HOW NEURONS GENERATE HERITABLE MEMORIES?
Updated: Dec 6, 2022
We are interested in how information is represented in the nervous system, and how “the code” is implemented to produce behavior. In the broadest sense of the word, memory is what enables altering of future responses based on history. Many types of molecular mechanisms can retain memories in biological systems, for example, metabolic changes, epigenetic factors, stable bioelectrical circuit modes, or neuronal-circuits.
Transgenerationally transmitted information presents a unique opportunity for studying memory since it resides in specific cells (sperm or oocytes), and is thus amenable for biochemical characterization (e.g. sequencing). For example, we showed that memory of the parents’ life style can be recovered by sequencing small RNAs that transmit to the children (and grand grandchildren). New work from our lab reveals that neuronal processes can generate heritable responses, regulating specific genes in the next generations and affecting the progeny’s behavior (Cell 2019). In the past we’ve found that small RNAs in worms can produce transgenerational changes, but transgenerational transfer of information from the nervous system is quite simply the Holy Grail, since the nervous system is unique in its ability to integrate responses about the environment as well as to integrate bodily responses. Therefore the idea that it could control also the fate of the progeny challenges our understanding of the limits of neurons and bodily responses. We found that neuronal production of small RNAs regulate a germline gene, saeg-2, for multiple generations, and that this transgenerational regulation affects the capacity of the progeny to find food, and to forage.
To understand molecular memories we are studying how C. elegans, Planaria, and songbirds, organisms that encode different types of memories. We are collaborating with computational neuroscientists, economists and linguists, trying to bridge the gaps between the type of neuroscience that is typically conducted by cognitive scientists, and the type of neuroscience that is typically studied by molecular biologists and geneticists. Specifically in C. elegans, since neuronal connectivity is largely hardwired and innate, it is very tempting to speculate that some types of learning and memory processes are achieved by gene regulation.
Artwork by Beata Edyta Mierzwa, https://www.beatascienceart.com/.