TITLE:
Qualitative Comparison between Rats and Humans in Quadrupedal and Bipedal Locomotion
AUTHORS:
Taisei Hosoido, Futoshi Mori, Keita Kiyoto, Takashi Takagi, Yukari Sano, Megumi Goto, Katsumi Nakajima, Naomi Wada
KEYWORDS:
Human; Rat; Evolution; Posture; Locomotion; Bipedal; Quadrupedal
JOURNAL NAME:
Journal of Behavioral and Brain Science,
Vol.3 No.1,
February
27,
2013
ABSTRACT:
Bipedal (Bp) locomotion is one of the most characteristic motor
behaviors in human beings. Innate quadrupedal (Qp) four-legged animals also
often walk bipedally. The walking posture, however, is significantly different
between the two. This suggests that although both have a potential to walk
bipedally, however, the human has a body scheme suitable for Bp locomotion,
probably its skeletal system. The skeletal system includes the lumbar lordosis,
sacral kyphosis, a round pelvis, a large femur neck angle, short feet, and so
on. To verify this hypothesis, we compared kinematic and EMG activities
between rats and humans during Qp and Bp locomotion on a treadmill belt. The
rat is a representative Qp animal, but it is able to acquire Bp walking
capability with motor learning. Although the mobile ranges of the hindlimb
joint are different during each locomotor pattern between rats and humans, both
showed replicable flexion and extension excursion patterns for
each joint depending on the locomotor phase. There are many phase-locked EMG
bursts between rats and humans during the same walking task and these are
observed in the proximal rather than the distal muscles. This suggests that
both rats and humans utilize similar neuronal systems for the elaboration of Qp
and Bp locomotion. It was interesting that both subjects showed more muscle
activities during non-natural locomotor patterns; Qp