Yoshimi Kaga

Developmental changes in frontal lobe function during a verbal fluency task: A multi-channel near-infrared spectroscopy study

OBJECTIVE Near-infrared spectroscopy (NIRS) is commonly used to investigate continuous changes of brain activation and has excellent time resolution. Verbal fluency task (VFT) is widely used as a neuropsychological test of frontal lobe function. The aim of this study was to investigate normal developmental change in frontal lobe function during VFT performance using multi-channel NIRS, specifically focusing on oxygenation hemoglobin (oxyHb) changes. METHODS The subjects were 9 adults and 37 childrens who were all healthy right-handed volunteers. Children were divided into four age groups (group A, 6-8 years; group B, 9-11 years; group C, 12-14 years; group D, 15-18 years). The [oxyHb] changes were measured with 22 channels of NIRS during VFT. We defined the frontopolar region as the region of interest for analysis, and calculated the Z-score to compare the data between groups. RESULTS The task performance changed with age. There were significant differences between group A and other groups. The Z-score of [oxyHb] also significantly increased with age, when comparing adults to groups A and B. The task performances decreased with time in all groups. In contrast, [oxyHb] only continued to increase in the adult group. CONCLUSION The verbal retrieval functions begin to mature in early adolescence and continue to grow up to adulthood.

Event-Related Potentials for Cognitive Assessment of Patients with Epilepsy

Event-related potentials (ERPs) are very useful for evaluating cognitive function in patients with neurological and psychiatric disorders. The method is noninvasive, economical, and offers a certain level of temporal resolution. This review focuses on cognitive functions in epilepsy patients using various ERPs, such as P300, mismatch negativity, NoGo potentials, cognitive negative variation and working memory paradigms. Patients with epilepsy show impaired cognitive functions in the form of selective attention, pre-attentive cognitive function, working memory and frontal inhibitory functions. These impairments come from either the epileptogenic focus or the effects of therapy. Antiepileptic drugs (AEDs) influence cognitive functions. These influences may be dose-dependent and can improve after discontinuation. By assessing various ERPs, the clinician can evaluate cognitive functions, differential diagnoses and the effects of AEDs in patients with epilepsy. Furthermore, these evaluations can lead to improved quality of life for patients.

Developmental changes in autonomic emotional response during an executive functional task: A pupillometric study during Wisconsin card sorting test

OBJECTIVE The autonomic nervous system has a deep relationship with the cognitive network when performing cognitive tasks. We hypothesize that autonomic emotional responses can affect cognitive function, especially executive function. The aim of this study was to clarify the involvement of the autonomic system during an executive functional task via developmental changes assessed using pupillometry. SUBJECTS AND METHODS Subjects were 16 healthy children and 9 healthy adults. Children were divided into 3 groups (Group A, 7-9years; Group B, 10-14years; Group C, 15-17years). Pupil diameter was recorded using an eye mark recorder during cognitive shift (CS) during the Wisconsin card sorting test (WCST). The rate of pupil variations was integrated and compared within each group, focusing on performance during CS. RESULTS Categories achieved (CA) in the behavioral results of WCST increased with age, with significant differences between Group A and other groups. The change of pupillary diameter was increased with CS and decreased at the correct answers after CS in adults. Changes of pupillary diameter with CS showed a linear increase with age, and the pattern of the pupillary response at the age of 10-14years was comparable to adults. The integrated rate of pupil diameter with CS increased with age, and there was a significant difference between Group A and adults. In addition, the degree of mydriasis correlated with the number of CA. CONCLUSION These findings suggest that autonomic emotional response play an important role as a part of the process for executive function.

O-2-24. Multimodal evoked potential study following posterior quadrantectomy in children with intractable epilepsy

To identify surgical effects on brainstem and cortical function objectively, we compared auditory brainstem response (ABR), somatosensory evoked potential (SEP) and flash visual evoked potential (fVEP) before and after posterior quadrantectomy (PQ) in 11 young children with intractable epilepsy associated with posterior quadrant cortical dysplasia. Mean age of seizure onset and the surgery was 1.4 months and 7.7 months old, respectively. Seven patients showed spasm and 2 had tonic seizures preoperatively. All had daily seizures before surgery, but after PQ, nine children (82%) reached seizure-free state. After surgery, interpeak latencies of wave I-V of ABR shortened bilaterally than before (p

S18-2. Advancement of research in event related potentials (ERP): Brain functional evaluation in children with developmental disorders

ERP is the measured brain response with electroencephalography that is direct result of a specific event. First cognitive components were discovered in the 1960s, and currently ERP is one of the most widely used methods in cognitive neuroscience research. The studies of ERP for pediatrics make advance with developmental disorders. It is possible for ERP to stimulate with suitable tasks for each disorder. Patients with ADHD have problems with executive functions, especially inhibitory function. NoGo potentials indicate inhibitory function. In ADHD children, the latency of NoGo potentials was prolonged. The patients of autistic spectrum disorder (ASD) have problems with sociality, communication and sympathies. The face related potentials were abnormal for ASD children, and they had different response during the pain stimulation against other people. Dyslexic patients have problems of phonological processing. The mismatch negativity during phonologic task was decreased in dyslexic children. N400 is elicited in a sentence reading task with semantically appropriate words, and auditory N400 was decreased in dyslexic children. Thus, ERP may be one of useful methods as diagnostic biomarker. Recently, simultaneous method with fMRI or fNIRS, and the combination of analysis with LORETA and DCM are reported, further development with research of ERP will be favorable.

