today i would like to talk to you about the biological basis for memory and in particular i'd like to impress upon you that memory is really underpinned by a an amazing molecular orchestration deep within your brain that actually allows you to remember and so in this way on the cellular and molecular level memory is really a particular kind of information storage that arises out of the genetic and environmental interface

and we can come to appreciate this when we consider that the environment the very context of this room represents a particular kind of information and so with that thought in mind i pose the following question rhetorically could it be that our fondest memories are but the remnants of past information codified within the molecular matrix of our brain and so to uh better understand this question i'll ask you to reimagine the world around

you not as it appears but as a reservoir of information that whirls about in mirrored form importantly as human beings we're biological organisms that are completely immersed in this information and moreover our survival is entirely dependent upon our ability to successfully navigate our surroundings in particular our survival is dependent upon our ability to detect and distinguish energy forms

such information is is is readily converted into sensations of sight touch taste and smell and hearing so that we may successfully navigate the frontier of our surroundings and so to this end the nervous system the biological apparatus that mediates these sensations must remain ever responsive to changes in environmental information and so in order to to accomplish this feat the cells of the nervous system neurons

are equipped and fitted with immense information sensing capabilities that capture process and represent environmental information as a distinct bioelectric code called neural activity neural activity is an intercellular language by which environmental information is coded and disseminated across the nervous system at rapid speeds when this information needs to be stored in the context of memory

neural activity dynamically directs cellular gene expression which stably codifies this information inside neuronal cells but it does it in a peculiar way it does it by actually storing that information in the morphology of the neuron in the shape and it does so at distinct structures these structures are synaptic structure now synaptic structure is interesting and important because it's essentially a biological hallmark of the vast and amazing

potential that dwells within us all it's particularly important and this rings true in the context of memory when we consider like i said just to walk you through the environment is really a particular kind of information that gets coded and represented in the nervous system as neural activity neural activity dynamically directs gene expression to store that information by modifying synaptic structure this is important

for some reasons that we can all appreciate it's important because it allows us to remember those experiences that would otherwise wane into obscurity while this latter premise provides some molecular reconciliation for the phenomenon that we call memory there's still so many great questions pending along this great frontier now importantly as a neuroscientist at harvard medical school much of my research is devoted to unveiling molecular details along this front mechanistically environmentally directed

gene expression requires a molecular link and this is what enamors me a molecular link capable of dynamically altering gene expression in response to neural activity now importantly the neuron has evolved a robust suite of regulatory sensors for exactly this purpose which include a special class of biomolecules that i study called micrornas now micrornas are important because they're indispensable regulators of gene expression within unique

dimensions of cellular time and space this is interesting and important because as i alluded to earlier the spatial character of the neuron is stratified across immense morphological polarity and complexity as you can see here this spatial dimensionality imposes unique time constraints on cellular gene expression primarily because gene expression or upstream modes of gene regulation rather occur within the nucleus which in some neurons can be

millimeters to meters vastly distant from synaptic structure these spatial and then for temporal demands are in part met through the regulatory action of micro rnas which are capable of regulating gene expression locally at the synapse which is critical for depositing that information through modifying synaptic morphology and this is the basis for the process or the information storage

that we understand as memory so importantly with that in mind what i would like you to take home tonight is that memory on the cellular and molecular level is a particular kind of information storage that precipitates through the genetic and environmental interaction and moreover the next time that you just so happen to reminisce about the good old days or the formative days of your youth i hope that you will also marvel over the great molecular orchestration deep within your brain that ever guides you back to the

nostalgia of yesteryear and i hope that you've been inspired and enamored by the vast biological potential that lives and breathes within us all thank you