Neuroscience
-
Many motor behaviors, from walking to speaking, are acquired through experience, in particular, through trial-and-error learning. The acquisition and maintenance of such motor behaviors in a wide range of species, including humans, appear to depend on cortical-basal ganglia circuits. In this review, we discuss recent studies in songbirds that have been pivotal in informing our current understanding of motor learning and cortical-basal ganglia function. ⋯ Computational and experimental studies highlight the importance of vocal motor variability as the substrate upon which reinforcement mechanisms could operate to shape developing song and to maintain adult song. Recent studies in songbirds indicate that this vocal motor variability is actively generated and modulated by a highly specialized cortical-basal ganglia circuit evolved for a single behavior, song. We argue that these and other recent findings illustrate how the tight association between a specialized neural circuit and a natural behavior make songbirds a unique and powerful model in which to investigate the neural substrates of motor learning and plasticity.
-
Songbirds provide a powerful animal model for investigating how the brain uses sensory feedback to correct behavioral errors. Here, we review a recent study in which we used online manipulations of auditory feedback to quantify the relationship between sensory error size, motor variability, and vocal plasticity. We found that although inducing small auditory errors evoked relatively large compensatory changes in behavior, as error size increased the magnitude of error correction declined. ⋯ This pattern suggests a simple and robust strategy for the brain to maintain the accuracy of learned behaviors by evaluating sensory signals relative to the previously experienced distribution of feedback. Drawing from recent studies of auditory neurophysiology and song discrimination, we then speculate as to the mechanistic underpinnings of the results obtained in our behavioral experiments. Finally, we review how our own and other studies exploit the strengths of the songbird system, both in the specific context of vocal systems and more generally as a model of the neural control of complex behavior.
-
A wide variety of species are used for the study of visual neuroscience. This is beneficial because fundamental mechanisms and theoretical principles of vision are likely to be highly conserved, while different species exhibit different visual capacities and present different technical advantages for experiments. ⋯ To some this may be surprising, as nocturnal rodents have often been presumed to have poor vision and weak visual behavior. This commentary will provide my personal perspective on how I came to work with rats; discuss an example research project for which rats have been advantageous; and comment on the opportunities and challenges of the preparation.
-
Animal models are a necessary component of systems neuroscience research. Determining which animal model to use for a given study involves a complicated calculus. ⋯ In this review, I discuss work done in my laboratory to investigate the neural mechanisms of color vision in the rhesus macaque. The emphasis is on the strengths of the macaque model, but shortcomings are also discussed.