Spatial relevance determines facilitatory and inhibitory effects of auditory covert spatial orienting.

Eight experiments examined the conditions necessary for covert orienting and inhibition of return (IOR) to occur in audition. Spatially uninformative auditory cues facilitated responses to auditory targets at short stimulus onset asynchronies (SOAs) and inhibited them at longer SOAs when the decision to respond was based on the location of the target (Experiments 1, 3, and 4). The same cues did not influence performance when the decision to respond was based on nonspatial criteria (Experiments 2, 5, and 7) unless the cues predicted the location of the target (Experiment 6). In the absence of cues, the location of a previous target influenced performance when the decision to respond was based on spatial, but not nonspatial, criteria (Experiment 8). These findings demonstrate that covert orienting and IOR occur in audition only when spatial relevance is established, presumably inducing use of location-sensitive neurons in generating responses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The suppression of reflexive visual and auditory orienting when attention is otherwise engaged.

Two experiments were conducted to examine whether abrupt onsets are capable of reflexively capturing attention when they occur outside the current focus of spatial attention, as would be expected if exogenous orienting operates in a truly automatic fashion. The authors established a highly focused attentional state by means of the central presentation of a stream of visual or auditory characters, which participants sometimes had to monitor. No intramodal reflexive cuing effects were observed in either audition or vision when participants performed either an exogenous visual or auditory orthogonal cuing task together with the central focused attention task. These results suggest that reflexive unimodal orienting is not truly automatic. The fact that cuing effects were eliminated under both unimodal and cross-modal conditions is consistent with the view that auditory and visual reflexive spatial orienting are controlled by a common underlying neural substrate. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Enhanced facilitation of spatial attention in schizophrenia.

Objective: While attentional functions are usually found to be impaired in schizophrenia, a review of the literature on the orienting of spatial attention in schizophrenia suggested that voluntary attentional orienting in response to a valid cue might be paradoxically enhanced. We tested this hypothesis with orienting tasks involving the cued detection of a laterally presented target stimulus. Method: Subjects were chronic schizophrenia patients (SZ) and matched healthy control subjects (HC). In Experiment 1 (15 SZ, 16 HC), cues were endogenous (arrows) and could be valid (100% predictive) or neutral with respect to the subsequent target position. In Experiment 2 (16 SZ, 16 HC), subjects performed a standard orienting task with unpredictive exogenous cues (brightening of the target boxes). Results: In Experiment 1, SZ showed a larger attentional facilitation effect on reaction time than HC. In Experiment 2, no clear sign of enhanced attentional facilitation was found in SZ. Conclusions: The voluntary, facilitatory shifting of spatial attention may be relatively enhanced in individuals with schizophrenia in comparison to healthy individuals. This effect bears resemblance to other relative enhancements of information processing in schizophrenia such as saccade speed and semantic priming. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rehearsal in spatial working memory

This article reports 3 experiments that tested a hypothesis regarding the nature of rehearsal in spatial working memory, one in which discrete shifts of spatial selective attention mediate the maintenance of location-specific representations. Experiment 1 demonstrated increases in visual processing efficiency for locations held in working memory, which suggested that attention was oriented toward these locations. Experiment 2 eliminated key alternative explanations for Experiment 1 by using an identical stimulus display with a nonspatial memory task, and little or no facilitation of processing at memorized locations was found under these conditions. Finally, Experiment 3 showed that spatial working memory was impaired when participants were hindered in their ability to attend to memorized locations. It is argued that these results implicate selective spatial attention as a rehearsal mechanism for spatial working memory.     

The influence of alertness on spatial and nonspatial components of visual attention.

Three experiments investigated whether spatial and nonspatial components of visual attention would be influenced by changes in (healthy, young) subjects’ level of alertness and whether such effects on separable components would occur independently of each other. The experiments used a no-cue/alerting-cue design with varying cue-target stimulus onset asynchronies in two different whole-report paradigms based on Bundesen’s (1990) theory of visual attention, which permits spatial and nonspatial components of selective attention to be assessed independently. The results revealed the level of alertness to affect both the spatial distribution of attentional weighting and processing speed, but not visual short-term memory capacity, with the effect on processing speed preceding that on the spatial distribution of attentional weighting. This pattern indicates that the level of alertness influences both spatial and nonspatial component mechanisms of visual attention and that these two effects develop independently of each other; moreover, it suggests that intrinsic and phasic alertness effects involve the same processing route, on which spatial and nonspatial mechanisms are mediated by independent processing systems that are activated, due to increased alertness, in temporal succession. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive spatial processing and the regulation of posture.

