Deciphering Mechanisms of Perceptual Silencing: From Molecules to Neural Systems
We and our collaborators seek to understand molecular mechanisms of long-term memory in identified elements of a memory-encoding circuit in vivo. Our work on the Drosophila olfactory system has a) outlined a simple neural circuit that encodes habituation memory; b) identified likely components and assembly mechanisms for neuronal ribonucleoprotein (RNP) granules; and c) shown how translational control mechanisms and RNP granules participate in mnemonic processes. Our studies indicate that olfactory habituation arises from the potentiation of inhibitory synapses from a sparse group of local interneurons onto excitatory output neurons in the antennal lobe. The underlying synaptic plasticity mechanism, scaled up from small to large circuits, can create negative images (or inhibitory engrams) of object-encoding cell assemblies and so potentially account for habituation across systems and species. This “negative-image model,” recently supported by observations in the mammalian auditory cortex, explains the key behavioral features of habituation (“gating” and “override”) better than any other current model. I will end by discussing arguments developed in collaboration with colleagues in Oxford, which suggest that inhibitory memory engrams, similar to those involved in habituation, can convert recently encoded memories into latent remote memories that remain accessible to recall, and speculate on possible implications for the function and physiology of sleep, atypical psychiatric states, and dreaming.
Date:
29 March 2019, 12:00 (Friday, 11th week, Hilary 2019)
Venue:
Small Lecture Theatre, Sherrington Building, South Parks Road
Speaker:
Mani Ramaswami (Trinity College, Dublin)
Organising department:
Department of Physiology, Anatomy and Genetics (DPAG)
Organiser:
Fiona Woods (University of Oxford, Department of Physiology Anatomy and Genetics, Centre for Neural Circuits and Behaviour)
Organiser contact email address:
fiona.woods@cncb.ox.ac.uk
Part of:
CNCB Seminar Series
Booking required?:
Not required
Audience:
Members of the University only
Editor:
Fiona Woods
