Preferences reveal dissociable encoding across prefrontal-limbic circuits

Individual preferences for the flavor of different foods and fluids exert a strong influence on behavior. Most current theories posit that preferences are integrated with other state variables in the orbitofrontal cortex (OFC), which is thought to derive the relative subjective value of available options to guide choice behavior. Here, we report that instead of a single integrated valuation system in the OFC, another complementary one is centered in the ventrolateral prefrontal cortex (vlPFC) in macaques. Specifically, we found that the OFC and vlPFC preferentially represent outcome flavor and outcome probability, respectively, and that preferences are separately integrated into value representations in these areas. In addition, the vlPFC, but not the OFC, represented the probability of receiving the available outcome flavors separately, with the difference between these representations reflecting the degree of preference for each flavor. Thus, both the vlPFC and OFC exhibit dissociable but complementary representations of subjective value, both of which are necessary for decision-making.

Dissociable representations of decision variables within subdivisions of macaque orbitofrontal and ventrolateral frontal cortex

Ventral frontal cortex (VFC) in macaques is involved in many affective and cognitive processes and has a key role in flexibly guiding reward-based decision-making. VFC is composed of a set of anatomically distinct subdivisions that are within the orbitofrontal cortex, ventrolateral prefrontal cortex, and anterior insula. In part, because prior studies have lacked the resolution to test for differences, it is unclear if neural representations related to decision-making are dissociable across these subdivisions. Here we recorded the activity of thousands of neurons within eight anatomically defined subregions of VFC in macaque monkeys performing a two-choice probabilistic task for different fruit juices outcomes. We found substantial variation in the encoding of decision variables across these eight subdivisions. Notably, ventrolateral subdivision 12l was unique relative to the other areas that we recorded from as the activity of single neurons integrated multiple attributes when monkeys evaluated the different choice options. Activity within 12o, by contrast, more closely represented reward probability and whether reward was received on a given trial. Orbitofrontal area 11m/l contained more specific representations of the quality of the outcome that could be earned later on. We also found that reward delivery encoding was highly distributed across all VFC subregions, while the properties of the reward, such as its flavor, were more strongly represented in areas 11m/l and 13m. Taken together, our work reveals the diversity of encoding within the various anatomically distinct subdivisions of VFC in primates.

Loneliness is related to smaller gray matter volumes in ACC and right VLPFC in people with major depression: a UK biobank study

The anterior cingulate cortex (ACC) and right ventrolateral prefrontal cortex (VLPFC) are thought to have important roles in loneliness (feeling of social isolation/exclusion) experience or regulation and in the pathophysiology of their disturbance in major depressive disorder (MDD). However, the structural abnormalities of these regions and the correlates with loneliness in MDD across the healthy population have not fully been clarified. The study analyzed the link between loneliness and gray matter volumes (GMVs) in the ACC and right VLPFC among 1,005 patients with MDD and 7,247 healthy controls (HCs) using UK Biobank data. Significant reductions in GMV in the right VLPFC were found in MDD males compared to HCs. MDD males also showed a higher association between loneliness and reduced GMVs in the right VLPFC and bilateral ACC than HCs. No such associations were found in MDD females. The findings suggest that loneliness may influence brain structures crucial for emotion experience and regulation, particularly in middle-older aged men with MDD. This highlights the potential adverse effects of loneliness on brain structure in MDD and suggests that social engagement could have a positive impact.

Graded functional organization in the left inferior frontal gyrus: evidence from task-free and task-based functional connectivity

The left inferior frontal gyrus has been ascribed key roles in numerous cognitive domains, such as language and executive function. However, its functional organization is unclear. Possibilities include a singular domain-general function, or multiple functions that can be mapped onto distinct subregions. Furthermore, spatial transition in function may be either abrupt or graded. The present study explored the topographical organization of the left inferior frontal gyrus using a bimodal data-driven approach. We extracted functional connectivity gradients from (i) resting-state fMRI time-series and (ii) coactivation patterns derived meta-analytically from heterogenous sets of task data. We then sought to characterize the functional connectivity differences underpinning these gradients with seed-based resting-state functional connectivity, meta-analytic coactivation modeling and functional decoding analyses. Both analytic approaches converged on graded functional connectivity changes along 2 main organizational axes. An anterior-posterior gradient shifted from being preferentially associated with high-level control networks (anterior functional connectivity) to being more tightly coupled with perceptually driven networks (posterior). A second dorsal-ventral axis was characterized by higher connectivity with domain-general control networks on one hand (dorsal functional connectivity), and with the semantic network, on the other (ventral). These results provide novel insights into an overarching graded functional organization of the functional connectivity that explains its role in multiple cognitive domains.

Emotion regulation of social pain: double dissociation of lateral prefrontal cortices supporting reappraisal and distraction

The dorsolateral prefrontal cortex (DLPFC) and ventrolateral prefrontal cortex (VLPFC) are both crucial regions involved in voluntary emotion regulation. However, it remains unclear whether the two regions show functional specificity for reappraisal and distraction. This study employed transcranial magnetic stimulation (TMS) to explore, in a real social interactive scenario, whether different lateral prefrontal regions play relatively specific roles in downregulating social pain via reappraisal and distraction. Participants initially took part in a social interactive game, followed by receiving either active (the DLPFC- or VLPFC-activated group, n = 100 per group) or control (the vertex-activated group, n = 100) TMS session. They were then instructed to use both distraction and reappraisal strategies to downregulate any negative emotions evoked by the social evaluation given by their peers who interacted with them previously. Results demonstrated that the TMS-activated DLPFC has a greater beneficial effect during distraction, whereas the activated VLPFC has a greater beneficial effect during reappraisal. This result investigated the direct experience of social pain and extended previous findings on empathy-related responses to affective pictures while also controlling for confounding factors such as empathic concern. Therefore, we are now confident in the double dissociation proposal of the DLPFC and VLPFC in distraction and reappraisal.

The VLPFC-Engaged Voluntary Emotion Regulation: Combined TMS-fMRI Evidence for the Neural Circuit of Cognitive Reappraisal

A clear understanding of the neural circuit underlying emotion regulation (ER) is important for both basic and translational research. However, a lack of evidence based on combined neuroimaging and neuromodulation techniques calls into question (1) whether the change of prefrontal-subcortical activity intrinsically and causally contributes to the ER effect; and (2) whether the prefrontal control system directly modulates the subcortical affective system. Accordingly, we combined fMRI recordings with transcranial magnetic stimulation (TMS) to map the causal connections between the PFC and subcortical affective structures (amygdala and insula). A total of 117 human adult participants (57 males and 60 females) were included in the study. The results revealed that TMS-induced ventrolateral PFC (VLPFC) facilitation led to enhanced activity in the VLPFC and ventromedial PFC (VMPFC) as well as attenuated activity in the amygdala and insula during reappraisal but not during nonreappraisal (i.e., baseline). Moreover, the activated VLPFC intensified the prefrontal-subcortical couplings via the VMPFC during reappraisal only. This study provides combined TMS-fMRI evidence that downregulating negative emotion involves the prefrontal control system suppressing the subcortical affective system, with the VMPFC serving as a crucial hub within the VLPFC-subcortical network, suggesting an indirect pathway model of the ER circuit. Our findings outline potential protocols for improving ER ability by intensifying the VLPFC-VMPFC coupling in patients with mood and anxiety disorders.SIGNIFICANCE STATEMENT Using fMRI to examine the TMS effect, we uncovered that the opposite neural changes in prefrontal (enhanced) and subcortical (attenuated) regions are not a byproduct of emotion regulation (ER); instead, this prefrontal-subcortical activity per se causally contributes to the ER effect. Furthermore, using TMS to amplify the neural changes within the ER circuit, the "bridge" role of the VMPFC is highlighted under the reappraisal versus nonreappraisal contrast. This "perturb-and-measure" approach overcomes the correlational nature of fMRI data, helping us to identify brain regions that causally support reappraisal (the VLPFC and VMPFC) and those that are modulated by reappraisal (the amygdala and insula). The uncovered ER circuit is important for understanding the neural systems underlying reappraisal and valuable for translational research.

Electric field distribution predicts efficacy of accelerated intermittent theta burst stimulation for late-life depression

Introduction

Repetitive transcranial magnetic stimulation (rTMS) is a promising intervention for late-life depression (LLD) but may have lower rates of response and remission owing to age-related brain changes. In particular, rTMS induced electric field strength may be attenuated by cortical atrophy in the prefrontal cortex. To identify clinical characteristics and treatment parameters associated with response, we undertook a pilot study of accelerated fMRI-guided intermittent theta burst stimulation (iTBS) to the right dorsolateral prefrontal cortex in 25 adults aged 50 or greater diagnosed with LLD and qualifying to receive clinical rTMS.

