Thalamic Functional Connectivity during Spatial Long-Term Memory and the Role of Sex.

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Neuroimaging

Background:

• The thalamus, specifically the anterior (AT) and mediodorsal (MD) nuclei, is recognized for its role in cognitive functions, including long-term memory.
• While anatomical connections of AT and MD are well-mapped, their functional connectivity during long-term memory tasks remains underexplored.

Purpose of the Study:

• To investigate the functional connectivity of AT and MD during spatial long-term memory.
• To identify potential sex differences in the functional connectivity patterns associated with AT and MD during this memory task.

Main Methods:

• Participants performed a spatial long-term memory task involving encoding and retrieval of abstract shapes.
• Functional magnetic resonance imaging (fMRI) was used to measure brain activity.
• Region-of-interest analyses focused on AT and MD functional connectivity.

Main Results:

• Functional connectivity of AT and MD extended beyond known anatomical connections, encompassing a wider network of long-term memory regions.
• Significant sex differences were observed in the functional connectivity patterns of a subset of these regions.
• A notable finding was anti-correlated activity between MD and the hippocampus, specific to females, aligning with rodent studies.

Conclusions:

• AT and MD play significant roles in spatial long-term memory.
• The functional roles of AT and MD in long-term memory may exhibit sex-specific characteristics.
• Observed sex differences in functional connectivity highlight the importance of considering sex as a biological variable in memory research.