Attending to global versus local stimulus features modulates neural processing of low versus high spatial frequencies: an analysis with event-related brain potentials

Abstract

Spatial frequency (SF) selection has long been recognized to play a role in global and local processing, though the nature of the relationship between SF processing and global/local perception is debated. Previous studies have shown that attention to relatively lower SFs facilitates global perception, and that attention to relatively higher SFs facilitates local perception. Here we recorded event-related brain potentials (ERPs) to investigate whether processing of low versus high SFs is modulated automatically during global and local perception, and to examine the time course of any such effects. Participants compared bilaterally presented hierarchical letter stimuli and attended to either the global or local levels. Irrelevant SF grating probes flashed at the center of the display 200 ms after the onset of the hierarchical letter stimuli could either be low or high in SF. It was found that ERPs elicited by the SF grating probes differed as a function of attended level (global versus local). ERPs elicited by low SF grating probes were more positive in the interval 196–236 ms during global than local attention, and this difference was greater over the right occipital scalp. In contrast, ERPs elicited by the high SF gratings were more positive in the interval 250–290 ms during local than global attention, and this difference was bilaterally distributed over the occipital scalp. These results indicate that directing attention to global versus local levels of a hierarchical display facilitates automatic perceptual processing of low versus high SFs, respectively, and this facilitation is not limited to the locations occupied by the hierarchical display. The relatively long latency of these attention-related ERP modulations suggests that initial (early) SF processing is not affected by attention to hierarchical level, lending support to theories positing a higher level mechanism to underlie the relationship between SF processing and global versus local perception.

Processing of Spatial-Frequency Altered Faces in Schizophrenia: Effects of Illness Phase and Duration

“…The rationale for these manipulations is supported by studies indicating that when forced to rely on either high or low SF data alone for face identification, healthy adults and children above 8 months of age tend to rely on low SF information, which may represent a tendency to initially encode the global structure of the face to determine identity [42] , [46] [47] , [48] . Recent ERP data also confirm the association between global and LSF processing, and local and HSF processing [49] .…”

Individual differences in involvement of the visual object recognition system during visual word recognition

“…This is because the RH OT system is known to be less sensitive to high spatial frequencies than the LH OT system (review in Flevaris et al, 2014), and these are precisely the frequencies needed for orthographic analysis. Consequently, the abstract orthographic representations provided by the RH OT system might not be as sharp as those that would be provided by the LH system.…”

“…One crucial reason is that the RH OT is known to be less sensitive to high spatial frequencies than the LH analog (e.g., Kitterle, Christman, & Hellige, 1990; see review in Flevaris, Martinez, & Hillyard, 2014). The differences between letters in printed text are precisely the kind of high spatial frequency information that the RH does not excel at extracting.…”

Objects seen as scenes: neural circuitry for attending whole or parts

“…These features also differ markedly between the global/local levels of Navon figures (e.g. see Figure 1 in (Flevaris et al, 2014)).…”