Time Perception and Motor Timing: A Common Cortical and Subcortical Basis Revealed by fMRI

et al. 2005

Psychological Research

112

137

A crucial demand in dual tasks suffering from a capacity limited processing mechanism is task-order scheduling, i.e. the control of the order in which the two component tasks are processed by this limited processing mechanism. The present study aims to test whether the lateral prefrontal cortex (LPFC) is associated with this demand. For this, 15 participants performed a psychological refractory paradigm (PRP) type dual task in an event-related functional magnetic resonance (fMRI) experiment. In detail, two choice reaction tasks, a visual (response with right hand) and an auditory (response with left hand), were presented with a temporal offset of 200 ms, while the participants were required to respond to the tasks in the order of their presentation. Importantly, the presentation order of the tasks changed randomly. Based on previous evidence, we argue that trials in which the present task order changed as compared to the previous trial (differentorder trials) impose higher demands on task coordination than same-order trials do. The analyses showed that cortical areas along the posterior part of the left inferior frontal sulcus as well as the right posterior middle frontal gyrus were more strongly activated in differentorder than in same-order trials, thus supporting the conclusion that one function of the LPFC for dual-task performance is the temporal coordination of two tasks. Furthermore, it is discussed that the present findings favour the active scheduling over the passive queuing hypothesis of dual-task processing.

Section: Parietal Corticessupporting

confidence: 49%

Task-order coordination in dual-task performance and the lateral prefrontal cortex: an event-related fMRI study

Szameitat

Lepsien

et al. 2005

Psychological Research

112

137

“…As this duration difference only occurred for the N400-like negativity effect that reflects semantic-thematic role assignment, but was not visible in the non-linguistic P300 effect (see Frisch et al, 2003), it is plausible that the rate of lexical-semantic information processing in the broader sense is changed as a result of unilateral basal ganglia lesions. In a recent paper, Grossman et al (2002) discussed evidence that the striatum may play a critical role in information processing speed (see also Rao et al, 2001;Schubotz et al, 2000). In accordance, it appears that while the time course of semantic-thematic processing is hampered by basal ganglia lesions, the process is still realized in an extended time window.…”

Section: Discussionmentioning

confidence: 90%

Syntactic language processing: ERP lesion data on the role of the basal ganglia

Kotz

Frisch

et al. 2003

J Int Neuropsychol Soc

Self Cite

122

The role of the basal ganglia in syntactic language processing was investigated with event-related brain potentials in fourteen neurologically impaired patients. Seven of these patients had basal ganglia lesions while 7 other patients primarily had lesions of the left temporo-parietal region excluding the basal ganglia. All patients listened to sentences that were either correct or included a verb argument structure violation. In previous experiments this type of violation elicited a biphasic pattern of an N400-P600 complex in young healthy participants. While the N400 may result from incorrect semantic-thematic role assignment, the P600 reflects the fact that verb information does not license the syntactic structure at present. Results of the patient experiment revealed a double dissociation: patients with left temporo-parietal lesions only show a P600, whereas patients with lesions of the basal ganglia showed no P600, but a negativity with extended duration that resembled an N400. The latter pattern not only confirms previous reports that the basal ganglia modulate the P600 but extends these results by showing that the N400 as a late semantic-thematic integration process appears partially modulated by the basal ganglia.

“…paradigm indicate that the premotor involvement does not A preliminary answer might be that attending to sequendepend on actual overt tracking movements, but is even tial patterns that are defined by object-specific properties present during mere perceptually tracking dynamic might give raise to manual movement representations in stimulus patterns [54][55][56]. Independently from actual the PMv, because the hand is the motor effector best…”

Section: Discussionmentioning

confidence: 99%

“…grasping (for comparison, see [55]), and which could be dissociated clearly from those which were activated by attention to dynamic spatial or dynamic temporal stimulus 2 . Materials and methods properties [54][55][56] and from those caused by attention to dynamic pitch properties [57].…”

Section: Introductionmentioning

confidence: 99%

Dynamic patterns make the premotor cortex interested in objects: influence of stimulus and task revealed by fMRI

Schubotz

Cognitive Brain Research

2002

Research in monkey and man indicates that the ventrolateral premotor cortex (PMv) underlies not only the preparation of manual movements, but also the perceptual representation of pragmatic object properties. However, visual stimuli without any pragmatic meaning were recently found to elicit selective PMv responses if they were subjected to a perceivable pattern of change. We used functional magnetic resonance imaging (fMRI) to investigate if perceptual representations in the PMv might apply not only to pragmatic, but also to dynamic stimulus properties. To this end, a sequential figure matching task that required the processing of dynamic features was contrasted with a non-figure control task (Experiment 1) and an individual figure matching task (Experiment 2). In order to control for potential influences of stimulus properties that might be associated with pragmatic attributes, different types of abstract visual stimuli were employed. The experiments yielded two major findings: if their dynamic properties are attended, then abstract 2D visual figures are sufficient to trigger activation within premotor areas involved in hand-object interaction. Moreover, these premotor activations are independent from stimulus properties that might relate to pragmatic features. The results imply that the PMv is engaged in the processing of stimuli that are usually or actually embedded within either a pragmatic or a dynamic context. 