Marta Moita
Marta Moita
Principal Investigator
martamoita[at]fchampalimaud.org
We are interested in understanding the neural mechanisms underlying behavioural plasticity. To behave in an adaptive manner animals have to make decisions based on an evaluation of the current circumstances and on their past experiences. Evaluating the current situation involves perceiving cues in the environment (e.g. smell of food), internal cues (e.g. hunger), the possible payoffs (e.g. amount of food and probability of getting it), and the costs involved (e.g. effor the animal has to make in order to obtain the food). In order to rely on past experiences, animals have to be able to form, store and retrieve memories of past events (e.g. “I’ve been here before and found food”). We are particularly interested in studying the neural basis of memory formation, and payoff evaluation. To do so, we chose to focus on a particular behavioural paradigm, Pavlovian Fear Conditioning. During conditioning, a previously neutral stimulus, such as a tone, is paired with an aversive stimulus, such as footshock, so that the tone and shock co-terminate. Animals quickly learn that the tone predicts shock delivery. After conditioning the tone elicits species-specific fear responses, such as freezing, where animals stop all movement except for respiration. This paradigm presents several advantages: it is conserved across species, from flies to humans; it entails fast robust learning and very long lasting memories; its underlying neural circuitry is very well described; furthermore, it may bring insights into the neural mechanisms undrlying axiety disorders.
Currently we are working on two major projects:
- Neural mechanisms underlying fear generalisation. In this project we aim at understanding the circuitry involved in establishing the specificity of the learned fear response. Although great progress has been made in the understanding of how rats learn to fear a tone that has been paired with a footshock, little is known about the mechanisms that establish the degree to which the acquired fear of the tone generalizes to other similar tones.
- Neural mechanism underlying learning about the association of stimuli separate in time. A number of structures have been implicated in learning the association between a tone and a footshock, when the tone is presented several seconds before the shock (auditory trace fear conditioning). Our goal is to study how these structures interact during this form of learning.
In these projects we use a combination of behavioural, pharmacological, molecular and electrophysiological tools. Currently we perform lesions and temporary inactivation to study the role of specific brain regions in fear learning. We are also setting up in vivo electrophysiology (multiple electrode recordings in awake behaving rats) and viral transfection to manipulate activity in specific populations of neurons.
Selected Publications
Blair, H.T., Sotres-Bayon, F., Moita, M.A.P., LeDoux, J.E. 2005. The lateral amygdala processes the value of conditioned and unconditioned aversive stimuli Neuroscience 133(2) :561-9
Moita, M.A.P., Erlich, J., Rosis, S., LeDoux, J.E. and Blair, H.T. 2004. Putting Fear in its Place: Remapping of hippocampal place cells during aversive contextual conditioning. Journal of Neuroscience 24(31) :7015-23
Moita, M.A.P., Rosis, S., Ledoux, J.E. and Blair, H.T. 2003. Hippocampal place cells acquire place specific auditory responses during fear conditioning Neuron 37(3): :485-97
Blair, H.T., Tinkelman, A., Moita, M.A.P., LeDoux, J.E. 2003. Associative plasticity in neurons of the lateral amygdala during auditory fear conditioning. In P. Shinnick-Gallagher, A. Pitkanen, A. Shekhar, and L. Cahill (Eds.), The Amygdala in Brain Function: Basic and Clinical Approaches Annals of the New York Academy of Sciences 985
Moita, M.A.P., Lamprecht, R., Nader, K. & LeDoux, J.E. 2002. Anchoring of PKA onto AKAP proteins in the amygdala is necessary for the consolidation of auditory fear memories. Nat. Neurosci. 5(9) :837-8 Link
de Bruin, J.P., Moita, M.P., de Brabander, H.M., Joosten, R.N. 2001. Place And Response Learning Of Rats In A Morris Water Maze: Differential Effects Of Fimbria Fornix And Medial Prefrontal Cortex Lesions Neurobiol. Learn. Mem. 75(2) :164-78