Comment on “Molecular and neural basis of contagious itch behavior in mice”

Abstract

Yu et al. (Reports, 10 March 2017, p. 1072) state that contagious itch occurs in mice based on imitative scratching in normal mice observing excessive scratching in genetically modified demonstrator mice. However, despite employing multiple behavioral analysis approaches, we were unable to extend these findings to normal mice observing the well-established histamine model of acute itch in demonstrator mice.

The mouse model of fragile X syndrome exhibits deficits in contagious itch behavior

“…The original discovery from Yu et al that mice exhibit visually transmitted contagious itch has been controversial 10 . Liljencrantz et al failed to reproduce contagious itch behavior with the adjacent home cages method from Yu et al 20 Barry et al then replied, strongly suggesting the use of the screen paradigm 21 . Later, Lu et al could not identify contagious itch behavior with a modified version of the screen paradigm from Yu et al, which removed the necessity to quantify look behavior 17 .…”

Response to Comment on “Molecular and neural basis of contagious itch behavior in mice”

“…lthough we (1) and Liljencrantz et al (2) used the same strain of mice, their experimental design was different from ours in several important aspects. Limiting factors complicate the detection of imitative scratch behavior in mice.…”

Central circuit mechanisms of itch

“…However, other groups 102,103 failed to reproduce the imitative scratching behavior in normal mice observing demonstrator mice receiving histamine application, nor did they detect significant temporally contiguous scratching in observer mice. In addition, the total scratching bouts during the entire observation period was also not different between observers and control mice 103 . Similarly, another study also failed to replicate contagious scratching in mice using an itching video-based paradigm, whereas itch sensation and responses were successfully elicited in humans 102 .…”