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Parietal cortex has long been considered essential for complex executive functions necessary during human decision-making (Mesulam, 1998). Following an introduction, Chapter 2 of this dissertation investigates one particularly pertinent region of parietal cortex called the intraparietal sulcus (IPS) in sensory and abstract decision-making processes. The IPS has been implicated in numerous functions that range from representation of visual stimuli to action planning, but its role in abstract decision-making has been unclear, in part because functions in sensorimotor processing often act as confounds. This thesis addresses this problem using a novel task developed to dissociate abstract decision-making from sensory salience, attentional control, and motor output. Functional MRI data were collected from healthy female and male subjects while they performed a policy abstraction task requiring use of a more abstract (second-order) rule to select between two less abstract (first-order) rules that informed the motor response. By identifying IPS subdivisions with preferential connectivity to prefrontal regions that are differentially responsive to task abstraction, we found that a caudal IPS (cIPS) subregion with strongest connectivity to the pre-premotor cortex (pre-PMd) was preferentially active for second-order cues, while a rostral IPS subregion (rIPS) with strongest connectivity to the dorsal premotor cortex (PMd) was active for attentional control over first-order cues. These effects for abstraction were seen in addition to cIPS activity that was specific to sensory salience, and rIPS activity that was specific to motor output. Notably, topographic responses to the second-order cue were detected along the caudal-rostral axis of IPS, mirroring the broader organization seen in lateral prefrontal cortex . Together these data demonstrate that subregions within IPS exhibit activity responsive to policy abstraction, and they suggest that IPS may be organized into fronto-parietal subnetworks that support hierarchical cognitive control.Chapter 3 next assessed whether parietal areas involved in decision-making vary as a function of strategy. One can perform the same goal-oriented task using different strategies (Morrison, Rosenbaum, Fair, & Chein, 2016). Studies have shown dissimilarities in neural activity for strategies that depend on unique sensory or mnemonic systems (Iaria, Petrides, Dagher, Pike, & Bohbot, 2003), but few have investigated if different strategies in performing a cognitive control task produce activation differences within the fronto-parietal control network if those strategies differ in the form of abstraction. Half of all trials in the same abstract decision-making task developed for this thesis required use of a hierarchically-defined “policy strategy”, and the other half permitted a heterarchical match/nonmatch “comparison strategy” (Badre, 2008). This unique design feature was next used to investigate whether frontal and parietal control regions implicated in policy abstraction differentially represent strategy when it employs different forms of abstraction. Previously collected fMRI data from healthy female and male subjects was re-analyzed. Accuracy was higher for trials allowing the comparison strategy, and a significant behavioral interaction was observed between sensory coherence of the second-order cue and strategy trial type. Across the brain, known decision-making regions for hierarchical policy abstraction tasks had increased activity for the policy strategy, including frontal regions pre-PMd and PMd. A region in the superior frontal sulcus covaried activity with subject strategy use. However, parietal activity did not strongly differentiate between the strategies, suggesting that IPS subregions specifically important for policy abstraction decision information may not preferentially represent control of hierarchical policy abstraction over other non-hierarchical types of task abstraction.Finally, Chapter 4 explores if retained versus removed working memory items are reflected in parietal activity during decision-making. Every discrete decision requires selection from at least two unique options, and in the absence of consistent external representations, those options are held in working memory. As a result, relevant working memory decision items are retained for use in a future motor response while irrelevant items must be removed to reduce retrieval interference (Lewis-Peacock, Drysdale, Oberauer, & Postle, 2012). Parietal cortex and IPS specifically are associated with working memory item representation and control (Chatham, Frank, & Badre, 2014; Cowan et al., 2011; M. D’Esposito et al., 1998), implicating it in possible retention and removal processes during decision-making. To test whether an active process of removal and/or retention exists in parietal cortex, fMRI data collected from the same abstract decision-making task developed for this thesis work were re-analyzed. A subset of the data were selected where second-order cues were presented in position 2 within a trial, effectively acting as a retro-cue for the relevance or irrelevance of the previously presented cue in position 1. Investigating activity at this timepoint would reveal working memory item removal if the previous cue was irrelevant, and retention if the cue was relevant. Hypothesis 1 predicted that parietal cortex would reflect an active process of content unbinding during irrelevant working memory item removal, but results instead suggested that removal may be a latent process that is undetectable via univariate imaging. Hypothesis 2 investigated working memory item retention and predicted that rIPS would increase activity for retaining response-relevant first-order contents while cIPS would not change activity for working memory control of first-order information. Contrary to these hypotheses, results revealed that rIPS did not significantly change activity for working memory item retention of relevant first-order information, while cIPS increased activity at this timepoint. This finding supports an alternative hypothesis that cIPS and rIPS should instead be considered to be primarily engaged with decision-making aspects of the policy abstraction task, and not necessarily implicated in aspects of working memory item retention. Continued research is necessary to further expose the neural underpinnings of working memory item removal and retention.

