Yasuko Okumura

Attention that covers letters is necessary for the left-lateralization of an early print-tuned ERP in Japanese hiragana

Extensive experience with reading develops expertise in acquiring information from print, and this is reflected in specific enhancement of the left-lateralized N170 component in event-related potentials. The N170 is generally considered to reflect visual/orthographic processing; while modulations of its left-lateralization related to phonological processes have also been indicated. However, in our previous study, N170-like response to Hiragana strings lacked left-lateralization when the stimuli were completely task-irrelevant in rapid-presentation sequences [Okumura et al. (2014). Early print-tuned ERP response with minimal involvement of linguistic processing in Japanese Hiragana strings. Neuroreport 25, 410-414]. This suggests that, despite the highly transparent character-to-syllable correspondence, the phonological mapping of Hiragana strings requires some kind of attention toward print. To verify this notion, the present study examined ERPs under the same experimental condition as in the previous study, except that the task required attention to a stimulus attribute (i.e., color). As a result, Hiragana words and nonwords elicited left-lateralized negative deflection in the occipito-temporal region during 130-170ms post-stimulus in comparison to symbol strings, but only when the print had a narrow intercharacter spacing. Moreover, we observed the enhancement of very early occipital ERP in response to words during 70-100ms. The present results suggest that visual attention plays a role in early print processing, which may contribute to our understanding of the mechanisms that underlie expert as well as impaired reading.

Early print-tuned ERP response with minimal involvement of linguistic processing in Japanese Hiragana strings.

The act of reading leads to the development of specific neural responses for print, the most frequently reported of which is the left occipitotemporal N170 component of event-related potentials. However, it remains unclear whether this electrophysiological response solely involves print-tuned neural activities. The present study examined an early print-tuned event-related potential response with minimal involvement of linguistic processing in a nonalphabetic language. Japanese Hiragana words, nonwords, and alphanumeric symbol strings were presented rapidly and the task was to detect the change in color of a fixation cross to restrict linguistic processing. As a result, Hiragana words and nonwords elicited a larger posterior N1 than alphanumeric symbol strings bilaterally, irrespective of intercharacter spacing. The fact that this N1 was enhanced specifically for rapidly presented Hiragana strings suggests the existence of print-tuned neural processes that are relatively independent of the influence of linguistic processing.

Excessive hemodynamic activity in the superior frontal cortex during the flanker task in children with attention deficit hyperactivity disorder

Near-infrared spectroscopy studies in children with attention deficit hyperactivity disorder (ADHD) have shown excessive prefrontal activity responsible for coping with interference. However, it is possible that the previous results were influenced by verbal, reading, and memory developments. The flanker task is an interference task that does not require a verbal response, reading, or memorization. We examined activity in the superior frontal cortex (SFC) during the flanker task in 12 children with ADHD and 14 children with typical development using near-infrared spectroscopy. SFC activity was significantly greater in children with ADHD than in those with typical development. The results showed excessive interference coping activity in children with ADHD irrespective of verbal, reading, and memory development. Moreover, SFC activity was positively correlated with the inattention subscale score of the ADHD rating scale. We suggest that children with ADHD need greater SFC activation to cope with interference, and the inefficient mechanism is demanding and hard to sustain, which causes inattention symptoms of children with ADHD.

Spatial working memory encoding type modulates prefrontal cortical activity

Spatial working memory (SWM) involves both simultaneous and sequential encoding, but the differences in their neural correlates are unclear. We investigated the differences in prefrontal cortex activity related to these SWM encoding types. We also examined the patterns of brain activity influencing individual visuospatial abilities (VSA). We conducted SWM tasks with two different conditions, sequential and simultaneous encoding, and examined hemodynamic activity in 39 healthy adults using near-infrared spectroscopy. The bilateral dorsolateral prefrontal cortex was activated more strongly in the sequential condition compared with the simultaneous condition. This suggests that prefrontal cortex activity underlying SWM is modulated by the type of encoding. We also found that individuals with high VSA showed weaker activation in the right-dorsolateral prefrontal cortex compared with those with lower VSA during the simultaneous condition. This hypoactivation is thought to reflect neural efficiency in the individuals with high ability. These findings are expected to lead to a better understanding of neural substrates for SWM.

Predictive factors of success in neurofeedback training for children with ADHD

ABSTRACT Introduction: Neurofeedback (NF) training aims the enhancement of self-regulation over brain activities. While it is largely recognized as an effective treatment for attention deficit hyperactivity disorder (ADHD), the existence of non-learners has also been reported. The present study explored pre-training assessment indices that could predict learners prior to NF training. Methods: Twenty-two children with ADHD participated in slow cortical potential (SCP) NF training and completed pre- and post-training assessments. Participants were classified into learners or non-learners based on their progress in the SCP regulation, and pre-training indices that differentiate the two groups were examined by decision tree analysis. Results and Discussion: The learner rate in NF training was 45.5%. Learners were predicted by pre-training cognitive and neurophysiological measures regarding Stroop tasks, which suggested relatively intact executive function as their characteristics. Given that NF training is not universally effective for children with ADHD, further studies are necessary to establish application criteria.

