View the peer-reviewed version (peerj.com/articles/2818), which is the preferred citable publication unless you specifically need to cite this preprint. Mild traumatic brain injury typically involves temporary impairment of neurological function. Previous studies used the water pressure or rotational injury for designing the device to make a rat mild traumatic brain injury model. The objective of this study was to make a simple model of mild traumatic brain injury in rat. The device consisted of a freefall impactor that was targeted onto the rat skull. The weight (175g) was freely dropped 30cm to rat's skull bregma. We installed a safety device made of acrylic panel. (Collins et al. 1999). Actually, hospital-treated MTBIs are no more than 26 100 to 300/100,000 (Harmon et al. 2013). Neurological, cognitive and behavioral deficits, caused 27 by MTBIs, are observed only for a short period of time. A headache, vomiting, cognitive slowing, 28 fatigue, dizziness, depression, and problems with attention and memory can be one of its 29 symptoms (d'Hemecourt. 2011; 39 However, such a damaging mechanism, which delivered shock to their head and fell down them, 40 could not induce MTBIs alone. In another study, shocks were delivered to the craniums of rats 41 equipped with helmet disks, but it was also complicated to put the helmet disk (Xu et al. 2014). 42 In the case of a method suggested by Tang et al., it was comparatively simple and did not cause 43 skull fracture
