Processing Of Affective Stimuli Research Articles

Strong somatic stimulation differentially regulates the firing properties of prefrontal cortex neurons

Among the brain structures involved in processing affective stimuli, the roles of the prefrontal cortex (PFC) and the mesocorticolimbic dopaminergic (DA) innervation are well established. In contrast to our understanding of the reward stimuli, less is known about how strong somatic stimulation is processed within the PFC. Here, we examined the effects of a strong pinch delivered to the rat posterior paw on spontaneous and current-evoked activity of PFC neurons using intracellular recordings in anesthetized rats. Following the paw pinch, pyramidal cells exhibited a significant decrease in spontaneous activity along with a significant increase in the current-evoked firing. The increase in current-evoked firing elicited by the paw pinch was inversely correlated with the baseline firing rate. Systemic administration of a selective dopamine D2 receptor antagonist partially blocked the effects elicited by the paw pinch on cortical excitability, whereas systemic administration of a D1 antagonist seems to facilitate paw-mediated increases in evoked firing. These results suggest that strong somatic stimuli decrease spontaneous firing while increasing depolarization-evoked firing in a DA receptor dependent manner. These mechanisms may help in the control of the signal to noise ratio or the salience of information processing in the PFC following strong somatic stimulation.

Early Processing of Threat Cues in Posttraumatic Stress Disorder—Evidence for a Cortical Vigilance-Avoidance Reaction

The present study investigated the influence of posttraumatic stress disorder (PTSD) on early visual processing of affective stimuli in survivors of war and torture. Trauma-exposed refugees with (n = 36) and without (n = 21) PTSD as well as unexposed control subjects (n = 16) participated in a magnetoencephalography study with pictures that varied in emotional content. We found evidence for a biphasic cortical response in patients with PTSD in comparison with the two control groups. In response to aversive (relative to neutral or positive) pictures, PTSD patients showed elevated cortical activity over right prefrontal areas as early as 130-160 msec after stimulus onset followed by a decrease of the affect-related response in the parieto-occipital cortex at 206-256 msec. The increased early activity in the right prefrontal cortex most likely represents an enhanced alarm response or the fear network toward aversive stimuli in PTSD, whereas the subsequent decreased activation in right parieto-occipital areas in response to aversive pictures seems to reflect the tendency to disengage from emotional content. This finding is consistent with the hypothesis of a vigilance-avoidance reaction pattern to threat in anxiety disorders and helps to reconcile contradicting results of over- and under-responsiveness in the sensory processing of threatening stimuli in PTSD.

Mindfulness and psychological process.

The author reviews the articles in the Special Section on Mindfulness, starting from the assumption that emotions evolved as signaling systems that need to be sensitive to environmental contingencies. Failure to switch off emotion is due to the activation of mental representations of present, past, and future that are created independently of external contingencies. Mindfulness training can be seen as one way to teach people to discriminate such "simulations" from objects and contingencies as they actually are. The articles in this Special Section show how even brief laboratory training can have effects on processing affective stimuli; that long-term meditation practitioners show distinct reactions to pain; that longer meditation training is associated with differences in brain structure; that 8 weeks' mindfulness practice brings about changes in the way emotion is processed showing that participants can learn to uncouple the sensory, directly experienced self from the "narrative" self; that mindfulness training can affect working memory capacity, and enhance the ability of participants to talk about past crises in a way that enables them to remain specific and yet not be overwhelmed. The implications of these findings for understanding emotion and for further research is discussed.

