The blink reflex and its modulation - Part 1: Physiological mechanisms

Area of Science:

• Neurophysiology
• Brainstem Reflexes

Background:

• The blink reflex (BR) is a crucial protective eye-closure reflex mediated by brainstem circuits.
• While commonly elicited by electrical stimulation, BR modulation by various sensory inputs is less understood.
• BR has a significant history in clinical neurophysiology.

Purpose of the Study:

• To provide a state-of-the-art overview of blink reflex modulation.
• To explore how different neurophysiological techniques can examine BR modulation.
• To highlight the importance of understanding BR modulation for clinical applications.

Main Methods:

• Review of talks from the Brainstem Special Interest Group at the International Congress of Clinical Neurophysiology 2022.
• Examination of various neurophysiological techniques for BR modulation analysis.
• Discussion of classical conditioning, prepulse, and paired-pulse stimulation.

Main Results:

• Various methods, including conditioning and stimulation techniques, can investigate BR modulation.
• BR can quantify top-down modulation based on stimulus context.
• Understanding nociceptive and non-nociceptive fiber roles is crucial for neural circuitry insights.

Conclusions:

• Understanding BR modulation principles is fundamental for valid clinical applications.
• BRs under general anesthesia may offer insights into brainstem functions not accessible in awake humans.
• This review consolidates current knowledge on BR physiology and modulation.