Developmental changes in autonomic responses are associated with future reward/punishment expectations: A study of sympathetic skin responses in the Markov decision task

OBJECTIVE Autonomic nervous system activity is recognized as a major component of emotional responses. Future reward/punishment expectations depend upon the process of decision making in the frontal lobe, which is considered to play an important role in executive function. The aim of this study was to investigate the relationship between autonomic responses and decision making during reinforcement tasks using sympathetic skin responses (SSR). METHODS Nine adult and 9 juvenile (mean age, 10.2years) volunteers were enrolled in this study. SSRs were measured during the Markov decision task (MDT), which is a reinforcement task. In this task, subjects must endure a small immediate loss to ultimately get a large reward. The subjects had to undergo three sets of tests and their scores in these tests were assessed and evaluated. RESULTS All adults showed gradually increasing scores for the MDT from the first to third set. As the trial progressed from the first to second set in adults, SSR appearance ratios remarkably increased for both punishment and reward expectations. In comparison with adults, children showed decreasing scores from the first to second set. There were no significant inter-target differences in the SSR appearance ratio in the first and second set in children. In the third set, the SSR appearance ratio for reward expectations was higher than that in the neutral condition. CONCLUSIONS In reinforcement tasks, such as MDT, autonomic responses play an important role in decision making. We assume that SSRs are elicited during efficient decision making tasks associated with future reward/punishment expectations, which demonstrates the importance of autonomic function. In contrast, in children around the age of 10years, the autonomic system does not react as an organized response specific to reward/punishment expectations. This suggests the immaturity of the future reward/punishment expectations process in children.

57. Developmental changes of oxy-Hb concentration during “rock, paper, scissors” task assessed by multi-channel NIRS

Objectives: Here we to investigate cognitive impairments reflected by partial omission mismatch negativity (MMN) aberration in schizophrenia. Methods: We recorded EEG during event-related functional MRI (fMRI) followed by diffusion tensor imaging (DTI) in 13 healthy volunteers and 12 schizophrenic patients. The fMRI data was analyzed on SPM08 and blood oxygenation level-dependent signals (BOLD) signal changes were calculated in region of interest analysis using MarsBaR software. In DTI analysis, the areas significantly deteriorated in patients compared to controls were detected with tract-based spatial statistics. Fractional anisotropy (FA) in white matter fibers related to each area was compared between groups using tract-specific analysis. The clinical manifestation in the patients was evaluated using the Positive and Negative Syndrome Scale. Results: A significant correlation was founded among data for each recording modality: EEG, fMRI and DTI. In particular, a correlation between FA in the left anterior cingulate cortex (ACC) and EEG/fMRI data was significant. The correlation analysis with SPM revealed a significant correlation between FA of the left ACC and BOLD activity in the left Heschl gyrus. Conclusion: Dysfunction of the left ACC and temporal lobe may specifically contribute to the MMN aberration in schizophrenia.

28. The development of mind and the frontal lobe function

The aim of this study was to study interhemispheric inhibition (IHI) after bilateral (bil-task) and right finger extension tasks (rttask). Participants were 16 healthy adults. The IHI was studied before and after the finger extension tasks (bil-task and rt-task) by paired-pulse technique with transcranial magnetic stimulation (TMS). MEPs were recorded with surface electrodes placed over the right extensor digitorum communis (EDC). The intensities of both condition and test stimuli were set at 120% of the resting motor threshold. The condition stimulus was applied to the right M1, and the test stimulus was applied to the left M1.The condition-test interval was set at 10 and 15 ms. The IHI ratio was obtained by mean conditioned MEP amplitude/mean test MEP amplitude. The IHI ratio increased significantly after bil-task and the increment lasted for 30 min. The IHI ratio also increased after rt-task, however, the increment did not last for 30 min. Our results suggest that the IHI is more disinhibited after the bilateral finger movements than the unilateral finger movements.

12. The ERP findings during a Go/NoGo task with different Chinese characters

Magnetic round coil stimulation over the spinal enlargement activates the spinal nerves at the neuro-foramina level. However, the cauda equina in spinal canal has never been activated. The aim of this study is to activate the cauda equina using specially-devised round coil of diameter 20 cm named Magnetic Augmented Translumbosacral Stimulation coil (MATS coil). Total 40 healthy subjects were recruited. Magnetic stimulation was performed to obtain compound muscle action potentials (CMAPs) from abductor hallucis muscle placing the edge of coil over the L1 and L3 spinous processes. The CMAPs were compared with those elicited by high-voltage electrical stimulation. Cauda equina conduction time (CECT) between L1 and neuro-foramina levels was also measured. The CMAP latencies to L1 level MATS coil stimulation were identical to those evoked by electrical stimulation at the same level. The CMAP latencies to L3 level MATS coil stimulation were variable in each subject. L1 level MATS coil stimulation activates the cauda equina at the root exit site from conus medullaris. L3 level MATS coil stimulation activates some mid part of cauda equina or the distal cauda equina due to current spread. The MATS coil allows us to evaluate spinal nerve conduction in the cauda equina.