RESEARCH ARTICLE Open Access Behavioral characterization

Parkinson’s disease (PD) is a complex neurodegenerative chronic disease affecting the dopaminergic system. First described by James Parkinson in 1817 [1], this disease affects mainly the substantia nigra pars compacta (SNc), also designated as area A9, where a massive dopaminergic degeneration takes place [2-4]. This brain area is the origin of the mesostriatal dopaminergic projections to the caudate/putamen complex [5]. Thus, degeneration in this pathway causes functional disruption of basal ganglia’s cir-cuitry [6], and the emergence of several physical hallmarks of PD, such as bradykinesia and tremors [7]. Though to a lesser extent, the mesocorticolimbic dopaminergic path-way, originated in area A10, is also affected as the disease progresses [8-11]. This event will lead to the development of several non-motor features of PD including depression, apathy, anhedonia, and dementia [8,12-14]. Although it was somewhat disregarded in the past, more recent evidence has shown that mood and cognitive change