Temporal aspects of visual search studied by transcranial magnetic stimulation

Ashbridge, Elisabeth; Walsh, Vincent; Cowey, Alan

doi:10.1016/s0028-3932(97)00003-1

Cited by 290 publications

(219 citation statements)

References 57 publications

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“…The dorsal site was chosen as an area of posterior parietal cortex (PPC) known to be involved in difficult conjunction visual search tasks that engage dorsal functions, and was identified by using a hunting procedure with the hard conjunction task, as described in Ashbridge et al (1997). The ventral site was chosen in relation to area right V5 (generally corresponding to 3 cm above the mastoid-inion and 5 cm lateral to the right) which was precisely identified 7 by localising the area where a train of TMS pulses (10 Hz, 500 ms) repeatedly elicited the strongest and most salient moving phosphenes (see Schenk et al, 2005) at the lowest TMS intensity.…”

Section: Tmsmentioning

confidence: 99%

Time course of the involvement of the ventral and dorsal visual processing streams in a visuospatial task

Ellison

Cowey

2007

Neuropsychologia

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. (2007) 'Time course of the involvement of the ventral and dorsal visual processing streams in a visuospatial task. ', Neuropsychologia., 45 (14). pp. 3335-3339. Further information on publisher's website:https://doi.org/10. 1016/j.neuropsychologia.2007.06.014 Publisher's copyright statement:Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details.

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Section: Tmsmentioning

confidence: 99%

Time course of the involvement of the ventral and dorsal visual processing streams in a visuospatial task

Ellison

Cowey

2007

Neuropsychologia

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“…The dorsal site was chosen as an area of posterior parietal cortex (PPC) known to be involved in difficult conjunction visual search tasks that engage dorsal functions. To this effect it was identified by using a hunting procedure with the hard conjunction task, as described in Ashbridge et al (1997) in which 10 trials of single-pulse TMS are given to each site in a 3 x 3 grid (each point 1 cm apart) around a central point 9 cm dorsal to the mastoid-inion and 6cm lateral to the right. The "hotspot" for activation is denoted by a roughly 100ms increase in reaction time compared to the trials in which no TMS was administered.…”

Section: Tmsmentioning

confidence: 99%

TMS can reveal contrasting functions of the dorsal and ventral visual processing streams

Ellison

Cowey

2006

Exp Brain Res

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. (2006) 'TMS can reveal contrasting functions of the dorsal and ventral visual processing streams.', Experimental brain research., 175 (4). pp. 618-625. Further information on publisher's website:https://doi.org/10.1007/s00221-006-0582-8Publisher's copyright statement:The original publication is available at www.springerlink.com Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Abstract:In order to investigate the functional specificity of the dorsal and ventral visual processing steams we used transcranial magnetic stimulation (TMS) to briefly disrupt one or the other while subjects performed three tasks, involving discrimination of colour or shape or relative position. TMS was delivered over right posterior parietal cortex (PPC) or right lateral occipital (LO) cortex, regions known to have visuospatial and object processing properties respectively. LO but not PPC stimulation had a significant effect on reaction time when subjects were asked to make a discrimination of relative shape. PPC stimulation had a significant effect when subjects were asked to discriminate relative position of the same shapes. Stimulation of LO also lengthened reaction times on the position task. There were no effects of stimulation at either site on colour discrimination. Results are discussed within the framework of how the dorsal stream and ventral stream are dissociated following their damage in neurological patients and possible ways in which they may interact in the normal brain.

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“…The necessity of the parietal cortex for shifting attention has also been demonstrated in normal participants with the application of transcranial magnetic stimulation (TMS), which produces a reversible "lesion" of a particular brain area. TMS applied to the parietal cortex produces a neglect-like impairment of contralateral detection during bilateral, but not unilateral, visual stimulation (Pascal-Leone, Gomez-Tortosa, Grafman, & Always, 1994) and also impairs performance on conjunction, but not feature, search (Ashbridge, Walsh, & Cowey, 1997). The role of the parietal cortex in the dynamic scaling of attention is less well established, although there is some supporting evidence from imaging (Fink et al, 1997) and lesion (Robertson, Lamb, & Knight, 1988) studies.…”

Section: Apoe Attention and The Cholinergic Systemmentioning

confidence: 99%

The apolipoprotein E gene, attention, and brain function.

Parasuraman¹,

Greenwood²,

Sunderland³

2002

Neuropsychology

108

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The ɛ4 allele of the apolipoprotein E (ApoE) gene is associated with alterations in brain function and is a risk factor for Alzheimer's disease (AD). Changes in components of visuospatial attention with ApoE-ɛ4, aging, and AD are described. Healthy middle-aged adults without dementia who have the ApoE-ɛ4 gene show deficits in spatial attention and working memory that are qualitatively similar to those seen in clinically diagnosed AD patients. The findings support an association between ApoE polymorphism and specific components of visuospatial attention. Molecular mechanisms that may mediate the ApoE-attention link by modulating cholinergic neurotransmission to the posterior parietal cortex are discussed. Studies of attention and brain function in ApoE-ɛ4 carriers without dementia can advance knowledge of the genetics of visual attention, may enhance understanding of the preclinical phase of AD, and may lead to better methods for early AD detection.Apolipoprotein E (ApoE) is an amino acid glycoprotein that is important in lipid storage, transport, and metabolism (Mahley, 1988). Although synthesized mainly in the liver, ApoE is also found in the peripheral and central nervous systems, including the brain. ApoE has long been of interest in medicine, but its importance in neuroscience increased dramatically with the identification of the ɛ4 allele of the ApoE gene on chromosome 19 as a major risk factor for the development of late-onset Alzheimer's disease (AD) in older adults Strittmatter et al., 1993). This discovery led to a growing number of studies examining the role of the ApoE gene in normal brain function and cognition, as well as in disorders such as AD, brain injury, and stroke (Higgins, Large, Rupniak, & Barnes, 1997;Horsburgh, McCarron, White, & Nicol, 2000; J. D. Smith, 2000).Polymorphisms of the ApoE gene are associated with significant alterations in brain morphology (Plassman et al., 1997) and cognitive functioning, including attention (Greenwood, Sunderland, Friz, & Parasuraman, 2000) and memory (Bondi et al., 1995). Studies of ApoE may thus reveal information relevant to the genetics of attention and memory in normal individuals. At the same time, such studies may identify cognitive and neural changes that may be characteristic of preclinical stages of AD. In this article, we review the role of the ApoE gene in normal cognition and in the development of deficits indicative of early AD.Currently, no reliable methods exist for the early detection and treatment of AD. New techniques for preventing, slowing the progression of, and treating AD are being urgently sought. Such efforts would be aided considerably if AD could be detected prior to the clinical diagnosis of AD and before irreversible brain changes occur (Daffner & Scinto, 2000). Postmortem studies show that neuropathological changes occur decades before the onset of NIH Public Access Author ManuscriptNeuropsychology. Author manuscript; available in PMC 2006 January 25. Published in final edited form as:Neuropsychology. 2002 April ; ...

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Temporal aspects of visual search studied by transcranial magnetic stimulation

Cited by 290 publications

References 57 publications

Time course of the involvement of the ventral and dorsal visual processing streams in a visuospatial task

Time course of the involvement of the ventral and dorsal visual processing streams in a visuospatial task

TMS can reveal contrasting functions of the dorsal and ventral visual processing streams

The apolipoprotein E gene, attention, and brain function.

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