Increased exploration, risk-taking and reward-seeking are the hallmarks of adolescence. These and related behaviors prepare the young to transition from the parent’s nest to independent living. Adolescence is also a period of heightened structural and functional brain reorganization, particularly within the mesocorticolimbic dopamine system, frontal cortex, striatum and amygdala - an interconnected network of brain regions that supports reward-directed behavior. The goal of this dissertation to further our understanding of ways in which the adolescent brain interacts with rewards. In Chapter 2, I present the results of a set of experiments demonstrating that adolescent rats do not differ from adults in a simple form of stimulus-reward learning but are willing to invest greater effort to obtain larger rewards. While previous studies have focused on the role of neurodevelopmental changes in the dopamine system and within the striatum in heightened reward seeking in adolescence, our data suggest that synaptic remodeling within the frontal cortex and amygdala may also contribute to enhanced reward sensitivity. Chapter 3 explores the long-term consequences of prescription drug exposure during the adolescent period of heightened reward sensitivity in rats. The data suggest that adolescent exposure to both fluoxetine and methylphenidate impairs learning and cognitive flexibility in adulthood in male rats long after the drug administration has been terminated. Adolescent methylphenidate exposure has the direst consequences, impairing both the initial learning and reversal of reward contingencies. The data also reveal sex differences: while females take longer to learn the task, they are also less vulnerable to the negative effects of drug exposure. In Chapter 5, I compare adult and adolescent humans in their approaches to solving the credit assignment problem (i.e., the problem of discovering which choices are responsible for rewards, introduced in Chapter 4). The data provide preliminary evidence for enhanced contingent credit assignment in adolescence. While adults integrate information about their previous decisions and past outcomes to guide their subsequent choices, adolescents are more narrowly focused on the most recent choice-reward history. In Chapter 6, I discuss the implications of the present work and offer cautious advice on drug abuse prevention and improvements in pedagogical practice.

A group of 27 healthy young adults solved a task involving the working memory (WM) activation, consisting of the comparison between the spatial orientations of two sequentially presented square-wave luminance gratings. We investigated the effective (directed) connectivity patterns between the frontal and postcentral cortical regions related to the visual system. The connectivity was assessed using vector autoregression modeling of EEG. It was shown that the strength of the top-down right-hemispheric connectivity patterns directed from the frontal cortex to the visual areas in θ frequency was significantly lower at the stage of stimulus retention in the WM than at the stage of stimulus anticipation. On the contrary, in the α band the descending influences were slightly more intense. The results of the study showed the frequency-dependent dynamics of the descending influences of the frontal cortex on visual areas and confirm that the frontal cortex plays the role of a controlling and modulating center in the brain system underlying WM.

Working memory (WM) supports the persistent representation of transient sensory information. Visual and auditory stimuli place different demands on WM and recruit different brain networks. Separate auditory- and visual-biased WM networks extend into the frontal lobes, but several challenges confront attempts to parcellate human frontal cortex, including fine-grained organization and between-subject variability. Here, we use differential intrinsic functional connectivity from 2 visual-biased and 2 auditory-biased frontal structures to identify additional candidate sensory-biased regions in frontal cortex. We then examine direct contrasts of task functional magnetic resonance imaging during visual versus auditory 2-back WM to validate those candidate regions. Three visual-biased and 5 auditory-biased regions are robustly activated bilaterally in the frontal lobes of individual subjects (N = 14, 7 women). These regions exhibit a sensory preference during passive exposure to task stimuli, and that preference is stronger during WM. Hierarchical clustering analysis of intrinsic connectivity among novel and previously identified bilateral sensory-biased regions confirms that they functionally segregate into visual and auditory networks, even though the networks are anatomically interdigitated. We also observe that the frontotemporal auditory WM network is highly selective and exhibits strong functional connectivity to structures serving non-WM functions, while the frontoparietal visual WM network hierarchically merges into the multiple-demand cognitive system.

