Role Of Prefrontal Cortex Research Articles

Distinct roles of prefrontal cortex neurons in set shifting.

Cognitive flexibility, the ability to adjust behavioral strategies in response to changing environmental contingencies, requires adaptive processing of internal states and contextual cues to guide goal-oriented behavior, and is dependent on prefrontal cortex (PFC) functions. However, the neurophysiological underpinning of how the PFC supports cognitive flexibility is not well understood and has been under active investigation. We recorded spiking activity from single PFC neurons in mice performing the attentional set-shifting task, where mice learned to associate different contextually relevant sensory stimuli to reward. We identified subgroups of PFC neurons encoding task context, choice and trial outcome. Putative fast-spiking neurons were more involved in representing outcome and choice than putative regular-spiking neurons. Regression model further revealed that task context and trial outcome modulated the activity of choice-encoding neurons in rule-dependent and cell type-dependent manners. Together, our data provide new evidence to elucidate PFC's role in cognitive flexibility, suggesting differential cell type-specific engagement during set shifting, and that both contextual rule representation and trial outcome monitoring underlie PFC's unique capacity to support flexible behavioral switching.

Memory’s gatekeeper: The role of PFC in the encoding of congruent events

Theoretical models conventionally portray the consolidation of memories as a slow process that unfolds during sleep. According to the classical Complementary Learning Systems theory, the hippocampus (HPC) rapidly changes its connectivity during wakefulness to encode ongoing events and create memory ensembles that are later transferred to the prefrontal cortex (PFC) during sleep. However, recent experimental studies challenge this notion by showing that new information consistent with prior knowledge can be rapidly consolidated in PFC during wakefulness and that PFC lesions disrupt the encoding of congruent events in the HPC. The contributions of the PFC to memory encoding have therefore largely been overlooked. Moreover, most theoretical frameworks assume random and uncorrelated patterns representing memories, disregarding the correlations between our experiences. To address these shortcomings, we developed a HPC-PFC network model that simulates interactions between the HPC and PFC during the encoding of a memory (awake stage), and subsequent consolidation (sleeping stage) to examine the contributions of each region to the consolidation of novel and congruent memories. Our results show that the PFC network uses stored memory "schemas" consolidated during previous experiences to identify inputs that evoke congruent patterns of activity, quickly integrate it into its network, and gate which components are encoded in the HPC. More specifically, the PFC uses GABAergic long-range projections to inhibit HPC neurons representing input components correlated with a previously stored memory "schema," eliciting sparse hippocampal activity during exposure to congruent events, as it has been experimentally observed.

Restoration of the Activity of the Prefrontal Cortex to the Nucleus Accumbens Core Pathway Relieves Fentanyl-Induced Hyperalgesia in Male Rats.

Functional connectivity between the prelimbic medial prefrontal cortex (PL-mPFC) and the core of the nucleus accumbens (NAc core) predicts pain chronification. Inhibiting the apoptosis of oligodendrocytes in the PL-mPFC prevents fentanyl-induced hyperalgesia in rats. However, the role of prefrontal cortex (PFC)-NAc projections in opioid-induced hyperalgesia (OIH) remains unclear. Herein, we explored the role of the PL-NAc core circuit in fentanyl-induced hyperalgesia. An OIH rat model was established, and patch-clamp recording, immunofluorescence, optogenetics, and chemogenetic methods were employed for neuron excitability detection and nociceptive behavioral assessment. Our results showed decreased activity of the right PL-mPFC layer V output neurons in rats with OIH. Similarly, the excitability of the NAc core neurons receiving glutamatergic projections from the PL-mPFC decreased in OIH rats, observed by the light-evoked excitatory postsynaptic currents/light-excited inhibitory postsynaptic currents ratio (eEPSC/eIPSC ratio). Fentanyl-induced hyperalgesia was reversed by optogenetic activation of the PL-NAc core pathway, and chemogenetic suppression of this pathway induced hyperalgesia in control (saline-treated) rats. However, behavioral hyperalgesia was not aggravated by this chemogenetic suppression in OIH (fentanyl-treated) rats. Our findings indicate that inactivation of the PL-NAc core pathway may be a cause of OIH and restoring the activity of this pathway may provide a strategy for OIH treatment.

