Mind

  The mechanisms by which respiratory stimuli induce arousal from sleep and the clinical significance of these arousals have been explored by numerous studies in the last two decades.  Evidence to date suggests that the arousal stimulus in nonrapid eye movement sleep (NREM) is related to the level of inspiratory effort rather than the individual stimuli that contribute to ventilatory drive.  A component of the arousal stimulus proportional to the level of inspiratory effort may originate in mechanoreceptors either in the upper airway or respiratory pump.  Medullary centers responsible for ventilatory drive may also send a signal proportionate to the level of drive to higher centers in the brain which are responsible for arousal.  Thus, the arousal stimulus may consist of multiple components, each increasing as inspiratory effort increases.  The level of effort triggering arousal is an index of the arousability of the brain (arousal threshold).  A deepe...

  Neuro-biology of Sleep By Dr.Manvir Bhatia & Ananya Sleep is an important and essential part of our lives. It rejuvenates us from all the fatigue.  However, sleep is a very complex phenomenon. It mainly consists of alternating phases of the rapid eye movement (REM) and the non-eye eye (NREM) phase.  The NREM is the first phase of sleep and consists of three phases followed by REM sleep.  The first stage of NREM sleep lasts only for the initial ten minutes when we start falling asleep. Muscle activity and eye movement start slowing down.  The second and third stages are those of deep sleep. The brain waves become slower, and  during stage 3, there is the presence of delta waves.  This is followed by REM sleep, during which brain activity is the same as that in the awakened state. It is characterized by heavy breathing, an increased heart rate, rapid eye movement, and muscle atonia.  Read on…