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Contrast sensitivity functions were measured for normal and specifically disabled readers in experiments which varied either field size or luminance level. The nature of the differences between groups was unaffected by field size, implying that spatial summation in specifically disabled readers is normal. Increasing luminance, however, increased the range(More)
Temporal contrast sensitivity for counterphase flicker was determined for specifically disabled and normal readers to investigate whether the two groups differ in the functioning of their transient systems. In experiment 1, temporal contrast sensitivity was measured over a range of temporal frequencies with a spatial frequency of 2 cycles deg-1. Disabled(More)
Contrast sensitivity functions for normal and specifically disabled readers were measured in two experiments. Each study showed that specifically disabled readers and controls differ in the pattern of relative sensitivity across spatial frequencies. Both studies provide evidence of differences between normal and disabled readers on measures of visual(More)
Possible transient-system deficiencies in subjects with specific reading disabilities (SRDs) were investigated in groups of 13-year-old SRDs and control normal readers. In experiment 1, in which a 6 Hz uniform-field flicker (UFF) mask and a stationary test stimulus were used, it was found that the overall effect of UFF masking was to reduce differences in(More)
There are two dominant theories of affective picture processing; one that attention is more deeply engaged by motivationally relevant stimuli (i.e., stimuli that activate both the appetitive and aversive systems), and two that attention is more deeply engaged by aversive stimuli described as the negativity bias. In order to identify the theory that can best(More)
OBJECTIVE It has been suggested that alcohol-related brain impairments progress on a continuum from subtle deficits in social drinkers through to end-state Korsakoff syndrome. The aim of the present study was to investigate whether heavy levels of social drinking have an adverse effect on sober cognitive functioning in young nonalcoholic adults. METHOD(More)
We have cloned a partial cDNA encoding murine stem cell factor (SCF) and show that the gene is syntenic with the Sl locus on mouse chromosome 10. Using retroviral vectors to immortalize fetal liver stromal cell lines from mice harboring lethal mutations at the Sl locus (Sl/Sl), we have shown that SCF genomic sequences are deleted in these lines.(More)
The effects of .7 ml/kg alcohol and 200 mg caffeine on the P200, N200, P300 and N500 difference wave components of the event-related potential and on reaction time (RT) were examined in 16 females who performed both simple and choice RT tasks. Alcohol slowed the decision time (DT) component of reaction time, lengthened the latency of the P200 and P300(More)
Partial cDNA and genomic clones of rat stem cell factor (SCF) have been isolated. Using probes based on the rat sequence, partial and full-length cDNA and genomic clones of human SCF have been isolated. Based on the primary structure of the 164 amino acid protein purified from BRL-3A cells, truncated forms of the rat and human proteins have been expressed(More)
A vowel [a]-like, synthesized speech wave was perturbated by defined and comparable jitter and shimmer levels. The signal-to-noise ratio was calculated from the speech wave spectra. Noise emerges in those spectral regions in which the harmonics have high amplitudes, that is, at low frequencies and in the formant regions. Jitter created noise levels(More)