The locus of recognition memory signals in human cortex depends on the complexity of the memory representations

According to a Swiss Army Knife model of the brain, cognitive functions such as episodic memory and face perception map onto distinct neural substrates. In contrast, representational accounts propose that each brain region is best explained not by which specialized function it performs, but by the type of information it represents with its neural firing. In a functional magnetic resonance imaging study, we asked whether the neural signals supporting recognition memory fall mandatorily within the medial temporal lobes (MTL), traditionally thought the seat of declarative memory, or whether these signals shift within cortex according to the content of the memory. Participants studied objects and scenes that were unique conjunctions of pre-defined visual features. Next, we tested recognition memory in a task that required mnemonic discrimination of both simple features and complex conjunctions. Feature memory signals were strongest in posterior visual regions, declining with anterior progression toward the MTL, while conjunction memory signals followed the opposite pattern. Moreover, feature memory signals correlated with feature memory discrimination performance most strongly in posterior visual regions, whereas conjunction memory signals correlated with conjunction memory discrimination most strongly in anterior sites. Thus, recognition memory signals shifted with changes in memory content, in line with representational accounts.

Automated summary

According to the Swiss Army Knife model, cognitive functions such as episodic memory and face perception are supported by specific neural substrates. However, the representational accounts propose that brain regions are best explained by the type of information they represent, rather than specialized function. In a study using functional magnetic resonance imaging, researchers investigated whether the neural signals supporting recognition memory are exclusively located in the medial temporal lobes (MTL), or if they shift within the cortex based on memory content. The results showed that memory signals for simple features were strongest in posterior visual regions and declined towards the MTL, while memory signals for complex conjunctions followed the opposite pattern. These findings suggest that recognition memory signals change according to memory content, supporting the representational accounts.