Psycho physiological Effects of two Meditative States Described in yoga Texts.

Abstract

ABSTRACT BACKGROUND In ancient yoga texts, there are two meditative states described. One is dhäraëä, which requires focusing, the second is dhyäna, during which there is no focusing, but an expansive mental state is reached. The earlier study on changes in brainstem auditory evoked potentials following four mental states described in yoga texts viz., caïcalatä (random thinking), ekägratä (focusing without meditation), dhäraëä (focused meditation) and dhyäna (meditative defocussing or effortless meditation) showed significant increase in wave V peak latency during caïcalatä, ekägratä and dhäraëä but not in dhyäna (Kumar et al., 2010). The results suggest that dhyäna practice alone does not delay auditory information transmission at the brainstem level, whereas caïcalatä, ekägratä and dhäraëä showed delay in auditory information processing at the inferior collicular level since the wave V corresponds to that level. Another study assessed the performance in a cancellation task at the beginning and end of the four types of session viz., caïcalatä, ekägratä, dhäraëä, and dhyäna (Kumar & Telles, 2009). The performance in cancellation task improved significantly after dhäraëä and was worse after caïcalatä, suggesting better attention after dhäraëä. The changes in mid-latency auditory evoked potentials during these four mental states have not been studied.