Investigated the interaction between postural regulation and spatial processing by having 24 college students perform L. R. Brooks's (see record 1968-04936-001) spatial and nonspatial memory tasks either while sitting or while maintaining a difficult standing balance position. The balance task disrupted spatial but not nonspatial memory performance. Balance steadiness during spatial and nonspatial memory conditions did not differ. Results suggest that cognitive spatial processing may rely on neural mechanisms that are also required for the regulation of posture. Findings support the idea that spatial processing may rely on phylogenetically older systems. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatial attention and implicit sequence learning: Evidence for independent learning of spatial and nonspatial sequences.

This research investigated whether regular spatial orienting sequences can be learned implicitly and independently of response requirements. In a new version of a serial response task introduced by M. J. Nissen and P. Bullemer (1987) participants had to discriminate between objects that could occur at different locations. Independent sequences determined the succession of locations and objects. Even participants who were not aware of any regularities exhibited evidence for learning of both sequences (Experiment 1). Experiment 2 showed that the joint learning of spatial and object sequences was as efficient as learning of single sequences and that it even occurred when learning required memory for past sequence elements and attention was blocked through a secondary tone-counting task. Results are consistent with the idea that independent systems may exist for the implicit acquisition of spatial and nonspatial regularities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Covert spatial orienting in audition: Exogenous and endogenous mechanisms.

Covert orienting in hearing was examined by presenting auditory spatial cues prior to an auditory target, requiring either a choice or detection response. Targets and cues appeared on the left or right of Ss' midline. Localization of the target in orthogonal directions (up vs down or front vs back, independent of target side) was faster when cue and target appeared on the same rather than opposite sides. This benefit was larger and more durable when the cue predicted target side. These effects cannot reflect criterion shifts, suggesting that covert orienting enhances auditory localization. Fine frequency discriminations also benefited from predictive spatial cues, although uninformative cues only affected spatial discriminations. No cuing effects were observed in a detection task. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Functional differentiation along the anterior-posterior axis of the hippocampus in monkeys

We tested whether the primate hippocampus was functionally heterogenous along its anterior-posterior axis. Two monkeys were trained on both a spatial and nonspatial memory task and the incidence of spatial and nonspatial delay activity in the anterior, middle, and posterior hippocampus was noted. Spatial delay activity (activity in the delay period after the sample stimulus on the spatial memory task) was more common in the posterior than the anterior hippocampus, whereas nonspatial delay activity (activity in the delay period after the sample stimulus on the nonspatial memory task) was evenly distributed throughout the hippocampus. Furthermore, delay neurons in the anterior hippocampus exhibited scalloping delay activity, whereas those in the middle and posterior hippocampus did not. These findings suggest that the hippocampus is functionally heterogeneous and that the posterior regions may be more important for processing spatial information, whereas the anterior regions may be more important for directing or coding movements to points in space.     

Competition Between Endogenous and Exogenous Orienting of Visual Attention.

The relation between reflexive and voluntary orienting of visual attention was investigated with 4 experiments: a simple detection task, a localization task, a saccade toward the target task, and a target identification task in which discrimination difficulty was manipulated. Endogenous and exogenous orienting cues were presented in each trial and their validity was manipulated orthogonally to examine whether attention mechanisms are mediated by separate systems and whether they have additive and independent effects on visual detection and discrimination. The results showed that each orienting mechanism developed its typical and independent effect in every case except for the difficult identification task. A theoretical framework for understanding the relationship between endogenous and exogenous orienting of attention is proposed, tested, and confirmed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interactions Between Phasic Alerting and Spatial Orienting: Effects of Normal Aging and Alzheimer's Disease.

The effects of aging and Alzheimer's disease (AD) on phasic alerting and exogenous spatial orienting were examined within a single precuing task. Phasic alerting decreased with normal aging and was completely eliminated with AD. AD patients also demonstrated an increased spatial orienting effect, attributable to an increased benefit from spatial orienting that was associated with a decreased benefit from nonselective alerting. These results suggest that performance within the precuing paradigm reflects the product of an interaction between nonselective alerting processes and spatially selective orienting processes. The results also highlight the importance of simultaneously assessing alerting and orienting within the same task, because changes attributable to alerting may otherwise be attributed incorrectly to changes in 1 or more processes associated with spatial orienting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

How do selected arrows guide visuospatial attention? Dissociating symbolic value and spatial proximity.

