Bhagavad Gita 8.12
Closing the gates of the body, drawing the forces of his mind into the heart, and, by the power of meditation, concentrating his vital energy in the brain;
सर्वद्वाराणि संयम्य मनो हृदि निरुध्य च।
मूर्ध्न्याधायात्मनः प्राणमास्थितो योगधारणाम्॥sarvadvārāṇi saṃyamya mano hṛdi nirudhya ca|
mūrdhnyādhāyātmanaḥ prāṇamāsthito yogadhāraṇām||
English translation (above): Shri Purohit Swami (1935), public domain. Sanskrit text via github.com/gita/gita (Unlicense).