What does climbing mean exactly? Assessing spatiotemporal gait characteristics of inclined locomotion in parrots.

At what inclination does climbing begin? In this paper, we investigate the transition from walking to climbing in two species of parrot (Agapornis roseicollis and Nymphicus hollandicus) that are known to incorporate both their tail and their craniocervical system into the gait cycle during vertical climbing. Locomotor behaviors ranging in inclination were observed at angles between 0° and 90° for A. roseicollis, and 45°-85° degrees for N. hollandicus. Use of the tail in both species was observed at 45° inclination, and was joined at higher inclinations (> 65°) by use of the craniocervical system. Additionally, as inclination approached (but remained below) 90°, locomotor speeds were reduced while gaits were characterized by higher duty factors and lower stride frequency. These gait changes are consistent with those thought to increase stability. At 90°, A. roseicollis significantly increased its stride length, resulting in higher overall locomotor speed. Collectively these data demonstrate that the transition between horizontal walking and vertical climbing is gradual, incrementally altering several components of gait as inclinations increase. Such data underscore the need for further investigation into how exactly "climbing" is defined and the specific locomotor characteristics that differentiate this behavior from level walking.

The dual function of prokinesis in the feeding and locomotor systems of parrots.

Prokinesis, a mode of avian cranial kinesis involving motion between the neurocranium and upper beak, has long been investigated in biomechanical analyses of avian feeding and drinking. However, the modern avian beak is also used for non-feeding functions. Here, we investigate the dual function of prokinesis in the feeding and locomotor systems of the rosy-faced lovebird (Agapornis roseicollis). Lovebirds and other parrots utilize their beak both during feeding and as a third limb during vertical climbing. Thus, we experimentally measured both force-generating potential and movement of the rosy-faced lovebird mandible and maxilla (via prokinetic flexion of the craniofacial hinge) during tripedal climbing and mandibular/maxillary adduction. We found that whereas the maxilla is primarily responsible for generating force during locomotion, the mandible is primarily responsible for generating force during forceful jaw adduction, hinting at a remarkable capacity to alter prokinetic function with differing neuromuscular control. The ability of the prokinetic apparatus to perform functions with competing optimality criteria via modulation of motor control illustrates the functional plasticity of the avian cranial kinesis and sheds new light on the adaptive significance of cranial mobility.

No cuts, no buts: Satisfaction of first-year medical students with a hybrid prosection-based model for learning gross anatomy during the Covid-19 pandemic.

Few realized the extent of disruption that the Covid-19 global pandemic would impose upon higher anatomical education. While many institutions were obliged to adopt a fully-remote online model, the New York Institute of Technology College of Osteopathic Medicine strove to develop a curriculum that would allow medical students to receive an in-person anatomy education. A hybrid model that emphasized learning from prosected cadavers and self-study stations was implemented, with the remainder of the students' time directed toward studying at home. Through an anonymous survey aimed at gleaning student satisfaction, this study demonstrates that this hybrid prosection-based anatomy course aligned with student preferences both assuming no health risk (64.6% agreed) and given the current risk of contracting Covid-19 (78.5% agreed). Generally, students felt that their education was equal to that of previous years (Likert scale = 3.24 ± 1.05), fostered an appreciation for anatomy (4.56 ± 0.59), promoted teamwork (4.13 ± 0.85), and prepared them for practical examinations (4.18 ± 0.74). Linear mixed-effect models demonstrated that specific differences in results could be attributed to students' preconceived preferences toward student-led dissections and to past medical training. Importantly, most students "disagree" (1.97 ± 1.00) that they were concerned about the risk of exposure to Covid-19 during in-person anatomy laboratory sessions. Areas requiring improvement were identified by the model, including the provision of access to the cadavers outside of the regularly scheduled laboratory times (3.89 ± 1.08). These findings should be utilized when designing future gross anatomy courses in response to the "new normal".