The role of prefrontal cortex and temporoparietal junction in interpersonal comfort and emotional approach

Our perception of physical distance to individuals and stimuli is influenced by our mental distance and relatedness. The present study aimed to investigate the role of the dorsolateral prefrontal cortex (dlPFC), ventromedial prefrontal cortex (vmPFC), and right temporoparietal junction (rTPJ) in interpersonal comfortable distance and approach behaviors towards emotional stimuli. Twenty healthy volunteers received brain stimulation in four separate sessions with a one-week interval, including anodal left dlPFC, anodal right vmPFC, anodal rTPJ, and sham condition, with an extracranial return electrode. Our results revealed an increase in interpersonal distance during anodal rTPJ stimulation and a decrease in distance to positive pictures during anodal vmPFC stimulation. These findings suggest that the rTPJ plays a role in the perceptual component of self-other distancing, while the vmPFC is involved in approaching positive emotions.

Heart rate variability (HRV) changes and cortical volume changes in a randomized trial of five weeks of daily HRV biofeedback in younger and older adults

Previous studies indicate that the structure and function of medial prefrontal cortex (PFC) and lateral orbitofrontal cortex (OFC) are associated with heart rate variability (HRV). Typically, this association is assumed to reflect the PFC's role in controlling HRV and emotion regulation, with better prefrontal structural integrity supporting greater HRV and better emotion regulation. However, as a control system, the PFC must monitor and respond to heart rate oscillatory activity. Thus, engaging in regulatory feedback during heart rate oscillatory activity may over time help shape PFC structure, as relevant circuits and connections are modified. In the current study with younger and older adults, we tested whether 5 weeks of daily sessions of biofeedback to increase heart rate oscillations (Osc+ condition) vs. to decrease heart rate oscillations (Osc− condition) affected cortical volume in left OFC and right OFC, two regions particularly associated with HRV in prior studies. The left OFC showed significant differences in volume change across conditions, with Osc+ increasing volume relative to Osc−. The volume changes in left OFC were significantly correlated with changes in mood disturbance. In addition, resting low frequency HRV increased more in the Osc+ than in the Osc− condition. These findings indicate that daily biofeedback sessions regulating heart rate oscillatory activity can shape both resting HRV and the brain circuits that help control HRV and regulate emotion.

A New Framework to Interpret Individual Inter-Hemispheric Compensatory Communication after Stroke.

Stroke constitutes the main cause of adult disability worldwide. Even after application of standard rehabilitation protocols, the majority of patients still show relevant motor impairment. Outcomes of standard rehabilitation protocols have led to mixed results, suggesting that relevant factors for brain re-organization after stroke have not been considered in explanatory models. Therefore, finding a comprehensive model to optimally define patient-dependent rehabilitation protocols represents a crucial topic in clinical neuroscience. In this context, we first report on the rehabilitation models conceived thus far in the attempt of predicting stroke rehabilitation outcomes. Then, we propose a new framework to interpret results in stroke literature in the light of the latest evidence regarding: (1) the role of the callosum in inter-hemispheric communication, (2) the role of prefrontal cortices in exerting a control function, and (3) diaschisis mechanisms. These new pieces of evidence on the role of callosum can help to understand which compensatory mechanism may take place following a stroke. Moreover, depending on the individual impairment, the prefrontal control network will play different roles according to the need of high-level motor control. We believe that our new model, which includes crucial overlooked factors, will enable clinicians to better define individualized motor rehabilitation protocols.

Consciousness: What is the role of prefrontal cortex?

Consciousness, its neural underpinnings, and the role of frontal cortex are highly debated topics. New evidence shows that human frontal cortex can bias conscious perception. What does this really mean about its contribution to consciousness?

Role of prefrontal cortex during Sudoku task: fNIRS study.

BackgroundSudoku is a popular cognitively stimulating leisure-time activity. Many studies have been directed toward finding an algorithm to solve Sudoku, but the investigation of the neural substrates involved in Sudoku has been challenging.MethodsSudoku task was divided into two steps to understand the differential function of the prefrontal cortex (PFC) while applying heuristic rules. PFC activity was recorded at 16 optode locations using functional near infrared spectroscopy. Classical two-way analysis of variance as well as general linear model-based approach was used to analyze the data from 28 noise-free recordings obtained from right-handed participants.Results Post hoc analysis showed a significant increase in oxyhemoglobin concentrations and decrease in deoxyhemoglobin concentrations at all 16 optode locations during step 1 (3 × 3 subgrids) and step 2 (easy level 9 × 9 Sudoku) when compared with the rest (p < 0.0001). Contrasting the step 2 – step 1 revealed that medial regions of PFC were preferentially activated.ConclusionBoth the medial and lateral regions of PFC are activated during Sudoku task. However, the medial regions of PFC play a differential role, especially when we consider searching and selecting the heuristic rules. Thus, Sudoku may be used for cognitive remediation training in neuropsychiatric disorders involving PFC.