Methods

Participants underwent baseline behavioral assessment, cognitive testing, and structural and functional MRI to generate individualized targets and perform electric field modeling. Forty-five sessions of iTBS were delivered over 9 days (1800 pulses per session, 50-min inter-session interval). Assessments and testing were repeated after 15 sessions (Visit 2) and 45 sessions (Visit 3). Primary outcome measure was the change in depressive symptoms on the Inventory of Depressive Symptomatology-30-Clinician (IDS-C-30) from Visit 1 to Visit 3.

Results

Overall there was a significant improvement in IDS score with the treatment (Visit 1: 38.6; Visit 2: 31.0; Visit 3: 21.3; mean improvement 45.5%) with 13/25 (52%) achieving response and 5/25 (20%) achieving remission (IDS-C-30 < 12). Electric field strength and antidepressant effect were positively correlated in a subregion of the ventrolateral prefrontal cortex (VLPFC) (Brodmann area 47) and negatively correlated in the posterior dorsolateral prefrontal cortex (DLPFC).

Conclusion

Response and remission rates were lower than in recently published trials of accelerated fMRI-guided iTBS to the left DLPFC. These results suggest that sufficient electric field strength in VLPFC may be a contributor to effective rTMS, and that modeling to optimize electric field strength in this area may improve response and remission rates. Further studies are needed to clarify the relationship of induced electric field strength with antidepressant effects of rTMS for LLD.

The role of ventrolateral prefrontal cortex on voluntary emotion regulation of social pain

The right ventrolateral prefrontal cortex (rVLPFC) is highly engaged in emotion regulation of social pain. However, there is still lack of both inhibition and excitement evidence to prove the causal relationship between this brain region and voluntary emotion regulation. This study used high-frequency (10 Hz) and low-frequency (1 Hz) repetitive transcranial magnetic stimulation (rTMS) to separately activate or inhibit the rVLPFC in two groups of participants. We recorded participants' emotion ratings as well as their social attitude and prosocial behaviors following emotion regulation. Also, we used eye tracker to record the changes of pupil diameter to measure emotional feelings objectively. A total of 108 healthy participants were randomly assigned to the activated, inhibitory or sham rTMS groups. They were required to accomplish three sequential tasks: the emotion regulation (cognitive reappraisal) task, the favorability rating task, and the donation task. Results show that the rVLPFC-inhibitory group reported more negative emotions and showed larger pupil diameter while the rVLPFC-activated group showed less negative emotions and reduced pupil diameter during emotion regulation (both compared with the sham rTMS group). In addition, the activated group gave more positive social evaluation to peers and donated more money to a public welfare activity than the rVLPFC-inhibitory group, among which the change of social attitude was mediated by regulated emotion. Taken together, these findings reveal that the rVLPFC plays a causal role in voluntary emotion regulation of social pain and can be a potential brain target in treating deficits of emotion regulation in psychiatric disorders.

Preferences reveal separable valuation systems in prefrontal-limbic circuits

Individual preferences for the flavor of different foods and fluids exert a strong influence on behavior. Most current theories posit that preferences are integrated with other state variables in orbitofrontal cortex (OFC), which is thought to derive the relative subjective value of available options to drive choice behavior. Here we report that instead of a single integrated valuation system in OFC, another separate one is centered in ventrolateral prefrontal cortex (vlPFC) in macaque monkeys. Specifically, we found that OFC and vlPFC preferentially represent outcome flavor and outcome probability, respectively, and that preferences are separately integrated into these two aspects of subjective valuation. In addition, vlPFC, but not OFC, represented the outcome probability for the two options separately, with the difference between these representations reflecting the degree of preference. Thus, there are at least two separable valuation systems that work in concert to guide choices and that both are biased by preferences.

Graded functional organisation in the left inferior frontal gyrus: evidence from task-free and task-based functional connectivity

The left inferior frontal gyrus (LIFG) has been ascribed key roles in numerous cognitive domains, including language, executive function and social cognition. However, its functional organisation, and how the specific areas implicated in these cognitive domains relate to each other, is unclear. Possibilities include that the LIFG underpins a domain-general function or, alternatively, that it is characterized by functional differentiation, which might occur in either a discrete or a graded pattern. The aim of the present study was to explore the topographical organisation of the LIFG using a bimodal data-driven approach. To this end, we extracted functional connectivity (FC) gradients from 1) the resting-state fMRI time-series of 150 participants (77 female), and 2) patterns of co-activation derived meta-analytically from task data across a diverse set of cognitive domains. We then sought to characterize the FC differences driving these gradients with seed-based resting-state FC and meta-analytic co-activation modelling analyses. Both analytic approaches converged on an FC profile that shifted in a graded fashion along two main organisational axes. An anterior-posterior gradient shifted from being preferentially associated with high-level control networks (anterior LIFG) to being more tightly coupled with perceptually-driven networks (posterior). A second dorsal-ventral axis was characterized by higher connectivity with domain-general control networks on one hand (dorsal LIFG), and with the semantic network, on the other (ventral). These results provide novel insights into a graded functional organisation of the LIFG underpinning both task-free and task-constrained mental states, and suggest that the LIFG is an interface between distinct large-scale functional networks.

The ventrolateral prefrontal cortex is part of the modular working memory system: A functional neuroanatomical perspective

For many years, the functional role of the ventrolateral Pre-Frontal Cortex (PFC) was associated with executive functions, specifically in the context of non-affective cognitive processes. However, recent research has suggested that the ventrolateral PFC is also involved in the attention system. The Ben Shalom model of the functional organization of the prefrontal cortex (2019) posits that the ventrolateral PFC selects perceptual stimuli after integration by the adjacent ventromedial PFC. This article reviews the state-of-the-art findings to better understand the role of the ventrolateral PFC in the selection of perceptual information as grounded in the Ben Shalom model. Numerous studies have reported converging evidence for the selective role of this area. However, most argue that this perceptual selection takes place through the active updating of information values linked to goal-oriented actions. These studies thus view the ventrolateral PFC as part of a system that actively manipulates and changes processed information such as the working memory function, rather than being part of the attention system. In agreement with this view, this review suggests that this area is part of a complex and modular working memory system and illustrates with reference to Diamond's work on ADD. This working memory system is functionally and anatomically dispersed and includes the dorsolateral PFC, the ACC, the parietal cortex, the basal ganglia, and the cerebellum. Hence, future research should continue to explore the specific neurofunctional roles of these areas in working memory systems, and the connections between the different subareas in this complex array.

Dynamic and stable population coding of attentional instructions coexist in the prefrontal cortex

A large body of recent work suggests that neural representations in prefrontal cortex (PFC) are changing over time to adapt to task demands. However, it remains unclear whether and how such dynamic coding schemes depend on the encoded variable and are influenced by anatomical constraints. Using a cued attention task and multivariate classification methods, we show that neuronal ensembles in PFC encode and retain in working memory spatial and color attentional instructions in an anatomically specific manner. Spatial instructions could be decoded both from the frontal eye field (FEF) and the ventrolateral PFC (vlPFC) population, albeit more robustly from FEF, whereas color instructions were decoded more robustly from vlPFC. Decoding spatial and color information from vlPFC activity in the high-dimensional state space indicated stronger dynamics for color, across the cue presentation and memory periods. The change in the color code was largely due to rapid changes in the network state during the transition to the delay period. However, we found that dynamic vlPFC activity contained time-invariant color information within a low-dimensional subspace of neural activity that allowed for stable decoding of color across time. Furthermore, spatial attention influenced decoding of stimuli features profoundly in vlPFC, but less so in visual area V4. Overall, our results suggest that dynamic population coding of attentional instructions within PFC is shaped by anatomical constraints and can coexist with stable subspace coding that allows time-invariant decoding of information about the future target.

A preliminary study on predictors of treatment response to repetitive transcranial magnetic stimulation in patients with treatment-resistant depression in Japan

BACKGROUND

Brain imaging studies have reported that the effect of repetitive transcranial magnetic stimulation (rTMS) is associated with the activities of the dorsolateral prefrontal cortex (DLPFC) and ventral medial prefrontal cortex (VMPFC). However, few studies have been conducted in Japanese patients.

AIM

We aimed to identify brain regions associated with depressive symptom changes by measuring regional cerebral blood flow (rCBF) in the DLPFC and VMPFC before and after the high-frequency rTMS to the left DLPFC in Japanese patients with treatment-resistant depression.