Effects of alcohol on cognitive control: MEG analysis in temporal and spectral domains

Event Abstract Back to Event Effects of alcohol on cognitive control: MEG analysis in temporal and spectral domains Sanja Kovacevic1*, Sheeva Azma2, Jason Sherfey1, Sarah Sheldon1, Andrei Irimia1 and Ksenija Marinkovic1 1 Univ. California San Diego, Radiology, United States 2 Georgetown University, United States Moderate alcohol intoxication impairs executive functions as it interferes with the ability to evaluate competing demands of a task, inhibit maladaptive responses, and apply the necessary behavioral adjustments. In order to examine effects of alcohol on spatio-temporal processing stages of cognitive control in both time- and frequency-domains, we used anatomically-constrained magnetoencephalography (aMEG). 306 channels of the MEG signal were recorded from the whole head (Elekta Neuromag). Noise-normalized distributed minimum norm inverse solutions were constrained to each person’s cortical surface reconstructed from anatomical MRI scans and averaged across subjects. Source estimates of broadband frequency power were obtained with wavelet method. Healthy subjects took part in both alcohol (0.6 g/kg ethanol for men, 0.55 g/kg women) and placebo conditions as they participated in a modified Stroop task that combined reading and color naming of color-related and non-color words. Strong Stroop interference effect was reflected in lower accuracy and longer response times (RTs) on incongruent trials. Alcohol increased error rates overall, without affecting RTs. The overall activation spread along the ventral visual pathway into left temporal and prefrontal areas. Incongruous stimuli activated the anterior cingulate and dorsolateral prefrontal areas more than other stimuli, in agreement with their executive contributions. Alcohol decreased early activity in the visual areas (~90 ms) and it attenuated the anterior cingulate activation during conflict detection and response stages. Spectral analysis of the baseline period indicated alcohol-induced changes of power in lower frequency bands. Alcohol affects stimulus processing, conflict monitoring and response execution stages during the Stroop interference task. The resulting impairment of executive function may result in poor self-control, with an inability to refrain from drinking contributing to alcohol dependence. Conference: Biomag 2010 - 17th International Conference on Biomagnetism , Dubrovnik, Croatia, 28 Mar - 1 Apr, 2010. Presentation Type: Poster Presentation Topic: Neurocognition and Functional Connectivity Citation: Kovacevic S, Azma S, Sherfey J, Sheldon S, Irimia A and Marinkovic K (2010). Effects of alcohol on cognitive control: MEG analysis in temporal and spectral domains. Front. Neurosci. Conference Abstract: Biomag 2010 - 17th International Conference on Biomagnetism . doi: 10.3389/conf.fnins.2010.06.00420 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 09 Apr 2010; Published Online: 09 Apr 2010. * Correspondence: Sanja Kovacevic, Univ. California San Diego, Radiology, San Diego, United States, skovacevic@ucsd.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Sanja Kovacevic Sheeva Azma Jason Sherfey Sarah Sheldon Andrei Irimia Ksenija Marinkovic Google Sanja Kovacevic Sheeva Azma Jason Sherfey Sarah Sheldon Andrei Irimia Ksenija Marinkovic Google Scholar Sanja Kovacevic Sheeva Azma Jason Sherfey Sarah Sheldon Andrei Irimia Ksenija Marinkovic PubMed Sanja Kovacevic Sheeva Azma Jason Sherfey Sarah Sheldon Andrei Irimia Ksenija Marinkovic Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Alterations in the processing of non-drug-related affective stimuli in abstinent heroin addicts

Long-term exposure to drug may alter the neural system associated with affective processing, as evidenced by both clinical observations and behavioral data documenting dysfunctions in emotional experiences and processing in drug addicts. Although many imaging studies examined neural responses to drug or drug-related cues in addicts, there have been few studies explicitly designed to reveal their neural abnormalities in processing non-drug-related natural affective materials. The present study asked abstinent heroin addicts and normal controls to passively view standardized affective pictures of positive, negative, or neutral valence and compared their brain activities with functional MRI. Compared to normal controls, addicts showed reduced activation in right amygdala in response to the affective pictures, consistent with previous reports of blunted subjective experience for affective stimuli in addicts. Furthermore, in two visual cortical areas BA 19 and 37, while the controls showed greater responses to positive pictures than to negative ones replicating literature findings, the addicts showed the opposite pattern. The results reveal a complex pattern of altered processing of non-drug-related affective materials in addicts showing both heightened and blunted neural responses in different brain regions and for different stimulus valence. The present study highlights the importance of brain imaging research on drug addicts' processing of affective stimuli in understanding disruptions in their emotion circuitry.

