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Priorelli, M.

Publications and source records attributed to Priorelli, M..

2 recordsLinked to original sources

Deep kinematic inference affords efficient and scalable control of bodily movements

Performing goal-directed movements requires mapping goals from extrinsic (workspace-relative) to intrinsic (body-relative) coordinates and then to motor signals. Mainstream approaches based on Optimal Control realize the mappings by minimizing cost functions, which is computationally demanding. Instead, Active Inference uses generative models to produce sensory predictions, which allows a cheaper inversion to the motor signals. However, devising generative models to control complex kinematic chains like the human body is challenging. We introduce a novel Active Inference architecture that affords a simple but effective mapping from extrinsic to intrinsic coordinates via inference and easily scales up to drive complex kinematic chains. Rich goals can be specified in both intrinsic and extrinsic coordinates using attractive or repulsive forces. The proposed model reproduces sophisticated bodily movements and paves the way for computationally efficient and biologically plausible control of actuated systems.

neuroscience↗

Flexible Intentions in the Posterior Parietal Cortex: An Active Inference Theory

AO_SCPLOWBSTRACTC_SCPLOWWe present a normative computational theory of how neural circuitry may support visually-guided goal-directed actions in a dynamic environment. The model builds on Active Inference, in which perception and motor control signals are inferred through dynamic minimization of generalized prediction errors. The Posterior Parietal Cortex (PPC) is proposed to maintain constantly updated expectations, or beliefs over the environmental state, and by manipulating them through flexible intentions it is involved in dynamically generating goal-directed actions. In turn, the Dorsal Visual Stream (DVS) and the proprioceptive pathway implement generative models that translate the high-level belief into sensory-level predictions to infer targets, posture, and motor commands. A proof-of-concept agent embodying visual and proprioceptive sensors and an actuated upper limb was tested on target-reaching tasks. The agent behaved correctly under various conditions, including static and dynamic targets, different sensory feedbacks, sensory precisions, intention gains, and movement policies; limit conditions were individuated, too. Active Inference driven by dynamic and flexible intentions can thus support goal-directed behavior in constantly changing environments, and the PPC putatively hosts its core intention mechanism. More broadly, the study provides a normative basis for research on goal-directed behavior in end-to-end settings and further advances mechanistic theories of active biological systems.

neuroscience↗