METHOD

Fourteen patients participated in the rTMS study and were assessed with the 17-item Hamilton depression rating scale (HAM-D₁₇ ). Among them, 13 participants underwent magnetic resonance imaging scan of the brain using the arterial spin labeling method. The rCBF was calculated using the fine stereotactic region of interest template (FineSRT) program for automated analysis. We focused on eight regions reported in previous studies.

RESULTS

Depression severity significantly decreased after 2 week (HAM-D₁₇ :11.4 ± 2.8, P = 0.00027) and 4 week (HAM-D₁₇ : 11.0 ± 3.7, P = 0.0023) of rTMS treatment. There was no significant change in rCBF at each region in the pre-post design. However, there was a significantly negative correlation between baseline rCBF in the right DLPFC and the improvement in HAM-D₁₇ score (r = -0.559, P = 0.047).

CONCLUSION

We obtained supportive evidence for the effectiveness of rTMS to the prefrontal cortex in treatment-resistant depression, which may be associated with reduced rCBF of the right DLPFC before initiation of rTMS.

Different Roles of the Left and Right Ventrolateral Prefrontal Cortex in Cognitive Reappraisal: An Online Transcranial Magnetic Stimulation Study

The ventrolateral prefrontal cortex (VLPFC) plays a pivotal role in cognitive reappraisal. Previous studies suggested a functional asymmetry of the bilateral VLPFC, but the evidence is still insufficient during cognitive reappraisal. In this study, we conducted an online single-pulse transcranial magnetic stimulation (spTMS) to investigate the causal and distinct roles of the left and right VLPFC in reappraisal. Participants were instructed to reappraise (down-regulate) or attend to pictures depicting social exclusion scenarios while the spTMS was applied over the left or right VLPFC of the participants’ brains. The results showed that spTMS of either the left or the right VLPFC would increase reappraisal difficulty. Meanwhile, the outcome of reappraisal (measured by self-reported negative feelings) significantly deteriorated when the right (but not the left) VLPFC was temporally interrupted by spTMS, while the verbal fluency during oral reporting of the reappraisal strategy was significantly reduced when the left VLPFC was interrupted by spTMS. Taken together, these findings provide causal evidence for the involvement of left and right VLPFC with distinct roles: while the left VLPFC is responsible for the linguistic especially semantic process of generating and selecting appraisals according to the goal of emotion regulation, the right VLPFC plays a critical role in inhibiting inappropriate negative emotions and thoughts generated by the effective scenarios. These findings deepen our understanding of the neurocognitive mechanism of emotion regulation.

The causal role of the bilateral ventrolateral prefrontal cortices on emotion regulation of social feedback

The ventrolateral prefrontal cortices (VLPFC) are crucial regions involved in voluntary emotion regulation. However, the lateralization of the VLPFC in downregulating negative emotions remains unclear; and whether the causal role of the VLPFC is generalizable to upregulating positive emotions is unexplored. This study used transcranial magnetic stimulation (TMS) to examine the causal relationship between the left/right VLPFC and social emotion reappraisal. One hundred and twenty participants were randomly assigned to either active (left and right VLPFC groups, n = 40/40) or sham (vertex, n = 40) TMS groups. Participants were instructed to passively receive social feedback or use reappraisal strategies to positively regulate their emotions. While the subjective emotional rating showed that the bilateral VLPFC facilitated the reappraisal success, the electrophysiological measure of the late positive potential (LPP) demonstrated a more critical role of the right VLPFC on social pain relief (decreased LPP amplitudes) and social reward magnification (enhanced LPP amplitudes). In addition, the influence of emotion regulation on social evaluation was found to be mediated by the memory of social feedback, indicating the importance of memory in social behavioral shaping. These findings suggest clinical protocols for the rehabilitation of emotion-regulatory function in patients with affective and social disorders.

Flexible versus Fixed Spatial Self-Ordered Response Sequencing: Effects of Inactivation and Neurochemical Modulation of Ventrolateral Prefrontal Cortex

Previously, studies using human neuroimaging and excitotoxic lesions in non-human primate have demonstrated an important role of ventrolateral prefrontal cortex (vlPFC) in higher order cognitive functions such as cognitive flexibility and the planning of behavioral sequences. In the present experiments, we tested effects on performance of temporary inactivation (using GABA receptor agonists) and dopamine (DA) D2 and 5-HT2A-receptor (R) blockade of vlPFC via local intracerebral infusions in the marmoset. We trained common marmosets to perform spatial self-ordered sequencing tasks in which one cohort of animals performed two and three response sequences on a continuously varying spatial array of response options on a touch-sensitive screen. Inactivation of vlPFC produced a marked disruption of accuracy of sequencing which also exhibited significant error perseveration. There were somewhat contrasting effects of D2 and 5-HT2A-R blockade, with the former producing error perseveration on incorrect trials, though not significantly impairing accuracy overall, and the latter significantly impairing accuracy but not error perseveration. A second cohort of marmosets were directly compared on performance of fixed versus variable spatial arrays. Inactivation of vlPFC again impaired self-ordered sequencing, but only with varying, and not fixed spatial arrays, the latter leading to the consistent use of fewer, preferred sequences. These findings add to evidence that vlPFC is implicated in goal-directed behavior that requires higher-order response heuristics that can be applied flexibly over different (variable), as compared with fixed stimulus exemplars. They also show that dopaminergic and serotonergic chemomodulation has distinctive effects on such performance.SIGNIFICANCE STATEMENT This investigation employing local intracerebral infusions to inactivate the lateral prefrontal cortex (PFC) of the New World marmoset reveals the important role of this region in self-ordered response sequencing in variable but not fixed spatial arrays. These novel findings emphasize the higher order functions of this region, contributing to cognitive flexibility and planning of goal directed behavior. The investigation also reports for the first time somewhat contrasting neuromodulatory deficits produced by infusions of dopamine (DA) D2 and 5-HT2A receptor (R) antagonists into the same region, of possible significance for understanding cognitive deficits produced by anti-psychotic drugs.

The VLPFC versus the DLPFC in Downregulating Social Pain Using Reappraisal and Distraction Strategies

The dorsolateral prefrontal cortex (DLPFC) and ventrolateral PFC (VLPFC) are both crucial structures involved in voluntary emotional regulation. However, it remains unclear whether the functions of these two cortical regions that are involved in emotional regulation, which are usually active in non-social situations, could be generalized to the regulation of social pain as well.

The dorsolateral prefrontal cortex (DLPFC) and ventrolateral PFC (VLPFC) are both crucial structures involved in voluntary emotional regulation. However, it remains unclear whether the functions of these two cortical regions that are involved in emotional regulation, which are usually active in non-social situations, could be generalized to the regulation of social pain as well. This study employed transcranial magnetic stimulation (TMS) to examine the causal relationship between the DLPFC/VLPFC and the emotional regulation of social pain via distraction and reappraisal. Ninety human participants (45 males and 45 females) initially underwent either active (DLPFC/VLPFC, n = 30/30) or sham (vertex, n = 30) TMS sessions. Participants were then instructed to use both distraction and reappraisal strategies to downregulate any negative emotions evoked by social exclusion pictures. Convergent results of the subjective emotional rating and electrophysiological indices demonstrated that: (1) both the DLPFC and VLPFC highly facilitate the downregulation of affective responses caused by social exclusion, revealing a causal role of these lateral PFCs in voluntary emotional regulation of both non-social and social pain; and (2) these two cortical regions showed relative functional specificity for distraction (DLPFC) and reappraisal (VLPFC) strategies, which helps to refine the cortical targeting of therapeutic protocols. In addition, the TMS effect was sustainable for at least 1 h, showcasing the potential feasibility of using this method in clinical practice. Together, these findings provide cognitive and neural evidence for the targeting of the VLPFC and/or the DLPFC to improve emotional regulation abilities, especially in social contexts.

SIGNIFICANCE STATEMENT This study aimed to examine the role of the dorsolateral prefrontal cortex (DLPFC) and ventrolateral PFC (VLPFC) in emotional regulation, particularly in response to social pain through the use of distraction and reappraisal strategies, as this is a relatively underexplored area of inquiry. This study makes a significant contribution to the literature because our results provide novel empirical information on the role of these cortical structures in the processing of negative emotions elicited within certain social contexts. As such, our findings have potential clinical implications, paving the way for future clinicians to be able to accurately target specific brain regions among patients struggling with impaired social cognition abilities, including those diagnosed with posttraumatic stress disorder, autism spectrum disorder, social anxiety disorder, and depression.

