Studies have shown the existence of minor developmental cortical malformations, including microgyria, in the brains of dyslexics. Concomitant studies have shown that language-impaired individuals exhibit severe deficits in the discrimination of rapidly presented auditory stimuli, including phonological and nonverbal stimuli (i.e., sequential tones). In an effort to relate these results, male rats with neonatally induced microgyria were tested in an operant paradigm for auditory discrimination of stimuli consisting of two sequential tones. Subjects were shaped to perform a go/no-go target identification, using water reinforcement. Stimuli were reduced in duration from 540 to 249 msec across 24 d of testing. Results showed that all subjects were able to discriminate at longer stimulus durations. However, bilaterally lesioned subjects showed specific impairment at stimulus durations of 332 msec or less, and were significantly depressed in comparison to shams. Right- and left-lesioned subjects were significantly depressed in comparison to shams at the shortest duration (249 msec). These results suggest a possible link between the neuropathologic anomalies and the auditory temporal processing deficits reported for language-impaired individuals.

In 3 studies adult male rats showed significantly better discrimination of tone sequences with the right ear than with the left ear. This result parallels similar findings of left-hemisphere specialization for auditory temporal processing in humans and nonhuman primates. Furthermore, because clinical evidence supports a link between specialization of the left hemisphere for auditory temporal processing and for speech processing, these results may reflect evolutionary precursors to left-hemisphere language specialization. Because male rats showed a stronger ear advantage than female rats, the findings may relate to evidence of a stronger right ear advantage in men than in women. Finally, results suggest that neonatal handling enhances lateralization for auditory temporal processing in both sexes. Combined results implicate neuroendocrine mechanisms as important factors in the development of lateralization for auditory temporal processing.

Neonatally induced microgyric lesions produce defects in rapid auditory processing in adult male rats. Given that females across species are less susceptible to the deleterious effects of neural injury and that treatment with neuroprotective agents at the time of injury can reduce neural damage, the authors tested the effects of sex and neuroprotectant exposure on the behavioral consequences of microgyric lesions in rats. Results showed that sham but not microgyric males were able to perform the task at the fastest rate of stimulus presentation. Microgyric females, in contrast, discriminated at all stimulus conditions and did not differ from female shams. Microgyric males treated with MK-801 had reduced cortical damage and performed the discrimination at the fastest condition. Results suggest that females are less susceptible to the behavioral effects of neocortical microgyria and that MK-801 may ameliorate the behavioral consequences of these lesions in male rats. Freezing injury to the cortical plate of newborn rats leads to the formation of a focal area of cortical microdysgenesis resembling four-layered microgyria (

Research!America, the largest not-for-profit alliance of groups and individuals in the UnitedStates dedicated to public outreach about research, conducts a number of programs for researchers as part of its commitment to step up the frequency and effectiveness of communication about science to elected officials, the media, and the public. This report describes these programs, emphasizing how they help scientists promote an open dialogue with journalists about research and its benefits. Data from surveys commissioned by Research!America and Sigma Xi, an international scientific honorary society, are incorporated. Scientists'accountability and accessibility to the public whose interests they serve are also discussed, as are techniques for becoming effective advocates for increased funding in medical and health research.

Previous research suggests that left hemisphere specialisation for processing speech m ay specifically depend on rate-specific parameters, with rapidly successive or faster changing acoustic stimuli (e.g. stop consonant±vow el syllables) processed preferentially by the left hemisphere. The current study further investigates the involvem ent of the left hemisphere in processing rapidly changing auditory information, and examines the effects of sex on the organisation of this function. Twenty subjects participated in an auditory discrimination task involving the target identification of a two-tone sequence presented to one ear, paired with white noise to the contralateral ear. Analyses demonstrated a right ear advantage for m ales only at the shorter interstimulus interval durations (mean = 20msec) whereas no ear advantage was observed for women. These results suggest that the male brain is more lateralised for the processing of rapidly presented auditory tones, specifically at shorter stimulus durations.