Elsevier

Neuroscience

Volume 142, Issue 1, 29 September 2006, Pages 119-123
Neuroscience

Cognitive neuroscience
Hemiextinction induced by transcranial magnetic stimulation over the right temporo-parietal junction

https://doi.org/10.1016/j.neuroscience.2006.06.023Get rights and content

Abstract

Whereas it is widely accepted that the parietal cortex is crucial for visual attention, the role of the temporal cortex and the temporo-parietal junction (TPJ) is less clear. There are clinical reports of patients with lesions in different posterior temporal areas which exhibit contralateral visual neglect but this syndrome seems to be less frequent than in patients with parietal lesions. In a previous study, we could show that single-pulse transcranial magnetic stimulation (TMS) over the right inferior parietal cortex is capable to induce both neglect-like and extinction-like impairments of performance in normal subjects. In the present study, we used this method to examine the functional role of the superior temporal gyrus (STG) and the TPJ of the right hemisphere for visuo-spatial attention. Healthy volunteers were asked to detect small dots appearing for 40 ms unilaterally on right or left side or bilaterally on a computer screen. TMS was applied over the TPJ or STG. TMS over the TPJ induced an extinction-like behavioral pattern to the contralateral hemifield. TMS over the STG had no effect. The results demonstrate a functional involvement of the TPJ in visuo-attentional processing of competing stimuli in both hemifields. This region is part of the cortical network mediating stimulus-driven attention which is relevant for processing of competing stimuli.

Section snippets

Subjects

Fourteen subjects participated in the study (eight males, six females, mean age (24.7±1.8 [S.D.] years) All subjects were right-handed according to the Edinburgh Inventory (Oldfield, 1971), had normal or corrected to normal vision and had no history of neurological abnormalities. The protocol was approved by the local institutional review board and all subjects gave their written informed consent.

Visual stimuli

Small black dots of 2×2, 2×3, 3×3, 3×4, or 4×5 pixels were presented on a computer screen against

Results

In all experiments, subjects correctly identified catch trials to a high degree, TMS had no influence on catch trial identification (mean correct response 98.2% all sham stimulation experiments, 97.6% all real stimulation experiments, P>0.5, Student’s t-test).

For reaction times, repeated-measures ANOVA, with “TMS” (real, sham), “site of TMS” (TPJ, STG), “site of visual stimulus” (right, left, bilateral) and “TMS onset time” (150 ms, 250 ms) as within-subject factors demonstrated no significant

Discussion

The present study found that TMS over the right TPJ induces an extinction effect to the left visual hemifield, whereas TMS over the right STG has no differential effect on detection of bilateral stimuli. During unilateral stimulus presentation, TMS over TPJ induced a slight amelioration of detection of ipsilateral stimuli, whereas detection of contralateral stimuli was unimpaired.

The results of the present study extend the results of previous TMS studies on the functional representation of

Conclusion

In conclusion, the present study showed that TMS over the TPJ induces an extinction-like behavioral pattern, whereas TMS over the STG had no effect on the attentional processes tested here. The results indicate an involvement of the TPJ, which is part of the ventral frontoparietal network, in attentional processing of competing visual stimuli.

Acknowledgments

This study was supported by Deutsche Forschungsgemeinschaft (DFG) (KFO 112/1) and the IZKF “BIOMAT” Interdisciplinary Center for Clinical Research at the faculty of Medicine at the RWTH Aachen University (Project N68-f). I.G.M. is funded by the Deutsche Forschungsgemeinschaft (ME 2104/3-1).

References (32)

  • A. Ellison et al.

    An exploration of the role of the superior temporal gyrus in visual search and spatial perception using TMS

    Brain

    (2004)
  • B. Fierro et al.

    Contralateral neglect induced by right posterior parietal rTMS in healthy subjects

    Neuroreport

    (2000)
  • B. Fierro et al.

    Timing of right parietal and frontal cortex activity in visuo-spatial perception: a TMS study in normal individuals

    Neuroreport

    (2001)
  • G.R. Fink et al.

    Neural consequences of competing stimuli in both visual hemifields: a physiological basis for visual extinction

    Ann Neurol

    (2000)
  • C.C. Hilgetag et al.

    Enhanced visual spatial attention ipsilateral to rTMS-induced “virtual lesions” of human parietal cortex

    Nat Neurosci

    (2001)
  • A.E. Hillis et al.

    Anatomy of spatial attention: insights from perfusion imaging and hemispatial neglect in acute stroke

    J Neurosci

    (2005)
  • Cited by (74)

    View all citing articles on Scopus
    View full text