The dopaminergic system dynamic in the time perception: a review of the evidence.

Dopaminergic system plays a key role in perception, which is an important executive function of the brain. Modulation in dopaminergic system forms an important biochemical underpinning of neural mechanisms of time perception in a very wide range, from milliseconds to seconds to longer daily rhythms. Distinct types of temporal experience are poorly understood, and the relationship between processing of different intervals by the brain has received little attention. A comprehensive understanding of interval timing functions should be sought within a wider context of temporal processing, involving genetic aspects, pharmacological models, cognitive aspects, motor control and the neurological diseases with impaired dopaminergic system. Particularly, an unexplored question is whether the role of dopamine in interval timing can be integrated with the role of dopamine in non-interval timing temporal components. In this review, we explore a wider perspective of dopaminergic system, involving genetic polymorphisms, pharmacological models, executive functions and neurological diseases on the time perception. We conclude that the dopaminergic system has great participation in impact on time perception and neurobiological basis of the executive functions and neurological diseases.

Evoked Potential in Panic Disorder Patients: A Systematic Review.

Researchers have been using the electroencephalogram to better understand the cognitive and neurobiological bases of panic disorder (PD) through the P300 component; this is an electric potential of the cerebral cortex that is generated in response to external sensorial stimuli and which involves more complex neurophysiological processes related to stimulus interpretation; it is then used to investigate possible alterations in the information processing and attention of patients suffering from this disorder. Aiming to verify the results found by experimental articles already published about P300 in PD patients and the information processing differences between PD patients and healthy controls, a systematic review of the PubMed and Institute for Scientific Information databases was conducted. The selection criterion involved those articles, written in English, which referred to an experimental research that focused on the P300 component, with a sample composed of PD (or panic attacks) patients. Seven articles were found that fit the selected criteria. Most of the articles show that these patients suffer from: impaired information processing and attention, an inability to automatically respond to new stimuli, and impaired interpretation of internal and external stimuli related to the disorder. Such impairment may be related to an unspecified dysfunction in the limbic-reticular structures, which would affect: active, focused and short-term attention, working and short-term memory, recognition and decision making. Some limitations were highlighted, such as the use of small samples and possible comorbidity with other disorders, which did not allow clearer results. This research can contribute to understand the neurobiological differences of PD patients and develop treatments based on such evidence.