Prefrontal projections modulate recurrent circuitry in the insular cortex to support short-term memory
Jian Yao1, Ruiqing Hou2, Hongmei Fan2
1Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China; Lingang Laboratory, Shanghai 200031, China.
Cell Reports
|February 15, 2024
Summary
Long-range brain connections from the medial prefrontal cortex (mPFC) to the anterior agranular insular cortex (aAIC) are crucial for short-term memory (STM). Modulating these mPFC-aAIC pathways directly impacts memory performance and neural communication.
Area of Science:
- Neuroscience
- Cognitive Neuroscience
- Systems Neuroscience
Background:
- Short-term memory (STM) relies on neural circuits, but the interplay between long-range and local connections is not fully understood.
- The medial prefrontal cortex (mPFC) and anterior agranular insular cortex (aAIC) are implicated in memory tasks, yet their specific interaction in STM remains unclear.
Purpose of the Study:
- To investigate the role of long-range projections from the mPFC to the aAIC in supporting short-term memory encoding.
- To determine how these projections influence neural activity, functional connectivity, and information transfer within the aAIC during an olfactory delayed-response task.
Main Methods:
- Utilized optogenetics and electrophysiology in head-fixed mice performing an olfactory delayed-response task.
- Analyzed spike-correlogram data to assess functional coupling (FC) between memory neurons.
- Manipulated mPFC-aAIC projections via optogenetics (suppression and excitation) to observe effects on behavior and neural activity.
Main Results:
- Optogenetic suppression of mPFC-aAIC projections impaired behavioral performance, reduced the proportion of memory neurons, and decreased memory-specific FC within the aAIC.
- Optogenetic excitation of these projections enhanced behavioral performance, increased memory neurons, and strengthened memory-specific FC.
- mPFC-aAIC projections bidirectionally modulated the efficacy of STM information transfer to downstream neurons.
Conclusions:
- Long-range projections from the mPFC to the aAIC play a critical role in supporting short-term memory encoding.
- These prefrontal projections actively modulate insular neuronal functional connectivity and memory-coding capacity.
- The findings elucidate a key mechanism by which prefrontal-insular interactions contribute to short-term memory.
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