Beta oscillations following performance feedback predict subsequent recall of task-relevant information

Reward delivery in reinforcement learning tasks elicits increased beta power in the human EEG over frontal areas of the scalp but it is unclear whether these 20–30 Hz oscillations directly facilitate reward learning. We previously proposed that frontal beta is not specific to reward processing but rather reflects the role of prefrontal cortex in maintaining and transferring task-related information to other brain areas. To test this proposal, we had subjects perform a reinforcement learning task followed by a memory recall task in which subjects were asked to recall stimuli associated either with reward feedback (Reward Recall condition) or error feedback (Error Recall condition). We trained a classifier on post-feedback beta power in the Reward Recall condition to discriminate trials associated with reward feedback from those associated with error feedback and then tested the classifier on post-feedback beta power in the Error Recall condition. Crucially, the model classified error-related beta in the Error Recall condition as reward-related. The model also predicted stimulus recall from post-feedback beta power irrespective of feedback valence and task condition. These results indicate that post-feedback beta power is not specific to reward processing but rather reflects a more general task-related process.

0075 Neural Correlates of Cognitive Fatigue in Parkinson Disease

Abstract Introduction Parkinson’s disease (PD) is a common neurodegenerative disease affecting millions of people world-wide. Fatigue is a prevalent and debilitating non-motor symptom in PD. However, the neural correlates underlying cognitive fatigue are poorly understood. Our previous studies suggested that continuous performance of a simple but mentally demanding psychomotor vigilance task (PVT) induced cognitive fatigue, operationalized as subjective exhaustion and time-on-task performance decline. Here we used arterial spin labeling (ASL) perfusion fMRI to investigate regional cerebral blood flow (CBF) changes in PD patients during cognitive fatigue induced by continuous performance of 20-min PVT. Methods Twenty-one PD patients completed a 20-min PVT during the ASL scan and two additional 4-min resting-state ASL scans before and after PVT. Reaction times (RTs) and regional CBF changes throughout the PVT as well as during pre- and post-task resting baselines were measured. Cognitive fatigue was analyzed by dividing the entire PVT performance into five quintiles in addition to the immediate measurement of self-rated fatigue before and after PVT. Results PD patients demonstrated significantly increased self-reported fatigue ratings after the task (p &amp;lt; 0.05) and progressively slower RTs across quintiles (p &amp;lt; 0.05). Perfusion data showed that the PVT activates the right middle frontal cortex, right inferior parietal lobe, right insula, bilateral occipital cortex, and right cerebellum (FDR corrected). Moreover, the bilateral middle frontal gyri were less active during the post-task rest compared to the pre-task rest. Conclusion These results demonstrated that cognitive fatigue has an ongoing effect on brain activity after a period of continuous mental effort and supported the critical role of prefrontal cortex in mediating cognitive fatigue in PD. The findings also suggest the utility of continuous PVT as an appropriate paradigm to induce and examine cognitive fatigue in PD. Support Supported in part by Parkinson’s Foundation Translational Research Grant and NIH grants R01-MH107571, R21-AG051981, and P30-NS045839.

The Role of Prefrontal Cortex in Cognitive Flexibility and Control

The Role of Prefrontal Cortex in Cognitive Flexibility and Control

The role of prefrontal cortex in the central mechanism of tinnitus

临床发现耳鸣患者常伴有认知和情感功能障碍，而认知和情感障碍也会导致甚至加重耳鸣。耳鸣的发病机制尚不清楚，近年来涉及认知和情感功能的非听觉相关脑区在耳鸣发生发展中的作用越来越受到关注。前额叶皮层作为中枢"感觉门控"的一部分，参与高级认知功能并对脑的感觉信息实施调控。本文就前额叶皮层在耳鸣中枢机制中的调控作用作一综述，以期为耳鸣治疗提供新方向。.

The role of prefrontal cortex in the control of feature attention in area V4

When searching for an object in a cluttered scene, we can use our memory of the target object features to guide our search, and the responses of neurons in multiple cortical visual areas are enhanced when their receptive field contains a stimulus sharing target object features. Here we tested the role of the ventral prearcuate region (VPA) of prefrontal cortex in the control of feature attention in cortical visual area V4. VPA was unilaterally inactivated in monkeys performing a free-viewing visual search for a target stimulus in an array of stimuli, impairing monkeys’ ability to find the target in the array in the affected hemifield, but leaving intact their ability to make saccades to targets presented alone. Simultaneous recordings in V4 revealed that the effects of feature attention on V4 responses were eliminated or greatly reduced while leaving the effects of spatial attention on responses intact. Altogether, the results suggest that feedback from VPA modulates processing in visual cortex during attention to object features.

