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 Divergence of rodent and primate medial frontal cortex functional connectivity

2020 ◽  
Vol 117 (35) ◽  
pp. 21681-21689 ◽  
Author(s):  
David J. Schaeffer ◽  
Yuki Hori ◽  
Kyle M. Gilbert ◽  
Joseph S. Gati ◽  
Ravi S. Menon ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Frontal Cortex ◽  
Nonhuman Primates ◽  
Functional Organization ◽  
Brain Connectivity ◽  
Medial Frontal Cortex ◽  
Preclinical Model ◽  
Preclinical Research ◽  
Ultra High Field ◽  
Dorsolateral Prefrontal

With the medial frontal cortex (MFC) centrally implicated in several major neuropsychiatric disorders, it is critical to understand the extent to which MFC organization is comparable between humans and animals commonly used in preclinical research (namely rodents and nonhuman primates). Although the cytoarchitectonic structure of the rodent MFC has mostly been conserved in humans, it is a long-standing question whether the structural analogies translate to functional analogies. Here, we probed this question using ultra high field fMRI data to compare rat, marmoset, and human MFC functional connectivity. First, we applied hierarchical clustering to intrinsically define the functional boundaries of the MFC in all three species, independent of cytoarchitectonic definitions. Then, we mapped the functional connectivity “fingerprints” of these regions with a number of different brain areas. Because rats do not share cytoarchitectonically defined regions of the lateral frontal cortex (LFC) with primates, the fingerprinting method also afforded the unique ability to compare the rat MFC and marmoset LFC, which have often been suggested to be functional analogs. The results demonstrated remarkably similar intrinsic functional organization of the MFC across the species, but clear differences between rodent and primate MFC whole-brain connectivity. Rat MFC patterns of connectivity showed greatest similarity with premotor regions in the marmoset, rather than dorsolateral prefrontal regions, which are often suggested to be functionally comparable. These results corroborate the viability of the marmoset as a preclinical model of human MFC dysfunction, and suggest divergence of functional connectivity between rats and primates in both the MFC and LFC.

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.

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.

scholarly journals Pretreatment Source Location and Functional Connectivity Network Correlated With Therapy Response in Childhood Absence Epilepsy: A Magnetoencephalography Study

2021 ◽  
Vol 12 ◽  
Author(s):  
Ke Zhang ◽  
Jintao Sun ◽  
Yulei Sun ◽  
Kai Niu ◽  
Pengfei Wang ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Frontal Cortex ◽  
Region Of Interest ◽  
Therapy Response ◽  
Source Location ◽  
Absence Epilepsy ◽  
Response To Therapy ◽  
Medial Frontal Cortex ◽  
Childhood Absence Epilepsy ◽  
Source Imaging

Objective: This study aims to investigate the differences between antiepileptic drug (AED) responders and nonresponders among patients with childhood absence epilepsy (CAE) using magnetoencephalography (MEG) and to additionally evaluate whether the neuromagnetic signals of the brain neurons were correlated with the response to therapy.Methods: Twenty-four drug-naïve patients were subjected to MEG under six frequency bandwidths during ictal periods. The source location and functional connectivity were analyzed using accumulated source imaging and correlation analysis, respectively. All patients were treated with appropriate AED, at least 1 year after their MEG recordings, their outcome was assessed, and they were consequently divided into responders and nonresponders.Results: The source location of the nonresponders was mainly in the frontal cortex at a frequency range of 8–12 and 30–80 Hz, especially 8–12 Hz, while the source location of the nonresponders was mostly in the medial frontal cortex, which was chosen as the region of interest. The nonresponders showed strong positive local frontal connections and deficient anterior and posterior connections at 80–250 Hz.Conclusion: The frontal cortex and especially the medial frontal cortex at α band might be relevant to AED-nonresponsive CAE patients. The local frontal positive epileptic network at 80–250 Hz in our study might further reveal underlying cerebral abnormalities even before treatment in CAE patients, which could cause them to be nonresponsive to AED. One single mechanism cannot explain AED resistance; the nonresponders may represent a subgroup of CAE who is refractory to several antiepileptic drugs.

Sign in / Sign up

Export Citation Format

Share Document