Shinya Sakai

Does the Human Dorsal Stream Really Process a Category for Tools

Previously, Almeida et al. (2008) used a technique called Continuous Flash Suppression to show that human dorsal stream cortical areas specifically responded to a “tool category.” Here, we used the same technique to clarify what attributes of tools are processed in the dorsal stream. We examined surface attributes and shape. A significant priming effect was found when we removed surface attributes by using line drawings instead of photographs. In a second experiment, we manipulated shape and we found that there were no significant priming effects when we used nonelongated tool pictures as tool prime stimuli. To better clarify the effect of shape attributes on priming effects, we conducted a further experiment using elongated stick-like rectangles as prime stimuli and found that elongated shapes significantly shortened the reaction time to the tool pictures as target stimuli. Additionally, when elongated vegetables were used as prime stimuli, the reaction time to the tool pictures as target stimuli was also significantly shortened, but there was no effect when stubby vegetables were used. Finally, when we controlled for orientation by presenting rotated elongated stick-like rectangles, diamond shapes, and cut circles as prime stimuli, we found that rectangles replicated the same significant priming effect as previous experiments, but the others did not. These results suggest that the dorsal stream processes elongated shapes but does not process the tool category specifically.

Brain activity during the flow experience : A functional near-infrared spectroscopy study

Flow is the holistic experience felt when an individual acts with total involvement. Although flow is likely associated with many functions of the prefrontal cortex (PFC), such as attention, emotion, and reward processing, no study has directly investigated the activity of the PFC during flow. The objective of this study was to examine activity in the PFC during the flow state using functional near-infrared spectroscopy (fNIRS). Twenty right-handed university students performed a video game task under conditions designed to induce psychological states of flow and boredom. During each task and when completing the flow state scale for occupational tasks, change in oxygenated hemoglobin (oxy-Hb) concentration in frontal brain regions was measured using fNIRS. During the flow condition, oxy-Hb concentration was significantly increased in the right and left ventrolateral prefrontal cortex. Oxy-Hb concentration tended to decrease in the boredom condition. There was a significant increase in oxy-Hb concentration in the right and left dorsolateral prefrontal cortex, right and left frontal pole areas, and left ventrolateral PFC when participants were completing the flow state scale after performing the task in the flow condition. In conclusion, flow is associated with activity of the PFC, and may therefore be associated with functions such as cognition, emotion, maintenance of internal goals, and reward processing.

Neural activity associated with enhanced facial attractiveness by cosmetics use

Previous psychological studies have shown that make-up enhances facial attractiveness. Although neuroimaging evidence indicates that the orbitofrontal cortex (OFC) shows greater activity for faces of attractive people than for those of unattractive people, there is no direct evidence that the OFC also shows greater activity for the face of an individual wearing make-up than for the same face without make-up. Using functional magnetic resonance imaging (fMRI), we investigated neural activity while subjects viewed 144 photographs of the same faces with and without make-up (48 with make-up, 48 without make-up, and 48 scrambled photographs) and assigned these faces an attractiveness rating. The behavioral data showed that the faces with make-up were rated as more attractive than those without make-up. The imaging data revealed that the left OFC and the right hippocampus showed greater activity for faces with make-up than for those without make-up. Furthermore, the activities of the right anterior cingulate cortex, left hippocampus, and left OFC increased with increasing facial attractiveness resulting from cosmetics use. These results provide direct evidence of the neural underpinnings of cosmetically enhanced facial attractiveness.

The Flow State Scale for Occupational Tasks: Development, Reliability, and Validity

Objective/Background The degree of a patients absorption in tasks as a measure of rehabilitation effectiveness has yet to be studied. The objective of this study is to develop a scale that can measure a patients flow state in a clinical situation such as occupational therapy (OT). Methods The final 14 items were determined from the comprehensive assessment of item analysis results by a preliminary experiment. A total of 240 participants engaged in computer games that induced three psychological states: flow, anxiety, and boredom. After performing each task, participants completed our flow scale and the State-Trait Anxiety Inventory (STAI). The reliability was calculated using Cronbachs alpha coefficient. The validity was confirmed from three viewpoints, namely, the correlation coefficient with the STAI, the discrimination power of each psychological state, and the accuracy of factor structure. An occupational analysis of various activities was also conducted to confirm that the computer game task was representative of measurable activities. Results Cronbachs alpha coefficient was .918. The total score of the scale was significantly negatively correlated with the total score of STAI (r = -.537, p < .01). A significant difference among each psychological state was observed (p < .01). Covariance structure analysis indicated that the model fit index showed an acceptable fit. The computer game task used in this experiment was closely related to games, crafts, learning, cooking, and playing an instrument. Conclusion Our flow scale appears to have satisfactory reliability and validity to verify quantitatively whether the occupational tasks used in OT can effectively provide a flow experience for patients.

Alpha-band rhythm modulation under the condition of subliminal face presentation: MEG study

The human brain has two streams to process visual information: a dorsal stream and a ventral stream. Negative potential N170 or its magnetic counterpart M170 is known as the face-specific signal originating from the ventral stream. It is possible to present a visual image unconsciously by using continuous flash suppression (CFS), which is a visual masking technique adopting binocular rivalry. In this work, magnetoencephalograms were recorded during presentation of the three invisible images: face images, which are processed by the ventral stream; tool images, which could be processed by the dorsal stream, and a blank image. Alpha-band activities detected by sensors that are sensitive to M170 were compared. The alpha-band rhythm was suppressed more during presentation of face images than during presentation of the blank image (p=.028). The suppression remained for about 1 s after ending presentations. However, no significant difference was observed between tool and other images. These results suggest that alpha-band rhythm can be modulated also by unconscious visual images.

