Biology subjects

Goldberg, J. H.

Publications and source records attributed to Goldberg, J. H..

3 recordsLinked to original sources

bioRxiv2018

A circuit motif in the songbird basal ganglia for computing predicted performance quality

Ventral tegmental area (VTA) dopamine neurons signal prediction error, the difference between actual and predicted outcome, but it remains unclear how error is computed. Here we identify in songbirds a ventral basal ganglia (vBG) region that is required for song learning and that sends prediction error signals to VTA. During singing, vBG neurons heterogeneously encoded song timing, auditory error, predicted error, and the difference between the two (prediction error). Viral tracing revealed inputs to vBG from auditory and vocal motor thalamus, auditory and vocal motor cortex, and VTA. Our findings reveal a classic actor-critic circuit motif in which a ventral critic learns the prediction component of a prediction error signal that is relayed by VTA to a dorsal actor (the vocal motor BG nucleus Area X). A circuit motif for computing reward prediction error can compute predicted performance quality during motor sequence learning.

neuroscience↗

bioRxiv2018

Cortical control of kinematic primitives in mice performing a hold-still-center-out reach task

Motor sequences are constructed from primitives, hypothesized building blocks of movement, but mechanisms of primitive generation remain unclear. Using automated homecage training and a novel forelimb sensor, we trained freely-moving mice to initiate forelimb sequences with clearly resolved submillimeter-scale micromovements followed by millimeter-scale reaches to learned spatial targets. Hundreds of thousands of trajectories were decomposed into millions of kinematic primitives, while closed-loop photoinhibition was used to test roles of motor cortical areas. Inactivation of contralateral motor cortex reduced primitive peak speed but, surprisingly, did not substantially affect primitive direction, initiation, termination, or complexity, resulting in isomorphic, spatially contracted trajectories that undershot targets. Our findings demonstrate separable loss of a single kinematic parameter, speed, and identify conditions where loss of cortical drive reduces the gain of motor primitives but does not affect their generation, timing or direction. The combination of high precision forelimb sensing with automated training and neural manipulation provides a system for studying how motor sequences are constructed from elemental building blocks.

neuroscience↗

bioRxiv2017

The segregation of vocal circuits solves a credit assignment problem associated with multi-objective reinforcement learning

Motor circuits vary in topographic organization, ranging from a coarse relationship between neuron location and function to highly localized regions controlling specific behaviors. For unclear reasons, vocal learning circuits lie at this second extreme: they repeatedly evolved to be spatially segregated from other parts of the motor system. Here we show that spatially segregated motor circuits can solve a specific problem that arises when an animal tries to learn two things at once. We trained songbirds in vocal and place learning paradigms with brief strobe light flashes and noise bursts. Strobe light negatively reinforced place learning but did not affect song syllable learning. Noise bursts positively reinforced place preference but negatively reinforced syllable learning. These double dissociations indicate that vocalization-related reinforcement signals specifically target the vocal motor system, while place-related reinforcement signals specifically target the navigation system. Non-global, target-specific reinforcement signals have established utility in machine implementation of multi-objective learning. In vocal learners, such signals could enable an animal to practice vocalizing as it does other things such as forage for food or learn to walk.

neuroscience↗