Dissertação
{en_GB=Manipulations of striatal temperature cause dose dependent changes in duration judgments} {} EVALUATED
{pt= , en=Time, like space, is a fundamental dimension of animals’ worlds. To behave adaptively, organisms must extract temporal structure from experience and construct temporally patterned behavior. The striatum is the main input of the basal ganglia and has been implicated in several time-dependent functions such as reinforcement learning and timing behavior. Previous work from the lab manipulated and recorded the activity of striatal neurons while rats performed an interval categorization psychophysical task. It was found that simultaneously recorded neuronal ensembles could judge time as well as the animal and that striatal neurons were necessary for duration judgments, as muscimol infusions produced a clear decrease in temporal sensitivity. Lastly, these studies showed that time was encoded in the speed of population dynamics: faster dynamics were correlated with longer duration judgments and vice-versa. To directly assess whether variability in the speed of striatal population dynamics causes variability in duration judgments, we experimentally manipulated striatal temperature during task performance using a custom-made thermoelectric device. Behavioral sessions were divided in fixed-time blocks: control blocks (in which the device was set to body temperature), interspersed with manipulation blocks (in which the temperature changed between different doses). Here we show that cooling/warming striatal tissue caused graded underestimation/overestimation of duration, respectively. Critically, motor-related variables were not affected. These data strongly support the hypothesis that dynamics in neural populations underlie duration estimation, and establish the dorsal striatum as a locus within neural circuitry where a decision variable related to elapsed time and independent of motor function may be manipulated.}
novembro 26, 2018, 15:0
Publicação
Obra sujeita a Direitos de Autor
Orientação
ORIENTADOR
Patrícia Margarida Piedade Figueiredo
Departamento de Bioengenharia (DBE)
Professor Auxiliar
