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Visuospatial attention can either be "narrowly" focused on (zooming in) or "widely" distributed to (zooming out) different locations in space. In the current functional magnetic resonance imaging study, we investigated the shared and differential neural mechanisms underlying the dynamic "zooming in" and "zooming out" processes while potential distance confounds from visual inputs between zooming in and zooming out were controlled for. When compared with zooming out, zooming in differentially implicated left anterior intraparietal sulcus (IPS), which may reflect the functional specificity of left anterior IPS in focusing attention on local object features. By contrast, zooming out differentially activated right inferior frontal gyrus, which may reflect higher demands on cognitive control processes associated with enlarging the attentional focus. A conjunction analysis between zooming in and zooming out revealed significant shared activations in right middle temporal gyrus, right superior occipital gyrus, and right superior parietal cortex. The latter result suggests that the right posterior temporal-occipital-parietal system, which is known to be crucial for the control of spatial attention, is involved in updating the internal representation of the spatial locations that attentional processing is associated with.

Hierarchical figures in which large (global) forms are constructed from smaller (local) forms (Navon, 1977) have proved valuable in studies of perceptual organisation and hemispheric specialisation in both healthy volunteers and a wide range of neurological and psychiatric patients. In studies using Navon figures, normal young adults typically identify global forms faster than local forms. When the global and local forms are incongruent (e.g., a large E made of smaller Rs), global forms often interfere with local form identification more than vice versa. In two conditions on the same subjects, we contrasted the performance of young (mean age 22 years) and older (mean age 58 years) healthy volunteers on global and local processing. In the directed attention task, subjects were instructed to detect a target letter that occurred at the prespecified local or global level. The young subjects showed, as expected, faster reaction times (RTs) to detect global targets. In contrast, the older subjects showed significantly faster RTs to the local targets. Likewise, in a divided attention task, in which subjects were instructed to detect a target letter that could occur at either the local or the global level, the young adults were slightly quicker to detect the global targets and the older subjects were significantly quicker to detect the local targets. Error rates were generally low and there was no significant speed/accuracy trade-off in either condition. The observed local precedence effects in healthy older subjects were unexpected and are discussed in reference to previous work on differential hemispheric aging. That work has suggested that the left hemisphere is preferentially biased toward local processing and ages relatively slowly while the right hemisphere is biased toward global processing and ages relatively quickly. The implications of such putative differential aging for the interpretation of pathological local/global processing in neurological and psychiatric diseases are also emphasised.

Hierarchically organized figures (for example, a large E made up of smaller N's) are frequently used to investigate directed and divided attention. Investigations of neurological and psychiatric patients, and also tachistoscopic and functional neuroimaging studies on healthy subjects, typically find the right hemisphere to be specialized for the processing of global stimuli and the left hemisphere to be specialized for the processing of local stimuli. In the current study, a group of 12 patients with visuo-spatial neglect (NP) after right hemisphere lesions and 12 age and sex-matched control subjects (CO) performed a directed and a divided attention task with hierarchically organized letters. As expected, faster reaction times were found for control subjects than for neglect patients, especially for the directed global attention task. Lower error rates were found for CO and NP for local than for global targets during the divided attention condition. Local on global interference was found for both groups in reaction times. These local processing advantages for older healthy adults have been reported previously. Additionally, an impairment in the divided attention task was found in both groups, but especially for global targets in NP. This impairment is consistent with other evidence of difficulty in disengaging attention shown by patients with visuo-spatial neglect.

Previous neuropsychological and functional imaging studies have suggested that the right hemisphere is crucially involved in spatial cognition. By contrast, much less is known about the putative left hemisphere specialization for aspects of temporal cognition. Accordingly, we studied with functional magnetic resonance imaging the neural mechanisms underlying attention to stimulus onset synchrony or orientational congruence with identical pairs of geometric figures. In each trial, two rhombuses were presented, each 4 degrees peripheral to a central fixation cross, in the left and right visual hemifields. In half of the trials, subjects were asked to judge and indicate via button presses whether the rhombuses appeared simultaneously. In the other half of the trials, subjects indicated whether the orientation of the rhombuses was the same (Factor 1, task, temporal synchrony, orientation). In half of the trials, subjects responded with their right hand and in the other half with their left hand (Factor 2, hand, right, left). Data were analyzed using SPM99 and a random-effects model. Attention to orientation differentially activated right temporo-occipital cortex. Attention to stimulus onset synchrony activated left anterior superior temporal gyrus, left inferior parietal cortex, left medial frontal gyrus, and right operculum. Activation of right temporo-occipital cortex for attention to stimulus orientation is in good agreement with previous functional neuroimaging studies of stimulus orientation. More importantly, activation of a predominantly left-hemispheric network with attention to stimulus onset synchrony extends the results of previous functional imaging, psychophysical, and neuropsychological studies of temporal processing.

