Investigating the composition of the direct LGN-V5/MT pathway and its implication in Autism Spectrum Disorder

• Applicant: Professorin Dr. Katharina von Kriegstein
• Subject Area: Human Cognitive and Systems Neuroscience
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 570489486

Visual processing pathways, beyond the primary visual pathway, remain poorly understood despite their potential significance in shaping behaviour and contributing to neurodevelopmental disorders such as dyslexia and autism. The LGN-V5/MT pathway by-passes primary visual cortex (V1), by directly connecting the lateral geniculate nucleus (LGN) of the thalamus to the extrastriate visual cortex area V5/MT. The pathway plays a critical role in visual motion processing in the human brain. Motion processing is relevant not only for seeing moving objects in space, but also for human communication. For example, facial movements reveal emotion and speech information. Despite its potential importance, the composition and organization of the LGN-V5/MT pathway is not well-defined. Our aim is to enhance the understanding of the LGN-V5/MT pathway and its potential implications in autism spectrum disorder (ASD). ASD is characterised by communication and social interaction difficulties, but also by sensory alterations such as difficulties with visual motion processing.We plan to investigate the composition of the direct LGN-V5/MT pathway using high-resolution imaging techniques including 7-Tesla functional magnetic resonance imaging (fMRI) and 3-Tesla Connectom diffusion-weighted imaging. We will identify the magnocellular and parvocellular parts of the LGN (mLGN, pLGN) and employ probabilistic tractography to determine whether the direct LGN-V5/MT pathway originates in mLGN, pLGN, or both. We plan to relate the tract strength to motion perception behaviour. Based on the known functional roles of mLGN and V5/MT in visual motion processing, we expect that the direct LGN-V5/MT pathway originates predominantly in the mLGN in humans and that its strength is related to visual motion perception ability.In ASD, there are two opposing views on subcortical sensory pathway alterations. One view implies alterations of the magnocellular part of the visual pathways. The alternative view includes alteration of the pathway between pulvinar and V5/MT. Consistent with the former view, 7T-fMRI results revealed reduced responses in bilateral mLGN in individuals with ASD for stimuli optimized for mLGN. Based on these findings, we plan to test for structural alterations of the mLGN-V5/MT in ASD with the specific hypothesis that there are alterations in the mLGN-V5/MT tract, but not in the pLGN-V5/MT tract. We will also test the assumption of the alternative view, i.e., that there are alterations in the pulvinar-V5/MT pathway in ASD.The planned research represents an innovative effort to uncover the intricacies of the LGN-V5/MT pathway, shedding light on its significance in both typical visual processing and ASD. Leveraging advanced neuroimaging techniques, our study may provide insights that advance our understanding of sensory processing, including motion perception, and potential alterations of specific parts of the LGN-V5/MT pathway in ASD.

• DFG Programme: Research Grants
• Co-Investigator: Dr. Christa Müller-Axt