Limericks are good for your health. Or for remembering disinhibition anyway.

Some of you may remember that we ran a limerick competition. Well we now have a winner. Alison Klossner, by popular vote, has taken out the very big prize of a few hundred dollars worth of Cynergy Professional education seminars.  Alison’s limerick captures that intriguing pathophysiological characteristic of people in chronic pain – cortical disinhibition. In particular, it is referring to a mechanism that is thought to underpin the decrease in tactile acuity that occurs as pain persists.  Clinically, we can detect this as an increase in two point discrimination threshold (TPD), accompanied by normal tactile perception threshold (eg Moseley GL. I can’t find it! Distorted body image and tactile dysfunction in patients with chronic back pain).  Imaging studies reveal ‘cortical reorganisation’ that is characterised by overlap of S1 receptive fields (eg Maihofner C. et al. Patterns of cortical reorganization in complex regional pain syndrome). This is different to cortical reorganisation that is characterised by increased precision of receptive fields, such as that seen for the left fingers of violinists (eg Elbert T et al., Increased cortical representations of the fingers of the left hand in string players).  Tactile acuity depends on cortical inhibition and when cortical inhibition is lost, DISinhibition, tactile acuity suffers. Treatment aimed at increased tactile acuity has some positive effects in people with phantom limb pain (Flor H et al., Effect of sensory discrimination training on cortical reorganisation and phantom limb pain or CRPS (eg Moseley GL, et al., Tactile discrimination, but not tactile stimulation alone, reduces chronic limb pain).  So, congratulations Alison on a great limerick and a great way to remember the concept of cortical disinhibition. I can just imagine the S1 cell with hands on hips, leaning with attitude, and saying ‘yah, like, wot evah!’

A S1 cell is in the Queue
But its moments to fire are few
When its voltage retires
By its neighbor it fires
Saying “I’m so disinhibited with you”
-Alison Klossner

References

ResearchBlogging.org

Moseley GL (2008). I can’t find it! Distorted body image and tactile dysfunction in patients with chronic back pain. Pain, 140 (1), 239-43 PMID: 18786763

Maihöfner C, Handwerker HO, Neundörfer B, & Birklein F (2003). Patterns of cortical reorganization in complex regional pain syndrome. Neurology, 61 (12), 1707-15 PMID: 14694034

Elbert T, Pantev C, Wienbruch C, Rockstroh B, & Taub E (1995). Increased cortical representation of the fingers of the left hand in string players. Science (New York, N.Y.), 270 (5234), 305-7 PMID: 7569982

Flor H, Denke C, Schaefer M, & Grüsser S (2001). Effect of sensory discrimination training on cortical reorganisation and phantom limb pain. Lancet, 357 (9270), 1763-4 PMID: 11403816

Moseley GL, Zalucki NM, & Wiech K (2008). Tactile discrimination, but not tactile stimulation alone, reduces chronic limb pain. Pain, 137 (3), 600-8 PMID: 18054437