Interestingly, while increased attention may help compensate for difficulty initiating voluntary actions, it may interfere with habitual actions, such as walking. People with FND may be more focused on consciously controlling their actions because they have trouble doing this. Participants with FND made more precise judgements of when they became aware of the intention to move when compared to healthy controls, perhaps indicating greater attention to movement initiation. Impaired (or delayed) awareness of the will to move in FND may result in sense of decreased voluntariness and control of their movements.” Lead author Kwangyeol Baek commented, “Libet’s seminal study (1983) and following studies of volition in neuroscience suggest that ‘voluntariness’ can be an illusory feeling occurring from that a person is aware of his/her own action intention ahead of actual movement. This may suggest that positive motor symptoms in particular are the result of decreased ability to consciously ‘veto’ unconsciously initiated actions. This delay was particularly evident in patients with positive motor symptoms (e.g., tremor) compared to those with negative symptoms (e.g., weakness). They also measured the strength of connections, or functional connectivity, between brain areas associated with intentional movement whilst participants were resting.įindings, published earlier this year in Psychological Medicine, showed delayed awareness of intention to move relative to the movement itself in FND patients compared to healthy controls. The research team measured brain activity whilst participants completed the task. Twenty-five FND patients and 24 healthy controls completed Libet’s clock task while having a functional MRI scan. In their recent study, the group from Cambridge hypothesised that patients with FND would be aware of the intention to move for a shorter time before the movement occurred, suggesting an impairment in the awareness of the ‘will’ to move. Libet suggested that the time between awareness of the intention and the movement itself (typically 200ms) is important for conscious control of actions, as it was in this time that actions could be consciously ‘vetoed’. Libet measured brain activity using electroencephalography (EEG) whilst people were doing this task, and he found that brain activity associated with finger movement occurred before participants were aware of their intention to move their finger. Libet’s clock task requires people to move their finger whilst watching a clock, and note the time when they intended to move their finger (referred to as ‘W judgements’) and the time when they felt the movement occur (referred to as ‘M judgements’). To do this, they used a task called Libet’s clock, which was first devised in the 1980s to study consciousness. A team of researchers at the University of Cambridge and Addenbrooke’s hospital aimed to discover how conscious awareness of movement initiation may be altered in FND. The symptoms of FND may be caused by reduced conscious processing of sensations and actions. Lead authors on the study Nuria Doñamayor (Left) and Kwangyeol Baek (Right)
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