LAUSR

INTRODUCTION The role of the cerebellum in motor function is well recognized. However, its role in higher nervous system activities such as cognition, emotion, endocrine, and autonomic are less known. The present study aims to show direct dento-amygdala projections using a biotinylated dextran amine (BDA) tracer in rats and 3-tesla high-resolution diffusion tensor imaging (DTI) based tractography in humans. METHODS Wistar albino rats were pressure injected with the BDA tracer into the dentate nucleus of the cerebellum. Labeled cells and axons were documented. The high-resolution 3-tesla tractography data were obtained from the Human Connectome Project (HCP) database. Dento-amygdala tracts were analyzed using DSI studio software. RESULTS An experimental study showed bilateral projections between the dentate nucleus and the central, basal, and ipsilateral projections with the lateral nuclei of the amygdala. The fibers from the dentate nucleus reached the amygdala via the superior cerebellar peduncle (SCP), the contralateral fibers crossed in the decussation of SCP at the midbrain. The dento-amygdala results of the experimental study highly corresponded with the 3-tesla tractography findings on humans. Additionally, DTI findings showed that most of the dentate fibers passed through the hypothalamus before reaching the amygdala, and the amygdala of the two sides is connected via the anterior commissure. DISCUSSION The 3-tesla DTI data in adult humans showed both direct dento-amygdala and indirect dento-hypothlamo-amygdala projections. Thus, may indicate cerebellar contribution in the modulation of emotional and autonomic functions. Further, can explain the emotional and cognitive deficits that occur in patients with cerebellar or SCP damage.