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Saccadic eye movements are preceded by profound changes in visual perception. These changes have been linked to the phenomenon of 'forward remapping', in which cells begin to respond to stimuli that appear in their post-saccadic receptive field before the eye has moved. Few studies have examined the perceptual consequences of remapping of areas of impaired sensory acuity, such as the blindspot. Understanding the perceptual consequences of remapping of scotomas may produce important insights into why some neurovisual deficits, such as hemianopia are so intractable for rehabilitation. The current study took advantage of a naturally occurring scotoma in healthy participants (the blindspot) to examine pre-saccadic perception at the upcoming location of the blindspot. Participants viewed stimuli monocularly and were required to make stimulus-driven vertical eye-movements. At a variable latency between the onset of saccade target (ST) and saccade execution a discrimination target (DT) was presented at one of 4 possible locations; within the blindspot, contralateral to the blindspot, in post-saccadic location of the blindspot and contralateral to the post-saccadic location of the blindspot. There was a significant perceptual impairment at the post-saccadic location of the blindspot relative to the contralateral post-saccadic location of the blindspot and the post-saccadic location of the blindspot in a no-saccade control condition. These data are consistent with the idea that the visual system includes a representation of the blindspot which is remapped prior to saccade onset. [ABSTRACT FROM AUTHOR]

Visual perception and saccadic eye-movements are more precise when directed at isoeccentric locations along the horizontal compared to vertical meridian. This effect is known as horizontal-vertical anisotropy (HVA). Given that the eye-movement system plays an important role in spatial short-term memory (STM) it was hypothesized that spatial STM would also show a horizontal-vertical anisotropy. Consistent with this hypothesis an online experiment revealed a significant HVA in spatial STM (Experiment 1). This effect persisted even when eye-movements were precluded by using very short display durations (Experiment 2). However, there was no HVA in a colour span or orientation change detection task. It is argued that the HVA in spatial STM may result from greater imprecision in the representation of spatial locations along the vertical meridian relative to the horizontal meridian in the spatial maps underpinning spatial STM, a bilateral field advantage, or some combination of these mechanisms. [ABSTRACT FROM AUTHOR]

It has been proposed that covert visual search can be fast, efficient, and stimulus driven, particularly when the target is defined by a salient single feature, or slow, inefficient, and effortful when the target is defined by a nonsalient conjunction of features. This distinction between fast, stimulus-driven orienting and slow, effortful orienting can be related to the distinction between exogenous spatial attention and endogenous spatial attention. Several studies have shown that exogenous, covert orienting is limited to the range of saccadic eye movements, whereas covert endogenous orienting is independent of the range of saccadic eye movements. The current study examined whether covert visual search is affected in a similar way. Experiment 1 showed that covert visual search for feature singletons was impaired when stimuli were presented beyond the range of saccadic eye movements, whereas conjunction search was unaffected by array position. Experiment 2 replicated and extended this effect by measuring search times at 6 eccentricities. The impairment in covert feature search emerged only when stimuli crossed the effective oculomotor range and remained stable for locations further into the periphery, ruling out the possibility that the results of Experiment 1 were due to a failure to fully compensate for the effects of cortical magnification. The findings are interpreted in terms of biased competition and oculomotor theories of spatial attention. It is concluded that, as with covert exogenous orienting, biological constraints on overt orienting in the oculomotor system constrain covert, preattentive search. [ABSTRACT FROM AUTHOR]

Visual perception can be influenced by the content of working memory. Previous studies have shown this influence can be enough to improve unconscious visual discrimination in healthy participants and conscious visual discrimination in neuropsychological patients with extinction. Here, these findings are extended by examining the effects of holding an object in working memory on unconscious visual perception in a person with hemianopia. The results revealed significantly enhanced detection accuracy when there was an exact match between the colour and orientation of the discrimination target and the item in working memory. However, the facilitatory effect was greatly reduced when only colour or orientation was matched with the item being held in memory. A control experiment confirmed these effects were not due to visual priming. These results are consistent with the proposal that working memory guided perceptual facilitation is driven by signal enhancement. More broadly, the data are interpreted in terms of a biased competition account of visual perception. [ABSTRACT FROM AUTHOR]

Salient peripheral cues produce a transient shift of attention which is superseded by a sustained inhibitory effect. Cueing part of an object produces an inhibitory cueing effect (ICE) that spreads throughout the object. In dynamic scenes the ICE stays with objects as they move. We examined object-centred attentional facilitation and inhibition in a patient with visual form agnosia. There was no evidence of object-centred attentional facilitation. In contrast, object-centred ICE was observed in 3 out of 4 tasks. These inhibitory effects were strongest where cues to objecthood were highly salient. These data are evidence of a neuropsychological dissociation between the facilitatory and inhibitory effects of attentional cueing. From a theoretical perspective the findings suggest that ‘grouped arrays’ are sufficient for object-based inhibition, but insufficient to generate object-centred attentional facilitation. [ABSTRACT FROM AUTHOR]

We typically move attention around the environment with overt eye-movements. However, it is also possible to orient attention covertly, such that the 'spotlight' of attention is moved independently of the locus of gaze. While there is enduring debate about the relationship between the mechanisms controlling covert and overt attention, one influential view is that shifts of covert attention are achieved by planning (but not executing) and overt eye movement. We have previously shown that placing stimuli at locations beyond the effective oculomotor range (EOMR) interfered with covert, exogenous orienting to peripheral cues but not covert endogenous orienting driven by symbolic cues (e.g. Smith et al., 2012; Smith & Casteau 2019). Here, we examined whether the association between exogenous attention and the EOMR observed in cueing tasks generalised to visual search tasks. We first measured the EOMR for each participant, then presented search arrays that were either within or beyond their EOMR. Feature search was significantly slower when stimuli were presented beyond the range of eye-movements whereas conjunction search was unaffected. In a second study we parametrically varied the location of the array to better establish how well changes in search performance mapped onto the range of eye-movements. The results confirmed that preattentive search was restricted to the locations within the range of eye-movement. We conclude that optimal covert, exogenous orienting of attention depends on the oculomotor system, consistent with an Oculomotor Readiness hypothesis of Exogenous Orienting. [ABSTRACT FROM AUTHOR]

Biased competition theory assumes that shift of attention is biased towards visual stimuli that matched the content of the visual working memory (VWM) and this bias might be due to a competition between eye-movement motor plans and memory object location. Here, we measured the effect of holding an item in VWM on pre-saccadic shift of attention by measuring attention when the goal of an eye-movement is congruent or incongruent with the location of an object sharing properties with the VWM content. Participants performed an eye-movement towards a previously specified location (Saccade Target, ST) and make a discrimination decision (Discrimination Target, DT). They also had to retain a visual feature in VWM for the whole duration of the trial (Memory Target; MT). There were four different conditions: 1) MT congruent with ST and DT, 2) MT congruent with DT but incongruent with ST, 3) MT congruent with ST but incongruent with DT, 4) MT incongruent with ST and DT. As expected, pre-saccadic attentional facilitation was greatest when the VWM content, the saccade direction and the discrimination location were all congruent, and abolished when ST, DT and MT were at different locations. Critically, when the ST and DT were in the same location but the MT at a different location pre-saccadic attentional facilitation was significantly reduced, suggesting competition between the saccade goal and the MT. Our results suggest that, the attention bias linked to the content of VWM can be understand as a competition between different saccade goals in the oculomotor system. [ABSTRACT FROM AUTHOR]