The perception of shape does not necessarily require viewing an explicit outline figure. Using event-related functional magnetic resonance imaging we examined the time courses of neural activations provoked by shapes defined by (1) lines, (2) illusory contour inducers, and (3) reversed inducers. SPM99 was used to analyze the common and differential neural responses associated with the stimuli and their temporal derivatives. Illusory figures versus reversed inducers activated extrastriate cortex. Reversed inducers versus illusory figures activated the right parietal cortex. For both illusory and line contours versus reversed inducers, analysis of the temporal derivatives showed earlier activations in extrastriate and left parietal cortex and for line contours also in the extrastriate cortex bilaterally and in the right parietal cortex; these earlier activations were mirrored by differences in reaction times with subjects responding more slowly to shapes defined by reversed inducers. The results show substantial bottom-up effects (in occipital cortex) in the recognition of illusory and explicit shapes. By contrast, in stimuli where the shape must be inferred, there is greater reliance on right parietal cortex, consistent with increased attentional demands and top-down processing. The temporal derivatives provide useful information on the differential timing of the associated hemodynamic responses in occipital, parietal, and motor cortex.

Patients who seem to "ignore" objects or people on one side of space have been described in the medical literature for well over a century. The term "visuospatial neglect" is now used to describe the cluster of behaviors whereby patients after unilateral cerebral lesions (most frequently of right parietal cortex) fail to attend or explore (predominantly) the side of space contralateral to the lesion. Although the condition comprises a complex disruption of space-related behaviors, the prevailing view was that the different symptoms could be accommodated in terms of damage to one of three different cognitive mechanisms mediating attention (e.g., K. M. Heilman and E. Valenstein, Ann. Neurol. 5: 166-170, 1979), intention (R. T. Watson, E. Valenstein, and K. Heilman, Ann. Neurol. 3: 505-508, 1978), and/or representation (E. Bisiach, Q. J. Exp. Psychol. 46: 435-461, 1993). The general consensus favors an attentional deficit but the notion of attention has always proved conceptually slippery and difficult to operationalize (P. W. Halligan and J. C. Marshall, Cogn. Neuropsychol. 11: 167-206, 1994a). In this paper, we consider how drawing performance after right brain damage in patients with "visual neglect" reveals the involvement and interplay of several cognitive deficits, including aspects of mental representation and spatial awareness., (Copyright 2001 Academic Press.)

Some highlights of the ongoing study of visuospatial cognition from Descartes to the advent of functional neuroimaging are reviewed. We emphasize that parietal cortex contains multiple representations of space, appropriate to the demands of perception and action in near and far space. Converging evidence from the behavioral effects of relatively focal brain lesions on different aspects of spatial cognition and from the locus of maximal physiological activation when normal volunteers perform spatial tasks is described. Clinical pathologies of spatial attention, including visual extinction, simultanagnosia, and unilateral neglect, are examined for the light they cast on the basic functions of brain circuits involving the parietal lobes., (Copyright 2001 Academic Press.)

Bisection of horizontal lines is used as a clinical test of spatial cognition in patients with left visuospatial neglect after right hemisphere lesions. Bisection of vertical lines has also been employed, albeit less frequently. Interestingly, normal subjects often bisect horizontal lines too far left and vertical lines too high. We used fMRI to investigate whether vertical/horizontal stimulus orientation interacts with the neural mechanisms associated with line bisection judgments (the Landmark task). For control of orientation per se, subjects performed a visual detection task with the same stimuli. Statistical analysis of evoked BOLD responses employed SPM99. The Landmark task increased neural activity (P < 0.05, corrected) in the superior and inferior parietal lobes bilaterally, though predominantly on the right; early visual processing areas bilaterally; and cerebellar vermis, left cerebellar hemisphere, anterior cingulate, and prefrontal cortex bilaterally. Vertical lines (relative to horizontal lines and vice versa) increased neural activity in early visual processing areas, consistent with differential retinotopic stimulation. In addition, vertical lines activated right parietooccipital and superior posterior parietal cortex bilaterally. No significant interactions between the neural mechanisms associated with task and stimuli were observed. Increased neural activation in parietal and parietooccipital cortex associated with vertical lines may reflect increased attentional demands associated with this stimulus orientation. The right hemispheric dominance observed in posterior parietal during the Landmark task irrespective of stimulus orientation is consistent with lesion studies. Our results suggest that the behavioral patterns observed in normal subjects and neurological patients result from different stimulus effects rather than differential task demands., (Copyright 2001 Academic Press.)

