Visualizing traumatic stress-induced structural plasticity in a medial amygdala pathway using mGRASP.

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Cellular Neuroscience

Background:

• Traumatic stress can cause lasting behavioral changes, but the neural mechanisms are unclear.
• Structural plasticity, or long-term neural adaptability, is a potential mechanism.
• The medial amygdala (MeApv) to ventromedial hypothalamus (VmHvl) pathway is implicated in stress-induced aggression.

Purpose of the Study:

• To investigate structural plasticity in the MeApv-VmHvl pathway following acute traumatic stress.
• To identify the molecular mechanisms underlying stress-induced synaptic changes.

Main Methods:

• Used mGRASP imaging to visualize synaptic modifications in the MeApv-VmHvl pathway in mice.
• Applied acute foot shock stress to induce traumatic stress.
• Utilized chemogenetics to inhibit CaMKIIα-expressing neurons and MK-801 (NMDAR antagonist) to probe molecular mechanisms.

Main Results:

• Acute stress significantly increased synapse formation in the MeApv-VmHvl pathway.
• Chemogenetic inhibition of MeApv neurons reduced stress-induced synapse formation.
• NMDAR blockade with MK-801 prevented stress-induced synaptic changes.

Conclusions:

• Traumatic stress induces enduring structural plasticity in the MeApv-VmHvl neural pathway.
• NMDAR-dependent mechanisms are critical for these stress-induced synaptic alterations.
• This structural plasticity may underlie persistent behavioral issues like PTSD and social deficits.