Previous research on the control of visuospatial attention showed that overlearned symbols like arrows have the potential to induce involuntary shifts of attention. Following work on the role of attentional control settings and of the content of working memory in the involuntary deployment of visuospatial attention, Pratt and Hommel (2003) found that this unintentional orienting by an arrow depended on its top-down selection, contingent on the attentional control settings, that is to say, the target selection cue. However, in this study, each arrow was closer to the location it indicated than to any other location, raising the issue of attention being drawn to the arrow location, facilitating processing at adjacent locations, rather than pushed to the symbolically cued location. In the present study, we dissociated symbolic cueing and spatial proximity cueing by the selected arrow. The results support the proximity cueing hypothesis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Alerting and orienting in Alzheimer's disease.

Recently, researchers (E. Festa-Martino, B. R. Ott, & W. C. Heindel, 2004, see record 2004-12990-007; A. Tales, J. L. Muir, A. Bayer, R. Jones, & R. J. Snowden, 2002; A. Tales, J. L. Muir, A. Bayer, & R. J. Snowden, 2002; see record 2002-06031-015) have found significantly abnormal spatial orienting together with the abolishment of the alerting effect in Alzheimer's disease (AD). However, these research groups differed in their interpretation of the results. A. Tales, J. L. Muir, A. Bayer, R. Jones, and R. J. Snowden (2002) and A. Tales, J. L. Muir, A. Bayer, and R. J. Snowden (2002) explained their data in terms of two independent processes, whereas E. Festa-Martino et al. (2004) interpreted their findings as indicative of an inverse association, namely that the increased spatial orienting effect in AD was the direct result of the abolition of the phasic alerting effect. In this further study examining exogenous spatial orienting and phasic alerting, the authors present evidence to suggest that the increased spatial orienting effect in AD is not the result of a decreased phasic alerting effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A static color discontinuity can capture spatial attention when the target is an abrupt-onset singleton.

C. L. Folk, R. W. Remington, and J. C. Johnston's (1992) contingent involuntary orienting hypothesis states that a salient visual feature will involuntarily capture attention only when the observer's attentional set includes similar features. In four experiments, when the target's relevant feature was its being an abruptly onset singleton, attentional capture occurred for a static discontinuity cue that was the boundary between a group of red Xs contiguously joined to a group of green Os within a single row. Such an attentional capture effect is novel and contrary to Folk et al.'s (1992) hypothesis, because the attentional set for the target should have included abrupt onset but not color discontinuity, which was the feature that captured attention. These capture effects were involuntary because they occurred even when the target never appeared in the same location as the cue, and color could not have been used as a cue to signal the appearance of the target array (cf. B. S. Gibson & E. M. Kelsey, 1998). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Alerting and orienting in Alzheimer's disease: Are they interdependent? Reply to Festa et al. (2006).

The area of contention between E. Festa-Martino, B. R. Ott, and W. C. Heindel (2004; see record 2004-12990-007) and A. Tales and colleagues (A. Tales, J. L. Muir, A. Bayer, R. Jones, & R. J. Snowden, 2002; A. Tales, J. L. Muir, A. Bayer, & R. J. Snowden, 2002; see record 2002-06031-015) is whether the Alzheimer's disease (AD)-related increased spatial orienting effect is attributable directly to the decreased phasic alerting effect or whether they are two separate effects. In a subsequent study, A. Tales, R. J. Snowden, M. Brown, and G. Wilcock (2006; see record 2006-20657-014) have provided evidence to suggest that the increased spatial orienting effect in AD is not necessarily the result of a decreased phasic alerting effect, as an AD-related increase in spatial orienting effect occurred under conditions in which the phasic alerting effect was the same for both groups. In a commentary to this article, E. K. Festa, B. R. Ott, and W. C. Heindel (2006; see record 2006-20657-015) discuss what they suggest may be potential confounding factors within the authors' study. In this reply, further data in support of the authors' interpretation are provided, and the authors address the points highlighted by Festa et al. (2006). In addition, the authors request that if Festa et al. (2006) are to account for the changes in spatial orienting effects in AD in terms of the shifts in the phasic alerting effects, then how do they postulate how so small a change in one can produce so large a change in the other? (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Motivation sharpens exogenous spatial attention.