The neglect syndrome is a cluster of neurologic symptoms commonly found after right hemisphere damage. This study investigates the degree of association between the main components in a representative sample of 69 patients at 2 to 3 days poststroke. Despite evidence of statistically significant associations between components, many dissociations were found, indicating that neglect is a highly heterogeneous condition.

Objectives: The aim was to investigate whether patients with Parkinson's disease (PD) make movements that are of smaller amplitude when required to attend to a secondary task at the same time as performing a motor task., Methods: Thirteen patients with idiopathic Parkinson's disease (mean age, 67.1 yrs) and 14 healthy control subjects (mean age, 66.2 yrs) were tested. The motor task was repeated opposition of the thumb and forefinger and the secondary task was a lexical decision task., Results: The PD patients made hypometric movements, and the amplitude was further decreased when they performed the secondary task at the same time. There was no significant change for the control subjects., Conclusion: The unpaced motor task was less automatic for the PD patients than for the control subjects, and hence more subject to interference from a secondary task. We relate this to the underactivation of the supplementary motor cortex (SMA).

Visual attention can be primarily allocated to either where an object is in space (with little emphasis on the structure of the object itself) or to the structure of the object (with little emphasis on where in space the object is located). Using PET measures of regional cerebral blood flow (rCBF) to index neural activity, we investigated the shared and specific functional anatomy underlying both of these types of visual attention in a controlled non-cueing non-blocked paradigm that involved identical stimuli across the conditions of interest. The interaction of eye movements with these attentional systems was studied by introducing fixation or free vision as an additional factor. Relative to the control condition, object-based and space-based attention showed significant activations of the left and right medial superior parietal cortex and the left lateral inferior parietal cortex, the left prefrontal cortex and the cerebellar vermis. Significant differential activations were observed during object-based attention in the left striate and prestriate cortex. Space-based attention activated the right prefrontal cortex and the right inferior temporal-occipital cortex. Differential neural activity due to free vision or fixation was observed in occipital areas only. Significant interactions of free vision/fixation on activations due to object-based and space-based attention were observed in the right medial superior parietal cortex and left lateral inferior parietal cortex, respectively. The study provides direct evidence for the importance of the parietal cortex in the control of object-based and space-based visual attention. The results show that object-based and space-based attention share common neural mechanisms in the parietal lobes, in addition to task specific mechanisms in early visual processing areas of temporal and occipital cortices.

We report a case of severe visuo-spatial neglect consequent upon right-hemisphere stroke. At the time of testing, the patient had no visual field cut and no significant hemiparesis. Conventional testing on cancellation tasks with the right hand revealed reliable left neglect, but performance was significantly improved when the left hand was used. Investigations of (manual) line bisection showed normal performance with the right hand but right neglect when the left hand was used. Right neglect was also observed on a purely perceptual version of the line bisection task. We argue that the attentional vectors of the cerebral hemispheres can be modulated by (perceptual) task-demands and by (motoric) response-demands.

The perceptual world is organized hierarchically: the forest consists of trees, which in turn have leaves. Visual attention can emphasize the overall picture (global form) or the focal details of a scene (local components). Neuropsychological studies have indicated that the left hemisphere is biased towards local and the right towards global processing. The underlying attentional and perceptual mechanisms are maximally impaired by unilateral lesions to the temporal and parietal cortex. We measured brain activity of normal subjects during two experiments using 'hierarchically' organized figures. In a directed attention task, early visual processing (prestriate) areas were activated: attention to the global aspect of the figures activated the right lingual gyrus whereas locally directed attention activated the left inferior occipital cortex. In a subsequent divided attention task, the number of target switches from local to global (and vice versa) covaried with temporal-parietal activation. The findings provide direct evidence for hemispheric specialization in global and local perception; furthermore, they indicate that temporal-parietal areas exert attentional control over the neural transformations occurring in prestriate cortex.

