening to the sound. The results revealed that the Stroop effect was caused only when the presented color was classified as the color related to the presented sound. This showed that subjective labeling played a role in the regulation of the effect of crossmodal correspondences. These findings should contribute to the explanation of crossmodal correspondences through semantic mediation.

The Optimization of the Light-Source Spectrum Utilizing Neural Networks for Detecting Oral Lesions.

Any change in the light-source spectrum modifies the color information of an object. The spectral distribution of the light source can be optimized to enhance specific details of the obtained images; thus, using information-enhanced images is expected to improve the image recognition performance via machine vision. However, no studies have applied light spectrum optimization to reduce the training loss in modern machine vision using deep learning. Therefore, we propose a method for optimizing the light-source spectrum to reduce the training loss using neural networks. A two-class classification of one-vs-rest among the classes, including enamel as a healthy condition and dental lesions, was performed to validate the proposed method. The proposed convolutional neural network-based model, which accepts a 5 × 5 small patch image, was compared with an alternating optimization scheme using a linear-support vector machine that optimizes classification weights and lighting weights separately. Furthermore, it was compared with the proposed neural network-based algorithm, which inputs a pixel and consists of fully connected layers. The results of the five-fold cross-validation revealed that, compared to the previous method, the proposed method improved the F1-score and was superior to the models that were using the immutable standard illuminant D65.

Spontaneous motor tempo contributes to preferred music tempo regardless of music familiarity.

Music, and listening to music, has occurred throughout human history. However, it remains unclear why people prefer some types of music over others. To understand why we listen to a certain music, previous studies have focused on preferred tempo. These studies have reported that music components (external), as well as participants' spontaneous motor tempo (SMT; internal), determine tempo preference. In addition, individual familiarity with a piece of music has been suggested to affect the impact of its components on tempo preference. However, the relationships among participants' SMT, music components, and music familiarity as well as the influence of these variables on tempo preference have not been investigated. Moreover, the music components that contribute to tempo preference and their dependence on familiarity remain unclear. Here, we investigate how SMT, music components, and music familiarity simultaneously regulate tempo preference as well as which music components interact with familiarity to contribute to tempo preference. A total of 23 participants adjusted the tempo of music pieces according to their preferences and rated the familiarity of the music. In addition, they engaged in finger tapping at their preferred tempo. Music components, such as the original tempo and the number of notes, were also analyzed. Analysis of the collected data with a linear mixed model showed that the preferred tapping tempo of participants contributed to the preferred music tempo, regardless of music familiarity. In contrast, the contributions of music components differed depending on familiarity. These results suggested that tempo preference could be affected by both movement and memory.

Universality and superiority in preference for chromatic composition of art paintings.

Color composition in paintings is a critical factor affecting observers' aesthetic judgments. We examined observers' preferences for the color composition of Japanese and Occidental paintings when their color gamut was rotated. In the experiment, observers were asked to select their preferred image from original and three hue-rotated images in a four-alternative forced choice paradigm. Despite observers' being unfamiliar with the presented artwork, the original paintings (0 degrees) were preferred more frequently than the hue-rotated ones. Furthermore, the original paintings' superiority was observed when the images were divided into small square pieces and their positions randomized (Scrambled condition), and when the images were composed of square pieces collected from different art paintings and composed as patchwork images (Patchwork condition). Therefore, the original paintings' superiority regarding preference was quite robust, and the specific objects in the paintings associated with a particular color played only a limited role. Rather, the original paintings' general trend in color statistics influenced hue-angle preference. Art paintings likely share common statistical regulations in color distributions, which may be the basis for the universality and superiority of the preference for original paintings.

Overestimation of eye size: People see themselves with bigger eyes in a holistic approach.

A face contains crucial information for identification; moreover, face recognition is superior to other types of recognition. Notably, one's own face is recognized better than other familiar faces. However, it is unclear whether one's own face, especially one's own internal facial features, is represented more accurately than other faces. Here, we investigated how one's own internal facial features were represented. We conducted a psychological experiment in which the participants were required to adjust eye size to the real size in photos of their own or well-known celebrities' faces. To investigate why individuals' own and celebrity facial representations were different, two types of photos were prepared, with and without external features. It was found that the accuracy of eye size for one's own face was better than that for celebrities' faces in the condition without external features, in which holistic processing was less involved than in the condition with external features. This implies that the eye size of one's own face was represented more accurately than that of other familiar faces when external features were removed. Moreover, the accuracy of the eye size of one's own face in the condition with external features was worse than that in the condition without external features; the adjusted eye size in the condition with external features was larger than that in the condition without external features. In contrast, for celebrities' faces, there was no significant difference between the conditions with and without external features. The adjusted eye sizes in all conditions were overestimated compared to real eye sizes. Previous research indicated that eye size was adjusted to a larger size when evaluating as more attractive, in which the evaluation is related to holistic processing. Based on this perspective, it could be that one's own face was represented as more attractive in the condition with external features in the current study. Taken together, the results indicated that the representation of own eye size, which is an internal facial feature, was affected by the visibility of the external features.

