What is transduction in pain processing?

• A. Transmission of pain to brain
• B. Awareness of pain
• C. Activation of pain receptors
• D. Modification of pain

Answer: (C)

Transduction is the first step in pain processing, where a noxious stimulus is converted into an electrical signal by activating peripheral nociceptors, the pain receptors. The stimulus opens ion channels in these free nerve endings, creating a receptor potential that triggers action potentials traveling toward the central nervous system. Inflammation or tissue injury can release mediators like prostaglandins or bradykinin that lower the threshold of these receptors, making them more responsive. This stage is distinct from transmission (carrying the signal along nerves to the spinal cord), perception (the conscious awareness of pain), and modulation (the CNS’s ability to amplify or dampen pain signals). So activating pain receptors is the transduction process.