Thesis defense Tamas Dalmay (Donders sereis 472)
24 November 2020
Promotor: prof. dr. M. Helmstaedter
Co-promotor: dr. J. Letzkus (Max Planck Institute for Brain Research, Germany)
The role of temporal neocortex in threat memory
Understanding neocortical function is a central goal of neuroscience research. A prerequisite for achieving this is knowledge of the specific behavioral processes to which defined neocortical areas and pathways contribute. Previous lesion and inactivation studies across different sensory modalities and behavioral tasks have yielded diverse results, with perturbation of neocortical areas often producing little or no behavioral deficit. In this thesis, I take advantage of Pavlovian auditory threat conditioning as a well-controlled learning paradigm in which to investigate the critical involvement of defined areas and output pathways of temporal neocortex, including auditory cortex and temporal association cortex. Using a combination of optogenetics and viral tracing, I show that auditory cortex is selectively required for memory with complex auditory stimuli, while being dispensable for memory with simple stimuli. In contrast, temporal association cortex is required for memory with simple as well as complex stimuli. Furthermore, more temporal areas of neocortex are enriched in neurons projecting to the amygdala, and the projection from temporal neocortex to the amygdala is required for complex stimulus memory. Taken together, these results identify stimulus complexity as an organizing feature governing the critical involvement of auditory cortex, and additionally reveal temporal association cortex as a critical hub for threat memory.