Short-term antidepressant treatment modulates amygdala response to happy faces

We have previously demonstrated that antidepressant medication facilitates the processing of positive affective stimuli in healthy volunteers. These early effects of antidepressants may be an important component in the therapeutic effects of antidepressant treatment in patients with depression and anxiety. Here we used functional magnetic resonance imaging in a double-blind, randomised, placebo-controlled between-groups design to investigate the effects of short-term (7-10 days) treatment with the selective serotonin reuptake inhibitor, citalopram, on the amygdala response to positive and negative facial expressions in healthy volunteers. Citalopram was associated with increased amygdala activation to happy faces relative to placebo control, without changes in levels of mood or anxiety. These early, direct effects of antidepressant administration on emotional processing are consistent with a cognitive neuropsychological model of antidepressant action.

A model comparison of COMT effects on central processing of affective stimuli

The number of studies on imaging genetics has risen considerably over the last few years, and haplotypes are being increasingly applied as a model to increase the explained variance in functional brain activation. Haplotypes, however, are not always the preferable approach. While such highly complex models have a greater capacity for fitting data, they might also lead to over-fitting. This study compares individual single nucleotide polymorphisms (SNPs) with haplotypes by applying both models to effects of catechol-O-methyltransferase (COMT), one of the most extensively studied genes in psychiatric research and imaging genetics, on the central processing of affective cues. To our knowledge, this is the first study to compare haplotypes and SNPs of the COMT gene in an imaging genetics study. The model comparison in this study is based on the Akaike Information Criterion (AIC) and the Bayesian Information Criterion (BIC), introducing the novel concepts of posterior evidence ratio maps and best model maps. Findings reveal the simplest model, comprising only the well studied COMT Val158Met polymorphism, to be the most informative one. These results do not necessarily mean that haplotype models are in general inferior to individual SNP analysis. They do underline, however, that techniques for model comparison such as the ones used in this study need to be employed to establish whether the increase in likelihood provided by a more complex haplotype-based model is large enough to warrant the increase in model complexity.

Spatial gradient for unique-feature detection in patients with unilateral neglect: Evidence from auditory and visual search

Patients with unilateral spatial neglect following right hemisphere damage are impaired in detecting contralesional targets in both visual and haptic search tasks, and often show a graded improvement in detection performance for more ipsilesional spatial locations. In audition, multiple simultaneous sounds are most effectively perceived if they are distributed along the frequency dimension. Thus, attention to spectro-temporal features alone can allow detection of a target sound amongst multiple simultaneous distracter sounds, regardless of whether these sounds are spatially separated. Spatial bias in attention associated with neglect should not affect auditory search based on spectro-temporal features of a sound target. We report that a right brain damaged patient with neglect demonstrated a significant gradient favouring the ipsilesional side on a visual search task as well as an auditory search task in which the target was a frequency modulated tone amongst steady distractor tones. No such asymmetry was apparent in the auditory search performance of a control patient with a right hemisphere lesion but no neglect. The results suggest that the spatial bias in attention exhibited by neglect patients affects stimulus processing even when spatial information is irrelevant to the task.

