The activation of nociceptive pathway and the preserved tactile pathway after sensory nerve injury

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K21387
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Basic / Social brain science; Neurophysiology / General neuroscience
• Research Institution: Tokyo Women's Medical University
• Principal Investigator: Osaki Hironobu 東京女子医科大学, 医学部, 助教 (30747697)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: イメージング / 視床 / 大脳皮質 / 神経損傷 / 触覚 / 痛覚

Outline of Final Research Achievements

Peripheral nerve injury modifies the ascending neural pathway. To identify the modified pathway, in vivo intrinsic signal imaging system and a transgenic mouse (Krox20-Ai32) were used. The Krox20-Ai32 mouse expresses channel-rhodopsin (ChR2) selectively in the maxillary region of the principal trigeminal nucleus. By using this mouse, the whisker sensory related area in the primary somatosensory cortex (S1), known as barrel field, can be activated. There was no difference in the sizes of barrel field before and after whisker sensory nerve transection. This means that the tactile pathway into the cortex is preserved. It is also known that the threshold of nociceptive response becomes lower after nerve injury. By using the intrinsic signal imaging, the activation of the nociceptive responsive area in S1 was observed after nerve injury. This means peripheral nerve injury activated nociceptive pathway. These results suggest that the basic mechanism of “phantom limb pain”.

Free Research Field

神経生理学