Spatial Selective Attention Affects Early Extrastriate But Not Striate Components of the Visual Evoked Potential

Abstract

The effects of spatial selective attention on sensory processing in visual cortical areas were investigated by means of visual evoked potential (VEP) recordings and source localization techniques. Patterned stimuli were rapidly presented in random order to the left and right visual fields while subjects maintained central fixation and attended to one visual field at a time. Attended stimuli evoked enhanced P1 (100-130 msec) and N1 (120-200 msec) components of the VEP, whereas no effects of attention were observed on the C1 (50-100 msec) or P2 (200-240 msec) components. Spatiotemporal dipole modeling of the early VEP sources was carried out in relation to MRI-defined cortical anatomy. The dipolar generator of the C1 component was found to lie in calcarine cortex, the human homologue of area V1, whereas the attention-sensitive P1 generator was localized to ventral-lateral occipital cortex, within extrastriate area 19. These results support the hypothesis that spatial attention does not affect the initial activity evoked in area V1 but rather produces an enhancement within extrastriate visual areas of sensory signals arising from stimuli at attended locations.

Electrophysiological correlates of spatial orienting towards angry faces: A source localization study

“…It is, however, unclear how the use of angry versus fearful faces may have altered our results. The C1 to the probe was also not modulated by attention, consistent with previous research (e.g., Clark & Hillyard, 1996;Di Russo, Martinez, & Hillyard, 2003;Mangun, 1995;Martinez, Anllo-Vento, Sereno, Frank, Buxton, Dubowitz et al, 1999). Taken together, results suggest the C1 component is not a reliable index of early emotion-related neural activation arising from the primary visual cortex or selective attention towards emotionally significant stimuli.…”

“…It is, however, unclear how the use of angry versus fearful faces may have altered our results. The C1 to the probe was also not modulated by attention, consistent with previous research (e.g., Clark & Hillyard, 1996; Di Russo, Martinez, & Hillyard, 2003;Mangun, 1995; Martinez, Anllo-Vento, Sereno, Frank, Buxton, Dubowitz et al, 1999 (Clark & Hillyard, 1996;Di Russo, et al, 2003;Mangun, 1995; Mangun, Hinrichs, Scholz, Mueller-Gaerner, Herzog, Krause et al, 2001; Martinez, Di Russo, AnlloVento, Sereno, Buxton & Hillyard, 2001; Martinez et al, 1999). However, given differences in source localization and dissociations observed for these components under various attentional manipulations (which were not measured here), the P1 and N1 might reflect distinct aspects of spatial attention (Hillyard, Luck, & Mangun, 1994;Mangun & Hillyard, 1990).…”

“…Others have reported, however, larger N170 amplitudes for angry faces (Kolassa & Milner, 2006), fearful faces (Blau et al, 2007), and personally salient faces (Pizzagalli et al, 2002) compared with other emotional expressions and larger N1 amplitudes have been repeatedly associated with greater attentional processing (Clark & Hillyard, 1996;Di Russo, et al, 2003;Mangun, 1995;Mangun, Hinrichs, Scholz, Mueller-Gaerner, Herzog, Krause et al, 2001;Martinez, Di Russo, AnlloVento, Sereno, Buxton & Hillyard, 2001;Martinez et al, 1999). However, given differences in source localization and dissociations observed for these components under various attentional manipulations (which were not measured here), the P1 and N1 might reflect distinct aspects of spatial attention (Hillyard, Luck, & Mangun, 1994;Mangun & Hillyard, 1990).…”

Meaning and modality: Influences of context, semantic memory organization, and perceptual predictability on picture processing.

“…In this case, in addition to effects of context and category membership in the N400 time windows, we see effects of context (but not category) on much earlier components, namely the frontal N1 (50-150 ms) and the P2 (150-250 ms). The frontal N1 has been linked to allocation of visuospatial attention and has been hypothesized to reflect the output of a capacity-limited attentional system (e.g., Clark & Hillyard, 1996;Mangun, Hillyard, & Luck, 1993). Enhanced N 1 amplitudes are observed, for example, in response to target stimuli presented at attended relative to unattended locations.…”

A brief introduction to the use of event-related potentials in studies of perception and attention

“…First, we see the C1 component which flips polarity based in whether the eliciting stimulus appears in the upper or lower visual field and is believed to be generated by activity in primary visual cortex (Clark, Fan, & Hillyard, 1995; Clark & Hillyard, 1996; Estevez & Spekreijse, 1974; Jeffreys & Axford, 1972). This initial deflection is followed by the P1 and N1 components as information propagates through the visual system and perceptual analysis is performed (Heinze et al, 1994; Heinze, Mangun, & Hillyard, 1990; Luck, 1995; Vogel & Luck, 2000).…”