Auditory fear conditioning, a learning paradigm in which a rat can form an association between a previously neutral tone and a painful stimulus, is believed to occur via the persistent strengthening of synaptic connections, termed long-term potentiation (LTP), in the lateral amygdala (LA). Protein synthesis is necessary for both consolidation and reconsolidation of fear conditioning memory, and this may suggest a role for synapse remodeling. Auditory information enters the LA via plastic synapses from both the thalamus and cortex, but the functional and anatomical relationship between these synapses is unclear. The proposed project will begin to investigate the relative roles of these synapses in fear conditioning memory and their structural underpinnings. First, the protein synthesis-dependence of LTP consolidation and reconsolidation will be compared between the cortical and thalamic input pathways using a behaviorally relevant induction protocol. Second, serial section electron microscopy will be used to examine ultrastructural changes in LA synapses that occur during consolidation of fear conditioning and LTP, including changes in synapse size, synapse number, and local protein synthesis. Tracer injections will allow comparison of cortical and thalamic synapses under all conditions. A better understanding of the synaptic basis of the formation and maintenance of fear memories is important for the development of interventions for psychiatric disorders involving fear associations, such as phobias. ? ? ?
|Ostroff, Linnaea E; Botsford, Benjamin; Gindina, Sofya et al. (2017) Accumulation of Polyribosomes in Dendritic Spine Heads, But Not Bases and Necks, during Memory Consolidation Depends on Cap-Dependent Translation Initiation. J Neurosci 37:1862-1872|
|Ostroff, Linnaea E; Manzur, Mustfa K; Cain, Christopher K et al. (2014) Synapses lacking astrocyte appear in the amygdala during consolidation of Pavlovian threat conditioning. J Comp Neurol 522:2152-63|
|Ostroff, Linnaea E; Cain, Christopher K; Jindal, Neha et al. (2012) Stability of presynaptic vesicle pools and changes in synapse morphology in the amygdala following fear learning in adult rats. J Comp Neurol 520:295-314|
|Christianson, John P; Fernando, Anushka B P; Kazama, Andy M et al. (2012) Inhibition of fear by learned safety signals: a mini-symposium review. J Neurosci 32:14118-24|
|Ostroff, Linnaea E; Cain, Christopher K; Bedont, Joseph et al. (2010) Fear and safety learning differentially affect synapse size and dendritic translation in the lateral amygdala. Proc Natl Acad Sci U S A 107:9418-23|