Role of the Human Medial Frontal Cortex in Task Switching: A Combined fMRI and TMS Study

2002 ◽  
Vol 87 (5) ◽  
pp. 2577-2592 ◽  
Author(s):  
M.F.S. Rushworth ◽  
K. A. Hadland ◽  
T. Paus ◽  
P. K. Sipila
Keyword(s):  
Frontal Cortex ◽  
Task Switching ◽  
Response Selection ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Blood Oxygenation ◽  
Cortical Activation ◽  
Medial Frontal Cortex ◽  
Stimulus Selection ◽  
Task Set ◽  
Fmri Session

We used event-related functional magnetic resonance imaging (fMRI) to measure brain activity when subjects were performing identical tasks in the context of either a task-set switch or a continuation of earlier performance. The context, i.e., switching or staying with the current task, influenced medial frontal cortical activation; the medial frontal cortex is transiently activated at the time that subjects switch from one way of performing a task to another. Two types of task-set-switching paradigms were investigated. In the response-switching (RS) paradigm, subjects switched between different rules for response selection and had to choose between competing responses. In the visual-switching (VS) paradigm, subjects switched between different rules for stimulus selection and had to choose between competing visual stimuli. The type of conflict, sensory (VS) or motor (RS), involved in switching was critical in determining medial frontal activation. Switching in the RS paradigm was associated with clear blood-oxygenation-level-dependent signal increases (“activations”) in three medial frontal areas: the rostral cingulate zone, the caudal cingulate zone, and the presupplementary motor area (pre-SMA). Switching in the VS task was associated with definite activation in just one medial frontal area, a region on the border between the pre-SMA and the SMA. Subsequent to the fMRI session, we used MRI-guided frameless stereotaxic procedures and repetitive transcranial magnetic stimulation (rTMS) to test the importance of the medial frontal activations for task switching. Applying rTMS over the pre-SMA disrupted subsequent RS performance but only when it was applied in the context of a switch. This result shows, first, that the pre-SMA is essential for task switching and second that its essential role is transient and limited to just the time of behavioral switching. The results are consistent with a role for the pre-SMA in selecting between response sets at a superordinate level rather than in selecting individual responses. The effect of the rTMS was not simply due to the tactile and auditory artifacts associated with each pulse; rTMS over several control regions did not selectively disrupt switching. Applying rTMS over the SMA/pre-SMA area activated in the VS paradigm did not disrupt switching. This result, first, confirms the limited importance of the medial frontal cortex for sensory attentional switching. Second, the VS rTMS results suggest that just because an area is activated in two paradigms does not mean that it plays the same essentialrole in both cases.

Interference with Performance of a Response Selection Task that has no Working Memory Component: An rTMS Comparison of the Dorsolateral Prefrontal and Medial Frontal Cortex

2001 ◽  
Vol 13 (8) ◽  
pp. 1097-1108 ◽  
Author(s):  
K. A. Hadland ◽  
M. F. S. Rushworth ◽  
R. E. Passingham ◽  
M. Jahanshahi ◽  
J. C. Rothwell
Keyword(s):  
Working Memory ◽  
Frontal Cortex ◽  
Response Times ◽  
Memory Load ◽  
Response Selection ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Selection Task ◽  
Medial Frontal Cortex ◽  
Memory Element ◽  
Dorsolateral Prefrontal