Cognitive framing modulates emotional processing through dorsolateral prefrontal cortex and ventrolateral prefrontal cortex networks: A functional magnetic resonance imaging study

INTRODUCTION

In this study, we show new evidence for the role of ventrolateral prefrontal cortex-dorsolateral prefrontal cortex (VLPFC-DLPFC) networks in the cognitive framing of emotional processing.

METHOD

We displayed neutral and aversive images described as having been sourced from artistic material to one cohort of subjects (i.e., the art-frame group; n = 19), while identical images, this time identified as having been sourced from documentary material (i.e., the doc-frame group; n = 20) were shown to a separate cohort.

RESULTS

Using functional magnetic resonance imaging (fMRI), we employed a linear parametric model showing that relative to the doc-frame group the art-frame group exhibited a modulation of amygdala activity in response to aversive images. The attenuated amygdala activity in the art-frame group supported our hypothesis that reduced amygdala activity was driven by top-down DLPFC inhibition of limbic responses. A psychophysiological interaction (PPI) analysis demonstrated that VLPFC activity correlated with amygdala activity in the art-frame group, but not in the doc-frame group for the contrast [Aversive > Neutral].

CONCLUSION

The role of the VLPFC in cognitive control suggests the hypothesis that it alongside DLPFC insulates against embodied emotional responses by inhibiting automatic affective responses.

Reinforcement-Sensitive Personality Traits Associated With Passion in Heterosexual Intimate Relationships: An fNIRS Investigation

According to the triangular theory of love, passion is an indispensable component of romantic love. Some brain imaging studies have shown that passionate arousal in intimate relationships is associated with the reward circuits in the brain. We hypothesized that the individual reward sensitivity trait is also related to passion in intimate relationships, and two separate studies were conducted in the present research. In the first study, 558 college students who were currently in love were selected as participants. The correlation between intimacy and reinforcement sensitivity in individuals identifying as heterosexual was explored using the Sensitivity to Punishment and Sensitivity to Reward Questionnaire, the Passionate Love Scale, and the Triangular Love Scale. In the second study, participants were 42 college students who were also currently in love. Functional near-infrared spectroscopy (fNIRS) was adopted to explore the neurophysiological interaction between reward sensitivity and emotional arousal induced in participants when presented a photograph of their partner, a friend, or a stranger. The results showed that reward sensitivity was positively correlated with passion, and punishment sensitivity was negatively correlated with intimacy and commitment. Significant interactions between reward sensitivity and photograph type were found, and the triangular part of the inferior frontal gyrus showed a particular relevance to the reward-sensitive personality trait toward partners. Overall, the findings support reinforcement sensitivity theory and suggest that reinforcement-sensitive personality traits (personality traits of reward and punishment sensitivity) are associated with all three components of love, with only reward sensitivity being related to passion.

Common neural responses to romantic rejection and acceptance in healthy adults

Although romantic rejection and acceptance have a strong impact on mood in adults, their neural response patterns are relatively unexplored. The present study used functional magnetic resonance imaging (fMRI) to examine neural responses to romantic rejection and acceptance in 36 healthy men and women, ages 18-53 years. Activations during rejection showed extensive anatomical overlap with activations during acceptance in the ventrolateral prefrontal cortex (vlPFC) and anterior insula (AI). In an analysis of sex differences, men and women did not differ in behavioral responses; however, men showed greater activation to romantic rejection and acceptance in the left vlPFC and AI compared to women. The vlPFC and AI may play a role in social cognition, tuned to detect the intentions and feelings of others whether they are positive or negative. In the context of romantic rejection and acceptance, this activation may signal the intent of others who are desired by the individual, leading to changes in mood, self-esteem, and social motivation.

Transcranial Electric Current Stimulation During Associative Memory Encoding: Comparing tACS and tDCS Effects in Healthy Aging

Associative memory is one of the first cognitive functions negatively affected by healthy and pathological aging processes. Non-invasive brain stimulation (NIBS) techniques are easily administrable tools to support memory. However, the optimal stimulation parameters inducing a reliable positive effect on older adult’s memory performance remain mostly unclear. In our randomized, double-blind, cross-over study, 28 healthy older adults (16 females; 71.18 + 6.42 years of age) received anodal transcranial direct (tDCS), alternating current in the theta range (tACS), and sham stimulation over the left ventrolateral prefrontal cortex (VLPFC) each once during encoding. We tested associative memory performance with cued recall and recognition tasks after a retention period and again on the following day. Overall, neither tDCS nor tACS showed effects on associative memory performance. Further analysis revealed a significant difference for performance on the cued recall task under tACS compared to sham when accounting for age. Our results suggest that tACS might be more effective to improve associative memory performance than tDCS in higher aged samples.

The right VLPFC and downregulation of social pain: A TMS study

Previous studies have demonstrated that the right ventrolateral prefrontal cortex (RVLPFC) is crucially involved in downregulating physical and social pain. However, it remains unclear whether the RVLPFC is more specific to either physical or social pain. The present study compares the role of RVLPFC in emotion regulation in physical‐ and social‐pain conditions using repetitive transcranial magnetic stimulation (rTMS). A total of 60 healthy participants underwent active (n = 30) or sham (n = 30) rTMS over the RVLPFC. Following each TMS session, participants performed a non‐reappraisal and then a reappraisal task to downregulate imagined physical or social pain evoked by pictures. Self‐reported negative emotional ratings and electroencephalogram data were recorded during the emotion regulation task. Participants were then required to rate the valence and arousal of those pictures 30 min after the task. It is found that rTMS‐activated RVLPFC led to reductions in subjective negative feelings and amplitudes of the late positive potential during reappraisal; however, these effects were found exclusively in the social‐pain condition. Participants also reported higher positive valence for socially, compared to physically, painful pictures after 30 min of the task. Behavioral and electrophysiological evidence both supported the functional specificity of RVLPFC in regulation of social pain. The prominent delayed effect of rTMS makes it possible to consider the potential application of rTMS‐VLPFC in clinical practice for social pain relief.

An investigation of the relationship between psychopathy and greater gray matter density in lateral prefrontal cortex

Psychopathic traits predispose individuals toward antisocial behavior. Such antagonistic acts often result in "unsuccessful" outcomes such as incarceration. What mechanisms allow some people with relatively high levels of psychopathic traits to live "successful", unincarcerated lives, in spite of their antisocial tendencies? Using neuroimaging, we investigated the possibility that "successful" psychopathic individuals exhibited greater development of neural structures that promote "successful" self-regulation, focusing on the ventrolateral prefrontal cortex (VLPFC). Across two structural magnetic resonance imaging studies of "successful" participants (Study 1: N = 80 individuals in long-term romantic relationships; Study 2: N = 64 undergraduates), we observed that gray matter density in the left and right VLPFC was positively associated with psychopathic traits. These preliminary results support a compensatory model of psychopathy, in which "successful" psychopathic individuals develop inhibitory mechanisms to compensate for their antisocial tendencies. Traditional models of psychopathy that emphasize deficits may be aided by such compensatory models that identify surfeits in neural and psychological processes.

Functional connectivity reveals dissociable ventrolateral prefrontal mechanisms for the control of multilingual word retrieval

This functional magnetic resonance imaging study established that different portions of the ventrolateral prefrontal cortex (vlPFC) support reactive and proactive language control processes during multilingual word retrieval. The study also examined whether proactive language control consists in the suppression of the nontarget lexicon. Healthy multilingual volunteers participated in a task that required them to name pictures alternately in their dominant and less‐dominant languages. Two crucial variables were manipulated: the cue‐target interval (CTI) to either engage (long CTI) or prevent (short CTI) proactive control processes, and the cognate status of the to‐be‐named pictures (noncognates vs. cognates) to capture selective pre‐activation of the target language. The results of the functional connectivity analysis showed a clear segregation between functional networks related to mid‐vlPFC and anterior vlPFC during multilingual language production. Furthermore, the results revealed that multilinguals engage in proactive control to prepare the target language. This proactive modulation, enacted by anterior vlPFC, is achieved by boosting the activation of lexical representations in the target language. Finally, control processes supported by both mid‐vlPFC and the left inferior parietal lobe, were similarly engaged by reactive and proactive control, possibly exerted on phonological representations to reduce cross‐language interference.