Prefrontal Cortex Role in Stress Processing and Regulation

Regulation and processing of the stress are the important roles of the prefrontal cortex. During exposing to stress, various regions of the prefrontal cortex will be activated like lateral and ventromedial prefrontal cortex and medial orbitofrontal cortex. Amygdala responses to the stress as a natural mechanism but long-term stimulation of the amygdala leads to its dysfunction and consequently prefrontal cortex dysfunction. Due to the inverse relationship between prefrontal cortex and amygdala, increasing in the activity of the prefrontal cortex leads to reduced activity of the amygdala. Hypothalamic-pituitary-adrenal axis would be modulated by the ventromedial prefrontal cortex in stress. During negative emotions regulation, the amygdalar activity and cortisol response would be decreased and the ventromedial prefrontal cortex activity would be increased. The role of ventromedial prefrontal cortex and amygdala connection is important for fear extinction after exposing to the stress. There would be a close relationship between amygdala and prefrontal cortex and sustained the overactivity of the amygdala would influence the regulatory function of the prefrontal region in an adverse direction.

Spatiotemporal analysis of category and target-related information processing in the brain during object detection

To recognize a target object, the brain implements strategies which involve a combination of externally sensory-driven and internally task-driven mechanisms. While several studies have suggested a role for frontal brain areas in enhancing task-related representations in visual cortices, especially in the lateral-occipital cortex, they have remained silent about the type of information transferred to visual areas. However, the recently developed methods of representational connectivity analysis, allowed us to track the movement of different types of information in the brain. Accordingly, we designed an EEG object detection experiment and inspected the spatiotemporal dynamics of category- and target-related information across the brain. Results showed that the prefrontal area initiated the processing of target-related information. This information was then transferred to posterior brain areas during stimulus presentation probably to facilitate object detection and to direct the decision-making procedure. We also observed that, as compared to category-related information, the target-related information could predict the behavioral performance more accurately, suggesting the dominant representation of internal compared to external information in brain signals. These results provided new evidence about the role of prefrontal cortices in the processing of task-related information in the brain during object detection.

Neuropsychologiczne aspekty percepcji muzyki

The article reviews selected neuropsychological studies on brain correlates of music perception. First, the role and specialization of auditory cortex is discussed, focusing on differences between primary/secondary cortices as well as hemispheric asymmetry. Second, brain structures giving rise to emotional experiences during music listening are discussed, along with several possible explanatory mechanisms. Third, studies showing strengthened relationships between motor and auditory areas of the brain are demonstrated in the context of relative easiness of music to organize actions. The last part of the article focuses on the role of prefrontal cortex in building musical expectations and error perception. The influence of additional variables, such as listener’s musical training, on the observed effects is also discussed.

Ikasketaren eta oroimenaren oinarri estruktural eta molekularrak

Azpimarratzekoa da garunak egunerokotasunean bizi izandako esperientziak gordetzeko eta, portaera gidatzeko, informazio hori gogorarazteko duen gaitasuna. Garuneko neurona-zirkuitu espezifikoek funtzio jakinetan parte hartzen dute, eta bekoki aurreko kortexa eta hipokanpoa bereziki garrantzitsuak dira ikasketa eta oroimen prozesuetan. Are gehiago, N-metil-D-aspartato (NMDA) hartzailea prozesu hauen substratu molekular gisa identifikatu da. Izan ere, NMDA hartzaileen azpiunitateen konposizioa eta neurogarapeneko erregulazioa plastikotasun sinaptikoarekin zuzenki erlazionatuta daude. Halaber, faktore neurotrofikoak ezinbestekoak dira plastikotasun sinaptikoan aldaketak eragiteko eta, ondorioz, kognizioaren hobekuntza bat lortzeko. Artikulu honetan, bekoki aurreko kortexaren eta hipokanpoaren anatomia, funtzioa eta eremu bien arteko elkarrekintzaren berrikuspena egiteaz gain, ikasketa eta oroimen prozesuetan duten parte-hartzea deskribatzen da. Azkenik, itu molekularren modulazioak duen efektua ere aztertzen da, NMDA hartzaileei eta faktore neurotrofikoei arreta berezia jarriz.