Cognitive flexibility is an essential prerequisite for goal-directed behavior, and daily observations already show that it deteriorates when one is engaged in a task for a (too) long time. Yet, the neural mechanisms underlying such fatigability effect in cognitive flexibility are poorly understood. We examined how theta, alpha, and beta frequency event-related synchronization and desynchronization processes during cued memory-based task switching are modulated by time-on-task effects. We put special emphasis on the examination of functional neuroanatomical regions being associated with these modulations, using EEG beamforming. We show clear declines in task switching performance (increased switch costs) with time on task. For processes occurring before rule switching or repetition processes, we show that anticipatory attentional sampling and selection mechanisms associated with fronto-parietal structures are modulated by time-on-task effects but sensory areas (occipital cortex) also show fatigability-dependent modulations. After target stimulus presentation, the allocation of processing resources for response selection as reflected by theta-related activity in parietal cortices is compromised with time on task and similarly a concomitant increase in alpha and beta band-related attentional processing or gating mechanisms in frontal and occipital regions. Yet, considering the behavioral data showing an apparent decline in performance, this probably compensatory increase is still insufficient to allow reasonable performance. The same is likely the case for processes occurring before rule switching or repetition processes. Comparative analyses show that modulations of alpha band activity are as strongly modulated by fatigability as theta band activity. Implications of these findings for theoretical concepts on fatigability are discussed.

Prior research has demonstrated that the frontal lobes play a critical role in the top–down control of behavior, and damage to the frontal cortex impairs performance on tasks that require executive control [Burgess, P. W., & Stuss, D. T. Fifty years of prefrontal cortex research: Impact on assessment. Journal of the International Neuropsychological Society, 23, 755–767, 2017; Stuss, D. T., & Levine, B. Adult clinical neuropsychology: Lessons from studies of the frontal lobes. Annual Review of Psychology, 53, 401–433, 2002]. Across executive functioning tasks, performance deficits are often quantified as the number of false alarms per total number of nontarget trials. However, most studies of frontal lobe function focus on individual task performance and do not discuss commonalities of errors committed across different tasks. Here, we describe a neurocognitive account that explores the link between deficient frontal lobe function and increased false alarms across an array of experimental tasks from a variety of task domains. We review evidence for heightened false alarms following frontal deficits in episodic long-term memory tests, working memory tasks (e.g., n-back), attentional tasks (e.g., continuous performance tasks), interference control tasks (e.g., recent probes), and inhibitory control tasks (e.g., go/no-go). We examine this relationship via neuroimaging studies, lesion studies, and across age groups and pathologies that impact the pFC, and we propose 11 issues in cognitive processing that can result in false alarms. In our review, some overlapping neural regions were implicated in the regulation of false alarms. Ultimately, however, we find evidence for the fractionation and localization of certain frontal processes related to the commission of specific types of false alarms. We outline avenues for additional research that will enable further delineation of the fractionation of the frontal lobes' regulation of false alarms.

The frontal lobes make a significant contribution to the formation of individual personality traits, in connection with which it is important to identify the links between the parameters of the bioelectric activity of the frontal cortex and the indicators of psychological tests. The aim of this work was to study the relationship between the indicators of extraversion and neuroticism of the subjects and the parameters of their EEG. For the first time, differences in these relationships were found at rest and during standard functional tests, without the use of additional specialized loads. The study involved healthy subjects of both sexes, average age 19.3 years; all subjects are right-handed. To identify the level of extraversion and neuroticism, the standard Eysenck test (option B) was used. The EEG was recorded using the bipolar derivation method. 19 electrodes were exposed in accordance with the international Jasper system 1020%. EEG was recorded at rest with eyes closed and during functional tests: eye opening, hyperventilation, photostimulation. The correlation coefficients of the index and absolute power of the EEG with the level of extraversion and neuroticism were calculated both for the entire sample of subjects and for individual groups according to the level of extraversion and the level of neuroticism. For the entire sample of subjects, positive significant correlations of EEG power with the level of extraversion and negative with the level of neuroticism were revealed. In the groups of subjects with high, medium and low levels of extraversion and neuroticism, the differences in correlation relationships with EEG parameters are more pronounced. In these groups, these differences are more often manifested when performing functional tests than at rest with closed eyes.

