Multimodal neuroimaging evidence linking memory and attention systems during visual search cued by context

Abstract

Visual search can be facilitated by the learning of spatial configurations that predict the location of a target among distractors. Neuropsychological and functional magnetic resonance imaging (fMRI) evidence implicates the medial temporal lobe (MTL) memory system in this contextual cueing effect, and electroencephalography (EEG) studies have identified the involvement of visual cortical regions related to attention. This work investigated two questions: (1) how memory and attention systems are related in contextual cueing; and (2) how these systems are involved in both short- and long-term contextual learning. In one session, EEG and fMRI data were acquired simultaneously in a contextual cueing task. In a second session conducted 1 week later, EEG data were recorded in isolation. The fMRI results revealed MTL contextual modulations that were correlated with short- and long-term behavioral context enhancements and attention-related effects measured with EEG. An fMRI-seeded EEG source analysis revealed that the MTL contributed the most variance to the variability in the attention enhancements measured with EEG. These results support the notion that memory and attention systems interact to facilitate search when spatial context is implicitly learned.

A new approach to modeling the influence of image features on fixation selection in scenes

“…Generalized linear mixed models. Our response variable is binary-for a given observer and image a given grid cell was either fixated (1) or not (0). The observation matrix comprised 155,520 entries of zeros and ones (45 images × 72 subjects × 48 grid cells).…”

“…Research using simple displays has shown that attention and memory are coupled, as evidenced by interference between attention and features of items in visual working memory . In the context of natural scenes, however, it has remained controversial which features drive attention.…”

“…Research using simple displays has shown that attention and memory are coupled, as evidenced by interference between attention and features of items in visual working memory. 1,2 In the context of natural scenes, however, it has remained controversial which features drive attention. Since eye movements are highly correlated with the path of visual attention, 3 this question can be operationalized by asking which properties make a region of a complex scene likely to be fixated.…”

“…For each patch, local image statistics are extracted from the image feature maps. Third, the empirical eye-fixation data are mapped onto the scene analysis grid: For each observer and image it is coded whether a given image patch was fixated (1) or not (0) throughout the trial. Generalized linear mixed models (GLMMs) are then used to assess the impact of various image features on selecting image patches for fixation.…”

Introduction to Competitive Visual Processing Across Space and Time: Attention, Memory, and Prediction

“…Kasper, Grafton, Eckstein, and Giesbrecht combine EEG and fMRI to probe contextual cueing, in which learned stimulus configurations speed up target selection. They show that attentional processes interact with hippocampus‐related memory both for short‐ and long‐term implicit learning . Trapp and Bar review evidence that predictive top‐down activation biases competitive processing in favor of the correct stimulus interpretation, and suggest the orbitofrontal cortex as a neural substrate for such computation …”