Tomás Ryan’s research focuses on the fundamental biology of memory storage in the brain. Recent studies have shown that spatial memories are encoded as sparse populations of cells that are activated during learning and are necessary for the retrieval of specific memories. These cells can be operationally defined as “memory engram cells” and the focus of Ryan’s research is to understand how engram cells are able to store specific memories as information. To address this question the Ryan group engages in experimental studies of memory encoding, storage, and retrieval in the mouse. The approach is experimental and interdisciplinary, including behavioral neuroscience, optogenetics, engram labeling technology, electrophysiology, calcium imaging, and molecular genetics.
What have I achieved during my fellowship?
The goal of this project is to investigate the true nature of infantile amnesia in mouse models using memory engram labelling technology. All mammals experience amnesia in their lifetime. While about 30% of adults will suffer from Alzheimer’s disease, 100% of the human population experience infantile amnesia, which is the loss of memories formed in early childhood (prior to 2–4 years). Though infantile amnesia is likely the cost of crucial cognitive developmental processes, it is also a constraint and limitation on education and learning during the formative years.
The specific scientific aims of this Jacobs Research Fellowship were to utilize recently developed memory engram labelling technology to permanently label specific memory engrams in juvenile mice (2-3 weeks of age) and then to attempt to retrieve the lost memories after the mice have reached adulthood (8 weeks of age). Engram technology in combination with behavioral studies of mice provides an unprecedented opportunity to investigate infantile amnesia in a way that has not been previously possible using the traditional methods of cognitive psychology or behavioral neuroscience. This project starting in our new laboratory in March 2017, because of the support of the Jacobs Foundation, and it has since developed into a successful series of projects and funding diversification.
My plans for the future
Currently, progress in understanding the controllability and modifiability of specific memories in humans is blocked by the invasive nature of modern neuroscience technologies used in the investigation of memory engrams in non-human animals. To bridge this divide, we propose a translational program that aims at closely integrating research strategies in rodent and human studies. To that end, we will build on early rodent experimental findings and translate them to human studies of infantile amnesia. More specifically, we aim at identifying non-invasive behavioral and neural measures of engram ensemble activity. Ultimately, the availability of non-invasive engram markers will allow to develop and evaluate the effects and efficacy of interventions for targeted re-activation or suppression of specific memories in the service of improved learning and therapy.