Mechanoreceptors, which are stretch sensors, respond to alveolar inflation Zodiac yoga poses and deflation, with electrical discharges that encode information sent to vagal afferents Yu, 2005. Zodiac yoga poses This input goes to the homeostatic system as an important form of peripheral feedback from the body to the brain, influencing emotional and cognitive processing, as described by Craig 2003 and Damasio 1999 see Sidebar 3. Alterations in respiratory patterns, registered by sensory receptors, change the visceral somatosensory input carried by vagal afferents to the brain. This may explain how different yoga breath techniques can lead to rapid changes in emotional states, cognitive processing, representations of bodily feeling states, and the reactions and behaviors linked to those feeling states.
Over time, yoga breathing tends to normalize SNS activity and increase PNS tone see Figure 3.1. The central autonomic network includes higher centers such as the medial prefrontal cortex mPFC that inhibit lower centers such as the amygdala Thayer & Brosschot, 2005. When the mPFC is hypoactive and the amygdala is hyperactive, as occurs in depression and post-traumatic stress disorder PTSD, the inhibitory mechanisms may fail to modulate emotions such as fear and anger, leading to dysregulation of emotional responses and behaviors.