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Human Stick Balancing: Tuning Lèvy Flights To Improve Balance Control, Juan Luis Cabrera, John Milton
Human Stick Balancing: Tuning Lèvy Flights To Improve Balance Control, Juan Luis Cabrera, John Milton
WM Keck Science Faculty Papers
State-dependent, or parametric, noise is an essential component of the neural control mechanism for stick balancing at the fingertip. High-speed motion analysis in three dimensions demonstrates that the controlling movements made by the fingertip during stick balancing can be described by a Lévy flight. The Lévy index, , is approximately 0.9; a value close to optimal for a random search. With increased skill, the index does not change. However, the tails of the Lévy distribution become broader. These observations suggest a Lévy flight that is truncated by the properties of the nervous and musculoskeletal system; the truncation decreasing as skill …
Synaptic Transformations Underlying Highly Selective Auditory Representations Of Learned Birdsong, Melissa J. Coleman, Richard Mooney
Synaptic Transformations Underlying Highly Selective Auditory Representations Of Learned Birdsong, Melissa J. Coleman, Richard Mooney
WM Keck Science Faculty Papers
Stimulus-specific neuronal responses are a striking characteristic of several sensory systems, although the synaptic mechanisms underlying their generation are not well understood. The songbird nucleus HVC (used here as a proper name) contains projection neurons (PNs) that fire temporally sparse bursts of action potentials to playback of the bird's own song (BOS) but are essentially silent when presented with other acoustical stimuli. To understand how such remarkable stimulus specificity emerges, it is necessary to compare the auditory-evoked responsiveness of the afferents of HVC with synaptic responses in identified HVC neurons. We found that inactivating the interfacial nucleus of the nidopallium …