Is Extinction Following Parietal Damage an Interhemispheric Disconnection Phenomenon?

Marzi, Carlo Alberto; Fanini, Alessandra; Girelli, Massimo; Ipata, Anna E.; Miniussi, Carlo; Prior, Massimo; Smania, Nicola

doi:10.1007/978-3-642-60661-8_24

Cited by 17 publications

(20 citation statements)

References 36 publications

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“…The important point here is that, following presentations in the left visual eld of stimuli similar to those used in the present study, the responses of intact areas of the directly stimulated right hemisphere were as good as in the intact left hemisphere. On the contrary, the indirect (ipsilateral) responses of either hemisphere were small or lacking, and this can be interpreted as an impairment of callosal functioning (see Marzi et al, 1997). For our present purposes, this provides evidence for a minor role of volume conduction in our results.…”

Section: Discussionmentioning

confidence: 47%

“…They have different cerebral lesions but share a similar interruption of interhemispheric transfer. The rst patient CZ (male, 50 years old, see Marzi et al, 1997, for clinical details), 2 years before ERP testing, suffered from a vascular accident in the territory of the middle cerebral artery. Magnetic resonance imaging (MRI) revealed a large parietal-tempoFigur e 7.…”

Section: Discussionmentioning

confidence: 99%

“…However, one should consider that, in principle, the earliest stage of summation might be located even at subcortical visual sites, such as the superior colliculus. The presence of an RTE in patients who underwent callosotomy (ReuterLorenz et al, 1995;Marzi et al, 1997) or hemispherectomy (Tomaiuolo et al, 1997) suggests a subcortical locus of coactivation. It is notoriously dif cult to record ERP activity generated by subcortical structures (Coles & Rugg, 1995), and it is unlikely that coactivation effect caused by the RTE occurring at the level of the superior colliculus could be detected by our ERP recordings.…”

Section: Discussionmentioning

confidence: 99%

“…Furthermore, in the visual modality, the effect is not retinotopic in the sense that it occurs independently of the absolute and relative position of the redundant signals in the visual eld. The RTE can also be demonstrated when stimuli are presented in different hemi elds (i.e., to different cerebral hemispheres) and far from the vertical meridian Marzi et al, 1997;Reuter-Lorenz, Nozawa, Gazzaniga, & Hughes, 1995). The primary visual areas are known to be interconnected by means of the corpus callosum only for visual-eld representations that are close to the vertical meridian (see Marzi, 1986, for a review).…”

Section: Introductionmentioning

confidence: 99%

“…Marzi et al (1996) have found that patients showing extinction of contralesional visual stimuli as a consequence of a unilateral lesion of the right parietaltemporal cortex show an RTE despite their reporting only one stimulus of a pair. Finally, Reuter-Lorenz et al (1995) and Marzi et al (1997) have documented that subjects who underwent a complete section of the corpus callosum show a large RTE when stimuli are presented to different hemispheres even though they show extinction of stimuli presented to the left visual eld (LVF) during bilateral stimulation. Taken together, these ndings suggest that the RTE is likely to be subserved by visual areas other than the primary visual cortex.…”

Section: Introductionmentioning

confidence: 99%

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Neural Site of the Redundant Target Effect: Electrophysiological Evidence

Miniussi

Girelli

Marzi

1998

Journal of Cognitive Neuroscience

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105

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n The present study represents an attempt to nd an electrophysiological correlate of the redundant targets effect, or RTE (i.e., the speeding up of reaction time, or RT, for redundant vs. single targets). Subjects made a speeded response either to one small checkerboard presented to the left or right of xation or to a pair of identical checkerboards presented simultaneously to both hemi elds. Both single and double targets could appear either in the upper or lower visual hemi eld. The task required detection but not discrimination of the stimuli. During task performance, we recorded the event-related potentials (ERPs) elicited by the checkerboard targets. As in previous studies, we found that manual RTs to bilateral stimuli were faster than those to unilateral stimuli. This effect was more marked for lower-than for upper-eld stimuli and could not be ascribed to probability summation. In addition, we found that the P1 and N1 components of the visual ERP had a shorter latency for bilateral than for summed unilateral stimuli presented to the two hemi elds. In parallel with the behavioral ndings, the latency values for the above components showed a larger RTE for lower-eld stimuli. These ndings indicate that the RTE occurs at the level of early visual processing, probably in the extrastriate visual cortex, rather than at late decisional or premotor stages. n

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Section: Discussionmentioning

confidence: 47%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Neural Site of the Redundant Target Effect: Electrophysiological Evidence

Miniussi

Girelli

Marzi

1998

Journal of Cognitive Neuroscience

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125

105

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Asymmetry of interhemispheric communication

Marzi

2010

WIRES Cognitive Science

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The role of the corpus callosum (CC) in ensuring communication between the cerebral hemispheres is an undisputed great discovery of the 20th century. In the past 20 years, it has been repeatedly shown by behavioral and electrophysiological experiments that callosal transmission is asymmetric. It is faster from the right to the left hemispheres for a host of behavioral and cognitive processes. The functional meaning and the neural bases of the asymmetry are still being investigated but one possibility is that it is related to a larger proportion of cortical neurones, projecting their axon from the right to the left hemisphere than in the reverse direction in the CC. This asymmetry might be related to the necessity to rapidly access the left hemisphere for response during tasks mainly subserved by the right hemisphere. Copyright © 2010 John Wiley & Sons, Ltd. For further resources related to this article, please visit the WIREs website.

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Differential impairment of interhemispheric transmission in bipolar disease

et al. 2013

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There is abundant evidence that the cerebral white matter and in particular the corpus callosum show several structural abnormalities in both schizophrenia (SCZ) and bipolar disease (BD). However, which cognitive functions are impaired as a result of these anomalies is still unclear. Previous behavioural tests of interhemispheric crosstalk have shown a differential impairment in SCZ with interhemispheric transmission time, as tested with the Poffenberger paradigm, essentially normal but with an abnormally enhanced interhemispheric summation effect, as tested with the redundant signal effect. The present study was inspired by this discrepancy and by the more general question of a possible overlap between the pathophysiology of SCZ and BD. We tested both SCZ and BD patients in the Poffenberger paradigm and redundant signal effect and found a similar dissociation, namely a normal interhemispheric transfer time and an abnormal redundant signal effect. The only difference between the two groups was a selective slowing of speed of response of the dominant right hand in the SCZ group suggesting an impairment of left hemisphere functions. These results cast further light on the question of common and differential impairments of basic psychological functions in the two diseases.

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Is Extinction Following Parietal Damage an Interhemispheric Disconnection Phenomenon?

Cited by 17 publications

References 36 publications

Neural Site of the Redundant Target Effect: Electrophysiological Evidence

Neural Site of the Redundant Target Effect: Electrophysiological Evidence

Asymmetry of interhemispheric communication

Differential impairment of interhemispheric transmission in bipolar disease

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