Updated On: 16 August, 2014 11:16 AM IST | | Agencies
<p>Know why do you feel drowsy after a bad night's sleep? The answer lies in a few nerve cells in you brain that may control the switch between internal thoughts and external distractions</p>

New York: Know why do you feel drowsy after a bad night's sleep? The answer lies in a few nerve cells in you brain that may control the switch between internal thoughts and external distractions.
A critical part of the brain called thalamic reticular nucleus (TRN) that influences consciousness holds the key.