We outline a range of previous theoretical accounts of agrammatic comprehension in patients with Broca's aphasia. Specific attention is paid to patterns of preserved and impaired understanding of reversible actives and passives. We note that no prior account will allow for the existence of patients who show better comprehension of passives than actives. In three experiments, we compare and contrast the performance of two patients whose syntactic comprehension ability is in complementary distribution. The first patient (M.H.) performs well on simple actives, active questions, and active existentials, but is below chance on their corresponding passives. The second patient (B.M.) is at chance on simple actives, active questions and active existentials while scoring significantly above chance on their respective passives. We interpret both patterns of response in terms of the distinction drawn by Case theory between structural and inherent Case. The first patient's grammar cannot assign either structural or inherent Case and she must accordingly apply a non-linguistic linear strategy to assign thematic roles in all sentences. The second patient (B.M.) has a specific impairment of structural Case; he can accordingly not interpret actives (where Case is assigned configurationally) but can interpret passives (where Case is assigned lexically).

We report a patient (R.B.) who has shown gross left visuo-spatial neglect over the 3 years since he sustained a right parietal infarct. Although his neglect is severe on such tasks as line bisection, cancellation, and drawing, there are some domains of preserved perceptual performance: he can perceive subjective contours, he can use lateral symmetry as a cue to figure-ground segregation, and he benefits from some forms of global cueing. In a series of five experiments, we show that R.B. has a selective inability to analyse and copy accurately the left contours of geometric nonsense-figures. These results hold even when there is a single vertical contour (to be copied) that divides a rectangle or a circle into two sub-figures; this physically-identical boundary is copied more accurately when it is cued as the right edge of the left sub-figure than when it is cued as the left edge of the right sub-figure. These effects are not influenced by a manipulation in which R.B. is required to trace the outline of the relevant sub-figure with his finger immediately prior to drawing his copy. The results are interpreted in terms of classical Gestalt theories of figure-ground assignment. Pre-attentive (global) figure-ground parsing is basically intact; but when focal attention is demanded, only the right side of an object is coded as figure.

We derive some predictions about the character of left visuo-spatial neglect from two independent characteristics of normal hemispheric specialization: the contralateral orientation bias of each hemisphere and the association of local and panoramic processing with the left and right hemispheres, respectively. The predictions are then tested in three sets of experiments that manipulate focal and panoramic attention in estimations of the midpoints of lines and outline squares. The results from one patient are consistent with the model and with previously reported data from the same patient (Halligan and Marshall, 1993a) on a different task (line cancellation).

We investigated copying of simple contours by a patient with left neglect after right hemisphere lesion. The stimuli were rectangles or circles with one or two internal boundaries defined by a black-white or a two-colour contrast. On each trial, the patient attempted to copy the contour of one of the (prespecified) sub-figures defined by a boundary contrast. Copying was accurate when boundaries were the right edges of sub-figures; when physically identical boundaries were the left edges of the sub-figures, accurate copying was impossible. These results held even when, prior to copying, the patient traced the outline of the figure (and ground) with his finger. A 'representational' account of object-centred neglect is supported.

We report a case of severe left visuo-spatial neglect consequent upon right-hemisphere stroke. In Experiment 1, we show that while the patient bisects lines significantly to the right of true centre, he is extremely accurate in placing a mark at the centre of an equivalent outlined square. Experiment 2 confirms that the lateral and radial accuracy obtained in the latter (square) task cannot be predicted from the lateral and radial displacements found in horizontal and vertical (radial) line bisection; the experiment also shows that the individual horizontal lines of a square can be bisected significantly more accurately than the same lines presented individually. Experiment 3 shows that the crucial figural component requisite for the accurate estimation of lateral extent is a large vertical (radial) line in right space. The obtained figural modulation of neglect is consistent with the model in which a large, unitary stimulus in right space engages and enhances the lesioned right hemisphere's intrinsic capacity to deploy global attention.

