The practice of Yoga consists of three main activities: control of posture (asana), conscious control of breathing (pranayama), and control of mental activity (meditation). This review is focused on the possible role of Yoga (the combination of asana, pranayama, and dhyana), and pranayama and dhyana alone in generating measurable and observable changes in cognitive function and emotional control. To assess these changes, researchers adopted the following methods of investigation: magnetic resonance imaging (MRI), functional magnetic resonance imaging (fMRI), electroencephalography, and questionnaires regarding perceived emotional and psychological states. From the results obtained with MRI and fMRI, the main areas that resulted affected by the Yoga, pranayama and dhyana are the hippocampi, the amygdala, and the cerebral cortex. In detail, a higher activation and an increase in gray matter density or volume were found in the area of the hippocampus and the cerebral cortex, while a reduction in density and activation was found in the amygdala. These areas are crucial for the management of stress, emotional processes and cognitive control. The hippocampus is involved in memory processing and learning while the many positive changes in the cerebral cortex indicate a broader range of benefits (i.e. better emotional control, improved adaptive processes, fewer cognitive failures, better understanding, etc.), which will be different in regards of the cerebral cortex lobe taken under consideration. A high amygdala activation or density is an indicator of high-stress levels and emotional discomfort. The decreased activation and density reduction of the amygdala found in Yoga practitioners, paired with the questionnaires results, indicate a better response to stressful stimuli. These findings indicate how Yoga practitioners will benefit greatly from the practice and suggest how these activities could enhance positive neuroplastic modifications that could have, with the confirmation of further studies, interesting therapeutic consequences.
In recent decades, in the Western world has spread an ancient discipline from India, Yoga. The word Yoga comes from the Sanskrit root “yuj”, which can be translated as “union”, and indicates a very complex practice, closely linked to Indian culture, religious life, and traditions. Yoga consists mainly of three activities that are the control of posture (asana), breathing (pranayama) and meditation (dhyana). The posture control is determined by a number of positions that should be maintained for a minimum of 15 s to a maximum of variable duration depending on the position’s degree of difficulty, before moving on to the next one. The practice can become gradually more complex starting from simple positions that release the tensions of the spine, to those requiring prolonged strength and resistance. Pranayama is expressed first by observing and becoming aware of our natural breath and, later on, by the acquisition and exploration of different breath techniques. Finally, dhyana consists in experimenting a non-judgmental attitude towards the content of thought and, in an advanced phase, thoughts management and visualization. Its practices can be conducted into two different ways. On the one hand, “focused attention meditation” which concentrates on techniques that bring attention to a particular object of observation, be it mental, bodily or external; on the other, “open monitoring meditation” that resorts to techniques that seek to broaden the focus of all incoming information in each moment, whether they are sensations, emotions, and thoughts, without focusing on any of them. Nevertheless, most of the meditations use both approaches in a complementary way. A particular exercise that is similar in concept to meditation, but differs in its actualization, is the practice of reciting mantras, namely the rhythmic repetition of syllables and continuous, single words or short phrases for a certain period of time.