Neural Circuit Structure and Function.
We examine how simple neural circuits that drive movement of the limbs and axis are organized. Focal systems in the lab include the hindbrain and spinal cord circuit that drives startle behavior and the circuit that controls rhythmic movement of the pectoral fins (homologous to our forelimbs). We aim to map how neurons in these circuits are connected and their roles in movement. Most of our research in these systems has been performed in zebrafish, because the brain and spinal cord of the larvae are accessible for morphological and physiological studies; however, work in other species has also been important. It has helped us to identify behaviors, such as the S-start startle behavior, that are difficult to observe in larval zebrafish and allowed us to study behaviors that are not part of the zebrafish repertoire.
Several related publications (see pubs page): Green and Hale, 2013; Liu and Hale, 2014; Bierman et al., 2009; McLean et al., 2007; Hale et al., 2005; Hale et al., 2001. See full publication list and reference information on publications page.
Mechanosensation and proprioception.
Over the past few years we have begun to examine how limb mechanosensation may be used to modulate fin movements. In humans and other mammals, it was well known that proprioception, the sense of movement and position of the limbs in space, was critical for normal limb function. Little comparable work had been performed in fishes, and none in typical fin-based propulsion. Through a combination of morphology, physiology and behavioral experiments, we've found that the pectoral fins are mechanosensors and that this sensation modulates movement. We continue these experiments in a number of directions, including examining the relationship between fin bimechanics and mechanosensation.
A couple related papers: Williams et al., 2013; Phelan et al., 2010. See full publication list and reference information on publications page.
Evolution and Development of Neural Systems and Behavior.
A fundamental line of experiments in the lab investigates how movement systems change through time - both the short time frame of development and the longer time frame of evolution. We are interested in how systems change and how such changes, which often involve multiple body systems and functional demands are coordinated. In addition, by exploring movements systems across a range of species and locomotor behaviors we gain insight into structural and functional diversity in aquatic systems. Such breadth of study informs our work on evolutionary neuroscience, comparative biomechanics and collaborations with engineers on bio-inspired design.
Some related references: Hale, 1999; Thorsen et al., 2004; THorsen and Hale, 2005; Hale et al., 2006; Thorsen and Hale, 2007; Bierman et al., 2009; Phelan et al., 2010; King et al., 2011; Hale, 2014.