Causal Inference in the Multisensory Brain

When combining information across different senses, humans need to flexibly select cues of a common origin while avoiding distraction from irrelevant inputs. The brain could solve this challenge using a hierarchical principle by deriving rapidly a fused sensory estimate for computational expediency and, later and if required, filtering out irrelevant signals based on the inferred sensory cause(s). Analyzing time- and source-resolved human magnetoencephalographic data, we unveil a systematic spatiotemporal cascade of the relevant computations, starting with early segregated unisensory representations, continuing with sensory fusion in parietal-temporal regions, and culminating as causal inference in the frontal lobe. Our results reconcile previous computational accounts of multisensory perception by showing that prefrontal cortex guides flexible integrative behavior based on candidate representations established in sensory and association cortices, thereby framing multisensory integration in the generalized context of adaptive behavior.

Bullying the Brain? Longitudinal Links Between Childhood Peer Victimization, Cortisol, and Adolescent Brain Structure

Background: Childhood peer victimization is a stressful life experience associated with long-lasting adverse psychological consequences. While there is some evidence that victimization is associated with alterations in brain function, little is known about effects on brain structure. This study explored the relationships between childhood peer victimization, cortisol, and adolescent ventrolateral prefrontal cortex (vlPFC) structure in a sample of healthy children.

Methods: A total of 50 (M_age = 9.29 years at baseline) children participated in this longitudinal study. We examined whether diurnal cortisol levels (assessed at baseline) moderated the link between children’s self-reported peer victimization (assessed at baseline) and vlPFC surface area, gray matter volume, and thickness 5 years later.

Results: For boys, cortisol levels moderated the association between victimization and brain structure. For boys with a low daily cortisol output (assessed as area under the curve; AUC), high victimization was associated with a smaller right vlPFC surface area, and for boys with a high AUC, high victimization was associated with a larger right vlPFC surface area. In addition, for boys with a steeper diurnal slope, high victimization was associated with a smaller right vlPFC surface area, and for boys with a low flatter diurnal slope, high victimization was associated with a larger right vlPFC surface area.

Conclusion: These results indicate the differential influence of cortisol on the relationship between victimization and brain structure. Findings suggest that victimization may have differential effects on brain development in boys who are more versus less biologically sensitive to stress.

Proactive and reactive cognitive control rely on flexible use of the ventrolateral prefrontal cortex

The role of ventral versus dorsolateral prefrontal regions in instantiating proactive and reactive cognitive control remains actively debated, with few studies parsing cue versus probe-related activity. Rapid sampling (460 ms), long cue-probe delays, and advanced analytic techniques (deconvolution) were therefore used to quantify the magnitude and variability of neural responses during the AX Continuous Performance Test (AX-CPT; N = 46) in humans. Behavioral results indicated slower reaction times during reactive cognitive control (AY trials) in conjunction with decreased accuracy and increased variability for proactive cognitive control (BX trials). The anterior insula/ventrolateral prefrontal cortex (aI/VLPFC) was commonly activated across comparisons of both proactive and reactive cognitive control. In contrast, activity within the dorsomedial and dorsolateral prefrontal cortex was limited to reactive cognitive control. The instantiation of proactive cognitive control during the probe period was also associated with sparse neural activation relative to baseline, potentially as a result of the high degree of neural and behavioral variability observed across individuals. Specifically, the variability of the hemodynamic response function (HRF) within motor circuitry increased after the presentation of B relative to A cues (i.e., late in HRF) and persisted throughout the B probe period. Finally, increased activation of right aI/VLPFC during the cue period was associated with decreased motor circuit activity during BX probes, suggesting a possible role for the aI/VLPFC in proactive suppression of neural responses. Considered collectively, current results highlight the flexible role of the VLPFC in implementing cognitive control during the AX-CPT task but suggest large individual differences in proactive cognitive control strategies.

Ventrolateral prefrontal cortex activation during social exclusion mediates the relation between intolerance of uncertainty and trait aggression

Intolerance of uncertainty (IU) is an important individual difference factor that may contribute to trait-like aggression. Deficient engagement of the ventrolateral PFC (vlPFC) during social situations may also be a mechanism that links these two constructs. The aim of the current study was to test a proposed mediation model whereby IU is associated with trait aggression through neural activation of the vlPFC during a social exclusion task. Fifty-three adults with a range of impulsive-aggressive traits completed validated assessments of IU and trait aggression, and the 'Cyberball' social exclusion task during functional magnetic resonance imaging (fMRI). Results supported the mediation model such that greater levels of IU were associated with greater trait aggression through hypoactivation of the vlPFC during social exclusion. This study is the first to provide evidence suggesting that individuals higher in IU have difficulties engaging regulatory neural processes, which in-turn may increase the propensity for aggression.

Different Levels of Category Abstraction by Different Dynamics in Different Prefrontal Areas

Categories can be grouped by shared sensory attributes (i.e., cats) or a more abstract rule (i.e., animals). We explored the neural basis of abstraction by recording from multi-electrode arrays in prefrontal cortex (PFC) while monkeys performed a dot-pattern categorization task. Category abstraction was varied by the degree of exemplar distortion from the prototype pattern. Different dynamics in different PFC regions processed different levels of category abstraction. Bottom-up dynamics (stimulus-locked gamma power and spiking) in the ventral PFC processed more low-level abstractions, whereas top-down dynamics (beta power and beta spike-LFP coherence) in the dorsal PFC processed more high-level abstractions. Our results suggest a two-stage, rhythm-based model for abstracting categories.

Effective amygdala-prefrontal connectivity predicts individual differences in successful emotion regulation

The ability to voluntarily regulate our emotional response to threatening and highly arousing stimuli by using cognitive reappraisal strategies is essential for our mental and physical well-being. This might be achieved by prefrontal brain regions (e.g. inferior frontal gyrus, IFG) down-regulating activity in the amygdala. It is unknown, to which degree effective connectivity within the emotion-regulation network is linked to individual differences in reappraisal skills. Using psychophysiological interaction analyses of functional magnetic resonance imaging data, we examined changes in inter-regional connectivity between the amygdala and IFG with other brain regions during reappraisal of emotional responses and used emotion regulation success as an explicit regressor. During down-regulation of emotion, reappraisal success correlated with effective connectivity between IFG with dorsolateral, dorsomedial and ventromedial prefrontal cortex (PFC). During up-regulation of emotion, effective coupling between IFG with anterior cingulate cortex, dorsomedial and ventromedial PFC as well as the amygdala correlated with reappraisal success. Activity in the amygdala covaried with activity in lateral and medial prefrontal regions during the up-regulation of emotion and correlated with reappraisal success. These results suggest that successful reappraisal is linked to changes in effective connectivity between two systems, prefrontal cognitive control regions and regions crucially involved in emotional evaluation.

No Effects of Stimulating the Left Ventrolateral Prefrontal Cortex with tDCS on Verbal Working Memory Updating

The effects of transcranial direct current stimulation (tDCS) on dorsolateral prefrontal cortex functions, such as working memory (WM), have been examined in a number of studies. However, much less is known about the behavioral effects of tDCS over other important WM-related brain regions, such as the ventrolateral prefrontal cortex (VLPFC). In a counterbalanced within-subjects design with 33 young healthy participants, we examined whether online and offline single-session tDCS over VLPFC affects WM updating performance as measured by a digit 3-back task. We compared three conditions: anodal, cathodal and sham. We observed no significant tDCS effects on participants' accuracy or reaction times during or after the stimulation. Neither did we find any differences between anodal and cathodal stimulation. Largely similar results were obtained when comparing subgroups of high- and low-performing participants. Possible reasons for the lack of effects, including individual differences in responsiveness to tDCS, features of montage, task and sample characteristics, and the role of VLPFC in WM, are discussed.

Behavioral and Brain Activity Indices of Cognitive Control Deficits in Binge Drinkers

Heavy episodic drinking is prevalent among young adults and is a public issue of increasing importance. Its initiation and maintenance are associated with deficits in the capacity to inhibit automatic processing in favor of non-habitual responses. This study used functional magnetic resonance imaging (fMRI) to examine behavioral and brain activity indices of cognitive control during the Stroop task as a function of binge drinking. Heavy episodic drinkers (HED) reported consuming 5+/6+ drinks in two hours at least five times in the past six months and were compared to light drinkers (LED) who reported two or fewer binge episodes but were matched on demographics, intelligence and family history of alcoholism. Greater conflict-induced activity in the ventrolateral prefrontal cortex (VLPFC) and thalamus was observed in HED participants and it was positively correlated with alcohol intake and alcohol-related harmful consequences. HEDs maintained intact accuracy but at a cost of prolonged reaction times to high-conflict trials and increased ratings of task difficulty. Greater activation of the areas implicated in cognitive control is consistent with compensatory network expansion to meet higher cognitive demands. These results provide further insight into degradation of cognitive control in HEDs which may benefit development of detection and prevention strategies.