It has been suggested that the dorsolateral prefrontal cortex (DLPFC) is involved in free selection (FS), the process by which subjects themselves decide what action to perform. Evidence for this proposal has been provided by imaging studies showing activation of the DLPFC when subjects randomly generate responses. However, these response selection tasks have a hidden working memory element and it has been widely reported that the DLPFC is activated when subjects perform tasks which involve working memory. The primary aim of this experiment was to establish if the DLPFC is genuinely involved in response selection. We used repetitive transcranial magnetic stimulation (rTMS) to investigate whether temporary interference of the DLPFC could disrupt performance of a response selection task that had no working memory component. Subjects performed tasks in which they made bimanual sequences of eight nonrepeating finger movements. In the FS task, subjects chose their movements at random while a computer monitor displayed these moves. This visual feedback obviated the need for subjects to maintain their previous moves “on-line.” No selection was required for the two control tasks as responses were cued by the visual display. The attentional demands of the control tasks varied. In the high load (HL) version, subjects had to maintain their attention throughout the sequence, but this requirement was absent in the low load (LL) task. rTMS over the DLPFC slowed response times on the FS task and at the end of the sequence on the HL task, but had no effect on the LL task. rTMS over the medial frontal cortex (MFC) slowed response times on the FS task but had no effect on the HL task. This suggests that a response selection task without a working memory load will depend on the DLPFC and the MFC. The difference appears to be that the DLPFC is important when selecting between competing responses or when concentrating if there is a high attentional demand, but that the MFC is only important during the response selection task.

Selection for Action: The Medial Frontal Cortex Is an Executive Hub for Stimulus and Response Selection

2021 ◽  
pp. 1-28
Author(s):  
Dariusz Asanowicz ◽  
Bartłomiej Panek ◽  
Ilona Kotlewska
Keyword(s):  
Functional Connectivity ◽  
Frontal Cortex ◽  
Phase Synchronization ◽  
Visual Stimulation ◽  
Response Selection ◽  
Flanker Task ◽  
Medial Frontal Cortex ◽  
Conflict Condition ◽  
Underlying Processes ◽  
Selection For Action

Abstract This EEG study investigates the electrophysiological activity underlying processes of stimulus and response selection, and their executive orchestration via long-range functional connectivity under conflict condition, in order to shed more light on how these brain dynamics shape individual behavioral performance. Participants (n = 91) performed a modified flanker task, in which bilateral visual stimulation and a bimanual response pattern were employed to isolate the stimulus and response selection-related lateralized activity. First, we identified conflict-related markers of task-relevant processes; most importantly, the stimulus and response selection were evidenced by contra–ipsilateral differences in visual and motor activity, respectively, and executive control was evidenced by modulations of midfrontal activity. Second, we identified conflict-related functional connectivity between midfrontal and other task-relevant areas. The results showed that interregional phase synchronization in theta band was centered at the midfrontal site, interpreted here as a “hub” of executive communication. Importantly, the theta functional connectivity was more robust under the condition of increased demands for stimulus and response selection, including connectivity between the medial frontal cortex and the lateral frontal and motor areas, as well as cross-frequency theta–alpha coupling between the medial frontal cortex and contralateral visual areas. Third, we showed that individual differences in the measured conflict-related EEG activity, particularly the midfrontal N2, theta power, and global theta connectivity, predict the behavioral efficiency in conflict resolution.

scholarly journals Depression-like state induced by low-frequency repetitive transcranial magnetic stimulation to ventral medial frontal cortex in monkeys

2021 ◽  
Author(s):  
Shinya Nakamura ◽  
Yodai Kishimoto ◽  
Masaki Sekino ◽  
Motoaki Nakamura ◽  
Ken-Ichiro Tsutsui
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Frontal Cortex ◽  
Mood Disorders ◽  
Magnetic Stimulation ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Low Frequency ◽  
The Other ◽  
Medial Frontal Cortex ◽  
Behavioral Activity ◽  
Primate Model

The medial frontal cortex (MFC), especially its ventral part, has long been of great interest with respect to the pathology of mood disorders. A number of human brain imaging studies have demonstrated the abnormalities of this brain region in patients with mood disorders, however, whether it is critically involved in the pathogenesis of such disorders remains to be fully elucidated. In this study, we conducted a causal study to investigate how the suppression of neural activity in the ventral region of the MFC (vMFC) affects the behavioral and physiological states of monkeys by using repetitive transcranial magnetic stimulation (rTMS). By using low-frequency rTMS (LF-rTMS) as an inhibitory intervention, we found that LF-rTMS targeting the vMFC induced a depression-like state in monkeys, which was characterized by a reduced spontaneous behavioral activity, increased plasma cortisol level, impaired sociability, and decreased motivation level. On the other hand, no such significant changes in behavioral and physiological states were observed when targeting the other MFC regions, dorsal or posterior. We further found that the administration of an antidepressant agent, ketamine, ameliorated the abnormal behavioral and physiological states induced by the LF-rTMS intervention. These findings indicate the causal involvement of the vMFC in the regulation of mood and affect and the validity of the LF-rTMS-induced dysfunction of the vMFC as a nonhuman primate model of the depression-like state.