A Double Dissociation in the Roles of Serotonin and Mood in Healthy Subjects

BackgroundAffective disorders are associated with altered cognitive performance. However, the precise interaction between affect and cognition is unclear. The manipulation of serotonin (5-HT), a neurotransmitter implicated in affect, influences performance on “hot” cognitive tasks that require the processing of affective stimuli, but manipulation of affect via mood induction influences performance on “cold” cognitive tasks that do not involve affective stimuli. We attempted to disentangle the influence of affect on cognition by examining the effect of manipulating both serotonin (via acute tryptophan depletion [ATD]) and mood on established hot and cold cognitive tasks.MethodsIn a double blind, placebo-controlled crossover design, 33 healthy mood-induced (positive, negative, or neutral) subjects completed the (hot) affective go/no-go (AGNG) and (cold) one touch tower (OTT) following both placebo and ATD.ResultsMood influenced performance on the OTT but not AGNG; ATD influenced performance on the AGNG but not OTT.ConclusionsA double dissociation was demonstrated between the influence of ATD and mood on cognition, indicating that serotonin and mood are not closely linked. We hypothesize that this is due to the differences between emotions and moods and that aberrant cognition in affective disorders may be provoked through both bottom-up and top-down mechanisms.

A Middle‐Aged Female Serial Killer

The case of a 48-year-old woman accused of killing at least 12 elderly women and attempting to kill another one during the last 3 years is presented. Extensive neuropsychological, electrophysiological, and neuropsychiatric testing showed no evidence of a DSM-IV-TR Axis I diagnosis, but a decrease in executive functions and abnormalities in the processing of affective stimuli were found. Behavioral and psychophysiological studies revealed dissociation between knowing how to behave and actually behaving in socially acceptable ways. According to the woman, killing was just her response to "humiliating situations." Two potentially significant conditions in her past history are found: (i) childhood abuse; and (ii) multiple head injuries. It is conjectured that the nature of her crimes, paranoid and personality traits, a probable frontal brain dysfunction, as well as a specific demographic and social context represent unusual factors accounting for her violent behavior.

Subliminal processing of smoking-related and affective stimuli in tobacco addiction.

Cognitive processing biases toward smoking-related and affective cues may play a role in tobacco dependence. Because processing biases may occur outside conscious awareness, the current study examined processing of smoking-related and affective stimuli presented at subliminal conditions. A pictorial subliminal repetition priming task was administered to three groups: (1) Nonsmokers (n = 56); (2) Smokers (> or =10 cigarettes/day) who had been deprived from smoking for 12 h (n = 47); and (3) Nondeprived smokers (n = 66). Prime stimuli were presented briefly (17 ms) and were followed by a mask (to render them unavailable to conscious awareness) and then a target. Participants were required to make a speeded classification to the target. A posttask awareness check was administered to ensure that participants could not consciously perceive the briefly presented primes (i.e., smoking paraphernalia, neutral office supplies, and happy, angry, and neutral facial expressions). The groups differed in the degree to which they exhibited a processing bias for smoking-related stimuli, F(2, 166) = 4.99, p = .008. Deprived smokers exhibited a bias toward processing smoking (vs. neutral office supply) stimuli, F(1, 46) = 5.67, p = .02, whereas nondeprived smokers and nonsmokers did not (ps > .22). The three groups did not differ in the degree to which they exhibited a subliminal processing bias for affective stimuli. Tobacco deprivation appears to increase smokers' subliminal processing of smoking-related (vs. neutral) stimuli but does not influence subliminal processing of affective stimuli. Future research should investigate whether subliminal biases toward smoking-related stimuli influence relapse.

Serotonin and emotional processing: Does it help explain antidepressant drug action?

There is growing interest in the effects of antidepressant drug treatment on measures of emotional processing. Such actions may help us understand the role of monoamines in emotional dysfunction in depression and how antidepressant drug treatments work. Recent studies suggest that decreasing central serotonin function with tryptophan depletion can reinstate negative biases in recovered depressed patients, even at doses insufficient to induce changes in mood. Conversely, antidepressant drug administration increases the processing of positive emotional information in healthy volunteers and acutely depressed patients early in treatment. This increase in positive bias may provide a platform for subsequent cognitive restructuring and learning which contributes to the evolution of symptom change in depression. Functional neuroimaging studies suggest that these early antidepressant effects involve fronto-limbic and extra-striate circuitry suggestive of actions on both the initial appraisal and attentional processing of affective stimuli. This approach may therefore provide a framework for linking psychological and biological processes in emotional disorders and their treatment. Antidepressants may not directly modulate mood and anxiety but rather allow a different perspective for our ongoing evaluation of our self, the world and the future.