[Correction Notice: An erratum for this article was reported in Vol 7(4) of Emotion (see record 2007-17748-024). The supplemental materials link is as follows: http://dx.doi.org/10.1037/1528-3542.7.3.668.supp.] Although both attention and motivation affect behavior, how these 2 systems interact is currently unknown. To address this question, 2 experiments were conducted in which participants performed a spatially cued forced-choice localization task under varying levels of motivation. Participants were asked to indicate the location of a peripherally cued target while ignoring a distracter. Motivation was manipulated by varying magnitude and valence (reward and punishment) of an incentive linked to task performance. Attention was manipulated via a peripheral cue, which correctly predicted the presence of a target stimulus on 70% of the trials. Taken together, our findings revealed that the signal detection measure, reflecting perceptual sensitivity, increased as a function of incentive value during both valid and invalid trials. In addition, trend analyses revealed a linear increase in detection sensitivity as a function of incentive magnitude for both reward and punishment conditions. Our results suggest that elevated motivation leads to improved efficiency in orienting and reorienting of exogenous spatial attention and that one mechanism by which attention and motivation interact involves the sharpening of attention during motivationally salient conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Auditory spatial attention using interaural time differences.

Previous probe-signal studies of auditory spatial attention have shown faster responses to sounds at an expected versus an unexpected location, making no distinction between the use of interaural time difference (ITD) cues and interaural-level difference cues. In 5 experiments, performance on a same–different spatial discrimination task was used in place of the reaction time metric, and sounds, presented over headphones, were lateralized only by an ITD. In all experiments, performance was better for signals lateralized on the expected side of the head, supporting the conclusion that ITDs can be used as a basis for covert orienting. The performance advantage generalized to all sounds within the spatial focus and was not dissipated by a trial-by-trial rove in frequency or by a rove in spectral profile. Successful use by the listeners of a cross-modal, centrally positioned visual cue provided evidence for top-down attentional control. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Audiovisual links in endogenous covert spatial attention.

In 7 experiments we investigated cross-modal links for endogenous covert spatial orienting in hearing and vision. Participants judged the elevation (up vs. down) of auditory or visual targets regardless of their laterality or modality. When participants were informed that targets were more likely on 1 side, elevation judgments were faster on that side, even if the modality of the target was uncertain. When participants expected a target on a particular side in Just 1 modality, corresponding shifts of covert attention also took place in the other modality, as evidenced by faster elevation judgments on that side. However, it was possible to "split" auditory and visual attention when targets in the 2 modalities were expected on constant but opposite sides throughout a block, although covert orienting effects were larger when targets were expected on the same side in both modalities. These results show that although endogenous covert attention does not operate exclusively within a supramodal system, there are strong spatial links between auditory and visual attention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hippocampal and amygdaloid involvement in nonspatial and spatial working memory in rats: Effects of delay and interference.

Parametric manipulations of the task demand were used to examine the role of the hippocampus and amygdala in nonspatial and spatial working memory in male rats. Hippocampal lesions produced an immediate and long-lasting impairment of nonspatial working memory in an operant task. The memory deficits increased as the delay interval and the amount of proactive interference increased. Hippocampal lesions severely impaired spatial working memory in spatial alternation. Extensive postoperative testing reduced the magnitude of impairment of nonspatial but not spatial working memory. Amygdaloid lesions did not impair any aspect of performance in 2 tasks. The results suggest that the hippocampus, but not the amygdala, is involved in working memory and the task demand is a critical determinant for observing impairments of nonspatial working memory following hippocampal lesions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Motivation sharpens exogenous spatial attention": Correction to Engelmann and Pessoa (2007).

Reports an error in "Motivation sharpens exogenous spatial attention" by Jan B. Engelmann and Luiz Pessoa (Emotion, 2007[Aug], Vol 7[3], 668-674). The supplemental materials link is as follows: http://dx.doi.org/10.1037/1528-3542.7.3.668.supp. (The following abstract of the original article appeared in record 2007-11660-020.) Although both attention and motivation affect behavior, how these 2 systems interact is currently unknown. To address this question, 2 experiments were conducted in which participants performed a spatially cued forced-choice localization task under varying levels of motivation. Participants were asked to indicate the location of a peripherally cued target while ignoring a distracter. Motivation was manipulated by varying magnitude and valence (reward and punishment) of an incentive linked to task performance. Attention was manipulated via a peripheral cue, which correctly predicted the presence of a target stimulus on 70% of the trials. Taken together, our findings revealed that the signal detection measure, reflecting perceptual sensitivity, increased as a function of incentive value during both valid and invalid trials. In addition, trend analyses revealed a linear increase in detection sensitivity as a function of incentive magnitude for both reward and punishment conditions. Our results suggest that elevated motivation leads to improved efficiency in orienting and reorienting of exogenous spatial attention and that one mechanism by which attention and motivation interact involves the sharpening of attention during motivationally salient conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)