For many decades in psychology and the history of science the phenomenon of incubation has been known but not fully understood; this is the preparation of a solution to a problem during a period of relative rest. The aim of the present work was to use EEG data to seek patterns of resting state network connectivity during incubation associated with successful postincubation solution of tasks. Subjects carried out a remote associations tests in three stages: a fi rst attempt, incubation (listening to an audio recording irrelevant to solving the task), and a second attempt to solve the unsolved tasks. Subjects who after incubation solved at least one additional task showed a more marked association of the left sensorimotor cortex with the insula and a less marked association with the left dorsolateral frontal cortex during the period of incubation. These data are consistent with the view that at the stage of seeking a solution, the optimum situation is a combination of decreased activity in the executive control network, leading to defocusing of attention, and increased activity in the motivational salience network.

BACKGROUND AND OBJECTIVES Anabolic-androgenic steroid (AAS) use has become a major worldwide substance use disorder, affecting tens of millions of individuals. Importantly, it is now increasingly recognized that some individuals develop uncharacteristically violent or criminal behaviors when using AAS. We sought to summarize available information on this topic. METHODS We reviewed the published literature on AAS-induced behavioral effects and augmented this information with extensive observations from our clinical and forensic experience. RESULTS It is now generally accepted that some AAS users develop uncharacteristically violent or criminal behaviors while taking these drugs. Although these behaviors may partially reflect premorbid psychopathology, sociocultural factors, or expectational effects, accumulating evidence suggests that they are also attributable to biological effects of AAS themselves. The mechanism of these effects remains speculative, but preliminary data suggest a possible role for brain regions involved in emotional reactivity, such as the amygdala and regions involved in cognitive control, including the frontal cortex. For unknown reasons, these effects appear idiosyncratic; most AAS users display few behavioral effects, but a minority develops severe effects. CONCLUSION AND SCIENTIFIC SIGNIFICANCE Professionals encountering AAS users in clinical or forensic settings should be alert to the possibility of AAS-induced violence or criminality and should employ strategies to assess whether AAS is indeed a contributory factor in a given case. Further research is needed to elucidate the mechanism of AAS-induced violence and to explain why only a subset of AAS users appears vulnerable to these effects. (Am J Addict 2021;00:00-00).

Moving the hands or chewing in the encoding stage enhances memory, because body movement activates the frontal cortex, which is crucial to the memory process. However, how hand movement facilitates...

Identifying performance-based assessments of emotion regulation is needed for the study of myriad mood and neurological disorders. Color and form responses on the Rorschach Inkblot Method are valid measures of emotion response control, but have not been studied in relation to known neural correlations of emotion regulation. A discrepancy of color (CF + C) greater than form (FC) responses suggests low cognitive control over emotional responses. This preliminary report explores the discrepancy between form-color responses as a correlate of regional cortical thickness. A sample of community-dwelling adults were administered the Rorschach Inkblot Method and participated in a structural MRI scan. Greater middle frontal cortex thickness was associated with a positive discrepancy score [(CF + C) - FC], indicating less emotion response control (rs = 0.48, p

Psychological and physiological features of gifted schoolchildren in the context of the general tendency towards learning intensification and excessive use of technical means of learning determine their extreme sensitivity to the factors of the educational environment. The introduction of a meritocratic education system requires checking the compliance between the educational process organization and the psychological and physiological schoolchildren capabilities. This article describes the study on the comparison of neurocognitive processes of the secondary school pupils (10-11 years) in meritocratic (n = 60) and traditional (n = 26) educational systems based on the comparison of the relative spectral power of the electroencephalogram (EEG) frequency bands at rest state and cognitive load (mental arithmetic with subtraction). EEG potentials were led monopolarly from 21 locus according to the international system "10-20" using the average reference electrode. Artefact-free EEG datasets of 35–45 s length were registered and analyzed. The common characteristics of EEG patterns taken from the schoolchildren at meritocratic education include a significantly higher proportion of alpha activity in the frontal cortex and beta-2 activity throughout the convex cerebral surface at rest and cognitive load. Mental arithmetic caused changes in all EEG frequency bands, mainly in the frontoparietal network in the condition under meritocratic education, while under traditional education the changes were mainly registered in the delta band in the temporal and parietal cerebral cortex. We have found out that schoolchildren in the meritocratic system are characterized by a higher level of cerebral functional maturity and demonstrate more mature activation patterns of cortical structures during the mental arithmetic testing. This indicates the beneficial developmental impact of meritocratic education.

