Picture the difference: electrophysiological investigations of picture processing in the two cerebral hemispheres

Abstract

The nature of semantic memory and the role of the two cerebral hemispheres in meaning processing were examined using event-related brain potentials (ERPs) elicited by pictures in sentences. Participants read sentence pairs ending with the lateralized presentation of three target types: (1) expected pictures, (2) unexpected pictures from the expected semantic category, and (3) unexpected pictures from an unexpected category. ERPs to contextually unexpected pictures were more negative 350-500 ms (larger N400s) than those to expected pictures in both visual fields. However, while N400s to the two types of unexpected items did not differ with left visual field presentations, they were smaller to the unexpected items from the expected category with right visual field presentations. This pattern, previously observed to words [Brain Language 62 (1998) 149], suggests general differences in how the two hemispheres use context on-line. Other aspects of the N400 response-and effects on earlier ERP components-reveal differences between pictures and words, suggesting that semantic memory access is not modality-independent. The P2 component varied with ending type for right but not left visual field presentations, suggesting that the left hemisphere may use contextual information to prepare for the visual analysis of upcoming stimuli. Furthermore, there was clear evidence for an earlier negativity ("N300"), which varied with ending type but, unlike the N400, was unaffected by visual field of presentation. Overall, the results support our hypothesis that the left hemisphere actively uses top-down information to preactivate perceptual and semantic features of upcoming stimuli, while the right hemisphere adopts a "wait and see" integrative approach.

Both sides get the point: Hemispheric sensitivities to sentential constraint

“…P2s to words in weakly constraining contexts did not differ with VF, but those to words in strongly constraining contexts were larger (more positive) for RVF/LH presentation. This pattern is reminiscent of that observed for congruency effects with sentence-final pictures: larger P2s for congruent pictures, but only with initial presentation to the LH (Federmeier & Kutas, 2002). This pattern is also similar to behavioral effect patterns, in which contextual information facilitates response speed for RVF but not LVF words.…”

“…One of three types of sentence-final words was presented in the LVF or RVF: "expected exemplars" (e.g., FOOTBALL), "betweencategory violations" (e.g., CHESS), or "within-category violations" (e.g., BASEBALL). Two key findings emerged from this study and a follow-up using sentence-final pictures (Federmeier & Kutas, 2002): First, N400 responses in the two VFs were equally affected by congruencythat is, reduced for expected exemplars relative to between-category violations. Indeed, the responses to these two ending types were statistically indistinguishable in the two VFs.…”

“…When pictures were used as sentence endings (Federmeier & Kutas, 2002) and were presented initially to the RVF/LH, we found congruency effects on the P2 component, a frontally distributed positive-going potential that peaks around 200 msec. P2 amplitude modulations have been linked to the detection and analysis of visual features in selective attention tasks (Hillyard & Münte, 1984;Luck & Hillyard, 1994), with increased amplitudes for stimuli containing the target feature.…”

Verb aspect and the activation of event knowledge.

“…Specifically, the highly typical locations for events denoted by verbs elicited smaller P1s and P2s when these locations appeared in a prepositional phrase following verbs in the perfect aspect than those to locations in any of the other conditions. This pattern for the early sensory components differed from that observed for the following N400 component and thus cannot readily be explained by resorting to semantic expectancy in combination with ease of semantic integration (Federmeier & Kutas, 2002;Sereno, Brewer, & O'Donnell, 2003). These early potentials are known to be sensitive to manipulations of visual processing and visuospatial selective attention.…”

A Pool of Pairs of Related Objects (POPORO) for Investigating Visual Semantic Integration: Behavioral and Electrophysiological Validation

“…However, the N400 does not depend on stimulus modality and can be obtained using visual, non-verbal stimuli such as simple line drawings (Holcomb and McPherson 1994; Barrett and Rugg 1990), photographs of real objects (McPherson and Holcomb 1999), pairings of words and line drawings (Ganis et al 1996;Nigam et al 1992;Federmeier and Kutas 2002), natural scenes (Ganis and Kutas 2003;Mudrik et al 2010), and videos (Sitnikova et al 2008). The topographies and waveforms of N400 effects for words and visual objects are very similar.…”