Temporal Gating of Synaptic Competition in the Amygdala by Cannabinoid Receptor Activation
- Cellular and Systems Neurobiology, Chronic Diseases Research Center (CEDOC), NOVA Medical School, Universidade Nova de Lisboa, Lisboa 1169-056, Portugal
- Instituto Gulbenkian de Ciência, Oeiras 2780-156, Portugal
- Cellular and Systems Neurobiology, Chronic Diseases Research Center (CEDOC), NOVA Medical School, Universidade Nova de Lisboa, Lisboa 1169-056, Portugal, Instituto Gulbenkian de Ciência, Oeiras 2780-156, Portugal
Abstract The acquisition of fear memories involves plasticity of the thalamic and cortical pathways to the lateral amygdala (LA). In turn, the maintenance of synaptic plasticity requires the interplay between input-specific synaptic tags and the allocation of plasticity-related proteins. Based on this interplay, weakly activated synapses can express long-lasting forms of synaptic plasticity by cooperating with strongly activated synapses. Increasing the number of activated synapses can shift cooperation to competition. Synaptic cooperation and competition can determine whether two events, separated in time, are associated or whether a particular event is selected for storage. The rules that determine whether synapses cooperate or compete are unknown. We found that synaptic cooperation and competition, in the LA, are determined by the temporal sequence of cortical and thalamic stimulation and that the strength of the synaptic tag is modulated by the endocannabinoid signaling. This modulation is particularly effective in thalamic synapses, supporting a critical role of endocannabinoids in restricting thalamic plasticity. Also, we found that the availability of synaptic proteins is activity-dependent, shifting competition to cooperation. Our data present the first evidence that presynaptic modulation of synaptic activation, by the cannabinoid signaling, functions as a temporal gating mechanism limiting synaptic cooperation and competition.
- Sponsoring Organization:
- USDOE Office of Nuclear Energy (NE), Nuclear Fuel Cycle and Supply Chain
- OSTI ID:
- 1604472
- Journal Information:
- Cerebral Cortex, Journal Name: Cerebral Cortex Journal Issue: 7 Vol. 30; ISSN 1047-3211
- Publisher:
- Oxford University PressCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
Evidence for presynaptically silent synapses in the immature hippocampus
Role of the site of synaptic competition and the balance of learning forces for Hebbian encoding of probabilistic Markov sequences