Active inhibition of task-irrelevant sounds and its neural basis in patients with attention deficits after traumatic brain injury

Abstract Primary objective: To examine active inhibition of irrelevant stimuli and evaluate its neural basis using functional near infrared spectroscopy in patients with attention deficits after traumatic brain injury (TBI). Research design: Case control study. Methods and procedures: Ten patients with TBI and 10 healthy control subjects participated in this study. The Paced Auditory Serial Addition Test (PASAT) was performed with (distracting PASAT) and without (PASAT) distracting Japanese kana phonetic characters presented between each number. A block design was used. Subjects alternately performed each task three times. Main outcomes and results: Healthy controls performed better than patients with TBI on both the tasks. When performing the PASAT, healthy controls showed significant activity in every region of interest except the right lateral prefrontal cortex (PFC), but patients with TBI showed significant activity only in the left anterior PFC and left lateral PFC. When performing the distracting PASAT, the right lateral PFC was active in healthy controls, but not in patients with TBI. Conclusion: These results confirm that patients with moderate-to-severe TBI were affected by distractors that influenced order processing. It is suggested that the working memory of patients with TBI was affected by distracting stimuli, whereas that of healthy individuals was not.

Differential activation of the ventromedial prefrontal cortex between male and female givers of social reputation

Accumulating evidence has shown the profound influence of social reputation on human behavior and has implicated the ventromedial prefrontal cortex (vmPFC) in representing subjective values induced by social interaction. However, little is known regarding how the vmPFC encodes subjective pleasantness induced by social reputation received from others. We used functional magnetic resonance imaging (fMRI) to investigate how the vmPFC in males and females encodes the subjective pleasantness of social reputation received from the same gender and from the opposite gender. Behavioral data showed that positive reputation was perceived to be more pleasant than negative reputation. Intriguingly, both male and female subjects showed greater differences in the pleasantness scores between the positive reputation condition and the negative reputation condition from females than between positive and negative reputations from males. Imaging data revealed that the left vmPFC specifically contributed to the processing of positive reputation. The activity patterns of the vmPFC corresponded to the gender differences in behavior during the processing of social reputation. These results indicate that the vmPFC plays a role in representing the subjective value of positive social reputation and that this region might be a final computational site in a stream of value-based decision-making processes.

Gender differences in ventromedial prefrontal cortex activity associated with valuation of faces

Psychological studies have indicated that males exhibit stronger preferences for physical attributes in the opposite gender, such as facial attractiveness, than females. However, whether gender differences in mate preference originate from differential brain activity remains unclear. Using functional magnetic resonance imaging (fMRI), we investigated the patterns of brain activity in the ventromedial prefrontal cortex (vmPFC), a region critical for the valuation of faces, in response to elderly male, elderly female, young male, and young female faces. During fMRI, male and female subjects were presented with a face and asked to rate its pleasantness. Following fMRI, the subjects were presented with pairs of faces and asked to select the face that they preferred. We analyzed the vmPFC activity during the pleasantness-rating task according to the gender of the face stimulus (male and female) and the age of the face stimulus (elderly and young). Consistent with the results of previous studies, the vmPFC activity parametrically coded the subjective value of faces. Importantly, the vmPFC activity was sensitive to physical attributes, such as the youthfulness and gender of the faces, only in the male subjects. These findings provide a possible neural explanation for gender differences in mate preference.

Flow Experience During Attentional Training Improves Cognitive Functions in Patients with Traumatic Brain Injury: An Exploratory Case Study

Objective/Background Flow is the holistic experience that occurs when an individual acts with total involvement. The objective of this study was to examine the effects of attention training that induces flow experience for patients with attention-deficit disorder after traumatic brain injury (TBI). Methods A two-patient case report with a within-subject AB design was conducted. Two patients with attention deficit after TBI were recruited for attention training. Two types of video game tasks for attention training were created, one inducing flow (flow task) and the other not (control task). Patient A performed the flow task for 14 days after receiving general occupational therapy (OT) for 11 days. Patient B performed the flow task for 15 days after performing the control task for 10 days. We examined training effects using neuropsychological tests. The Flow State Scale for Occupational Tasks was administered to identify the patients flow state. To evaluate the training effect, we used visual analysis, the two-standard deviation band method, and effect-size analyses. Results Both Patient A and Patient B showed improvement on the Continuous Performance Test, Symbol Digit Modalities Test, and Moss Attention Rating Scale after the flow task. Patient B also showed improvement on the Trail Making Test. Conclusion The results for Patient A suggested that the flow task was more effective than general OT for improving attention deficits. Moreover, the results for Patient B suggested that the flow task was more effective than the control task. Attention training inducing flow experience may thus facilitate improvement of attention.

Flow experience enhances the effectiveness of attentional training: A pilot randomized controlled trial of patients with attention deficits after traumatic brain injury

BACKGROUND Flow is an optimal psychological state when people engage in a training task, and it is a theory explaining the absorbed state. OBJECTIVE To investigate the additional effect of flow on attention deficits for chronic patients after traumatic brain injury. METHODS Twenty patients were randomly assigned to the flow group (n = 10) or the control group. Patients performed a video game task, one inducing flow (flow group) and the other not (control group) for 4 weeks, and they were assessed with the flow state scale for occupational tasks (FSSOT) regularly and neuropsychological tests at baseline, after intervention, and at 4 weeks after intervention (follow-up). RESULTS Although both groups significantly improved their attentional function after intervention, patients in the flow group tended to show more improvement of attention. The effect size of the neuropsychological test of attention was positive, and its value was small to medium. There was a significant positive correlation between improvement of attention and the FSSOT score. CONCLUSIONS Attention training with induction of the flow was associated with greater improvement of attention. The results of this study may provide provisional evidence of the effectiveness of rehabilitation considering the patients psychological state.