The mesencephalic locomotor region (MLR) has been initially identified as a supraspinal center capable of initiating and modulating locomotion. Whereas its functional contribution to locomotion has been widely documented throughout the phylogeny from the lamprey to humans, there is still debate about its exact organization. Combining kinematic and electrophysiological recordings in mouse genetics, our study reveals that glutamatergic neurons of the cuneiform nucleus initiate locomotion and induce running gaits, whereas glutamatergic and cholinergic neurons of the pedunculopontine nucleus modulate locomotor pattern and rhythm, contributing to slow-walking gaits. By initiating, modulating, and accelerating locomotion, our study identifies and characterizes distinct neuronal populations of this functional region important to locomotor command.

Locomotion results from an interplay between biomechanical constraints of the muscles attached to the skeleton and the neuronal circuits controlling and coordinating muscle activities. Quadrupeds exhibit a wide range of locomotor gaits. Given our advances in the genetic identification of spinal and supraspinal circuits important to locomotion in the mouse, it is now important to get a better understanding of the full repertoire of gaits in the freely walking mouse. To assess this range, young adult C57BL/6J mice were trained to walk and run on a treadmill at different locomotor speeds. Instead of using the classical paradigm defining gaits according to their footfall pattern, we combined the inter-limb coupling and the duty cycle of the stance phase, thus identifying several types of gaits: lateral walk, trot, out-of-phase walk, rotary gallop, transverse gallop, hop, half-bound, and full-bound. Out-of-phase walk, trot, and full-bound were robust and appeared to function as attractor gaits (i.e., a state to which the network flows and stabilizes) at low, intermediate, and high speeds respectively. In contrast, lateral walk, hop, transverse gallop, rotary gallop, and half-bound were more transient and therefore considered transitional gaits (i.e., a labile state of the network from which it flows to the attractor state). Surprisingly, lateral walk was less frequently observed. Using graph analysis, we demonstrated that transitions between gaits were predictable, not random. In summary, the wild-type mouse exhibits a wider repertoire of locomotor gaits than expected. Future locomotor studies should benefit from this paradigm in assessing transgenic mice or wild-type mice with neurotraumatic injury or neurodegenerative disease affecting gait.

Sammendrag:The rising number of older people living with disabilities and chronic diseases has increased home care needs. Studies and reviews exploring preventive approaches have proliferated, creating a need for a synthesis of evidence. We conducted a systematic review of systematic reviews to evaluate the effectiveness of preventive home visiting approaches for older people. Of the 5,973 citations identified in over 30 scientific and grey literature databases, 10 papers met all inclusion criteria. Systematic reviews were considered if they included controlled trials comparing interventions with and without professional home care. We found that interventions often included comprehensive geriatric assessments and follow-up visits. Results indicate that multidimensional preventive home visiting programs might have the potential to reduce mortality, in particular for younger subjects, and show a potential to improve functional autonomy, but these findings should be interpreted with caution due to the diversity of the interventions analysed.Omsorgsbiblioteket har ikke tilgang til å publisere dette dokumentet i fulltekst. Kanskje ditt lokale bibliotek kan hjelpe deg, eller kanskje du kommer videre med lenken nedenfor.

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