Moving in response to an unseen visual stimulus.

Objective: Whether consciousness has a causal role in voluntary movements is not clear. Backward masking blocks a stimulus from becoming conscious, but it can trigger movement in a reaction time paradigm. We hypothesize that if backward masking is used in a choice reaction time paradigm, when the visible stimulus (S2) differs from the masked stimulus (S1), the movement will often differ from conscious intent.

Prevalence of anxiety and depression risk during the prepartum period in the different groups of women and responses from the Italian National Health Service.

Background: Specific screening for anxiety and depression in pregnant women is important to identify those at risk and to provide timely intervention. The aims of the study were: 1) to compare the risk of anxiety and depression in four groups of pregnant women belonging to four types of healthcare centers distinguished by the level of risk: at low-risk; at high-risk for an obstetric reason; at high-risk for fetal anomalies; at high-risk for psychiatric conditions and 2) to identify the response that the National Health Service offers to women positively screened for anxiety and depression.

Methods: A cross-sectional study was conducted on 2801 pregnant women, cared for by National Health Service, divided into four groups: 1) low-risk pregnancy (N.

Physiological and introspective antecedents of tics and movements in adults with tic disorders.

Objective: To investigate the subjective phenomenon and the neural underpinnings of tics compared with voluntary movements in patients with tic disorders.

Methods: We recorded electroencephalographic and electromyographic data while subjects completed a Libet clock paradigm. Patients and healthy volunteers reported the times of W (willing to move) and M (movement occurrence) while performing voluntary movements.

What is the intention to move and when does it occur?

In 1983 Benjamin Libet and colleagues published a paper apparently challenging the view that the conscious intention to move precedes the brain's preparation for movement. The experiment initiated debates about the nature of intention, the neurophysiology of movement, and philosophical and legal understanding of free will and moral responsibility. Here we review the concept of "conscious intention" and attempts to measure its timing.