scholarly journals The Role of Prefrontal Cortex in Verbal Episodic Memory: rTMS Evidence

2003 ◽  
Vol 15 (6) ◽  
pp. 855-861 ◽  
Author(s):  
Marco Sandrini ◽  
Stefano F. Cappa ◽  
Simone Rossi ◽  
Paolo M. Rossini ◽  
Carlo Miniussi
Keyword(s):  
Prefrontal Cortex ◽  
Episodic Memory ◽  
Phase Retrieval ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Unrelated Word ◽  
Study Phase ◽  
Memory Processing ◽  
Dorsolateral Prefrontal ◽  
The Right

Long-term, episodic memory processing is supposed to involve the prefrontal cortex asymmetrically. Here we investigate the role of the dorsolateral prefrontal cortex (DLPFC) in encoding and retrieval of semantically related or unrelated word pairs. Subjects were required to perform a task consisting of two parts: a study phase (encoding), in which word pairs were presented, and a test phase (retrieval), during which stimuli previously presented had to be recognized among other stimuli. Consistently with our previous findings using pictures, repetitive transcranial magnetic stimulation (rTMS) had a significant impact on episodic memory. The performance was significantly disrupted when rTMS was applied to the left or right DLPFC during encoding, and to the right DLPFC in retrieval, but only for unrelated word pairs. These results indicate that the nature of the material to be remembered interacts with the encoding–retrieval DLPFC asymmetry; moreover, the crucial role of DLPFC is evident only for novel stimuli.

scholarly journals Reducing future fears by suppressing the brain mechanisms underlying episodic simulation

2016 ◽  
Vol 113 (52) ◽  
pp. E8492-E8501 ◽  
Author(s):  
Roland G. Benoit ◽  
Daniel J. Davies ◽  
Michael C. Anderson
Keyword(s):  
Prefrontal Cortex ◽  
Dorsolateral Prefrontal Cortex ◽  
Ventromedial Prefrontal Cortex ◽  
Episodic Simulation ◽  
Dorsolateral Prefrontal ◽  
Future Events ◽  
The Right ◽  
Development Of Anxiety ◽  
The Brain

Imagining future events conveys adaptive benefits, yet recurrent simulations of feared situations may help to maintain anxiety. In two studies, we tested the hypothesis that people can attenuate future fears by suppressing anticipatory simulations of dreaded events. Participants repeatedly imagined upsetting episodes that they feared might happen to them and suppressed imaginings of other such events. Suppressing imagination engaged the right dorsolateral prefrontal cortex, which modulated activation in the hippocampus and in the ventromedial prefrontal cortex (vmPFC). Consistent with the role of the vmPFC in providing access to details that are typical for an event, stronger inhibition of this region was associated with greater forgetting of such details. Suppression further hindered participants’ ability to later freely envision suppressed episodes. Critically, it also reduced feelings of apprehensiveness about the feared scenario, and individuals who were particularly successful at down-regulating fears were also less trait-anxious. Attenuating apprehensiveness by suppressing simulations of feared events may thus be an effective coping strategy, suggesting that a deficiency in this mechanism could contribute to the development of anxiety.

Causal Role of the Dorsolateral Prefrontal Cortex in Belief Updating under Uncertainty

2020 ◽  
Vol 31 (1) ◽  
pp. 184-200
Author(s):  
Stefan Schulreich ◽  
Lars Schwabe
Keyword(s):  
Prefrontal Cortex ◽  
Dorsolateral Prefrontal Cortex ◽  
Causal Role ◽  
Uncertain Environments ◽  
Belief Updating ◽  
Frontoparietal Network ◽  
Dorsolateral Prefrontal ◽  
The Right ◽  
Normative Value

Abstract Adaptive performance in uncertain environments depends on the ability to continuously update internal beliefs about environmental states. Recent correlative evidence suggests that a frontoparietal network including the dorsolateral prefrontal cortex (dlPFC) supports belief updating under uncertainty, but whether the dlPFC serves a “causal” role in this process is currently not clear. To elucidate its contribution, we leveraged transcranial direct current stimulation (tDCS) over the right dlPFC, while 91 participants performed an incentivized belief-updating task. Participants also underwent a psychosocial stress or control manipulation to investigate the role of stress, which is known to modulate dlPFC functioning. We observed enhanced monetary value updating after anodal tDCS when it was normatively expected from a Bayesian perspective. A model-based analysis indicates that this effect was driven by belief updating. However, we also observed enhanced non-normative value updating, which might have been driven instead by expectancy violation. Enhanced normative and non-normative value updating reflected increased vs. decreased Bayesian rationality, respectively. Furthermore, cortisol increases were associated with enhanced positive, but not with negative, value updating. The present study thereby sheds light on the causal role of the right dlPFC in the remarkable human ability to navigate uncertain environments by continuously updating prior knowledge following new evidence.

The Role of the Dorsal–Lateral Prefrontal Cortex in Reward Sensitivity During Approach–Avoidance Conflict

2021 ◽  
Author(s):  
Camarin E Rolle ◽  
Mads L Pedersen ◽  
Noriah Johnson ◽  
Ken-ichi Amemori ◽  
Maria Ironside ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Avoidance Behavior ◽  
Reward Sensitivity ◽  
Diffusion Modeling ◽  
Dorsolateral Prefrontal ◽  
Current Task ◽  
Approach Avoidance ◽  
Cortical Regions ◽  
The Right

Abstract Approach–Avoidance conflict (AAC) arises from decisions with embedded positive and negative outcomes, such that approaching leads to reward and punishment and avoiding to neither. Despite its importance, the field lacks a mechanistic understanding of which regions are driving avoidance behavior during conflict. In the current task, we utilized transcranial magnetic stimulation (TMS) and drift-diffusion modeling to investigate the role of one of the most prominent regions relevant to AAC—the dorsolateral prefrontal cortex (dlPFC). The first experiment uses in-task disruption to examine the right dlPFC’s (r-dlPFC) causal role in avoidance behavior. The second uses single TMS pulses to probe the excitability of the r-dlPFC, and downstream cortical activations, during avoidance behavior. Disrupting r-dlPFC during conflict decision-making reduced reward sensitivity. Further, r-dlPFC was engaged with a network of regions within the lateral and medial prefrontal, cingulate, and temporal cortices that associate with behavior during conflict. Together, these studies use TMS to demonstrate a role for the dlPFC in reward sensitivity during conflict and elucidate the r-dlPFC’s network of cortical regions associated with avoidance behavior. By identifying r-dlPFC’s mechanistic role in AAC behavior, contextualized within its conflict-specific downstream neural connectivity, we advance dlPFC as a potential neural target for psychiatric therapeutics.

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