• mice show equal performance to wild-type in the hanging grid test and forced swim test, and show almost no impairment of the righting reflex (J:100971)

• double mutants are unable to remain on the rotating rod

• in 3-month old mice, dilated axons are observed, but numbers are reduced ~10-fold compared to Tg(Thy1-MAPT)2Vln homozygotes in spinal cord and cerebral cortex

• axonal dystrophic changes are dramatically reduced in mice expressing both transgenes

• quadriceps is normal and devoid of any muscle wasting (J:100971)

• when lifted by tail, homozygotes flex the hind limbs, in contrast to wild-type which extend legs

• compared to wild-type mice, mutants are 90 times more likely to fall off of a rotating rod in a rotarod test; (J:100972)

• in 3 month old mice, dilated axons are detected in the spinal cord and cerebral cortex, although numbers are fewer than in Tg(Thy1-MAPT)1Vln homozygotes

• cytoskeletons of dilated axons are disrupted, with numerous randomly oriented microtubules engirdling accumulations of pleomorphic vesicles, dense-cored vesicles, and smooth endoplasmic reticulum; ratio of microtubules to neurofilaments in dilated axons is high relative to normal axons

• grouping of atrophic fibers and fascicular atrophy are observed