A machine learning approach using gait parameters to cluster TKA subjects into stable and unstable joints for discovery analysis.

Background: Patient-reported joint instability after total knee arthroplasty (TKA) is difficult to quantify objectively. Here, we apply machine learning to cluster TKA subjects using nine literature-proposed gait parameters as knee instability predictors and explore cluster reliability and consistency with self-organizing map (SOM) and k-means computation.

Methods: Subjects with TKA were retrieved from a data repository, supplemented by TKA patients with self-reported knee instability.

A locus coeruleus-dorsal CA1 dopaminergic circuit modulates memory linking.

Individual memories are often linked so that the recall of one triggers the recall of another. For example, contextual memories acquired close in time can be linked, and this is known to depend on a temporary increase in excitability that drives the overlap between dorsal CA1 (dCA1) hippocampal ensembles that encode the linked memories. Here, we show that locus coeruleus (LC) cells projecting to dCA1 have a key permissive role in contextual memory linking, without affecting contextual memory formation, and that this effect is mediated by dopamine.