@article {136,
	title = {Activity-dependent expression of Lmx1b regulates specification of serotonergic neurons modulating swimming behavior.},
	journal = {Neuron},
	volume = {67},
	year = {2010},
	month = {2010 Jul 29},
	pages = {321-34},
	abstract = {<p>Genetic programs, environmental factors, and electrical activity interact to drive the maturation of the brain. Although the cascade of transcription factors that leads to specification of the serotonergic phenotype has been well characterized, its interactions with electrical activity are not known. Here we show that spontaneous calcium spike activity in the hindbrain of developing Xenopus laevis larvae modulates the specification of serotonergic neurons via regulation of expression of the Lmx1b transcription factor. Activity acts downstream of Nkx2.2 but upstream of Lmx1b, leading to regulation of the serotonergic phenotype. Using global manipulation of activity and targeted alteration of Lmx1b expression, we also demonstrate that changes in the number of serotonergic neurons change larval swimming behavior. The results link activity-dependent regulation of a transcription factor to transmitter specification and altered behavior.</p>
},
	keywords = {Action Potentials, Animals, Behavior, Animal, Bromodeoxyuridine, Calcium, Electroporation, Embryo, Nonmammalian, gamma-Aminobutyric Acid, Gene Expression Regulation, Developmental, Green Fluorescent Proteins, Homeodomain Proteins, Membrane Potentials, Neurons, Otx Transcription Factors, Potassium Channels, Inwardly Rectifying, Raphe Nuclei, RNA, Messenger, Serotonin, Sodium Channels, Statistics, Nonparametric, Swimming, Transcription Factors, Tryptophan Hydroxylase, Xenopus laevis, Xenopus Proteins},
	issn = {1097-4199},
	doi = {10.1016/j.neuron.2010.06.006},
	author = {Demarque, Micha{\"e}l and Spitzer, Nicholas C}
}
@article {130,
	title = {Activity-dependent homeostatic specification of transmitter expression in embryonic neurons.},
	journal = {Nature},
	volume = {429},
	year = {2004},
	month = {2004 Jun 3},
	pages = {523-30},
	abstract = {<p>Neurotransmitters are essential for interneuronal signalling, and the specification of appropriate transmitters in differentiating neurons has been related to intrinsic neuronal identity and to extrinsic signalling proteins. Here we show that altering the distinct patterns of Ca2+ spike activity spontaneously generated by different classes of embryonic spinal neurons in vivo changes the transmitter that neurons express without affecting the expression of markers of cell identity. Regulation seems to be homeostatic: suppression of activity leads to an increased number of neurons expressing excitatory transmitters and a decreased number of neurons expressing inhibitory transmitters; the reverse occurs when activity is enhanced. The imposition of specific spike frequencies in vitro does not affect labels of cell identity but again specifies the expression of transmitters that are inappropriate for the markers they express, during an early critical period. The results identify a new role of patterned activity in development of the central nervous system.</p>
},
	keywords = {Action Potentials, Animals, Calcium, Calcium Signaling, Cell Differentiation, Cells, Cultured, Gene Expression Regulation, Homeostasis, Humans, Neurons, Neurotransmitter Agents, Organ Specificity, Phenotype, Potassium Channels, Inwardly Rectifying, Rats, Sodium Channels, Spinal Cord, Xenopus laevis},
	issn = {1476-4687},
	doi = {10.1038/nature02518},
	author = {Borodinsky, Laura N and Root, Cory M and Cronin, Julia A and Sann, Sharon B and Gu, Xiaonan and Spitzer, Nicholas C}
}
