Cortico-hippocampal network connections support the multidimensional quality of episodic memory

Introduction

This paper is concerned with how two previously described functional networks in the brain (Posterior medial and Anterior Temporal) work together to support high-dimensional reinstatement of episodic memories. PM network codes context and location, AT codes for items and emotion (includes the amygdala).

Methods

Authors use a highly naturalistic task in which subjects encode an item with color, a position in a room, and emotional valence. Thus, memories can be broken up into two continuous measures and one binary measure.

Results

Behavior

Subjects were faily good at this task, performance was above chance for all measures. Recalling one facet of memory (i.e. color) led to higher chance of recalling another facet (location), but precision of one memory was not dependent on the precision of the first. Thus, it can be said that the “gist” of episodic features are bound in memory.

• used those cool mixture models to seperate out responses for the continuous measures

Neural

• in general, they found that the AT and PM networks acted more seperately during encoding compared to retrieval
• during retrieval, there was increased communication between networks, as well as between the hippocampus and PMAT.
• The also found that the accuracy of the multidimensional memories scaled with connectivity in between all regions of these networks.
• And, as predicted, PM participated more in spacial memory, and AT participated more in color binding

Conclusion

Networks are cool and functional connectivity between these big regions is important for episodic retrieval.