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The functional role of the inferior parietal lobe in the dorsal and ventral stream dichotomy.

Singh-Curry V, Husain M - Neuropsychologia (2008)

Bottom Line: Some recent proposals have attempted to integrate aspects of IPL function that were not hitherto dealt with well, such as differences between the left and right hemisphere and the role of the right IPL in responding to salient environmental events.Here we critically appraise existing proposals regarding the functional architecture of the visual system, with special emphasis on the role of this region, particularly in the right hemisphere.We review evidence that shows the right IPL plays an important role in two different, but broadly complementary, aspects of attention: maintaining attentive control on current task goals as well as responding to salient new information or alerting stimuli in the environment.

View Article: PubMed Central - PubMed

Affiliation: UCL Institute of Cognitive Neuroscience, London, United Kingdom.

ABSTRACT
Current models of the visual pathways have difficulty incorporating the human inferior parietal lobe (IPL) into dorsal or ventral streams. Some recent proposals have attempted to integrate aspects of IPL function that were not hitherto dealt with well, such as differences between the left and right hemisphere and the role of the right IPL in responding to salient environmental events. However, we argue that these models also fail to capture adequately some important findings regarding the functions of the IPL. Here we critically appraise existing proposals regarding the functional architecture of the visual system, with special emphasis on the role of this region, particularly in the right hemisphere. We review evidence that shows the right IPL plays an important role in two different, but broadly complementary, aspects of attention: maintaining attentive control on current task goals as well as responding to salient new information or alerting stimuli in the environment. In our view, findings from functional imaging, electrophysiological and lesion studies are all consistent with the view that this region is part of a system that allows flexible reconfiguration of behaviour between these two alternative modes of operation. Damage to the right IPL leads to deficits in both maintaining attention and also responding to salient events, impairments that contribute to hemineglect, the classical syndrome that follows lesions of this region.

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Anatomy of monkey and human posterior parietal cortex. According to Brodmann's examination of the monkey and human posterior parietal cortex, there is no monkey homologue of the human IPL. In contrast, von Bonin and Bailey's parcellation of the monkey posterior parietal cortex corresponds closely to that of the human as outlined by von Economo – here the monkey SPL and IPL are homologous to the human SPL and IPL. Reproduced from Husain (1991) in: Vision and Visual Dysfunction: Vol 13. Dyslexia, published 1991, [MacMillan Press Scientific & Medical] with permission of Palgrave MacMillan.
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fig1: Anatomy of monkey and human posterior parietal cortex. According to Brodmann's examination of the monkey and human posterior parietal cortex, there is no monkey homologue of the human IPL. In contrast, von Bonin and Bailey's parcellation of the monkey posterior parietal cortex corresponds closely to that of the human as outlined by von Economo – here the monkey SPL and IPL are homologous to the human SPL and IPL. Reproduced from Husain (1991) in: Vision and Visual Dysfunction: Vol 13. Dyslexia, published 1991, [MacMillan Press Scientific & Medical] with permission of Palgrave MacMillan.

Mentions: Homology between the human and monkey PPC has been a controversial issue. Von Bonin and Bailey (1947) drew parallels between the SPL and IPL in both species (Fig. 1). Their parcellation of the monkey PPC closely corresponds to that of the human, according to von Economo's analysis (Von Economo, 1929). This has led more recent investigators such as Rizzolatti and Matelli to suggest that homology between monkey IPL and human SPL would imply a jump of the IPL across the IPS during the course of evolution, which they consider to be highly unlikely (Rizzolatti & Matelli, 2003). Instead, they draw parallels between the SPL in humans and monkeys, and the IPL across both species. In their view, these regions are largely homologous. We discuss the issue of homology of parietal sub-regions more fully later, when we examine Rizzolatti and Matelli's scheme for the processing of visual information.


The functional role of the inferior parietal lobe in the dorsal and ventral stream dichotomy.

Singh-Curry V, Husain M - Neuropsychologia (2008)

Anatomy of monkey and human posterior parietal cortex. According to Brodmann's examination of the monkey and human posterior parietal cortex, there is no monkey homologue of the human IPL. In contrast, von Bonin and Bailey's parcellation of the monkey posterior parietal cortex corresponds closely to that of the human as outlined by von Economo – here the monkey SPL and IPL are homologous to the human SPL and IPL. Reproduced from Husain (1991) in: Vision and Visual Dysfunction: Vol 13. Dyslexia, published 1991, [MacMillan Press Scientific & Medical] with permission of Palgrave MacMillan.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2697316&req=5

fig1: Anatomy of monkey and human posterior parietal cortex. According to Brodmann's examination of the monkey and human posterior parietal cortex, there is no monkey homologue of the human IPL. In contrast, von Bonin and Bailey's parcellation of the monkey posterior parietal cortex corresponds closely to that of the human as outlined by von Economo – here the monkey SPL and IPL are homologous to the human SPL and IPL. Reproduced from Husain (1991) in: Vision and Visual Dysfunction: Vol 13. Dyslexia, published 1991, [MacMillan Press Scientific & Medical] with permission of Palgrave MacMillan.
Mentions: Homology between the human and monkey PPC has been a controversial issue. Von Bonin and Bailey (1947) drew parallels between the SPL and IPL in both species (Fig. 1). Their parcellation of the monkey PPC closely corresponds to that of the human, according to von Economo's analysis (Von Economo, 1929). This has led more recent investigators such as Rizzolatti and Matelli to suggest that homology between monkey IPL and human SPL would imply a jump of the IPL across the IPS during the course of evolution, which they consider to be highly unlikely (Rizzolatti & Matelli, 2003). Instead, they draw parallels between the SPL in humans and monkeys, and the IPL across both species. In their view, these regions are largely homologous. We discuss the issue of homology of parietal sub-regions more fully later, when we examine Rizzolatti and Matelli's scheme for the processing of visual information.

Bottom Line: Some recent proposals have attempted to integrate aspects of IPL function that were not hitherto dealt with well, such as differences between the left and right hemisphere and the role of the right IPL in responding to salient environmental events.Here we critically appraise existing proposals regarding the functional architecture of the visual system, with special emphasis on the role of this region, particularly in the right hemisphere.We review evidence that shows the right IPL plays an important role in two different, but broadly complementary, aspects of attention: maintaining attentive control on current task goals as well as responding to salient new information or alerting stimuli in the environment.

View Article: PubMed Central - PubMed

Affiliation: UCL Institute of Cognitive Neuroscience, London, United Kingdom.

ABSTRACT
Current models of the visual pathways have difficulty incorporating the human inferior parietal lobe (IPL) into dorsal or ventral streams. Some recent proposals have attempted to integrate aspects of IPL function that were not hitherto dealt with well, such as differences between the left and right hemisphere and the role of the right IPL in responding to salient environmental events. However, we argue that these models also fail to capture adequately some important findings regarding the functions of the IPL. Here we critically appraise existing proposals regarding the functional architecture of the visual system, with special emphasis on the role of this region, particularly in the right hemisphere. We review evidence that shows the right IPL plays an important role in two different, but broadly complementary, aspects of attention: maintaining attentive control on current task goals as well as responding to salient new information or alerting stimuli in the environment. In our view, findings from functional imaging, electrophysiological and lesion studies are all consistent with the view that this region is part of a system that allows flexible reconfiguration of behaviour between these two alternative modes of operation. Damage to the right IPL leads to deficits in both maintaining attention and also responding to salient events, impairments that contribute to hemineglect, the classical syndrome that follows lesions of this region.

Show MeSH
Related in: MedlinePlus