Title: The development of automaticity in motor skill learning 

Abstract: The concept of automaticity is widely discussed across domains from psychology to sports science to rehabilitation and is considered a crucial milestone in learning continuous skills like driving, skiing, or performing surgery. However, most research on automaticity has focused on skills that involve discrete key presses and there is relatively little empirical evidence regarding how and when continuous skills become automatic. I will present experiments in which we probed the development of multiple facets of automaticity as participants learned a challenging, continuous motor skill over multiple days of practice. Our results show that automaticity is attained very early on in the course of learning – contrary to existing views which suggest that skills become automatic only once they are overlearned.

Title: Advancing the design and control of assistive robotics: Incorporating patient and clinician preferences 

Abstract: On paper, lower-extremity prosthetics and exoskeletons have improved greatly in the last decade; prosthetic knees employing ML-based intent recognition have enabled step-over-step stair traversal, untethered exoskeletons have reduced the metabolic cost of walking and running, and high-power exoskeletons have enabled people with spinal cord injuries to walk again. However, few of these advanced devices have made a true clinical impact. I posit that critical information is missing from the design and prescription processes: a robust, scientific understanding of the patient as the ultimate arbiter of optimal device performance. The overall goal of my past and future research is to advance the design, control, and prescription of prosthetics and exoskeletons, with a particular focus on better understanding patient perception of their assistive devices.

Title: Oscillopathies of Neural Control Mechanisms: Lessons From Computational Medicine

Abstract: Abnormal oscillations are implicated in many disease states that affect the function of neurons and neural circuits. Biological oscillations are also vital to many physiological functions. Paydarfar will present and discuss theoretical, experimental, and clinical observations on the initiation and termination of rhythms at the neuronal, tissue and organismic levels of the nervous system. Examples will include rhythmic discharges of neurons in epilepsy, reentrant excitation of cardiac conduction pathways in the diseased heart, episodic severe apnea, bradycardia, and hypoxia in preterm infants. Mathematical and computational methods can provide important insights into the etiology, prevention and treatment of oscillopathies.

Title: Universality of integer ratio biases in rhythmic movements 

Abstract: I will describe a current study in which we examine the human preference for small integer ratios in auditory rhythm perception and reproduction. Research suggests that integer ratios are universal features of rhythm, however specific rhythmic patterning is not fixed by biology, but is influenced by cultural listening experiences (Jacoby & McDermott, 2017). Previous models use probabilistic learning methods to estimate the likelihood of specific rhythmic ratios in sets of training stimuli. However, such statistical methods do not display any intrinsic bias toward integer ratios; they can internalize rhythmic priors that generate any arbitrary sequence of temporal intervals. The aims of this study are 1) to develop a model of Hebbian learning in oscillatory neural networks that learn rhythmic patterns, and 2) to explore potential physiological constraints on learning that would result in a preference for small integer interval ratios. We have developed a model that can internalize both the strengths and phases of internal connections, and by positing physiological constraints on the learned connections, it displays an intrinsic bias toward integer ratios. The model can also explain how cultural listening experiences influence the specific rhythmic patterns humans prefer. This suggests that the human preference for small integer ratios in auditory rhythm learning is in part based on physiological constraints on learning. The proposed model may help in understanding the neural mechanisms underlying rhythm perception, and how neural mechanisms can be influenced by cultural factors.

Title: Bioinspired robot locomotion through morphology (structure) and control co-design

Abstract: I will describe the challenges facing the design and control of two classes of locomotion systems: 1) hybrid, multi-modal systems and 2) small locomotion systems that dynamically interact with their environment. Robot morphology (structure) and locomotion control co-design is the backbone idea to address these challenges. Hybrid, multi-modal models must accommodate multiple mobility styles, including legged, aerial, and wheeled locomotion, in a single platform. These forms of mobility dictate conflicting requirements that make robot hardware design and control very challenging. For instance, the payload can negatively affect flight performance in aerial systems; in legged robots, high-torque actuators, which are bulky, are required to substantiate dynamic locomotion; aerial flight dynamics are nonlinear and continuous, whereas legged systems are switching nonlinear systems that intermittently interact with their environment. The second class of robots, small locomotion systems that dynamically interact with their environment, introduce challenges of a different nature. These systems are multi-joint with many passive and active coordinates. As a result, control design and actuation become very challenging due to prohibitive design restrictions such as limited computation resources, payload, power budget, etc. This talk will introduce examples from each type of mobility system that my group designed and briefly reports the hardware design paradigms and control approaches employed.

Title: Neural mechanisms of interactive behavior

Abstract: In psychology and neuroscience, behavior is often described as a serial process of encoding sensory information to build knowledge about the world, followed by cognitive mechanisms of knowledge manipulation and decision-making, followed by the planning and execution of movements. This view leads to a decomposition of brain functions into putative information processing systems for object recognition, memory, decision-making, action planning, etc., inspiring the search for the neural correlates of these processes. However, neurophysiological data does not support many of the predictions of these classic subdivisions. Instead, there is divergence and broad distribution of functions that should be unified, mixed representations combining functions that should be distinct, and a general incompatibility with the conceptual subdivisions posited by theories of information processing. In this talk, I will explore the possibility of resynthesizing a different set of functional subdivisions, guided by the growing body of data on the evolutionary process that produced the human brain. I will summarize, in chronological order, a proposed sequence of innovations that appeared in nervous systems along the lineage that leads from the earliest multicellular animals to humans. Along the way, functional subdivisions and elaborations will be introduced in parallel with the neural specializations that made them possible, gradually building up an alternative conceptual taxonomy of brain functions. These functions emphasize real-time, closed-loop interaction with the world, rather than for building explicit knowledge of the world, and the relevant representations emphasize pragmatic outcomes rather than decoding accuracy, mixing variables in the way seen in real neural data. I suggest that this alternative taxonomy may better delineate the real functional pieces into which the human brain is organized, and can offer a more natural mapping between behavior and neural mechanisms. As an example, I will discuss some recent results from neurophysiological studies of how the primate brain deliberates about and commits to voluntary actions.