Given an abstract from a research paper, your task is to identify and label relationships between chemical compounds and genes mentioned in the abstract.

The relationship type must be one of ['DOWNREGULATOR', 'SUBSTRATE', 'INDIRECT-REGULATOR', 'PART-OF', 'MODULATOR-ACTIVATOR', 'REGULATOR', 'INHIBITOR', 'COFACTOR', 'UPREGULATOR', 'ACTIVATOR', 'ANTAGONIST', 'NOT', 'INDIRECT-DOWNREGULATOR', 'SUBSTRATE_PRODUCT-OF', 'INDIRECT-UPREGULATOR', 'AGONIST', 'PRODUCT-OF', 'MODULATOR', 'DIRECT-REGULATOR', 'UNDEFINED', 'AGONIST-INHIBITOR', 'AGONIST-ACTIVATOR', 'MODULATOR-INHIBITOR'].

Please format your output as a JSON array. Each entry in the array should express a single relation, formatted as ["<Entity_A>", "<RELATION_A_B>", "<Entity_B>"]. If no relations can be found, please output an empty JSON array [].

Abstract:

Nicotine receptor gene CHRNA4 modulates early event-related potentials in auditory and visual oddball target detection tasks. The present study seeks to identify effects of a common genetic polymorphism in the human nicotinic alpha4beta2 receptor on components of the cognitive event-related potentials in auditory and visual modalities. The same sense thymine-to-cytosine polymorphism (c.1629T-C; Ser543Ser) was shown to preferentially modulate early components in both modalities. Specifically, the auditory N1 component amplitude was higher for T allele homozygotes than for C allele carriers. The visual P1 component revealed the same pattern of significant polymorphic modulation, but the later N1 amplitude differences were only marginally significant. There was no reliable indication of interactions between genotype and task factors. Parallel modulation of early latency modality-specific event-related potential (ERP) components in vision and audition may indicate that the CHRNA4 polymorphism affects factors that are common to top-down modulation of sensory processing across modalities.
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