@article{articled6673dfb,
title   = {Defensive freezing evoked by electrical stimulation of the periaqueductal gray: comparison between dorsolateral and ventrolateral regions},
author = {Vianna, Daniel Machado Luiz and Graeff, Frederico Guilherme and Brandão, Marcus Lira and Landeira-Fernandez, Jesus},
year = {2001},
doi = {10.1097/00001756-200112210-00049},
journal   = {Neuroreport}
}