Neurobiology of Arrhythmias in Children Prenatally Exposed to Cocaine

The neurobiological manifestations of sustained arrhythmias in children prenatally exposed to cocaine¹ are suggested by reports linking brainstem cardiovascular control to dopamine lateralized to the right hemisphere.² This hypothesis is supported by a study demonstrating that prenatal stress reduces dopamine turnover in the right nucleus accumbens, leading to depression in adult offspring.³ The fact that delay-dependent speeding of reaction time, indicating motor readiness, is abolished by depletion of dopamine subserving cardiovascular reactivity in challenging tasks² prompts identification of a subset of children who are at increased risk for significant arrhythmias under conditions of stress¹ by monitoring vocal hesitation and switching pauses.² This noninvasive method is supported by immobility in behavioral despair,³ lengthy pause times, and shortened reaction times following cocaine administration.⁴ It is also supported by the construct validity of response latencies, easily obtainable through microcomputer testing of spontaneous speech in emotionally