Visually guided behavior begins with inputs to sensory cortices, but the decision to initiate actions engages the frontal cortex. A new study dissects a microcircuit for visual-to-motor transformation in the anterior cingulate cortex of the mouse with implications for impulsivity and disease states.

Summary To navigate social environments, people must simultaneously hold representations about their own and others’ abilities. During self-other mergence, people estimate others’ abilities not only on the basis of the others’ past performance, but the estimates are also influenced by their own performance. For example, if we perform well, we overestimate the abilities of those with whom we are co-operating and underestimate competitors. Self-other mergence is associated with specific activity patterns in the dorsomedial prefrontal cortex (dmPFC). Using a combination of non-invasive brain stimulation, functional magnetic resonance imaging, and computational modeling, we show that dmPFC neurostimulation silences these neural signatures of self-other mergence in relation to estimation of others’ abilities. In consequence, self-other mergence behavior increases, and our assessments of our own performance are projected increasingly onto other people. This suggests an inherent tendency to form interdependent social representations and a causal role of the dmPFC in separating self and other representations., Highlights • During self-other mergence (SOM), people confuse one’s own with another’s performance • Brain stimulation over dorsomedial prefrontal cortex (dmPFC) alters neural SOM • Brain stimulation over dmPFC simultaneously alters behavioral SOM • This suggests a causal role of dmPFC in separating self and other representations, Wittmann et al. find that, after disrupting activity in the dorsomedial prefrontal cortex, humans merge performance estimates concerning other people with performance estimates about themselves. This suggests that representations of self and others are inherently interlinked and that intact dmPFC activity is needed for separating the two.

The self-defeating humor style is characterized by the excessive use of self-mockery, fawning over others and ineffective denial of negative emotions. The differences in brain structures responsible for self-defeating humor and the role of divergent thinking (DT) in this relationship have not been directly investigated in a large sample. Using voxel-based morphometry (VBM), we identified the association between regional gray matter volume (GMV) and self-defeating humor (assessed by the Humor Style Questionnaire) in 284 participants. Then, the role of DT (assessed by the Torrance Tests of Creative Thinking, TTCT) in the relationship between humor and the related brain regions was examined in the participants (N = 280). The results showed that self-defeating humor was significantly positively associated with the regional GMV in the left orbital frontal cortex (OFC) and that DT had a moderating effect on this relationship. Among the individuals with higher DT, a strong positive correlation was observed between self-defeating humor and the OFC, but among individuals with lower DT, this correlation was weaker. These results reveal that the interaction between brain structures and DT plays an important role in humor, thus providing new evidence enhancing our understanding of the mechanism of humor.

Consciously and subliminally processed information can both lead to conflicts that hinder goal-directed behaviour. Conflict monitoring processes are required to cope with situations where one or multiple conflicts occur. It has been suggested, that medial-frontal theta oscillations are associated with the implementation of cognitive control and that conflicts increase theta band activity. Still, a causal mechanistic understanding of theta oscillations during the resolution of combined subliminal and conscious conflicts is missing. To investigate this, we combined EEG signal decomposition methods with EEG beamforming approaches and used the obtained information to modulate theta oscillations with tACS in a second experiment. This showed that theta oscillations in the superior frontal cortex (BA6) and the left paracentral lobule encoded stimulus-related processes during the resolution of conflicts arising from both conscious and subliminal information processing. Response selection and motor-related processes encoded by theta oscillations were not similarly modulated. Thus, the joint modulation of conflicts by conscious and subliminal information affects very specific aspects of the information coded in theta oscillations. Results indicate, that entraining theta-oscillations using tACS modulates conflict resolution depending on the already existing theta activity level. In summary, the study provides further evidence that frontal theta oscillations play a crucial role in conflict monitoring and control.

Decades of electrophysiological research on top–down control converge on the role of the lateral frontal cortex in facilitating attention to behaviorally relevant external inputs. However, the involvement of frontal cortex in the top–down control of attention directed to the external versus internal environment remains poorly understood. To address this, we recorded intracranial electrocorticography while subjects directed their attention externally to tones and responded to infrequent target tones, or internally to their own thoughts while ignoring the tones. Our analyses focused on frontal and temporal cortices. We first computed the target effect, as indexed by the difference in high frequency activity (70–150 Hz) between target and standard tones. Importantly, we then compared the target effect between external and internal attention, reflecting a top–down attentional effect elicited by task demands, in each region of interest. Both frontal and temporal cortices showed target effects during external and internal attention, suggesting this effect is present irrespective of attention states. However, only the frontal cortex showed an enhanced target effect during external relative to internal attention. These findings provide electrophysiological evidence for top–down attentional modulation in the lateral frontal cortex, revealing preferential engagement with external attention.

