The paper continues the cycle of studies on the evolutionary link between the mechanisms of stress response formation and cognitive functions started in 1959 by M.E. Lobashev and V.B. Savvateev. We explore the role of a key neuroplasticity factor LIM kinase 1 (LIMK1) expressed in dopaminergic and serotonergic neurons in Drosophila genome stability, as well as learning and memory, both in standard conditions and when an organism exhibits a stress response to Earth’s weakened static magnetic field (WSMF). We demonstrate that a low LIMK1 level promotes learning acquisition, but not the formation of intermediate-term memory; at the same time, stress exposure restores the learning ability and memory formation in the Drosophila strain with an increased LIMK1 content. We identify inter-strain differences in the frequency of DNA double-strand breaks (DSBs) and show an increase in DSBs after the exposure to WSMF. The data obtained reveal the role of dopaminergic and serotonergic neurons not only in cognitive functions, but also as WSMF targets in the development of a stress response.