Facilitation of picture naming by focal transcranial magnetic stimulation of Wernicke's area

Abstract

On the basis of an evolutionary concept of language it was postulated that activation of the motor systems for arm movements, which are phylogenetically older, should facilitate language processes. In aphasic subjects picture naming can be improved by a concomitant movement of the dominant arm. In the present study it was investigated whether a similar facilitation can be observed in normal subjects by studying the effects of transcranial magnetic stimulation (TMS) on picture naming latencies. Suprathreshold focal TMS was applied to the left motor cortex for proximal arm muscles in right-handed subjects. The effects were compared with TMS of Wernicke's area. While TMS of the motor cortex and the non-dominant temporal lobe had no facilitatory effects, TMS of Wernicke's area decreased picture naming latencies significantly when TMS preceded picture presentation by 500 or 1000 ms. The observed effects depended on the intensity of the stimulus used. While clearly present with intensities of 35% and 55% of maximum output the facilitation disappeared with higher stimulation intensities. It is concluded that focal magnetic stimulation is able to facilitate lexical processes due to a general preactivation of language-related neuronal networks when delivered over Wernicke's area.

Event-Related Repetitive Transcranial Magnetic Stimulation of Posterior Superior Temporal Sulcus Improves the Detection of Threatening Postural Changes in Human Bodies

“…A variety of functional and behavioral studies support the notion that the amygdalae may strengthen the visual processing of emotional stimuli, which is thought to be carried out in extrastriate areas (Morris et al, 1998;Vuilleumier et al, 2004;Chouchourelou et al, 2006). Although in the present experiment it is difficult to attribute the rTMS effect to perceptual or memory processes, the reported modulation is in line with previous findings (Töpper et al, 1998;Grosbras and Paus, 2003;Hayward et al, 2004;Pulvermüller et al, 2005;D'Ausilio et al, 2009). In particular, our results may expand the state-dependent TMS literature on primary and higher-order (MT/V5) visual cortices (Silvanto et al, 2007(Silvanto et al, , 2008aSilvanto and Muggleton, 2008;Cattaneo et al, 2008;Silvanto and Cattaneo, 2010), demonstrating that the magnetic pulse activates cells that are less active in the instant of stimulation and may thus induce both facilitatory and inhibitory perceptual effects depending on the baseline activation of the stimulated population of cells (Matthews, 1999;Siebner et al, 2009).…”

Noninvasive Determination of Speech Dominance by Single Magnetic Stimulation of the Bilateral Hand Motor Cortex

“…21) Focal effects were identified in the digit span test but only for left hemisphere stimulation in patients with seizures of left temporal origin, 5) and focal magnetic stimulation delivered over Wernicke's area facilitated lexical processes because of general preactivation of language-related neuronal networks. 24) These investigations focused on facilitation of languagerelated processes by TMS. Our method measures the facilitation of motor potentials that occur during speech, so only requires that the study subject read aloud from a simple text.…”

“…The TMS of Wernicke's area was found to decrease by 500 to 1000 msec during a picture-naming presentation. 24) This long latency effect suggests that the types of excitability changes in language-related processes detected by TMS can be produced by the nonspecific preactivation of cortical networks.…”

Transient Functional Suppression and Facilitation of Japanese Ideogram Writing Induced by Repetitive Transcranial Magnetic Stimulation of Posterior Inferior Temporal Cortex

“…Low-frequency rTMS at 1 Hz over just anterior to Broca's area prolonged RTs for verb production (Shapiro et al, 2001), whereas rTMS at 20 Hz over Wernicke's area reduced RTs in a picture-naming task (Mottaghy et al, 1999). Moreover, the event-related TMS caused reduction of RTs in object naming or syntactic decision tasks when TMS was administered to Wernicke's or Broca's area at a specific timing (Topper et al, 1998;Sakai et al, 2002). To our knowledge, there are no evidences for inducing facilitation effect on the targeted region by low-frequency rTMS (Ͻ1 Hz), except for a certain type of preconditioning enhancing the plasticity.…”