Are ventrolateral and dorsolateral prefrontal cortices involved in the computerized Corsi block-tapping test execution? An fNIRS study

The Corsi block-tapping test (CBT) is an old neuropsychological test that, requiring the storage and the reproduction of spatial locations, assesses spatial working memory (WM). Despite its wide use in clinical practice, the specific contribution of prefrontal cortex (PFC) subregions during CBT execution has not been clarified yet. Considering the importance of spatial WM in daily life and the well-known role of ventrolateral-PFC/dorsolateral-PFC (VLPFC/DLPFC) in WM processes, the present study was aimed at investigating, by a 20-channel functional near-infrared spectroscopy (fNIRS) system (including four short-separation channels), the hemodynamic response of the VLPFC/DLPFC during a computerized version of the CBT. Thirty-nine university students were asked to perform CBT standard version (CBTs), block-suppression CBT (CBTb), and control task (CBTc). A VLPFC activation during CBTs and a DLPFC activation during CBTb were hypothesized. The results of the Bayesian analysis have not shown a delineated specific activation of VLPFC/DLPFC during either CBTs or CBTb. These results together with the related ones obtained by others using fMRI are not sufficient to definitively state the role of the PFC subregions during CBT execution. The adoption of high-density diffuse optical tomography would be helpful in further exploration of the PFC involvement in spatial WM tasks.

Desirability, availability, credit assignment, category learning, and attention: Cognitive-emotional and working memory dynamics of orbitofrontal, ventrolateral, and dorsolateral prefrontal cortices

BACKGROUND

The prefrontal cortices play an essential role in cognitive-emotional and working memory processes through interactions with multiple brain regions.

METHODS

This article further develops a unified neural architecture that explains many recent and classical data about prefrontal function and makes testable predictions.

RESULTS

Prefrontal properties of desirability, availability, credit assignment, category learning, and feature-based attention are explained. These properties arise through interactions of orbitofrontal, ventrolateral prefrontal, and dorsolateral prefrontal cortices with the inferotemporal cortex, perirhinal cortex, parahippocampal cortices; ventral bank of the principal sulcus, ventral prearcuate gyrus, frontal eye fields, hippocampus, amygdala, basal ganglia, hypothalamus, and visual cortical areas V1, V2, V3A, V4, middle temporal cortex, medial superior temporal area, lateral intraparietal cortex, and posterior parietal cortex. Model explanations also include how the value of visual objects and events is computed, which objects and events cause desired consequences and which may be ignored as predictively irrelevant, and how to plan and act to realise these consequences, including how to selectively filter expected versus unexpected events, leading to movements towards, and conscious perception of, expected events. Modelled processes include reinforcement learning and incentive motivational learning; object and spatial working memory dynamics; and category learning, including the learning of object categories, value categories, object-value categories, and sequence categories, or list chunks.

CONCLUSION

This article hereby proposes a unified neural theory of prefrontal cortex and its functions.

Neural Representations of Hierarchical Rule Sets: The Human Control System Represents Rules Irrespective of the Hierarchical Level to Which They Belong

Humans use rules to organize their actions to achieve specific goals. Although simple rules that link a sensory stimulus to one response may suffice in some situations, often, the application of multiple, hierarchically organized rules is required. Recent theories suggest that progressively higher level rules are encoded along an anterior-to-posterior gradient within PFC. Although some evidence supports the existence of such a functional gradient, other studies argue for a lesser degree of specialization within PFC. We used fMRI to investigate whether rules at different hierarchical levels are represented at distinct locations in the brain or encoded by a single system. Thirty-seven male and female participants represented and applied hierarchical rule sets containing one lower-level stimulus-response rule and one higher-level selection rule. We used multivariate pattern analysis to investigate directly the representation of rules at each hierarchical level in absence of information about rules from other levels or other task-related information, thus providing a clear identification of low- and high-level rule representations. We could decode low- and high-level rules from local patterns of brain activity within a wide frontoparietal network. However, no significant difference existed between regions encoding representations of rules from both levels except for precentral gyrus, which represented only low-level rule information. Our findings show that the brain represents conditional rules regardless of their level in the explored hierarchy, so the human control system did not organize task representation according to this dimension. Our paradigm represents a promising approach to identifying critical principles that shape this control system.SIGNIFICANCE STATEMENT Several recent studies investigating the organization of the human control system propose that rules at different control levels are organized along an anterior-to-posterior gradient within PFC. In this study, we used multivariate pattern analysis to explore independently the representation of formally identical conditional rules belonging to different levels of a cognitive hierarchy and provide for the first time a clear identification of low- and high-level rule representations. We found no major spatial differences between regions encoding rules from different hierarchical levels. This suggests that the human brain does not use levels in the investigated hierarchy as a topographical organization principle to represent rules controlling our behavior. Our paradigm represents a promising approach to identifying which principles are critical.

The Reduction of Ventrolateral Prefrontal Cortex Gray Matter Volume Correlates with Loss of Economic Rationality in Aging

The population of people above 65 years old continues to grow, and there is mounting evidence that as humans age they are more likely to make errors. However, the specific effect of neuroanatomical aging on the efficiency of economic decision-making is poorly understood. We used whole-brain voxel-based morphometry analysis to determine where reduction of gray matter volume in healthy female and male adults over the age of 65 years correlates with a classic measure of economic irrationality: violations of the Generalized Axiom of Revealed Preference. All participants were functionally normal with Mini-Mental State Examination scores ranging between 26 and 30. While our elders showed the previously reported decline in rationality compared with younger subjects, chronological age per se did not correlate with rationality measures within our population of elders. Instead, reduction of gray matter density in ventrolateral prefrontal cortex correlates tightly with irrational behavior. Interestingly, using a large fMRI sample and meta-analytic tool with Neurosynth, we found that this brain area shows strong coactivation patterns with nearly all of the value-associated regions identified in previous studies. These findings point toward a neuroanatomic locus for economic rationality in the aging brain and highlight the importance of understanding both anatomy and function in the study of aging, cognition, and decision-making.SIGNIFICANCE STATEMENT Age is a crucial factor in decision-making, with older individuals making more errors in choices. Using whole-brain voxel-based morphometry analysis, we found that reduction of gray matter density in ventrolateral prefrontal cortex correlates with economic irrationality: reduced gray matter volume in this area correlates with the frequency and severity of violations of the Generalized Axiom of Revealed Preference. Furthermore, this brain area strongly coactivates with other reward-associated regions identified with Neurosynth. These findings point toward a role for neuroscientific discoveries in shaping long-standing economic views of decision-making.

From Behavioral Facilitation to Inhibition: The Neuronal Correlates of the Orienting and Reorienting of Auditory Attention

Successful adaptive behavior relies on the ability to automatically (bottom-up) orient attention to different locations in the environment. This results in a biphasic pattern in which reaction times (RT) are faster for stimuli that occur in the same spatial location (valid) for the first few hundred milliseconds, which is termed facilitation. This is followed by faster RT for stimuli that appear in novel locations (invalid) after longer delays, termed inhibition of return. The neuronal areas and networks involved in the transition between states of facilitation and inhibition remain poorly understood, especially for auditory stimuli. Functional magnetic resonance imaging (fMRI) data were therefore collected in a large sample of healthy volunteers (N = 52) at four separate auditory stimulus onset asynchronies (SOAs; 200, 400, 600, and 800 ms). Behavioral results indicated that facilitation (valid RT < invalid RT) occurred at the 200 ms SOA, with inhibition of return (valid RT > invalid RT) present at the three longer SOAs. fMRI results showed several brain areas varying their activation as a function of SOA, including bilateral superior temporal gyrus, anterior thalamus, cuneus, dorsal anterior cingulate gyrus, and right ventrolateral prefrontal cortex (VLPFC)/anterior insula. Right VLPFC was active during a behavioral state of facilitation, and its activation (invalid – valid trials) further correlated with behavioral reorienting at the 200 ms delay. These results suggest that right VLPFC plays a critical role when auditory attention must be quickly deployed or redeployed, demanding heightened cognitive and inhibitory control. In contrast to previous work, the ventral and dorsal frontoparietal attention networks were both active during valid and invalid trials across SOAs. These results suggest that the dorsal and ventral networks may not be as specialized during bottom-up auditory orienting as has been previously reported during visual orienting.

