Sex-dependent cognitive and behavioral outcomes induced by repetitive cortical spreading depression in mice

Migraine with aura is clinically linked to cognitive impairment, yet sex differences and underlying mechanisms are unclear. Cortical spreading depression (CSD) is widely regarded as the electrophysiological correlate of migraine aura. Therefore, we utilized a mouse model of repetitive CSD to model recurrent aura events and investigate how this phenomenon modulates behavior and cognition in a sex-dependent manner. CSD was repeatedly induced in both male and female mice via epidural KCl application, using six consecutive stimuli at 20-minute intervals. Behavioral tests were performed to assess pain sensitivity, photophobia, anxiety, and cognitive function. Hippocampal neurogenesis and synaptic plasticity were examined via immunofluorescence and electrophysiology respectively. Repetitive CSD induced transient allodynia, which was most prominent on day 1 and fully recovered by day 5. This effect was more pronounced and longer-lasting in female mice. In contrast, photophobia observed in the CSD group was more prevalent in male mice. Repetitive CSD did not trigger anxiety-like behavior on either day 1 or day 7. During the Morris water maze probe trial on day 11, female mice in the CSD group exhibited a reduced number of platform crossings and decreased exploration distance in the target quadrant, while no such difference was observed in male mice. Conversely, in the novel location recognition test conducted on day 9 (with a 30-min interval), the CSD group showed a higher discrimination index than the SHAM group, specifically in female mice. These changes were accompanied by increased hippocampal neurogenesis. Moreover, enhanced long-term potentiation at the perforant path–dentate gyrus synapse was observed in females only. All cognitive alterations had recovered by 21 days post-CSD. Our study demonstrates that repetitive CSD stimulation elicits distinct, sex-dependent phenotypes. Allodynia was more pronounced and longer-lasting in female mice than in males. Moreover, cognitive alterations were observed only in female mice and exhibited a bidirectional pattern. While repetitive CSD impaired the consolidation or retrieval of long-term reference memory, it transiently enhanced short-term episodic memory. These changes occurred shortly after CSD stimulation and were reversible. Together, these results offer a novel perspective for investigating sex differences in migraine with aura and highlight the dual, dynamic influence of CSD on brain cognitive function.