Katha Upanishad Verse 2.3.16

The Upanishad describes the exit of the soul at the time of death. Among the hundred and one nerves (nadis) radiating from the heart, one (the Sushumna) leads directly to the crown of the head. Taking this upward path leads to immortality, while others lead back to various realms of rebirth.

Sanskrit Verse

शतं चैका च हृदयस्य नाड्यस्तासां मूर्धानमभिनिःसृतैका ।
तयोर्ध्वमायन्नमृतत्वमेति विष्वङ्ङन्या उत्क्रमणे भवन्ति ॥ १६ ॥

Transliteration

śataṃ caikā ca hṛdayasya nāḍyastāsāṃ mūrdhānamabhiniḥsṛtaikā |
tayordhvamāyannamṛtatvameti viṣvaṅṅanyā utkramaṇe bhavanti || 16 ||

Translation

A hundred and one are the nerves of the heart. Of them, one has gone out piercing the head; going up through it, one attains immortality; others at the time of death lead different ways.