PT  - JOURNAL ARTICLE
AU  - Kristina C. Backer
AU  - Bradley R. Buchsbaum
AU  - Claude Alain
TI  - Orienting Attention to Short-Term Memory Representations via Sensory Modality and Semantic Category Retro-Cues
AID  - 10.1523/ENEURO.0018-20.2020
DP  - 2020 Nov 02
TA  - eneuro
PG  - ENEURO.0018-20.2020
4099  - http://www.eneuro.org/content/early/2020/10/30/ENEURO.0018-20.2020.short
4100  - http://www.eneuro.org/content/early/2020/10/30/ENEURO.0018-20.2020.full
AB  - There is growing interest in characterizing the neural mechanisms underlying the interactions between attention and memory. Current theories posit that reflective attention to memory representations generally involves a fronto-parietal attentional control network. The present study aimed to test this idea by manipulating how a particular short-term memory (STM) representation is accessed – that is, based on its input sensory modality or semantic category – during functional magnetic resonance imaging (fMRI). Human participants performed a novel variant of the retro-cue paradigm, in which they were presented with both auditory and visual non-verbal stimuli followed by Modality, Semantic, or Uninformative retro-cues. Modality and, to a lesser extent, Semantic retro-cues facilitated response time relative to Uninformative retro-cues. The univariate and multivariate pattern analyses of fMRI time-series revealed three key findings. First, the Posterior Parietal Cortex (PPC), including portions of the Intraparietal Sulcus (IPS) and ventral Angular Gyrus (AG), had activation patterns that spatially overlapped for both Modality-based and Semantic-based reflective attention. Second, considering both the univariate and multivariate analyses, Semantic retro-cues were associated with a left-lateralized fronto-parietal network. Finally, the experimental design enabled us to examine how dividing attention cross-modally within STM modulates the brain regions involved in reflective attention. This analysis revealed that univariate activation within bilateral portions of the PPC increased when participants simultaneously attended both auditory and visual memory representations. Therefore, prefrontal and parietal regions are flexibly recruited during reflective attention, depending on the representational feature used to selectively access STM representations.Significance Statement This functional magnetic resonance imaging (fMRI) study sought to examine similarities and differences in neural activity when concrete (sensory modality) and abstract (semantic category) information is used to guide attention to short-term memory representations of non-verbal stimuli. The posterior parietal cortex (especially portions of Intraparietal Sulcus and left ventral Angular Gyrus (AG)) had activation patterns that were specific to both modality- and semantic-based reflective attention. Semantic-based reflective attention also recruited additional left-lateralized prefrontal regions and dorsolateral AG. Furthermore, dividing attention across sensory domains within memory was associated with stronger activation within the dorsomedial posterior parietal cortex. Thus, attentional orienting to memory flexibly recruits prefrontal and parietal regions as necessary, depending on the information used to selectively access memory representations.