Tamotsu Toshima

Frontal cerebral blood flow change associated with infant-directed speech

Objective: To examine the auditory perception of maternal utterances by neonates using near-infrared spectroscopy (NIRS). Methods: Twenty full-term, healthy neonates were included in this study. The neonates were tested in their cribs while they slept in a silent room. First, two probe holders were placed on the left and right sides of the forehead over the eyebrows using double-sided adhesive tape. The neonates were then exposed to auditory stimuli in the form of infant-directed speech (IDS) or adult-directed speech (ADS), sampled from each of the mothers, through an external auditory speaker. Results: A 2 (stimulus: IDS and ADS) × 2 (recording site: channel 1 (right side) and channel 2 (left side)) analysis of variance for these relative oxygenated haemoglobin values showed that IDS (Mean = 0.25) increased brain function significantly (F = 3.51) more than ADS (Mean = −0.26). Conclusions: IDS significantly increased brain function compared with ADS. These results suggest that the emotional tone of maternal utterances could have a role in activating the brains of neonates to attend to the utterances, even while sleeping.

The comparative and developmental study of auditory information processing in autistic adults

The present study examined brain functions related to information processing in autistic subjects, using auditory evoked potentials (AEP) and missing stimulus potentials (MSP). In order to study the development of autism, autistic adults served as subjects. Normal adults and children also served as control groups. Both normal and autistic adults showed normal patterns and lateralities with respect to AEP for music stimuli, but normal children did not show such matured patterns and lateralities. On the other hand, with respect to MSP, autistic adults showed matured patterns with a specific laterality. These results suggest that autistic subjects might develop some cognitive functions.

Independent age cues for infancy and older age in one face: evidence for rivalry in age perception.

Participants estimated the ages of infants, teens, and adults in their 20s and 60s, using averaged facial images, as well as digitally transformed images of two different age groups. Since a blended face has intermediate features of the component faces, age of the combined faces was hypothesized to be perceived as the mean age of the component faces. However, the perceived age was underestimated when the transformed face included an infant, but overestimated when the face included a person in their 60s. From this one may infer the faces of infants and adults in their 60s have strong age cues. The estimated ages for blended images of infants and adults in their 60s showed a clear bipolar distribution, with one peak at 5–9 years and the other at 50–54 years. Analysis of individual variation showed that the different response to infants–60s faces was related to variations in sensitivity to 60s faces, not to a general perceptual tendency or confused responses to ambiguous appearing faces. Thus, cues for infancy and older age are qualitatively independent and can co-exist in one face, yielding a rivalry in age perception.

Developmental change in cognitive organization underlying stroop tasks of Japanese orthographies.

Cognitive processes underlying Stroop interference tasks of two Japanese orthographies, hiragana (a phonetic orthography) and kanji (a logographic orthography) were studied from the developmental point of view. Four age groups (first, second, third graders, and university students) were employed as subjects. Significant interference was yielded both in the hiragana and in the kanji version. Performance time on interference task decreased with age. For elementary school children, the error frequency on the interference task was higher than that on the task of naming patch colors or on the task of reading words printed in black ink, but the error frequencies did not differ among tasks for university students. In the interference task more word reading errors were yielded in the kanji version than in the hiragana version during and after third grade. The findings suggested that (1) the recognition system of hiragana and of kanji becomes qualitatively different during and after third grade, (2) the integrative system, which organizes cognitive processes underlying Stroop task, develops with age, and (3) efficiency of the organization increases with age.

Perceived Parenting Mediates Serotonin Transporter Gene (5-HTTLPR) and Neural System Function during Facial Recognition: A Pilot Study

This study examined changes in prefrontal oxy-Hb levels measured by NIRS (Near-Infrared Spectroscopy) during a facial-emotion recognition task in healthy adults, testing a mediational/moderational model of these variables. Fifty-three healthy adults (male = 35, female = 18) aged between 22 to 37 years old (mean age = 24.05 years old) provided saliva samples, completed a EMBU questionnaire (Swedish acronym for Egna Minnen Beträffande Uppfostran [My memories of upbringing]), and participated in a facial-emotion recognition task during NIRS recording. There was a main effect of maternal rejection on RoxH (right frontal activation during an ambiguous task), and a gene × environment (G×E) interaction on RoxH, suggesting that individuals who carry the SL or LL genotype and who endorse greater perceived maternal rejection show less right frontal activation than SL/LL carriers with lower perceived maternal rejection. Finally, perceived parenting style played a mediating role in right frontal activation via the 5-HTTLPR genotype. Early-perceived parenting might influence neural activity in an uncertain situation i.e. rating ambiguous faces among individuals with certain genotypes. This preliminary study makes a small contribution to the mapping of an influence of gene and behaviour on the neural system. More such attempts should be made in order to clarify the links.