How dynamic is interhemispheric interaction? Effects of task switching on the across-hemisphere advantage

Abstract

Interaction between the cerebral hemispheres may allow both hemispheres to contribute their processing resources in order to cope efficiently with complex tasks [Banich, M. (1998). The missing link: the role of interhemispheric interaction in attentional processing. Brain and Cognition, 36,. The current study investigated whether the benefits of interhemispheric interaction arise because of top-down knowledge about the task built up over the course of a block of trials or because of the processing demands present in a single trial. Participants performed a less computationally complex physical identity task and a more complex adding task on within-visual field and across-visual field trials. Task differences in interhemispheric interaction were compared between the blocked and mixed conditions to investigate whether frequent task switches altered the pattern of interhemispheric resource recruitment. A similar interaction between task difficulty and trial type (across-or within-visual field presentation) was obtained for both the blocked and mixed conditions. The degree of task-dependency of interhemispheric interaction was not altered in the mixed condition. This finding supports the view that interhemispheric interaction becomes beneficial in response to the processing demands of an individual trial rather than as a result of top-down task knowledge.

Tracking post-error adaptation in the motor system by transcranial magnetic stimulation

“…Critically, we found an increase of the MEP amplitude 450 ms after an erroneous response. In imaging studies, activations ipsilateral to the motor response have been observed during the performance of complex motor tasks (Banich, 1998;Verstynen et al, 2005;Welcome and Chiarello, 2008). Previous studies have shown that the commission of an error engaged several regions involved in performance monitoring which resulted in either decreased activation or increased inhibition of the contralateral motor cortex (Marco-Pallare´s et al, 2008;Danielmeier and Ullsperger, 2011), which presumably might lead to the increase of excitability of the ipsilateral motor cortex shown in our data.…”

Motor Control and Neural Plasticity through Interhemispheric Interactions

“…Several studies have suggested that the speed of transcallosal conduction is limited in larger brains, which implies that the transfer and integration of information between both hemispheres through the corpus callosum require more time and energy in humans [3, 17]. Therefore, it may be more efficient to use one hemisphere and inhibit the other hemisphere during simple tasks (e.g., physical identity and face-matching tasks); this promotes intrahemispheric processing and brain lateralization [2, 18, 19]. …”

Noninvasive brain stimulation in the treatment of aphasia: Exploring interhemispheric relationships and their implications for neurorehabilitation

“…It is well established that activity in one cerebral hemisphere affects activity in the other via a rich network of interhemispheric connections (Ferbert, Priori, & Rothwell, 1992;Ilmoniemi et al, 1997), and that these interactions represent a dynamic process that can be flexibly modulated based on task demands or by exogenous stimulation (e.g., Banich, 1998;Silvanto et al, 2009;Welcome & Chiarello, 2008). Even though the functional properties of interhemispheric connections are yet to be fully elucidated, converging evidence suggests that, in many instances, these connections appear to operate in a mutually inhibitory manner.…”