How position, velocity, and temporal information combine in the prospective control of catching:data and model

The cerebral cortex contains circuitry for continuously computing properties of the environment and one's body, as well as relations among those properties. The success of complex perceptuomotor performances requires integrated, simultaneous use of such relational information. Ball catching is a good example as it involves reaching and grasping of visually pursued objects that move relative to the catcher. Although integrated neural control of catching has received sparse attention in the neuroscience literature, behavioral observations have led to the identification of control principles that may be embodied in the involved neural circuits. Here, we report a catching experiment that refines those principles via a novel manipulation. Visual field motion was used to perturb velocity information about balls traveling on various trajectories relative to a seated catcher, with various initial hand positions. The experiment produced evidence for a continuous, prospective catching strategy, in which hand movements are planned based on gaze-centered ball velocity and ball position information. Such a strategy was implemented in a new neural model, which suggests how position, velocity, and temporal information streams combine to shape catching movements. The model accurately reproduces the main and interaction effects found in the behavioral experiment and provides an interpretation of recently observed target motion-related activity in the motor cortex during interceptive reaching by monkeys. It functionally interprets a broad range of neurobiological and behavioral data, and thus contributes to a unified theory of the neural control of reaching to stationary and moving targets.

A study of the relational aspects of the culture of academic medicine

PURPOSE: The impact of medical school culture on medical students has been well studied, but little documentation exists regarding how medical faculty experience the culture in which they work. In an ongoing project, the National Initiative on Gender, Culture and Leadership in Medicine, the authors are investigating how the existing culture of academic medical institutions supports all faculty members' ability to function at their highest potential. METHOD: The authors conducted a qualitative study of faculty in five disparate U.S. medical schools. Faculty in different career stages and diverse specialties were interviewed regarding their perceptions and experiences in academic medicine. Analysis was inductive and data driven. RESULTS: Relational aspects of the culture emerged as a central theme for both genders across all career categories. Positive relationships were most evident with patients and learners. Negative relational attributes among faculty and leadership included disconnection, competitive individualism, undervaluing of humanistic qualities, deprecation, disrespect, and the erosion of trust. CONCLUSIONS: The data suggest that serious problems exist in the relational culture and that such problems may affect medical faculty vitality, professionalism, and general productivity and are linked to retention. Efforts to create and support trusting relationships in medical schools might enhance all faculty members' efforts to optimally contribute to the clinical, education, and research missions of academic medicine. Future work will document the outcomes of a five-school collaboration to facilitate change in the culture to support the productivity of all medical faculty. © 2009 Association of American Medical Colleges.