See One, Do One: Watching Action Boosts Brain Volume, Ability

Pauline Anderson

February 27, 2014

Watching a video demonstration of a simple right-handed activity, such as using a fork or a hammer, appears to affect brain volume and improve the ability of the viewer to perform that task, according to a new study.

"This is a preliminary study, considering the relatively small number of subjects, but it's quite interesting to see that just looking at videos, we can improve our ability to ameliorate our motor performance in a very significant way," said lead researcher Paolo Preziosa, MD, a resident in neurology at San Raffaele Hospital, Milan, Italy.

According to Dr. Preziosa, the results highlight the importance of plasticity, or the ability of the brain to adapt to environmental conditions, and support the possible role of the so-called mirror neuron system, in which neurons fire not only when a person acts but also when he or she observes the same action being performed by someone else.

Dr. Preziosa carried out the study along with principal investigator Massimo Filippi, MD, director of the Neuroimaging Research Unit, Department of Neurology, Scientific Institute and University "Vita e Salute," Ospedale San Raffaele in Milan.

The research was released February 18 and will be presented at the upcoming 66th Annual Meeting in American Academy of Neurology (AAN) meeting in Philadelphia.

Training Sessions

The study included 36 healthy right-handed persons who had no outstanding motor ability (eg, none were experienced piano or tennis players). Researchers assessed each participant's hand strength with a dynamometer and evaluated manual dexterity by counting the number of times each participant could tap his or her second finger on a mouse and the ability to put wooden pegs into holes, before and after a training session.

The10-day motor training sessions consisted of daily 10-minute passive mobilization exercises using the right hand. Also every day, participant watched 3 different 5-minute videos: Half watched nonaction landscapes scenes, such as mountains and sea shores (the environment group), while the others watched videos demonstrating simple everyday activities, such as using a hammer, cutting with a knife, or writing with a pencil (the action observation therapy, or AOT, group).

After watching the videos, both the environmental and AOT groups received instructions on performing specific actions and were asked to execute or imitate each demonstrated task with their right hand.

To assess the longitudinal volume variation of the different brain regions, researchers acquired 3-dimensional T1-weighted sequence scans using a 3-Tesla MRI scanner, before and after the training session.

The researchers found that the AOT participant who completed the training and watched the activity videos had a greater improvement of motor skill abilities, mainly in terms of strength, compared with those who watched the landscape videos, said Dr. Preziosa.

There were also changes in the brain. Volumetric changes in different brain regions after training were correlated with better motor performance in both groups.

"As expected, and as shown by previous studies, motor training determined structural brain changes in both groups, in term of volume, especially in regions of the motor network (the primary sensorimotor cortex and the cerebellum), in the visual network (the occipital cortex), and in regions related to cognitive functions, such as the cingulum," said Professor Filippi.

"After training, we found not only brain regions with an increased volume, suggesting that these might be more used and activated during such training, but also other regions that showed a reduced volume, which might be due to an 'optimization' of the wiring of networks involved in performing specific motor functions," he added.

Group Differences

But there were also some differences between the 2 groups. Those watching the action videos had an increased volume of the right cuneus and right insula and reduced volume in the right supplementary motor area. The environmental group had a decreased volume of several fronto-parieto-occipital regions, right middle and anterior cingulum, and right cerebellum.

Compared with the environmental group, the AOT group had an increased volume of the gray matter of the right cerebellum and left inferior frontal gyrus, which, importantly, is one of the main locations of mirror neurons.

The better improvement obtained in the AOT group may be due to the activation of this "mirror neuron system" and brain plasticity, said Dr. Preziosa. "If you watch videos of someone performing one action, this probably activates this system, and this might improve the ability of the brain to compensate for damage in patients with clinical impairment," said Professor Filippi.

The research could have implications for improving motor performance of patients with neurologic diseases and those who have lost the use of their hands, said Professor Filippi. He and his colleagues — including Dr. Preziosa — are already testing this notion on patients with multiple sclerosis.

The study was supported by the Italian Foundation for Multiple Sclerosis.

American Academy of Neurology (AAN) 66th Annual Meeting, Philadelphia, April 26 to May 3, 2014. Abstract 1074.

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