Stimulus-Related Inhibition of Task Set During Task Switching

2008 ◽  
Vol 55 (5) ◽  
pp. 322-327 ◽  
Author(s):  
Stefano Sdoia ◽  
Fabio Ferlazzo
Keyword(s):  
Task Switching ◽  
Response Selection ◽  
Selection Process ◽  
Reaction Times ◽  
Stimulus Level ◽  
Processing Stage ◽  
Stimulus Processing ◽  
Task Set ◽  
Task Sequences

Performance after a shifting of task is supported by the inhibition of the executed task, as revealed by slower reaction times (RTs) on alternating compared to nonalternating task sequences (ABA vs CBA). In the present study we investigated the role of stimulus processing in the establishment of task inhibition during task switching, irrespective of the response selection process. Comparing performance on AbA and CbA task sequences within a procedure in which the b-task only involved stimulus encoding processes for later comparison but response selection did not occur, we found slower RTs on AbA compared to CbA task sequences. This revealed that inhibition of the executed task can be triggered at the stimulus processing stage of the new task. In accordance, inhibition only emerged when interference between tasks occurred at the stimulus level, due to stimuli having features relevant for both the executed and the upcoming task.

scholarly journals At your own peril: An ERP study of voluntary task set selection processes in the medial frontal cortex

2007 ◽  
Vol 7 (4) ◽  
pp. 286-296 ◽  
Author(s):  
B. U. FORSTMANN ◽  
K. R. RIDDERINKHOF ◽  
J. KAISER ◽  
C. BLEDOWSKI
Keyword(s):  
Frontal Cortex ◽  
Medial Frontal Cortex ◽  
Task Set ◽  
Selection Processes

scholarly journals Hierarchically Organized Medial Frontal Cortex-Basal Ganglia Loops Selectively Control Task- and Response-Selection

2017 ◽  
Vol 37 (33) ◽  
pp. 7893-7905 ◽  
Author(s):  
Franziska M. Korb ◽  
Jiefeng Jiang ◽  
Joseph A. King ◽  
Tobias Egner
Keyword(s):  
Basal Ganglia ◽  
Frontal Cortex ◽  
Response Selection ◽  
Medial Frontal Cortex ◽  
Control Task

A Review of the Role of Cue Processing in Task Switching

2013 ◽  
Vol 221 (1) ◽  
pp. 5-14 ◽  
Author(s):  
Kerstin Jost ◽  
Wouter De Baene ◽  
Iring Koch ◽  
Marcel Brass
Keyword(s):  
Cognitive Control ◽  
Task Switching ◽  
Task Switch ◽  
Task Set ◽  
Switch Costs ◽  
Set Switching ◽  
Controversial Topic ◽  
Cue Encoding ◽  
Cue Processing

The role of cue processing has become a controversial topic in research on cognitive control using task-switching procedures. Some authors suggested a priming account to explain switch costs as a form of encoding benefit when the cue from the previous trial is repeated and hence challenged theories that attribute task-switch costs to task-set (re)configuration. A rich body of empirical evidence has evolved that indeed shows that cue-encoding repetition priming is an important component in task switching. However, these studies also demonstrate that there are usually substantial “true” task-switch costs. Here, we review this behavioral, electrophysiological, and brain imaging evidence. Moreover, we describe alternative approaches to the explicit task-cuing procedure, such as the usage of transition cues or the task-span procedure. In addition, we address issues related to the type of cue, such as cue transparency. We also discuss methodological and theoretical implications and argue that the explicit task-cuing procedure is suitable to address issues of cognitive control and task-set switching.

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