Organization of cortico-cortical pathways supporting memory retrieval across subregions of the left ventrolateral prefrontal cortex

Functional magnetic resonance imaging (fMRI) evidence indicates that different subregions of ventrolateral prefrontal cortex (VLPFC) participate in distinct cortical networks. These networks have been shown to support separable cognitive functions: anterior VLPFC [inferior frontal gyrus (IFG) pars orbitalis] functionally correlates with a ventral fronto-temporal network associated with top-down influences on memory retrieval, while mid-VLPFC (IFG pars triangularis) functionally correlates with a dorsal fronto-parietal network associated with postretrieval control processes. However, it is not known to what extent subregional differences in network affiliation and function are driven by differences in the organization of underlying white matter pathways. We used high-angular-resolution diffusion spectrum imaging and functional connectivity analysis in unanesthetized humans to address whether the organization of white matter connectivity differs between subregions of VLPFC. Our results demonstrate a ventral-dorsal division within IFG. Ventral IFG as a whole connects broadly to lateral temporal cortex. Although several different individual white matter tracts form connections between ventral IFG and lateral temporal cortex, functional connectivity analysis of fMRI data indicates that these are part of the same ventral functional network. By contrast, across subdivisions, dorsal IFG was connected with the midfrontal gyrus and correlated as a separate dorsal functional network. These qualitative differences in white matter organization within larger macroanatomical subregions of VLPFC support prior functional distinctions among these regions observed in task-based and functional connectivity fMRI studies. These results are consistent with the proposal that anatomical connectivity is a crucial determinant of systems-level functional organization of frontal cortex and the brain in general.

Resting state morphology predicts the effect of theta burst stimulation in false belief reasoning

When required to represent a perspective that conflicts with one's own, functional magnetic resonance imaging (fMRI) suggests that the right ventrolateral prefrontal cortex (rvlPFC) supports the inhibition of that conflicting self-perspective. The present task dissociated inhibition of self-perspective from other executive control processes by contrasting belief reasoning-a cognitive state where the presence of conflicting perspectives was manipulated-with a conative desire state wherein no systematic conflict existed. Linear modeling was used to examine the effect of continuous theta burst stimulation (cTBS) to rvlPFC on participants' reaction times in belief and desire reasoning. It was anticipated that cTBS applied to rvlPFC would affect belief but not desire reasoning, by modulating activity in the Ventral Attention System (VAS). We further anticipated that this effect would be mediated by functional connectivity within this network, which was identified using resting state fMRI and an unbiased model-free approach. Simple reaction-time analysis failed to detect an effect of cTBS. However, by additionally modeling individual measures from within the stimulated network, the hypothesized effect of cTBS to belief (but, importantly, not desire) reasoning was demonstrated. Structural morphology within the stimulated region, rvlPFC, and right temporoparietal junction were demonstrated to underlie this effect. These data provide evidence that inconsistencies found with cTBS can be mediated by the composition of the functional network that is being stimulated. We suggest that the common claim that this network constitutes the VAS explains the effect of cTBS to this network on false belief reasoning. Hum Brain Mapp 37:3502-3514, 2016. © 2016 Wiley Periodicals, Inc.

Beyond the Medial Regions of Prefrontal Cortex in the Regulation of Fear and Anxiety

Fear and anxiety are adaptive responses but if left unregulated, or inappropriately regulated, they become biologically and socially maladaptive. Dysregulated emotions are manifest in a wide variety of psychiatric and neurological conditions but the external expression gives little indication of the underlying causes, which are inevitably multi-determined. To go beyond the overt phenotype and begin to understand the causal mechanisms leading to conditions characterized by anxiety and disorders of mood, it is necessary to identify the base psychological processes that have become dysregulated, and map them on to their associated neural substrates. So far, attention has been focused primarily on the medial regions of prefrontal cortex (PFC) and in particular their contribution to the expression and extinction of conditioned fear. However, functional neuroimaging studies have shown that the sphere of influence within the PFC is not restricted to its medial regions, but extends into dorsal, ventrolateral (vlPFC) and orbitofrontal (OFC) regions too; although the causal role of these other areas in the regulation of fear and anxiety remains to be determined and in the case of the OFC, existing findings are conflicting. Here, we review the evidence for the contribution of these other regions in negative emotion regulation in rodents and old world and new world monkeys. We consider a variety of different contexts, including conditioned and innate fear, learned and unlearned anxiety and cost-benefit decision-making, and a range of physiological and behavioral measures of emotion. It is proposed that both the OFC and vlPFC contribute to emotion regulation via their involvement, respectively, in the prediction of future outcomes and higher-order attentional control. The fractionation of these neurocognitive and neurobehavioral systems that regulate fear and anxiety opens up new opportunities for diagnostic stratification and personalized treatment strategies.

Involvement of the Ventrolateral Prefrontal Cortex in Learning Others' Bad Reputations and Indelible Distrust

A bad reputation can persistently affect judgments of an individual even when it turns out to be invalid and ought to be disregarded. Such indelible distrust may reflect that the negative evaluation elicited by a bad reputation transfers to a person. Consequently, the person him/herself may come to activate this negative evaluation irrespective of the accuracy of the reputation. If this theoretical model is correct, an evaluation-related brain region will be activated when witnessing a person whose bad reputation one has learned about, regardless of whether the reputation is deemed valid or not. Here, we tested this neural hypothesis with functional magnetic resonance imaging (fMRI). Participants memorized faces paired with either a good or a bad reputation. Next, they viewed the faces alone and inferred whether each person was likely to cooperate, first while retrieving the reputations, and then while trying to disregard them as false. A region of the left ventrolateral prefrontal cortex (vlPFC), which may be involved in negative evaluation, was activated by faces previously paired with bad reputations, irrespective of whether participants attempted to retrieve or disregard these reputations. Furthermore, participants showing greater activity of the left ventrolateral prefrontal region in response to the faces with bad reputations were more likely to infer that these individuals would not cooperate. Thus, once associated with a bad reputation, a person may elicit evaluation-related brain responses on their own, thereby evoking distrust independently of their reputation.

Ventrolateral and dorsomedial frontal cortex lesions impair mnemonic context retrieval

The prefrontal cortex appears to contribute to the mnemonic retrieval of the context within which stimuli are experienced, but only under certain conditions that remain to be clarified. Patients with lesions to the frontal cortex, the temporal lobe and neurologically intact individuals were tested for context memory retrieval when verbal stimuli (words) had been experienced across multiple (unstable context condition) or unique (stable context condition) contexts; basic recognition memory of these words-in-contexts was also tested. Patients with lesions to the right ventrolateral prefrontal cortex (VLPFC) were impaired on context retrieval only when the words had been seen in multiple contexts, demonstrating that this prefrontal region is critical for active retrieval processing necessary to disambiguate memory items embedded across multiple contexts. Patients with lesions to the left dorsomedial prefrontal region were impaired on both context retrieval conditions, regardless of the stability of the stimulus-to-context associations. Conversely, prefrontal lesions sparing the ventrolateral and dorsomedial regions did not impair context retrieval. Only patients with temporal lobe excisions were impaired on basic recognition memory. The results demonstrate a basic contribution of the left dorsomedial frontal region to mnemonic context retrieval, with the VLPFC engaged, selectively, when contextual relations are unstable and require disambiguation.

Regional inactivations of primate ventral prefrontal cortex reveal two distinct mechanisms underlying negative bias in decision making

Dysregulation of the orbitofrontal and ventrolateral prefrontal cortices is implicated in anxiety and mood disorders, but the specific contributions of each region are unknown, including how they gate the impact of threat on decision making. To address this, the effects of GABAergic inactivation of these regions were studied in marmoset monkeys performing an instrumental approach-avoidance decision-making task that is sensitive to changes in anxiety. Inactivation of either region induced a negative bias away from punishment that could be ameliorated with anxiolytic treatment. However, whereas the effects of ventrolateral prefrontal cortex inactivation on punishment avoidance were seen immediately, those of orbitofrontal cortex inactivation were delayed and their expression was dependent upon an amygdala-anterior hippocampal circuit. We propose that these negative biases result from deficits in attentional control and punishment prediction, respectively, and that they provide the basis for understanding how distinct regional prefrontal dysregulation contributes to the heterogeneity of anxiety disorders with implications for cognitive-behavioral treatment strategies.