We report three studies of visual search in a patient with left neglect after a right parietal infarct. Manipulations whereby the patient's attention is explicitly drawn to the spatial extent of the page on which the stimuli for cancellation are displayed have little or no effect on the number of targets cancelled. The results are consistent with a "zoom lens" model of attentional deployment. "Neglect" on search tasks seems to reflect a systematic bias that emerges when global attention is constricted to permit analysis of local features.

In 'left' neglect--a frequent consequence of damage to posterior areas of the right cerebral hemisphere--the relational term 'left' immediately raises the question 'left of what?'. It is shown that on a simple copying task the answer can be 'left of the principal axis of the object or objects depicted'. Under conditions in which the stimulus material was intrinsically controlled for lateral extent and position, 'object-centred' neglect seemed to reflect some basic principles of perceptual parsing.

A new copying test has been devised to explore different forms of perceptuo-motor impairment in visuo-spatial neglect. The stimuli are constructed so that one hypercomplex figure can be transformed into two complex figures by deletion of part of the original drawing. Task performance by five patients with left neglect after right hemisphere damage is reported. Their copies illustrate the varied spatial "reference frames" within which visual neglect can be manifest.

Six patients with unilateral right hemisphere damage are reported. Each patient performed two tasks that are traditionally regarded as diagnostic for left (peripersonal) visuospatial neglect: target cancellation and horizontal line bisection. Two patients were unimpaired on both tasks, and two were impaired on both. The two remaining patients showed a classic (and reliable) double-dissociation between the tasks. One of the patients who scored within normal limits on both cancellation and bisection showed left sided omissions on representational drawing. We argue that these results question the validity of any unitary concept of unilateral visuo-spatial neglect in peripersonal space.

A patient with left visuo-spatial neglect after right fronto-parietal haemorrhage failed to cross out stimuli in left space on cancellation tests. Her bisections of horizontal lines were displaced significantly to the right of true centre. On drawing and copying tasks, she sometimes omitted features on the left (neglect) and sometimes transposed them to right space (allochiria). This co-occurrence of neglect and allochiria has been observed previously but has provoked little theoretical comment. We draw attention to aspects of the combination that seem critical to the interpretation of visuo-spatial neglect.

Forty four consecutive patients with acute hemispheric stroke and forty seven elderly controls with no neurological disease were assessed for visuo-spatial neglect, using a modified neglect test battery. Neglect was found to be equally common in patients with right hemisphere and left hemisphere stroke three days after stroke (72% versus 62%). It was more severe in those with a right hemisphere stroke and resolved more frequently in those with a left hemisphere stroke. The battery was validated against an occupational therapist's assessment of neglect on self-care tasks. The inter-observer reliability was good and it was possible to monitor changes over time with the battery.

Examination of 47 independent elderly subjects, matched with a population of patients with acute stroke, found that 55% made at least one omission on a battery of neglect tests. Up to 43% made omissions on any one test. Increasing age and other evidence of cognitive impairment were associated with impaired performance on the battery. Omissions were attributed to an age-related decline in visuo-spatial function. Cut-off points are provided to distinguish between such age-related impairment and visuospatial neglect. The importance of age-matched control studies in developing tests of cognitive impairment in stroke research is highlighted.

We report a case of mild visuo-spatial neglect consequent upon right-hemisphere stroke. At the time of testing, the patient had a complete left visual field deficit but only a very slight left hemiparesis. Under conventional testing conditions, line bisection performed with the right hand showed more severe left neglect than when performed with the left hand. This pattern of performance could, however, be modified, both quantitatively and qualitatively, by changing the starting position of the patient's hand when bisecting horizontal lines. The results suggest that spatio-motor cueing has a more profound effect upon task performance than does differential hemispheric activation per se. We also provide a demonstration that, in a normal subject, the starting position of the hand is likewise a crucial determinant of task performance. In this case, however, there is also an interaction between the hand (and hence hemisphere) deployed and the position of that hand in space.

We report a case study of (partial) recovery from left visuo-spatial neglect, followed by progressive deterioration. The patient, A.L., suffered a right-hemisphere stroke with left hemiplegia; over the 6 months post-stroke, the overall course of his neglect was monitored with the Behavioural Inattention Test at approximately monthly intervals. An experimental investigation of multitrial line bisection was also repeated six times and analysed both between and within sessions. The results confirm previous reports of a linear relationship between transection displacements and line length, and also of anomalous crossover with 'right neglect' at 'shorter' length. Both effects are reliable over time in this patient. The most striking finding, however, was 'recovery' within a session of the extended line bisection task. We discuss the theoretical and practical significance of this phenomenon in the context of attentional theories of neglect.