Several recent studies have interpreted multivariate evidence for stimulus-specific patterns of activity in parietal and/or frontal cortex as evidence for a representational function in those regions that is qualitatively similar to the representational functions of the visual system. Here we argue that although evidence that a brain system takes on a different configuration for each stimulus in a stimulus set is a necessary property for that system having a role in perceptual representation, such evidence is not specific for this function. Drawing on several recent examples from the recent literature, we offer alternative accounts for understanding stimulus-specificity in parietal and frontal cortex that are consistent with longstanding ideas that activity these regions is best understood as implementing control-related, rather than inherently representational, functions.

The use of allocentric cues for movement guidance is complex because it involves the integration of visual targets and independent landmarks and the conversion of this information into egocentric commands for action. Here, we focus on the mechanisms for encoding reach targets relative to visual landmarks in humans. First, we consider the behavioral results suggesting that both of these cues influence target memory, but are then transformed-at the first opportunity-into egocentric commands for action. We then consider the cortical mechanisms for these behaviors. We discuss different allocentric versus egocentric mechanisms for coding of target directional selectivity in memory (inferior temporal gyrus versus superior occipital gyrus) and distinguish these mechanisms from parieto-frontal activation for planning egocentric direction of actual reach movements. Then, we consider where and how the former allocentric representations of remembered reach targets are converted into the latter egocentric plans. In particular, our recent neuroimaging study suggests that four areas in the parietal and frontal cortex (right precuneus, bilateral dorsal premotor cortex, and right presupplementary area) participate in this allo-to-ego conversion. Finally, we provide a functional overview describing how and why egocentric and landmark-centered representations are segregated early in the visual system, but then reintegrated in the parieto-frontal cortex for action.

Structural modifications in the dendritic morphology of neurons occur following many forms of experience, including exposure to drugs, complex housing, and training in specific behavioral tasks. The present study examined morphological changes in orbitofrontal (OFC) and medial prefrontal cortex (mPFC) neurons of female rats following experience with a variety of social partners or nonsocial olfactory stimuli. We reasoned that experience with various social partners or olfactory stimuli, and the associated behavioral adaptations, would drive structural modifications in prefrontal cortex neurons engaged by these stimuli. Social experience was manipulated by providing rats with a novel cage-mate or housing the animal with the same cage-mate throughout the study. Similarly, olfactory experience was manipulated by introducing novel, nonsocial odors in the home cage or exposing the animals to the same home-cage odor throughout the study. Both forms of experience resulted in altered dendritic morphology in OFC neurons, whereas morphological changes in mPFC were comparatively small and limited to changes in spine density. These observations indicate that OFC and mPFC neurons respond differently to social and nonsocial olfactory stimulation in adulthood and join the growing body of data illustrating differential effects of experience on structural plasticity in OFC and mPFC. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

The anterior cingulate cortex (ACC) is implicated in effort exertion and choices based on effort cost, but it is still unclear how it mediates this cost-benefit evaluation. Here, male rats were trained to exert effort for a high-value reward (sucrose pellets) in a progressive ratio lever pressing task. Trained rats were then tested in two conditions: a no-choice condition where lever pressing for sucrose was the only available food option, and a choice condition where a low-value reward (lab chow) was freely available as an alternative to pressing for sucrose. Disruption of ACC—via either chemogenetic inhibition or excitation—reduced lever pressing in the choice, but not in the no-choice, condition. We next looked for value coding cells in ACC during effortful behavior and reward consumption phases during choice and no-choice conditions. For this, we utilized in vivo miniaturized fluorescence microscopy to reliably track responses of the same cells and compare how ACC neurons respond during the same effortful behavior where there was a choice versus when there was no-choice. We found that lever-press and sucrose-evoked responses were significantly weaker during choice compared to no-choice sessions, which may have rendered them more susceptible to chemogenetic disruption. Taken together, findings from our interference experiments and neural recordings suggest that a mechanism by which ACC mediates effortful decisions is in the discrimination of the utility of available options. ACC regulates these choices by providing a stable population code for the relative value of different options.Significance StatementThe anterior cingulate cortex (ACC) is implicated in effort-based decision making. Here, we used chemogenetics and in vivo calcium imaging to explore its mechanism. Rats were trained to lever press for a high-value reward and tested in two conditions: a no-choice condition where lever pressing for the high-value reward was the only option, and a choice condition where a low-value reward was also available. Inhibition or excitation of ACC reduced effort toward the high value option, but only in the choice condition. Neural responses in ACC were weaker in the choice compared to the no-choice condition. A mechanism by which ACC regulates effortful decisions is in providing a stable population code for the discrimination of the utility of available options.

