Parallel development of contour integration and visual contrast sensitivity at low spatial frequencies

Abstracts / International Journal of Psychophysiology 77 (2010) 239–287

component (Nc) will be quantified and analysed. Exploratory timefrequency analyses will be enacted. We expect that results obtained from the analysis of emotional categories will replicate earlier findings (e.g. Leppänen, Moulson, Vogel-Farley, and Nelson, 2007) and that results regarding the affective arousal and valence will allow additional understanding of the mechanisms underlying the emotional modulation of ERPs in infants. Leppänen, J. M., Moulson, M. C., Vogel-Farley, V. K., and Nelson, C. A. (2007). An ERP study of emotional face processing in the adult and infant brain. Child Development, 78, 232–245.

doi:10.1016/j.ijpsycho.2010.06.035

Stress reactivity in infants: Effects of infant temperament and maternal behavior Ildikó Tótha, Krisztina Lakatosa, Krisztina Kovácsb, Zita Tormaa, Judit Gervaia a Institute for Psychology, Hungarian Academy of Sciences, Budapest, Hungary b Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary Introduction: Stress reactivity in infants is often monitored by the change of salivary cortisol levels in a stressful situation. It has been shown that cortisol reactivity is varied among infants and less than 50% show an increase of cortisol level in standard stress tests. Our preliminary results are part of a complex research project aimed at studying biological and environmental effects on infants' social– emotional development. Methods: Thirty eight 12–13-month-old infants were tested in the standard, moderately stressful Strange Situation Procedure (SSP, Ainsworth et al., 1978) involving an approach by a strange female person and two brief separations from the mother. The videorecorded procedures were evaluated for infant and maternal behavior independently by expert coders with demonstrated reliability. Infants were classified as low- or high-reactive on the basis of behavioral stress expressed throughout the SSP. Maternal behavior was evaluated using the AMBIANCE scheme (Lyons-Ruth et al., 1999). Mothers displaying high levels of frightening, intrusive or helpless behavior were classified as atypical, and those showing low levels of such anomalous behaviors were grouped as typical. Saliva samples were collected from infants by absorbing microsponges before the SSP, and 20 and 40 min following the first separation from the mother. Saliva samples were assayed for cortisol in duplicate using a highly sensitive enzyme immunoassay (Salimetrics, State College, PA, USA). The test uses 25 μl of saliva per determination, has a lower limit sensitivity of 0.003 μg/dl, standard curve range from 0.012 to 3.0 μg/dl, and average intra-and inter-assay coefficients of variation 3.5% and 5.1% respectively. Multivariate ANOVA was used for statistical analysis with preand post-test cortisol levels as dependent, and classifications of infant reactivity and maternal behavior as independent variables. Results: Although MANOVA effects did not reach significance, there were significant effects of infant reactivity (F(1,37) = 4.0, p = 0.05) and maternal behavior (F(1,37) = 4.08, p = 0.05) on infants' post-stress salivary cortisol levels 20 minutes following maternal separation. An interaction effect of infant reactivity and maternal behavior was only marginally significant (F(1,37) = 2.85, p = 0.1). The expected cortisol increase following stress was shown in the highreactive group of infants with typically (optimally) behaving mothers only. Conclusions: These results show that hormonal (cortisol) stress response in infants depends on genetically regulated temperamental

241

disposition, as well as on environmental factors such as parenting. This interaction is suggested by the modulation of temperamental effect by maternal behavior. Similar to low-reactive infants, behaviorally high-reactive babies with atypical mothers also show a blunted cortisol response. These results, if replicated in the final large sample, will explain why a majority of infants do not show hormonal stress response and will also show how parenting may contribute to a dissociation of behavioral and physiological stress responses. doi:10.1016/j.ijpsycho.2010.06.036

Parallel development of contour integration and visual contrast sensitivity at low spatial frequencies K. Benedeka, M. Janákyc, G. Braunitzerb, A. Rokszinb, S. Kérib, Gy Benedekb a Department of Neurology, University of Szeged, Szeged, Hungary b Department of Physiology, University of Szeged, Hungary c Department of Ophthalmology, University of Szeged, Hungary It has been suggested that visual contrast sensitivity and contour integration functions exhibit a late maturation during adolescence. However, the relationship between these functions has not been investigated. The aim of this study was to assess the development of visual contrast sensitivity and contour integration in 152 healthy volunteers aged between 5 and 30 years. For the testing of contrast sensitivity, the computer-based Venus system (NeuroScientific, USA) was used, while for the assessment of contour integration, we applied circular contours made up of Gabors embedded in Gabor noise presented on cards. The results revealed a significant maturation of contrast sensitivity at low spatial frequencies (0.5, 1.2, and 1.9 cycles/ degree) and contour integration. The largest developmental step was observed for both contrast sensitivity and contour integration tasks when the 5–8-year olds were compared with the 9–11-year olds. There was a significant correlation between the development of low spatial frequency contrast sensitivity and contour integration. These results raise the possibility that the development of low spatial frequency processing may affect attentional mechanisms, which may have an impact on early contour integration. doi:10.1016/j.ijpsycho.2010.06.037

The consistency and stability of children's resting frontal EEG asymmetry Wei-Ju Lina, Cho-Yin Lub, Tsung-Min Hungc a Taiwan Hospitality and Tourism College, Shou-Feng County, Hualien, Taiwan b Taipei Physical Education College, Taiwan c National Taiwan Normal University, Taiwan Resting frontal α asymmetry can be a physiological marker that reflects individual affective types and motivational predispositions or traits. The purpose of this study was: firstly, to estimate the reliability of resting frontal EEG asymmetry as a physiology marker of affective traits in children, and secondly, to compare the reliability of various measuring variable sets. This study attempted to find out which measuring variable set could maintain acceptable reliability in the shortest interval recording time for the study of resting frontal EEG asymmetry in children. Methods: The internal consistency (Cronbach α) and test–retest stability (Pearson correlation) of resting frontal EEG theta2 and alpha power and asymmetry (ln(F4) − ln(F3)) were examined in 40 children (mean aged 5.79 ± .28) at five-month