A significant association between visual field deficits (VFD) and visuo-spatial neglect is well established, although cases of double-dissociation between the two conditions are not uncommon. It has been argued that VFD typically exacerbates the behavioural manifestations of neglect. We examined a series of 51 patients with unilateral right-hemisphere stroke for the presence of visual field deficit and visuo-spatial neglect. Patients were assigned to the neglect group (N+) or the non-neglect group (N-) on the basis of their aggregate scores on the recently standardised Behavioural Inattention Test (BIT). The association between neglect and VFD was confirmed. Four groups of eight patients (N+, VFD+; N+, VFD-; N-, VFD+; N-, VFD-) were then selected from the initial sample so that they were matched for age, IQ, and days post onset of stroke. Within the neglect groups, the severity of neglect did not differ significantly between those patients with and without VFD; within the non-neglect groups, scores on subtests of the BIT likewise did not differ (with the sole exception of Letter Cancellation) between the VFD+ and the VFD- subgroups. It was concluded that visual field deficits do not exacerbate neglect, and that poor functional recovery in many patients with VFDs is due to the association of sensory loss with the underlying causal factor of neglect.

In a previous study of line bisection, [Manning et al., Neuropsychologia 28, 647-655, 1990] we have shown that normal young adults show significant linear regressions of both transection displacement (TD) and standard deviation (SD) on line length. Furthermore, there was considerable individual variation in the magnitude of SDs and the direction and magnitude of TDs. These two sources of variance were uncorrelated. In the current study we provide a constructive replication of these findings on an older population that constitutes a more appropriate control sample for patients with stroke. The performance of four patients with right hemisphere stroke is then interpreted in terms of the constraints observed in normal subjects. All the patients showed qualitatively intact line bisection, but with quantitative impairments of varied severity. When analysed in two pairs, the patients also showed a double-dissociation between the magnitude of their mean transection displacements and the SDs of those means. This result is in conformity with the prediction based upon a lack of correlation between these two measures in normal subjects.

Investigations of left visuo-spatial neglect are reviewed with special reference to line bisection performance. Attention is then drawn to inconsistencies in the direction and magnitude of transection displacements in group studies of normal controls. We argue that the lack of reliable information about normal mechanisms for line bisection makes it impossible to interpret pathological performance in neglect. Accordingly, we report a case-series of 22 normal young adults, each of whom bisects 10 lines of differing lengths 10 times each. There is very substantial between-subject variation in both the magnitude and direction of the linear regression of transection displacement on line length; there are likewise considerable differences in the magnitude of the linear regression of standard deviation on line length. These two sources of individual variation are uncorrelated. We propose a psychophysical theory of line bisection, and suggest that the basic mechanisms responsible for task-performance are qualitatively intact in visuo-spatial neglect, albeit quantitatively impaired.

We report a case of severe visuo-spatial neglect consequent upon right hemisphere stroke. At time of testing, the patient had a left visual field deficit and a very mild left hemiparesis. Star cancellation and line bisection performed with the right hand revealed profound left neglect; tested with the left hand, performance was only slightly impaired. The results are compatible with recent accounts of differential hemispheric activation provoked by lateralized pre-motor programming.

A patient with severe left neglect after surgery for basilar aneurysm is described. Her performance on freehand line bisection was compared and contrasted with the results from computerised visual display unit (VDU) presentation. In the latter format the patient makes her transections with a "mouse" controlled cursor arrow. The technique provides rigorous control over starting position and also allows self-corrections. Although left neglect persisted at longer line lengths under these conditions, the magnitude of the effect decreased significantly; the cross-over point where right displacements change to left displacements as a function of line length also varied between the three conditions (freehand, left and right computer-start).

We report an investigation of unilateral visual neglect in 23 patients with right cerebro-vascular accident (CVA) and 3 with left CVA. On a modified version of Albert's test of line cancellation the patients show the typical errors of omission in the hemispace contralateral to the lesion. In addition, however, there is a significant effect of stimulus position in the vertical dimension; the patients made most errors in the lower quadrant of the array, contralateral to the site of lesion. We emphasize the importance of studying the distribution of attention along all spatial dimensions in the hemispatial neglect syndromes.