Introduction. Agrammatism is a disorder of grammatical structure due to damage to the dominant hemisphere of the brain. Despite numerous studies, the nature of agrammatism has not yet been elucidated. Objective. We aimed to determine the anatomical-clinical correlation of agrammatic aphasia, its characteristics and approaches to treatment. Methods. We accessed electronic databases of Serbian libraries and search engines on the Internet. Printed literature at the University Library in Belgrade was also used. Results. Analysis of the anatomical-clinical correlation of agrammatism showed higher activation of anterior and posterior areas of the brain during the production of verbs with a complex structure of arguments. The lower left frontal cortex plays a primary role in the production of grammatical sentences, while the temporoparietal cortex participates in the lexical processing of the argument structure of verbs and plays a key role in semantic integration. The key features of agrammatism in aphasia are impaired syntactic processing and difficulties in using verbs with a complex argument structure. We pointed out the approaches to the treatment of agrammatism which involve practicing the metalinguistic properties of verbs in terms of their arguments. Conclusion. Although agrammatism is primarily associated with lesions of the frontal cortex, damage to posterior cortical areas also contributes to its occurrence. Deficits in syntactic processing and difficulties in the use of verbs with a complex argument structure are at the heart of agrammatic aphasia. The treatment of agrammatism aims to recover the knowledge of verbs in terms of argument structure and semantic thematic roles.

In the last years, some studies have shown that behavior disorder seems in frontotemporal dementia is related to dysfunction in the fronto-subcortical circuitry. Objectives: We did a narrative literature review concerning fronto-subcortical circuitry and frontotemporal dementia (FTD). Methods: Manuscripts related to fronto-subcortical network and frontotemporal dementia were selected for further analysis. Results: From the executions of simple motor actions to the most complex behaviors like goal-direct behavior and social cognition, the fronto-subcortical circuitry involves an intrigued network of fibers that reaches to basal ganglia nuclei. Recently, researchers have shown five parallel fronto-subcortical circuits integrating and segregating information from the frontal cortex to basal ganglia. Understanding the relationship between the fronto-subcortical circuit dysfunctions and neurodegenerative diseases requires studying the functional anatomy and neurochemical basis involved. Conclusions: In this view, it is essential to review the functional anatomy of the fronto-subcortical network, and it’s correlated with clinical aspects to pursuing a better therapeutic approach.

Neurons in frontal and parietal cortex encode task variables during decision-making, but causal manipulations of the two regions produce strikingly different results. For example, silencing the posterior parietal cortex (PPC) in rats and monkeys produces minimal effects in perceptual decisions requiring integration of sensory evidence, but silencing frontal cortex profoundly impairs the same decisions. Here, we tested the causal roles of the rat frontal orienting field (FOF) and PPC in economic choice under risk. On each trial, rats chose between a lottery and a small but guaranteed surebet. The magnitude of the lottery was independently varied across trials and was indicated to the rat by the pitch of an auditory cue. As in perceptual decisions, both unilateral and bilateral PPC muscimol inactivations produced minimal effects. FOF inactivations produced substantial changes in behavior even though our task had no working memory component. We quantified control and bilateral inactivation behavior with a multi-agent model consisting of a mixture of a ‘rational’ utility-maximizing agent (U=Vρ) with two ‘habitual’ agents that either choose surebet or lottery. Effects of FOF silencing were best accounted for by a decrease inρ, the exponent of the utility function. The decrease inρcould be parsimoniously explained by a dynamical model where the FOF is part of a network that represents the value of the lottery to compare against a remembered boundary representing the value of the surebet. This dynamical model predicted that neurons in the FOF should increase their activity with increasing lottery values. In line with our predictions, single neurons recorded in the FOF encoded the value of the lottery even when controlling for choice. These results together demonstrate that FOF is a critical node in the neural circuit for decision under risk.