The olfactory sense, unique in its direct connection to the amygdala and hippocampus, can play a significant role in emotional memory (Lundström et al., 2011; Schlichting & Frankland, 2017). We aimed to explore how olfactory cues affect memory integration in two studies, based on our associative spatial memory paradigm (Liu et al., 2020). In study 1, we hypothesized that olfactory cues enhance memory encoding and retrieval compared to auditory cues due to specific neuronal input from the piriform cortex. In study 2, we proposed olfactory cues enhance memory compared to no context, with piriform cortex's augmenting role.
We tested 30 normosmic participants using 3T imaging at Donders Institute, with the Lundstrom olfactometer for odor delivery (Lundström et al., 2010). Our paradigm involved associating pictures to locations on a cartoon map, paired with a context stimulus (olfactory/auditory for study1; olfactory/none for study2). In an fMRI recall phase, participants indicated where on the map a previously shown picture was located and its associated smell or sound. More detailed recall questions were asked outside the MRI.
Preliminary results from study 1 show that both sound and smell stimulation led to reliable neuronal activity patterns. However, there was no observed interactive effect of memory retrieval in brain activity, nor significant behavioral differences between smell and sound contexts. Study 2 data acquisition is ongoing, and we intend to further analyze and pool results from both studies.
In preliminary summary olfactory context cues do not seem to have a neuronal or behavioural facilitative influence on memory integration when compared to auditory context.