Emotional discrimination during viewing unpleasant pictures: timing in human anterior ventrolateral prefrontal cortex and amygdala

The ventrolateral prefrontal cortex (VLPFC) and amygdala have critical roles in the generation and regulation of unpleasant emotions, and in this study the dynamic neural basis of unpleasant emotion processing was elucidated by using paired-samples permutation t-tests to identify the timing of emotional discrimination in various brain regions. We recorded the temporal dynamics of blood-oxygen-level-dependent (BOLD) signals in those brain regions during the viewing of unpleasant pictures by using functional magnetic resonance imaging (fMRI) with high temporal resolution, and we compared the time course of the signal within the volume of interest (VOI) across emotional conditions. Results show that emotional discrimination in the right amygdala precedes that in the left amygdala and that emotional discrimination in both those regions precedes that in the right anterior VLPFC. They support the hypotheses that the right amygdala is part of a rapid emotional stimulus detection system and the left amygdala is specialized for sustained stimulus evaluation and that the right anterior VLPFC is implicated in the integration of viscerosensory information with affective signals between the bilateral anterior VLPFCs and the bilateral amygdalae.

Early signs of anomalous neural functional connectivity in healthy offspring of parents with bipolar disorder

OBJECTIVES

Bipolar disorder (BD) has been associated with dysfunctional brain connectivity and with family chaos. It is not known whether aberrant connectivity occurs before illness onset, representing vulnerability for developing BD amidst family chaos. We used resting-state functional magnetic resonance imaging (fMRI) to examine neural network dysfunction in healthy offspring living with parents with BD and healthy comparison youth.

METHODS

Using two complementary methodologies [data-driven independent component analysis (ICA) and hypothesis-driven region-of-interest (ROI)-based intrinsic connectivity], we examined resting-state fMRI data in 8-17-year-old healthy offspring of a parent with BD (n = 24; high risk) and age-matched healthy youth without any personal or family psychopathology (n = 25; low risk).

RESULTS

ICA revealed that, relative to low-risk youth, high-risk youth showed increased connectivity in the ventrolateral prefrontal cortex (VLPFC) subregion of the left executive control network (ECN), which includes frontoparietal regions important for emotion regulation. ROI-based analyses revealed that high-risk versus low-risk youth had decreased connectivities between the left amygdala and pregenual cingulate, between the subgenual cingulate and supplementary motor cortex, and between the left VLPFC and left caudate. High-risk youth showed stronger connections in the VLPFC with age and higher functioning, which may be neuroprotective, and weaker connections between the left VLPFC and caudate with more family chaos, suggesting an environmental influence on frontostriatal connectivity.

CONCLUSIONS

Healthy offspring of parents with BD show atypical patterns of prefrontal and subcortical intrinsic connectivity that may be early markers of resilience to or vulnerability for developing BD. Longitudinal studies are needed to determine whether these patterns predict outcomes.

Neuropharmacological effect of atomoxetine on attention network in children with attention deficit hyperactivity disorder during oddball paradigms as assessed using functional near-infrared spectroscopy

The current study aimed to explore the neural substrate for atomoxetine effects on attentional control in school-aged children with attention deficit hyperactivity disorder (ADHD) using functional near-infrared spectroscopy (fNIRS), which can be applied to young children with ADHD more easily than conventional neuroimaging modalities. Using fNIRS, we monitored the oxy-hemoglobin signal changes of 15 ADHD children (6 to 14 years old) performing an oddball task before and 1.5 h after atomoxetine or placebo administration, in a randomized, double-blind, placebo-controlled, crossover design. Fifteen age-, gender-, and intelligence quotient-matched normal controls without atomoxetine administration were also monitored. In the control subjects, the oddball task recruited the right prefrontal and inferior parietal cortices. The right prefrontal and parietal activation was normalized after atomoxetine administration in ADHD children. This was in contrast to our previous study using a similar protocol showing methylphenidate-induced normalization of only the right prefrontal function. fNIRS allows the detection of differential neuropharmacological profiles of both substances in the attentional network: the neuropharmacological effects of atomoxetine to upregulate the noradrenergic system reflected in the right prefrontal and inferior parietal activations and those of methylphenidate to upregulate the dopamine system reflected in the prefrontal cortex activation.

Neuropharmacological effect of methylphenidate on attention network in children with attention deficit hyperactivity disorder during oddball paradigms as assessed using functional near-infrared spectroscopy

The current study aimed to explore the neural substrate for methylphenidate effects on attentional control in school-aged children with attention deficit hyperactivity disorder (ADHD) using functional near-infrared spectroscopy (fNIRS), which can be applied to young children with ADHD more easily than conventional neuroimaging modalities. Using fNIRS, we monitored the oxy-hemoglobin signal changes of 22 ADHD children (6 to 14 years old) performing an oddball task before and 1.5 h after methylphenidate or placebo administration, in a randomized, double-blind, placebo-controlled, crossover design. Twenty-two age- and gender-matched normal controls without methylphenidate administration were also monitored. In the control subjects, the oddball task recruited the right prefrontal and inferior parietal cortices, and this activation was absent in premedicated ADHD children. The reduced right prefrontal activation was normalized after methylphenidate but not placebo administration in ADHD children. These results are consistent with the neuropharmacological effects of methylphenidate to upregulate the dopamine system in the prefrontal cortex innervating from the ventral tegmentum (mesocortical pathway), but not the noradrenergic system from the parietal cortex to the locus coeruleus. Thus, right prefrontal activation would serve as an objective neurofunctional biomarker to indicate the effectiveness of methylphenidate on ADHD children in attentional control. fNIRS monitoring enhances early clinical diagnosis and the treatment of ADHD children, especially those with an inattention phenotype.

Correspondence of executive function related functional and anatomical alterations in aging brain

Neurocognitive aging studies have focused on age-related changes in neural activity or neural structure but few studies have focused on relationships between the two. The present study quantitatively reviewed 24 studies of age-related changes in fMRI activation across a broad spectrum of executive function tasks using activation likelihood estimation (ALE) and 22 separate studies of age-related changes in gray matter using voxel-based morphometry (VBM). Conjunction analyses between functional and structural alteration maps were constructed. Overlaps were only observed in the conjunction of dorsolateral prefrontal cortex (DLPFC) gray matter reduction and functional hyperactivation but not hypoactivation. It was not evident that the conjunctions between gray matter and activation were related to task performance. Theoretical implications of these results are discussed.

Impaired emotional learning and involvement of the corticotropin-releasing factor signaling system in patients with irritable bowel syndrome

BACKGROUND & AIMS

Alterations in central corticotropin-releasing factor signaling pathways have been implicated in the pathophysiology of anxiety disorders and irritable bowel syndrome (IBS). We aimed to characterize the effects of the corticotropin-releasing factor receptor 1 (CRF-R1) antagonist, GW876008, on brain and skin conductance responses during acquisition and extinction of conditioned fear to the threat of abdominal pain in subjects with IBS and healthy individuals (controls).

METHODS

We performed a single-center, randomized, double-blind, 3-period crossover study of 11 women with IBS (35.50 ± 12.48 years old) and 15 healthy women (controls) given a single oral dose (20 mg or 200 mg) of the CRF-R1 antagonist or placebo. Blood-oxygen level-dependent responses were analyzed using functional magnetic resonance imaging in a tertiary care setting.

RESULTS

Controls had greater skin conductance responses during acquisition than extinction, validating the fear-conditioning paradigm. In contrast, during extinction, women with IBS had greater skin conductance responses than controls-an effect normalized by administration of a CRF-R1 antagonist. Although the antagonist significantly reduced activity in the thalamus in patients with IBS and controls during acquisition, the drug produced greater suppression of blood-oxygen level-dependent activity in a wide range of brain regions in IBS patients during extinction, including the medial prefrontal cortex, pons, hippocampus, and anterior insula.

CONCLUSIONS

Although CRF signaling via CRF-R1 is involved in fear acquisition and extinction learning related to expected abdominal pain in patients with IBS and controls, this system appears to be up-regulated in patients with IBS. This up-regulation might contribute to the previously reported abnormal brain responses to expected abdominal pain.

Factors modulating neural reactivity to drug cues in addiction: a survey of human neuroimaging studies

Human neuroimaging studies suggest that neural cue reactivity is strongly associated with indices of drug use, including addiction severity and treatment success. However, little is known about factors that modulate cue reactivity. The goal of this review, in which we survey published fMRI and PET studies on drug cue reactivity in cocaine, alcohol, and tobacco cigarette users, is to highlight major factors that modulate brain reactivity to drug cues. First, we describe cue reactivity paradigms used in neuroimaging research and outline the brain circuits that underlie cue reactivity. We then discuss major factors that have been shown to modulate cue reactivity and review specific evidence as well as outstanding questions related to each factor. Building on previous model-building reviews on the topic, we then outline a simplified model that includes the key modulatory factors and a tentative ranking of their relative impact. We conclude with a discussion of outstanding challenges and future research directions, which can inform future neuroimaging studies as well as the design of treatment and prevention programs.