title: The timing of anterior temporal lobe involvement in semantic processing.
abstract: Despite indications that regions within the anterior temporal lobe (ATL) might make a crucial contribution to pan-modal semantic representation, to date there have been no investigations of when during semantic processing the ATL plays a critical role. To test the timing of the ATL involvement in semantic processing, we studied the effect of double-pulse TMS on behavioral responses in semantic and difficulty-matched control tasks. Chronometric TMS was delivered over the left ATL (10 mm from the tip of the temporal pole along the middle temporal gyrus). During each trial, two pulses of TMS (40 msec apart) were delivered either at baseline (before stimulus presentation) or at one of the experimental time points 100, 250, 400, and 800 msec poststimulus onset. A significant disruption to performance was identified from 400 msec on the semantic task but not on the control assessment. Our results not only reinforce the key role of the left ATL in semantic representation but also indicate that its contribution is especially important around 400 msec poststimulus onset. Together, these facts suggest that the ATL may be one of the neural sources of the N400 ERP component.
authors: University of Manchester.
authors: Rebecca L
authors: RL
authors: Jackson
authors: University of Manchester.
authors: Matthew A
authors: MA
authors: Lambon Ralph
authors: University of Manchester.
authors: Gorana
authors: G
authors: Pobric
mesh_terms: D005260:Female; D006801:Humans; D007600:Judgment / Q000502:physiology; D007807:Language Tests; D008297:Male; D009483:Neuropsychological Tests; D010364:Pattern Recognition, Visual / Q000502:physiology*; D011930:Reaction Time; D011932:Reading; D012660:Semantics; D013702:Temporal Lobe / Q000502:physiology*; D013997:Time Factors; D050781:Transcranial Magnetic Stimulation / Q000379:methods; D055815:Young Adult