Attention to pattern orientation: Negative cortical potentials, reaction time, and the selection process

Electrophysiological and behavioral indicants of selective attention to multifeature gratings

“…Before proceeding to a more detailed discussion of these two selection mechanisms, it should be noted that both feature-specific and grating-specific attentional processes were clearly evidenced in the extended negative voltage shift whose onset and peak occurred at approximately 175 and 250 msec, respectively. This finding lends further support to the view that this negative shift-termed N235 (Harter & Salmon, 1972) or "processing negativity'P-e-is actually a complexensemble of individual components depicting various stages in the information-processing hierarchy (see Harter, Aine, & Schroeder, 1982;Harter & Guido, 1980;Harter & Previc, 1978).…”

“…Their results supported this hypothesis in that the influence of selectiveattention to spatial frequency closely resembled the effects of spatial frequency-specificsuppression upon the VEP. Harter and Guido (1980) further demonstrated that the scalp topography of orientation-specific YEP attention effects was similar to that of the YEP effects associated with the processing of the pattern per se.In the present study, it was similarly hypothesized that the "endogenous" effects of selectively attending gratings of a particular spatial frequency and orientation would closely resemble the "exogenous" …”

“…The behavioral responses primarily reflected this latter, or grating-specific, attentional process. The results are discussed in terms of the role of sensory feature channels in mediating selective attention to visual stimuli and are related to various information processing models of visual pattern selection.The neural mechanisms underlying intramodal selective attention in humans have been investigated using the visual evoked potential (VEP) in a variety of different contexts (see Eason, Harter, & White, 1969;Harter & Guido, 1980;Harter & Previc, 1978;Harter & Salmon, 1972;Van Voorhis & Hillyard, 1977). Although the visual stimuli in these and other studies have varied along several types of dimensions, including spatial location, check size, orientation, and color, in no case have the attended and nonattended stimuli varied orthogonally along more than one feature dimension.…”

Attention to Features Precedes Attention to Locations in Visual Search: Evidence from Electromagnetic Brain Responses in Humans

“…It is instructive to compare the present results with previously reported feature-selective modulations of the ERP response in the N1 time range and beyond (Harter and Previc, 1978;Harter and Guido, 1980;Hillyard and Münte, 1984;Wijers et al, 1989;Anllo-Vento and Hillyard, 1996;Heslenfeld et al, 1997). In most of these studies, all stimuli were presented at attended locations, making it impossible to determine the relationship between attention to spatial and nonspatial features.…”

Event-related potential correlates of transient attention shifts to color and location

“…On the basis of these results, Mangun & Hillyard (1990) have proposed that spatial attention may consist of 'sensory gating' processes that modulate sensory processing in afferent visual pathways. In contrast, attending to non-spatial attributes like color, orientation, contour, or spatial frequency results in an enhanced negativity elicited by attended stimuli that starts beyond 150 ms and may extend up to 300 ms post-stimulus (Harter & Previc, 1978;Harter & Guido, 1980;Harter, Aine & Schroeder, 1982;Previc & Harter, 1982;Aine & Harter, 1984;Wijers, Mulder, Okita, Mulder & Scheffers, 1989;Wijers, Lamain, Slopsema, Mulder & Mulder, 1989;Kenemans, Kok & Smulders, 1993). The fact that attending to various non-spatial attributes results in qualitatively similar ERP modulations is in line with the general assumption that different non-spatial stimulus features are processed within a common visual sub-system, the so-called 'ventral pathway' (Ungerleider & Mishkin, 1982).…”