Enhancing memory performance with rTMS in healthy subjects and individuals with Mild Cognitive Impairment: the role of the right dorsolateral prefrontal cortex

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.

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Mechanistic link between right prefrontal cortical activity and anxious arousal revealed using transcranial magnetic stimulation in healthy subjects

Neuropsychopharmacology ◽

10.1038/s41386-019-0583-5 ◽

2019 ◽

Vol 45 (4) ◽

pp. 694-702 ◽

Cited By ~ 4

Author(s):

Nicholas L. Balderston ◽

Emily M. Beydler ◽

Camille Roberts ◽

Zhi-De Deng ◽

Thomas Radman ◽

...

Keyword(s):

Prefrontal Cortex ◽

Transcranial Magnetic Stimulation ◽

Healthy Subjects ◽

Magnetic Stimulation ◽

Dorsolateral Prefrontal Cortex ◽

Subcortical Structures ◽

Prefrontal Cortical ◽

Dorsolateral Prefrontal ◽

Before And After ◽

The Right

AbstractMuch of the mechanistic research on anxiety focuses on subcortical structures such as the amygdala; however, less is known about the distributed cortical circuit that also contributes to anxiety expression. One way to learn about this circuit is to probe candidate regions using transcranial magnetic stimulation (TMS). In this study, we tested the involvement of the dorsolateral prefrontal cortex (dlPFC), in anxiety expression using 10 Hz repetitive TMS (rTMS). In a within-subject, crossover experiment, the study measured anxiety in healthy subjects before and after a session of 10 Hz rTMS to the right dorsolateral prefrontal cortex (dlPFC). It used threat of predictable and unpredictable shock to induce anxiety and anxiety potentiated startle to assess anxiety. Counter to our hypotheses, results showed an increase in anxiety-potentiated startle following active but not sham rTMS. These results suggest a mechanistic link between right dlPFC activity and physiological anxiety expression. This result supports current models of prefrontal asymmetry in affect, and lays the groundwork for further exploration into the cortical mechanisms mediating anxiety, which may lead to novel anxiety treatments.

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

Cerebral Cortex ◽

10.1093/cercor/bhaa219 ◽

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.

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Effects on cognition of 20-day anodal transcranial direct current stimulation over the left dorsolateral prefrontal cortex in patients affected by mild cognitive impairment: a case-control study

Neurological Sciences ◽

10.1007/s10072-019-03903-6 ◽

2019 ◽

Vol 40 (9) ◽

pp. 1865-1872 ◽

Cited By ~ 2

Author(s):

Enrico Fileccia ◽

Vitantonio Di Stasi ◽

Roberto Poda ◽

Giovanni Rizzo ◽

Michelangelo Stanzani-Maserati ◽

...

Keyword(s):

Cognitive Impairment ◽

Prefrontal Cortex ◽

Mild Cognitive Impairment ◽

Direct Current ◽

Transcranial Direct Current Stimulation ◽

Dorsolateral Prefrontal Cortex ◽

Case Control Study ◽

Case Control ◽

Dorsolateral Prefrontal ◽

Control Study

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MEG activity of the dorsolateral prefrontal cortex during optic flow stimulations detects mild cognitive impairment due to Alzheimer’s disease

PLoS ONE ◽

10.1371/journal.pone.0259677 ◽

2021 ◽

Vol 16 (11) ◽

pp. e0259677

Author(s):

Moeko Noguchi-Shinohara ◽

Masato Koike ◽

Hirofumi Morise ◽

Kiwamu Kudo ◽

Shoko Tsuchimine ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Cognitive Impairment ◽

Prefrontal Cortex ◽

Mild Cognitive Impairment ◽

Optic Flow ◽

Dorsolateral Prefrontal Cortex ◽

Brodmann Area ◽

Maximum Power ◽

Neural Responses ◽

Dorsolateral Prefrontal

Dorsal stream, which has a neuronal connection with dorsolateral prefrontal cortex (DLPFC), is known to be responsible for detection of motion including optic flow perception. Using magnetoencephalography (MEG), this study aimed to examine neural responses to optic flow stimuli with looming motion in the DLPFC in patients with mild cognitive impairment due to Alzheimer’s disease (AD-MCI) compared with cognitively unimpaired participants (CU). We analyzed the neural responses by evaluating maximum source-localized power for the AD-MCI group (n = 11) and CU (n = 20), focusing on six regions of interest (ROIs) that form the DLPFC: right and left dorsal Brodmann area 9/46 (A9/46d), Brodmann area 46 (A46) and ventral Brodmann area 9/46 (A9/46v). We found significant differences in the maximum power between the groups in the left A46 and A9/46v. Moreover, in the left A9/46v, the maximum power significantly correlated with the Wechsler Memory Scale-Revised general memory score and delayed recall score. The maximum power in the left A9/46v also revealed high performance in AD-MCI versus CU classification with the area under the ROC curve of 0.90. This study demonstrated that MEG during the optic flow task can be useful in discriminating AD-MCI from CU.

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