Time irreversibility (asymmetry with respect to time reversal) is an important property of many time series derived from processes in nature. Some time series (e.g., healthy heart rate dynamics) demonstrate even more complex, multiscale irreversibility, such that not only the original but also coarse-grained time series are asymmetric over a wide range of scales. Several indices to quantify mul...

METHODS Thirty-six VLBW infants who underwent F-18 fluorodeoxyglucose (F-18 FDG) brain PET and MRI were prospectively enrolled, while infants with evidence of parenchymal brain injury on MRI were excluded. The regional glucose metabolic ratio and asymmetry index were calculated. The asymmetry index more than 10% (right > left asymmetry) or less than -10% (left > right asymmetry) were defined as...

We assessed cerebral asymmetry for language in 35 monozygotic twin pairs. Using DTI, we reconstructed the arcuate fasciculus in each twin. Among the male twins, right-handed pairs showed greater left-sided asymmetry of connectivity in the arcuate fasciculus than did those with discordant handedness, and within the discordant group the right-handers had greater left-sided volume asymmetry of the...

BACKGROUND AND PURPOSE This study sought to determine the degree of agreement between asymmetries of neuropsychological functioning and nine methods of quantifying asymmetries of regional cerebral blood flow. METHODS The regional cerebral blood flow methods combined three markers of cerebral blood flow asymmetry (percent hemispheric difference, maximum percent probe-pair asymmetry, and number...

Asymmetry in flight feather vane width is a major functional innovation associated with the evolution of flight in the ancestors of birds. However, the developmental and morphological basis of feather shape is not simple, and the developmental processes involved in vane width asymmetry are poorly understood. We present a theoretical model of feather morphology and development that describes the...

INTRODUCTION A growing body of literature suggests atypical cerebral asymmetry and interhemispheric interaction in ADHD. A common means of assessing lateralized brain function in clinical populations has been to examine the relative proportion of EEG alpha activity (8-12 Hz) in each hemisphere (i.e., alpha asymmetry). Increased rightward alpha asymmetry has been associated with ADHD-like traits...

Objective: To study 5-HT transport and 5-HT1A receptors in temporal lobe epilepsy (TLE) and depression. Methods: Thirteen patients had PET with [11C]DASB for 5-HTT and [18F]FCWAY for 5-HT1A receptor binding, MRI, and psychiatric assessment. Sixteen healthy volunteers had [11C]DASB, 19 had [18F] FCWAY, and 6 had both PET studies. We used a reference tissue model to estimate [11C]DASB binding. [1...

PURPOSE In prior work, a manually derived measure of vocal fold vibratory phase asymmetry correlated to varying degrees with visual judgments made from laryngeal high-speed videoendoscopy (HSV) recordings. This investigation extended this work by establishing an automated HSV-based framework to quantify 3 categories of vocal fold vibratory asymmetry. METHOD HSV-based analysis provided for cyc...

In this paper the N−S asymmetry of the soft X-ray flare index (FISXR) during the solar cycles 21, 22 and 23 has been analyzed. The results show the existence of a real N−S asymmetry which is strengthened during solar minimum. The slope of the regression lines fitted to the daily values of asymmetry time series has been found to be negative in all the three cycles. The yearly asymmetry curve can...

An emerging focus of research on autism spectrum disorder (ASD) targets the identification of early-developing ASD endophenotypes using infant siblings of affected children. One potential neural endophenotype is resting frontal electroencephalogram (EEG) alpha asymmetry, a metric of hemispheric organization. Here, we examined the development of frontal EEG alpha asymmetry in ASD high-risk and l...