Decreasing Heart Rate After Physical Activity Reduces Choking.

We occasionally place our bodies under pressure, for example, by playing sports or giving an important presentation at a business meeting. In such situations, most of us have experienced choking, which impairs performance. It has been reported that controlling the heart rate is effective at reducing anxiety, which is one of the causes of choking. Previous studies have proposed a method of reducing choking by undergoing special training for controlling heart rate. Here, we investigated whether a reduction in heart rate after physical activity reduces choking without any special training. Participants bowled under both high-pressure and low-pressure conditions. Before throwing the bowling ball, half of the participants ran on the spot (active condition), whereas the rest of the participants stood instead of running (inactive condition). After controlling for the baseline score, the bowling score in the high-pressure and active condition was significantly better than that in the inactive condition. Additionally, the reduction in heart rate in the active condition was larger than that in the inactive condition. These results suggest that the reduction in heart rate prevented choking without any specific training.

Active View and Passive View in Virtual Reality Have Different Impacts on Memory and Impression.

Virtual reality (VR) through a head-mounted display (HMD) can provide new experiences. However, it remains unclear how the characteristics of HMDs affect users' memory. To use HMDs more effectively and appropriately in several applied fields, including education, it is necessary to clarify what characteristics of HMDs affect users' memory. A head-tracking function mounted on an HMD helps to detect the user's head direction to enable a simulation experience akin to the real world. When we experience a simulation on an HMD, we actively perceive the visual world. In this study, we assessed how active/passive viewing affects users' memory of VR content. We conducted a psychological experiment in which participants watched a movie on an HMD. In the active viewing condition, the presented view changed depending on the participant's head direction. In the passive viewing condition, the presented view was a recorded movie that was shown to the participants in the active viewing condition. All participants took a memory test about the content presented in the movie on the day of viewing and 2 weeks later. The results showed that performance on the memory test in the active viewing condition was significantly lower than that in the passive viewing condition after 2 weeks. This result indicated that active viewing in VR inhibited users' memory compared to passive viewing. The current study contributes to the development of new VR techniques, such as educational learning.

Not explicit but implicit memory is influenced by individual perception style.

Not only explicit but also implicit memory has considerable influence on our daily life. However, it is still unclear whether explicit and implicit memories are sensitive to individual differences. Here, we investigated how individual perception style (global or local) correlates with implicit and explicit memory. As a result, we found that not explicit but implicit memory was affected by the perception style: local perception style people more greatly used implicit memory than global perception style people. These results help us to make the new effective application adapting to individual perception style and understand some clinical symptoms such as autistic spectrum disorder. Furthermore, this finding might give us new insight of memory involving consciousness and unconsciousness as well as relationship between implicit/explicit memory and individual perception style.

Reducing the Negative Effect of the Retention Interval on the Composite Face Recognition.

Our memories are quite fragile. We sometimes recognize something unseen as something seen before. This error often causes serious problems, such as the misidentification of composite faces in a criminal investigation. In such a scene, people occasionally claim to have seen a face that is actually a composite face consisting of facial parts separately seen before; this error is called the memory conjunction error. Although the likelihood of the memory conjunction error increases over time, previous studies suggest that it could be suppressed by the number of response options, which are expected to affect the criterion for the "Old" response. Our results show that the presence of three response options reduced the memory conjunction error. Additionally, providing information about the existence of composite faces affected the sensitivity for detecting old faces, whereas three response options affected the criterion. This study might contribute to the improvement of procedures for eyewitness testimony.

Warm-up cognitive activity enhances inhibitory function.

Society is aging worldwide. To promote the health and quality of life in elderly people, we must find a way to enhance and improve cognitive function, especially inhibitory function that suppresses inappropriate behaviors. Previous studies have indicated that warm-up cognitive activities enhanced the activation of appropriate behavior. As with the activation of appropriate behavior, inhibitory function is expected to be enhanced by a warm-up activity, although this theory has not yet been directly tested. Here, we investigated whether inhibitory function in a task was enhanced by a warm-up activity. We used a Navon task as a warm-up activity, in which reading small letters (local Navon task) required inhibitory function more than reading a large letter (global Navon task). The Stroop task was used as the subsequent task. Our results showed that the accuracy of the Stroop task after the local Navon task was higher than after the global Navon task. This outcome suggests that inhibitory function in the Stroop task was enhanced by the local Navon task, which was an inhibitory warm-up cognitive activity. Moreover, this study contributes to the development of new techniques of cognitive training to prevent the decline in inhibitory function during aging or other clinical scenarios, such as attention-deficit/hyperactivity disorder (ADHD).