HCRTR1 and major depressive disorder: Similarly, icv.HCRT‐1 rats also exhibited depressive‐like behavior and showed cognitive impairment in the Y‐maze, which consistent with previous studies showing that rats injected with hypocretin‐1 showed impaired spatial learning and memory function, accompanied by altered synaptic plasticity and reduced long‐term potentiation.[18] These suggest that changes in hypocretin‐1/HCRTR1 may be linked to cognitive impairment in depression.