Genotype effects on central processing of affective stimuli

In neuropsychiatric disorders, serotonergic dysfunction may contribute to negative affect in alcoholism and major depression, while dysfunction of central dopaminergic neurotransmission has been associated with motivational disorders in addiction and schizophrenia. Animal experiments revealed that 1) neurodevelopmentally early social isolation stress exposure is associated with altered serotonin turnover and transporters and 2), neurodevelopmentally early lesion of the temporolimbic cortex is associated with increased striatal dopamine release. In human studies, dopamine and serotonin transporters and receptors interact with central processing of reward-indicating and affectively positive and negative stimuli, and specific alterations in these interactions can be observed in schizophrenic, alcoholics and affective disorders. Monoamine effects on central processing of emotionally salient stimuli are genetically influenced, and besides single gene effect, gene-gene interactions have been postulated. Additive gene-gene effects are often assumed but difficult to test in behavioral genetics due to the small explained behavioral variance. Processing of unpleasant stimuli in the amygdala has been associated with a functional polymorphism (val158-met) in the catechol-O-methyltransferase (COMT) gene and independently with a functional polymorphism in the regulatory region of the serotonin transporter (5-HTT) gene. 5-HTT function may also be affected by a recently detected A/G exchange in the long allele (insertion) of the 5-HTT regulatory region. In individuals with more COMT met158 alleles and with more s or lG alleles of the 5-HTT regulatory region, aversive stimuli elicited greater neuronal activity in the bilateral amygdalae and hippocampi. These genotype effects were additive on amygdala and hippocampus activation by aversive versus neutral stimuli, indicating that COMT val158-met and 5-HTT genotype were additively associated with increased processing of aversive stimuli in the amygdalae. Functional brain imaging may be used to assess the interaction of multiple genotypes on neuronal activation in neuropsychiatric disorders.

The neurophysiological bases of emotion: An fMRI study of the affective circumplex using emotion‐denoting words

We aimed to study the neural processing of emotion-denoting words based on a circumplex model of affect, which posits that all emotions can be described as a linear combination of two neurophysiological dimensions, valence and arousal. Based on the circumplex model, we predicted a linear relationship between neural activity and incremental changes in these two affective dimensions. Using functional magnetic resonance imaging, we assessed in 10 subjects the correlations of BOLD (blood oxygen level dependent) signal with ratings of valence and arousal during the presentation of emotion-denoting words. Valence ratings correlated positively with neural activity in the left insular cortex and inversely with neural activity in the right dorsolateral prefrontal and precuneus cortices. The absolute value of valence ratings (reflecting the positive and negative extremes of valence) correlated positively with neural activity in the left dorsolateral and medial prefrontal cortex (PFC), dorsal anterior cingulate cortex, posterior cingulate cortex, and right dorsal PFC, and inversely with neural activity in the left medial temporal cortex and right amygdala. Arousal ratings and neural activity correlated positively in the left parahippocampus and dorsal anterior cingulate cortex, and inversely in the left dorsolateral PFC and dorsal cerebellum. We found evidence for two neural networks subserving the affective dimensions of valence and arousal. These findings clarify inconsistencies from prior imaging studies of affect by suggesting that two underlying neurophysiological systems, valence and arousal, may subserve the processing of affective stimuli, consistent with the circumplex model of affect.

