@article {47036,
	title = {Dopamine is required for the neural representation and control of movement vigor.},
	journal = {Cell},
	volume = {162},
	year = {2015},
	month = {2015 Sep 10},
	pages = {1418-30},
	abstract = {<p>Progressive depletion of midbrain dopamine neurons (PDD) is associated with deficits in the initiation, speed, and fluidity of voluntary movement. Models of\&nbsp;basal ganglia function focus on initiation deficits; however, it is unclear how they account for deficits in the speed or amplitude of movement (vigor). Using an effort-based operant conditioning task for head-fixed mice, we discovered distinct functional classes of neurons in the dorsal striatum that represent movement vigor. Mice with PDD exhibited a progressive reduction in vigor, along with a selective impairment of its neural representation in striatum. Restoration of dopaminergic tone with a synthetic precursor ameliorated deficits in movement vigor and its neural representation, while suppression of striatal activity during movement was sufficient to reduce vigor. Thus, dopaminergic input to the dorsal striatum is indispensable for the emergence of striatal activity that mediates adaptive changes in movement vigor. These results suggest refined intervention strategies for Parkinson{\textquoteright}s disease.</p>
},
	doi = {10.1016/j.cell.2015.08.014},
	author = {Panigrahi, Babita and Martin, Kathleen A and Li, Yi and Graves, Austin R and Vollmer, Alison and Olson, Lars and Mensh, Brett D and Karpova, Alla Y and Dudman, Joshua T}
}
@article {45458,
	title = {Behavioral variability through stochastic choice and its gating by anterior cingulate cortex.},
	journal = {Cell},
	volume = {159},
	year = {2014},
	month = {2014 Sep 25},
	pages = {21-32},
	abstract = {<p>Behavioral choices that ignore prior experience promote exploration and unpredictability but are seemingly at odds with the brain{\textquoteright}s tendency to use experience to optimize behavioral choice. Indeed, when faced with virtual competitors, primates resort to strategic counterprediction rather than to stochastic choice. Here, we show that rats also use history- and model-based strategies when faced with similar competitors but can switch to a "stochastic" mode when challenged with a competitor that they cannot defeat by counterprediction. In this mode, outcomes associated with an animal{\textquoteright}s actions are ignored, and normal engagement of anterior cingulate cortex (ACC) is suppressed. Using circuit perturbations in\&nbsp;transgenic rats, we demonstrate that switching between strategic and stochastic behavioral modes is controlled by locus coeruleus input into ACC. Our\&nbsp;findings suggest that, under conditions of uncertainty about environmental rules, changes in noradrenergic input alter ACC output and prevent erroneous beliefs from guiding decisions, thus enabling behavioral variation.</p>
},
	issn = {1097-4172},
	doi = {10.1016/j.cell.2014.08.037},
	author = {Tervo, Dougal G R and Proskurin, Mikhail and Manakov, Maxim and Kabra, Mayank and Vollmer, Alison and Branson, Kristin and Karpova, Alla Y}
}
