Acute head shaking precedes chronic corpus callosum deficits during repeated cocaine exposure in common marmosets

Background: Stimulant exposure can induce acute stereotyped behaviors and chronic alterations in brain connectivity and white matter integrity. However, the temporal sequence and molecular changes linking these cocaine-induced phenotypes remain unclear. Methods: We combined LabGym-based behavioral analysis, longitudinal brain imaging, and cross-species molecular analysis in 11 common marmosets (Callithrix jacchus; seven male, four female): four underwent behavioral and imaging studies, six provided molecular data, and one provided immunohistochemical data. Male Cryab knockout and wild-type mice underwent functional studies. Results: Acute cocaine (5 mg/kg, intraperitoneally) induced rapid, repetitive lateral head movements, defined as head shaking. After 1 and 10 months of repeated exposure, resting-state functional connectivity was altered in sensory, parietal, prefrontal, motor, and hippocampal regions. Changes were detected at 1 month, whereas diffusion tensor imaging showed reduced fractional anisotropy and axial diffusivity in the corpus callosum splenium at 10 months, with no significant genu changes. Cross-species transcriptomic and proteomic comparison identified DPYSL2 and DNM3 as shared axon-associated molecules. Western blotting showed reduced DPYSL2 in brain tissue from cocaine-treated marmosets. CRYAB localized to O4-positive callosal oligodendrocytes and increased following chronic cocaine exposure. Cryab knockout mice had reduced corpus callosum thickness, increased forced-swim immobility, and reduced open-field distance traveled, supporting a role for CRYAB in corpus callosum integrity and depression-related behavior. Conclusions: These findings show that acute cocaine-induced stereotyped head shaking precedes functional connectivity changes and later corpus callosum deficits. Reduced DPYSL2 may be associated with axonal dysfunction, whereas increased CRYAB may represent a response to cocaine-induced white matter stress.