title: A hypothesis about how early developmental methylmercury exposure disrupts behavior in adulthood.
abstract: Events that disrupt the early development of the nervous system have lifelong, irreversible behavioral consequences. The environmental contaminant, methylmercury (MeHg), impairs neural development with effects that are manifested well into adulthood and even into aging. Noting the sensitivity of the developing brain to MeHg, the current review advances an argument that one outcome of early MeHg exposure is a distortion in the processing of reinforcing consequences that results in impaired choice, poor inhibition of prepotent responding, and perseveration on discrimination reversals (in the absence of alteration of extradimensional shifts). Neurochemical correlates include increased sensitivity to dopamine agonists and decreased sensitivity to gamma-aminobutyric acid (GABA) agonists. This leads to a hypothesis that the prefrontal cortex or dopamine neurotransmission is especially sensitive to even subtle gestational MeHg exposure and suggests that public health assessments of MeHg based on intellectual performance may underestimate the impact of MeHg in public health. Finally, those interested in modeling neural development may benefit from MeHg as an experimental model.
authors: Department of Psychology, Auburn University, AL 36830, USA. Electronic address: newlamc@auburn.edu.
authors: M Christopher
authors: MC
authors: Newland
authors: Department of Psychology, Center for Neuroscience and Center for Basic and Translational Stroke Research, West Virginia University, Morgantown 26506, WV, USA.
authors: Miranda N
authors: MN
authors: Reed
authors: Department of Psychology, Idaho State University, Pocatello, ID 83209, USA.
authors: Erin
authors: E
authors: Rasmussen
mesh_terms: D000818:Animals; D001519:Behavior / Q000187:drug effects*; D001921:Brain / Q000187:drug effects*; D005260:Female; D008767:Methylmercury Compounds / Q000633:toxicity*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects
chemical_list: D008767:Methylmercury Compounds
keywords: Aging; Choice; Development; Discrimination reversal; Dopamine; Executive functions; Methylmercury; Perseveration