How do A delta nerve fibres produce the first sharp sensation of acute pain?

A delta nerve fibres are responsible for the initial, sharp sensation of acute pain due to their specific physiological structure and conduction speed. These fibres are characterized by a thin myelin covering, which allows them to conduct electrical impulses from tissues to the spinal cord more rapidly than unmyelinated fibres.1

When activated by mechanical or thermal stimuli, these fibres transmit signals that the brain interprets as a well-localized, quick sensation of pain. This process represents the first phase of the dual-phase experience of acute pain, preceding the slower, lingering sensation mediated by C fibres. Once these impulses reach the spinal cord, they synapse in the dorsal horn and are transmitted to the brain via the spinothalamic tract, which is associated with the conscious perception of pain.1