Why pain?

  1. Most common reason to seek medical attention: pain.

  2. Little success in translating laboratory findings to treatments for patients.

  3. Need for a nonsubjective method to measure "pain", a subjective experience.

Comparison of analgesic drugs

for osteoarthritis across species

TBD: To Be Determined


Functional magnetic resonance imaging (fMRI)

Deoxygenated hemoglobin

(Paramagnetic - decreasing magnetic resonance signals)

Decreasing blood flow

Oxygenated hemoglobin


Increasing blood flow

Once nerve cells are activated, local blood flow increases with oxygenated hemoglobin to supply oxygen, and the ratio of deoxygenated hemoglobin, which distorts local magnetic fields, decreases. This results in increased magnetic resonance signals. 

Brain activation = Increased MRI signal


PAG periaqueductal grey

S2 secondary somatosensory area


High brain activity

Nature Reviews Neurology 5(4):199-209, 2009


Stimulation for fMRI

Minimum 10 sets (15 minutes)
OFF/ON 1 set:
30 sec, 10 frames
OFF : resting state
ON : pain state

After scanning, a statistical map is produced, showing areas of activation following stimulation. The brain activation is statistically calculated by analyzing "OFF" and "ON" data sets. 

x : a raw score

µ : mean

σ : standard deviation

if z > 1.96, p < 0.05


fMRI can be applied to various NHP pain models

In vivo brain activation can be observed across NHP pain models

  • Chemotherapy-induced neuropathic pain

  • Postoperative pain

  • Visceral pain

  • Sciatic nerve ligation

  • Endometriosis

*Information described in this page is referred from the following publications.

  • Hama et al. Pain Research and Management. 2018

  • Ogawa et al. European Journal of Pharmacology. 2016

  • Ogawa et al. Osteoarthritis and Cartilage. 2016

  • Hama et al. CNS & Neurological Disorders - Drug Targets. 2016

  • Hama et al. CNS & Neurological Disorders -  Drug Targets. 2013


Please contact us for more details concerning our NHP models and services

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