Brain disorders are one of the greatest health challenges. It is estimated that around 30% of Europeans will suffer from a neurological and/or mental disorder at some point in their live. Given their immense socio-economic impact, it is therefore crucial to find new treatments for brain disorders.
However, cognition in the healthy brain relies on a tremendous complexity at the cellular and circuit levels. Part of this complexity resides in the presence of diverse interneuronal circuits that enable inhibitory interactions between brain modules. One such circuit is the inhibitory network found in the most superficial layer of the cortex (Layer 1, L1) that is strongly driven by contextual information from higher order brain modules (i.e. top-down signals).
In this project, I characterized the synaptic and circuit properties underlying the top-down control of cortical networks by L1 interneurons. My analysis revealed that the activity of L1 interneurons was strongly dependent on the N-methyl-D-aspartate receptor (NMDAR). Next, I found that normal sensorimotor function was dependent on L1 integration and was impaired upon deletion of the NMDAR in L1 interneurons. Those results therefore emphasized the important contribution of the cellular mechanisms (here the NDMAR) in L1 interneurons in shaping cortical processing in the healthy brain. Importantly, this study points to a new therapeutic target for NMDAR-related diseases such as schizophrenia or depression: L1 interneurons. By suggesting new therapeutic approaches for NMDAR-related disease, the fundamental knowledge generated in this action could therefore have crucial implications for brain disorders.