Applicability of the Movement Assessment Battery for Children-Second Edition (MABC-2) for Japanese Children Aged 3–6 Years: A Preliminary Investigation Emphasizing Internal Consistency and Factorial Validity

This study investigated the applicability of the Movement Assessment Battery for Children – Second Edition (MABC-2) for 3- to 6-year-old Japanese children, particularly addressing its internal consistency and factorial validity. The MABC-2 test set for 3- to 6-year-old children was administered to 252 children. Differences between Japanese children and those of the original normative sample (i.e. United Kingdom children) were investigated along with sex differences. The Japanese children aged 3–6 years were found to have higher Manual Dexterity and Balance component scores than children of the normative sample. Girls scored higher than boys on the Balance component. Results of several analyses showed good internal consistency of the MABC-2. Confirmatory factor analysis revealed that a theoretical three-component model of the MABC-2 was not fitted to Japanese children aged 3–6 years. Instead, a new three-component model was postulated and discussed. The new three-component model of the MABC-2, with Manual Dexterity, Static Balance and Ball Skills, and Dynamic Balance, has high factorial validity in Japanese children aged 3–6 years.

Right prefrontal cortex specialization for visuospatial working memory and developmental alterations in prefrontal cortex recruitment in school-age children

OBJECTIVE The right prefrontal cortex (PFC) plays an essential role in active processing within visuospatial working memory (VSWM). The aim of this study was to examine developmental changes in the recruitment patterns of the PFC during visuospatial memory tasks in school-age participants. METHODS We recruited 80 school-age children who were classified into three age groups: 7- to 8-year-old, 9- to 10-year-old, and 11- to 12-year-old children. We used near infrared spectroscopy (NIRS) to measure PFC activity during visuospatial memory task. Memory stimuli were presented either sequentially or simultaneously. RESULTS In all three groups, right-lateralized PFC activity was observed during sequential presentation, suggesting specialization of the right PFC for VSWM. During simultaneous presentation, right-lateralized PFC activity was not observed in 7- to 8-year-old children or 9- to 10-year-old children. In contrast, PFC activity was right-lateralized in 11- to 12-year-old children. CONCLUSIONS We suggest that specialization of the right PFC for VSWM is already present before school-age, but widely distributed activity in response to visuospatial memory tasks changes to more focal activity in VSWM-specific regions during the early school years. SIGNIFICANCE Using NIRS, we showed developmental changes in the recruitment patterns of the PFC during visuospatial memory tasks.

The relationship between the superior frontal cortex and alpha oscillation in a flanker task: Simultaneous recording of electroencephalogram (EEG) and near infrared spectroscopy (NIRS)

Activity in the alpha band of the electroencephalogram (EEG) reflects functional inhibition of the cerebral cortex. The superior frontal cortex (SFC) is known to control alpha activity. Based on this relationship between SFC and alpha, we hypothesized that SFC controlled alpha mediates proactive control over interference. In this study, we examined the relationship between SFC and alpha in the flanker task by simultaneously recording EEG and near infrared spectroscopy (NIRS). Forty participants performed a flanker task with occasional (compatible 75%, incompatible 25%) and successive (incompatible 100%) conditions. In the occasional condition, larger SFC activity was related to pre-stimulus alpha enhancement under occipital electrodes. This is consistent with a model in which SFC enhances pre-stimulus alpha activity, leading to proactive control over interference. However, we could not detect a correlation between SFC activity and alpha activity in the successive condition. Active inhibition may have been reduced by a need to continuously inhibit brain regions associated with the irrelevant information. This may have reduced the role of the SFC in controlling alpha activity. Based on these findings, we postulate that there are two cerebral mechanisms of proactive control over interference.

Print-specific N170 involves multiple subcomponents for Japanese Hiragana

Print-specific N170 in event-related potentials is generally considered to reflect relatively automatic processing for letter strings, which is crucial for fluent reading. However, our previous studies demonstrated that print-specific N170 for transparent Japanese Hiragana script consists of at least two subcomponents under rapid stimulus presentation: an attention-related left-lateralized N170 and a bilateral N170 associated with more automatic orthographic processes (Okumura, Kasai & Murohashi, 2014, 2015). The present study aimed to confirm the latter component by controlling presentation frequency of letters and nonlinguistic visual controls (i.e., symbols), but found a quite different pattern of results; an enhanced occipito-temporal positivity for words (80-120ms poststimulus) followed by the typical left-lateralized N170 and an enhanced parietal negativity for nonwords (150-200ms). These results should provide further insights into the interaction processes between attention and early stages of print processing.

Training Attention to the Other’s Need Improves Helping Behaviors in Children with Autism Spectrum Disorder: A Behavioral Analysis Using a Two-dimensional Motion Capture System

While children with autism spectrum disorder (ASD) can acquire helping behaviors through appropriate interventions, changes in behaviors prior to helping (pre-helping behaviors) remain unclear. In the present study, we examined the effects of social skills training (SST) on helping and pre-helping behaviors in two children with ASD by using a two-dimensional motion capture system. During the SST, the children learned one helping behavior that they lent their items to their partners, and we measured their head movements before initiating the helping behavior (i.e., pre-helping behavior). As a result of SST, the participants became able to help others in response to less explicit social stimuli after the intervention. Regarding pre-helping behaviors, the children with ASD before the intervention looked straight at the helpee (i.e., recipient of the help) more often than did typically-developing peers, and such a behavior was shown to increase after SST. These results indicate that although spontaneous attention to social stimuli may be reduced in children with ASD, success in attending to a helpee could lead to the emergence of helping behaviors. Moreover, the changes in pre-helping behavior indicate an increase in children’s attention to the helpee after the intervention, which may have enhanced their sensitivity to persons in need.