Role of prefrontal cortex in the extinction of drug memories

It has been recognized that drug addiction engages aberrant process of learning and memory, and substantial studies have focused on developing effective treatment to erase the enduring drug memories to reduce the propensity to relapse. Extinction, a behavioral intervention exposing the individuals to the drug-associated cues repeatedly, can weaken the craving and relapse induced by drug-associated cues, but its clinic efficacy is limited. A clear understanding of the neuronal circuitry and molecular mechanism underlying extinction of drug memory will facilitate the successful use of extinction therapy in clinic. As a key component of mesolimbic system, medial prefrontal cortex (mPFC) has received particular attention largely in that PFC stands at the core of neural circuits for memory extinction and manipulating mPFC influences extinction of drug memories and subsequent relapse. Here, we review the recent advances in both animal models of drug abuse and human addicted patients toward the understanding of the mechanistic link between mPFC and drug memory, with particular emphasis on how mPFC contributes to the extinction of drug memory at levels ranging from neuronal architecture, synaptic plasticity to molecular signaling and epigenetic regulation, and discuss the clinic relevance of manipulating the extinction process of drug memory to prevent craving and relapse through enhancing mPFC function.

Role of Prefrontal Cortex Anti- and Pro-inflammatory Cytokines in the Development of Abnormal Behaviors Induced by Disconnection of the Ventral Hippocampus in Neonate Rats.

Neonatal disconnection of ventral hippocampus (VH) outputs in rats has been reported to lead to post-pubertal behavioral and synaptic changes of relevance to schizophrenia. Increased oxidative and inflammatory load in the prefrontal cortex (PFC) has been suggested to mediate some of the effects of neonatal VH lesion (NVHL). In this study, we hypothesized that developmental imbalance of anti- and pro-inflammatory factors within the PFC might affect synaptic development thus contributing to the adult NVHL-induced behavioral deficits. Ibotenic acid-induced excitotoxic NVHL was performed in postnatal day (PD) 7 male Sprague-Dawley rats and the mRNA levels of select pro- and anti-inflammatory cytokines were measured in the medial PFC (mPFC) at two developmental time points (PD15 and PD60). We observed a development-specific increase of pro-inflammatory cytokine, interleukin (IL)-1β mRNA at PD15, and an overall reduction in the expression and signaling of transforming growth factor beta 1 (TGF-β1), an anti-inflammatory cytokine, at both PD15 and PD60 in the NVHL animals. These cytokine changes were not seen in the somatosensory cortex (SSC) or tissue surrounding the lesion site. Daily administration of systemic recombinant TGF-β1 from PD7-14 prevented the appearance of hyperlocomotion, deficits in prepulse inhibition (PPI) of startle and social interaction (SI) in post-pubertal (PD60) NVHL rats. Neonatal supplementation of TGF-β1 was also able to attenuate dendritic spine loss in the layer 3 mPFC pyramidal neurons of NVHL animals. These results suggest that early damage of the VH has long-lasting inflammatory consequences in distant connected structures, and that TGF-β1 has potential to confer protection against the deleterious effects of developmental hippocampal damage.

The role of prefrontal cortex in a moral judgment task using functional near-infrared spectroscopy.

BackgroundUnderstanding the neural basis of moral judgment (MJ) and human decision‐making has been the subject of numerous studies because of their impact on daily life activities and social norms. Here, we aimed to investigate the neural process of MJ using functional near‐infrared spectroscopy (fNIRS), a noninvasive, portable, and affordable neuroimaging modality.MethodsWe examined prefrontal cortex (PFC) activation in 33 healthy participants engaging in MJ exercises. We hypothesized that participants presented with personal (emotionally salient) and impersonal (less emotional) dilemmas would exhibit different brain activation observable through fNIRS. We also investigated the effects of utilitarian and nonutilitarian responses to MJ scenarios on PFC activation. Utilitarian responses are those that favor the greatest good while nonutilitarian responses favor moral actions. Mixed effect models were applied to model the cerebral hemodynamic changes that occurred during MJ dilemmas.Results and conclusionsOur analysis found significant differences in PFC activation during personal versus impersonal dilemmas. Specifically, the left dorsolateral PFC was highly activated during impersonal MJ when a nonutilitarian decision was made. This is consistent with the majority of relevant fMRI studies, and demonstrates the feasibility of using fNIRS, with its portable and motion tolerant capacities, to investigate the neural basis of MJ dilemmas.