The development of skilled walking in the rat

Abstract

The rat is an altricial species and consequently undergoes considerable postnatal development. Careful analysis of the emergence and disappearance of motor behaviours is essential to gain insight into the temporal pattern of maturation of motor system structures. This study presents a qualitative analysis of the developmental progression of skilled movement in the rat by using a skilled walking task. A new rung bridge task was used to expose rat pups to a novel environment in order to reveal their potential capabilities. Ten rat pups were filmed daily from postnatal day 7 through postnatal day 30 as they explored the rung bridge task. Discrete changes in skilled and non-skilled walking in fore- and hind-limbs were evaluated by scoring seven categories and 24 subcategories of motor behaviour, including limb flexion and extension, coordination, posture, sensorimotor responses, distal control, and tail use in rat pups. Frame-by-frame analysis of ambulatory movement revealed six distinct stages of locomotor development. The most significant transformation to mature gait patterns was found between postnatal days 15 and 19, and maturation of all motor behaviour was completed by postnatal day 27. The findings are discussed in relation to the maturation of underlying structures and their relevance to studies of brain damage.

Spatiotemporal Structure of REM Sleep Twitching Reveals Developmental Origins of Motor Synergies

“…In time, these motor synergies might be automatized and flexibly linked with other synergies to produce the more complex patterns of behavior that characterize waking life. There is as yet little information concerning the structural and functional relations among twitching and waking movements (e.g., locomotion [47]) in healthy subjects of any age or species. However, a recent investigation of motor behavior in human adults with REM sleep behavior disorder should encourage more work in this area [48].…”

Kinematics of treadmill locomotion in mice raised in hypergravity

“…Basic motor structures, like scapular and pelvic central pattern generators are functional [2] and many of the adult skeletal configurations are already present at birth [3], but the motor system matures slowly over the first postnatal weeks, and the pups do not walk spontaneously before the end of second week of life [1,4]. The development of locomotion fits the stages of neuroanatomical changes [5,6], but neither the force production by muscles nor the neuromuscular innervation patterns nor the maturational aspects of motoneurones alone explain the postponed development [7]. Indeed, walking patterns can be induced early after birth with an appropriate stimulation [8].…”

Motor deficits on a ladder rung task in male and female adolescent and adult CGG knock-in mice

“…Therefore, in the present study male and female mice ranging from 2 to 16 months of age were tested on a ladder rung task adapted from procedures reported by Soblosky et al [58, 59] and refined by Whishaw and colleagues [24, 25, 48, 49, 57–59], among others [4, 21, 56]. This task was chosen because it has been shown to be sensitive to subtle sensorimotor deficits in both mice and rats [24, 58].…”