GATE CONTROL THEORY (MELZACK & WALL)

Question 1

What is the Gate Control Theory by Melzack and Wall?

Answer 1

Proposes that the dorsal horn of the spinal contains a ‘nerve gate’ which regulates pain signals, and opens and closes based on the relative activity of large and small nerve fibers, which determine whether pain signals enter the brain. These fibers can be affected by psychological, emotional, behavioural factors.

Question 2

What is the dorsal horn?

Answer 2

Specific region in the spinal cord which processes sensory information from the peripheral nervous system via nerve fibers and then sends this information to the brain.

Question 3

What are small nerve fibers?

Answer 3

Transmit pain signals + percieve sharp and intense pain.

Question 4

What are large nerve fibers?

Answer 4

Transmit non-painful stimulus (touch and vibrations)

Question 5

The nerve gate is NOT a….

Answer 5

…NOT a physical structure, but a process that processes and transmits pain signals

Question 6

What factors can stimulate small nerve fibers to open the gate?

Answer 6

• Stress, focusing on the pain, mood disorders (depression + anxiety) can enhance the activity of small fibers, increasing pain intensity.

Question 7

What factors can stimulate the large nerve fibers and close the gate?

Answer 7

• Rubbing the area (competing signals)
• Analgesics (NSAIDS/Painkillers)
• Distractions

Question 8

Summarise the gate control theory process

Answer 8

1. Pain stimulus- when there is pain/ noxious stimulus- pain signals are transmitted from the peripheral nervous system and sent to the dorsal horn through nerve fibers.
2. Dorsal horn- where the nerve gate is located processses these pain signals, sending them to the brain.
3. The gate opens/ closes based on the relative activity of small/ large nerve fibers.
4. If small nerve fibers are more activity in response to injury, the gate opens allowing pain signals to reach the brain .
5. If large nerve fibers are more active in response to injury, the gate closes, preventing nerve signals from entering the brain.

Question 9

Name 1 strength and 1 weakness of the gate control theory?

Answer 9

Strengths (good explanatory power): Helps explain why people with similar injuries percieve and experience pain differently, and why factors like mood can influence pain perception.
Weakness (reductionist): simplifies pain modulation to a “gate” mechanism within the spinal cord, even though modern understanding shows that Pain involves complex interactions across many parts of the nervous system, especially in the brain, which the theory doesn’t fully explain.