Regulation of extracellular serotonin levels and brain-derived neurotrophic factor in rats with high and low exploratory activityMällo, Tanel; Kõiv, Kadri; Koppel, Indrek; Raudkivi, Karita; Uustare, Ain; Rinken, Ago; Timmusk, Tõnis; Harro, JaanusBrain research2008 / p. 110-117 : ill https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2568862/