Non-human animals comprising a humanized trkb locus

-46. (canceled)

-51. (canceled)

(canceled)

(canceled)

(canceled)

A targeting vector for generating a genetically modified endogenous TrkB locus encoding a TRKB protein,

• wherein the TRKB protein comprises a cytoplasmic domain, a transmembrane domain, and an extracellular domain, and all or part of the extracellular domain is encoded by a segment of the endogenous TrkB locus that has been deleted and replaced with an orthologous human TRKB sequence, and
• wherein the targeting vector comprises an insert nucleic acid comprising the orthologous human TRKB sequence flanked by a 5′ homology arm targeting a 5′ target sequence at the endogenous TrkB locus and a 3′ homology arm targeting a 3′ target sequence at the endogenous TrkB locus.