THEORIES OF PAIN: GATE CONTROL THEORY (Melzack & Wall 1965)

Question 1

Define the Gate Control Theory?

Answer 1

A theory that proposes
* The dorsol horn (in the spinal cord) contains a gate that either prevents/ allows pain signals from reaching the brain.

Question 2

What does the theory help to explain?

Answer 2

• WHY our emotional state or expectations affect pain perception

Question 3

Where is the dorsal horn located?

Answer 3

Spinal cord

Question 4

Dorsal horn

Answer 4

• Area of the spinal cord where the gating mechanism occurs.
• Recives info from SNF + LNF and sends this info to the brain.

small and large nerve fibres

Question 5

What are small nerve fibres?

Answer 5

• Pain fibres

Question 6

What are large nerve fibres?

Answer 6

• Fibers for touch, pressure (other skin sensations)

TOP

Question 7

The dorsal horn contains a gate. Which can open and close based on the….?

Answer 7

• Based on the relative activity of certain fibers.

Question 8

The Dorsal Horn recieves..

Answer 8

• Recives info from small nerve fibers and large nerve fibers.
• And sends this info to the brain.

Question 9

STAGE 1: EXPLAIN THE PROCESS OF PAIN ACCORDING TO THE GCT

Answer 9

1. Pain signals travel from the body –) Spinal cord
   (Through nerve fibres)

Question 10

STAGE 2: EXPLAIN THE PROCESS OF PAIN ACCORDING TO THE GCT

Answer 10

• The dorsal horn in the spinal cord contains a “gate”
• It can open an close (based on the relative activity of certain fibres)

Question 11

STAGE 3: EXPLAIN THE PROCESS OF PAIN ACCORDING TO THE GCT

Answer 11

• If small nerve fibres are MORE active (in response to injury) -) Gate opens -) Allowing pain signals to reaching the brain
• If large nerve fibres are activated-) they can inhibit the activity of SNF and close the gate-)- reducing pain signals from reaching the brain.

Large nerve fibers can be activated by rubbing pain area

Question 12

Why does rubbing the injured area simulate large nerve fibres? and thus reduce pain?

Answer 12

• Competition= The brain can only process so many signals at once, so the brain is distracted by touch signals

Reducing intensity of pain signals

Question 13

What OPENS the gate?

Answer 13

1. Physical injury
2. Emotional factors (stress, anxiety, depression)
3. Behavioural factors (focusing on the pain)

Question 14

What CLOSES the gate?

Answer 14

1. Analgesics (asprin)
2. Emotional factors: Postive moods
3. Behavioural factors: Focusing on things other than injury. Rubbing injured area.

Question 15

Strengths of the Gate Control Theory

Answer 15

• EXPLAINS VARIABILITY IN PAIN: helps explain why people experince pain differently, despite having similar injuries/ stimuli

Question 16

Weaknesses of the Gate Control Theory

Answer 16

• Reductionist:
• Simplifies pain modulation to a “gate” mechanism in the spinal cord.
• Despite modern understanding showing that pain involves complex interactions across the CNS

Pain modulation= the body’s way of adjusting how strong pain feels

Question 17

Why is the gate control theory reductionist?

Answer 17

• Simplifies pain modulation to a “gating” mechanism in the spinal cord.