Additive effects of serotonin transporter and tryptophan hydroxylase-2 gene variation on neural correlates of affective processing

Individual differences in brain response to emotional stimuli have previously been associated with gene variations within the serotonin transporter ( 5-HTT) and tryptophan hydroxylase-2 ( TPH2) genes. We recently reported that these two genes exhibit an additive effect, based on recordings of event-related potentials (ERPs) from individuals viewing emotional scenes. The current study was designed to replicate and extent this initial report in an independent study sample, and use functional magnetic resonance imaging (fMRI) to identify specific neural loci that may mediate the 5-HTT– TPH2 additive effect. Furthermore, we sought to obtain convergent evidence for a gene–gene additive effect by collecting fMRI data from the same individuals engaged in two different cognitive-affective tasks, using emotional and neutral facial expressions and word stimuli. We found evidence for an additive effect of 5-HTT– TPH2 genotype, which was most robust in the putamen, a region rich in both 5-HTT and TPH2 protein, but was also observed in the amygdala at a less stringent threshold, and in other cortical regions. The additive effect was more robust effect for visuospatial than for verbal stimuli, and more robust for negatively than for positively valenced stimuli. These findings confirm and extend the additive effect of two critical genes in the serotonergic regulation of neural processing of affective stimuli, and identify the striatum as a critical site where is gene–gene regulation takes place.

Ratio of dopamine synthesis capacity to D2 receptor availability in ventral striatum correlates with central processing of affective stimuli

Dopaminergic neurotransmission in the ventral striatum may interact with limbic processing of affective stimuli, whereas dorsal striatal dopaminergic neurotransmission can affect habitual processing of emotionally salient stimuli in the pre-frontal cortex. We investigated the dopaminergic neurotransmission in the ventral and dorsal striatum with respect to central processing of affective stimuli in healthy subjects. Subjects were investigated with positron emission tomography and [(18)F]DOPA for measurements of dopamine synthesis capacity and [(18)F]DMFP for estimation of dopamine D2 receptor binding potential. Functional magnetic resonance imaging was used to assess the blood-oxygen-level-dependent (BOLD) response to affective pictures, which was correlated with the ratio of [(18)F]DOPA net influx constant K(app)(in)/[(18)F]DMFP-binding potential (BP_ND) in the ventral and dorsal striatum. The magnitude of the ratio in the ventral striatum was positively correlated with BOLD signal increases elicited by negative versus neutral pictures in the right medial frontal gyrus (BA10), right inferior parietal lobe and left post-central gyrus. In the dorsal striatum, the ratio was positively correlated with BOLD signal activation elicited by negative versus neutral stimuli in the left post-central gyrus. The BOLD signal elicited by positive versus neutral stimuli in the superior parietal gyrus was positively correlated with the dorsal and ventral striatal ratio. The correlations of the ratio in the ventral and dorsal striatum with processing of affective stimuli in the named cortical regions support the hypothesis that dopamine transmission in functional divisions of the striatum modulates processing of affective stimuli in specific cortical areas.

Effects of dopaminergic modulation on electrophysiological brain response to affective stimuli

IntroductionSeveral theoretical accounts of the role of dopamine suggest that dopamine has an influence on the processing of affective stimuli. There is some indirect evidence for this from studies showing an association between the treatment with dopaminergic agents and self-reported affect.Materials and methodsWe addressed this issue directly by examining the electrophysiological correlates of affective picture processing during a single-dose treatment with a dopamine D2 agonist (bromocriptine), a dopamine D2 antagonist (haloperidol), and a placebo. We compared early and late event-related brain potentials (ERPs) that have been associated with affective processing in the three medication treatment conditions in a randomized double-blind crossover design amongst healthy males. In each treatment condition, subjects attentively watched neutral, pleasant, and unpleasant pictures while ERPs were recorded.ResultsResults indicate that neither bromocriptine nor haloperidol has a selective effect on electrophysiological indices of affective processing. In concordance with this, no effects of dopaminergic modulation on self-reported positive or negative affect was observed. In contrast, bromocriptine decreased overall processing of all stimulus categories regardless of their affective content.DiscussionThe results indicate that dopaminergic D2 receptors do not seem to play a crucial role in the selective processing of affective visual stimuli.

Functional neuroanatomy of the parahippocampal region in the rat: The perirhinal and postrhinal cortices

The parahippocampal region in the rodent brain includes the perirhinal, postrhinal, and entorhinal cortices, the presubiculum, and the parasubiculum. In recent years, the perirhinal and postrhinal cortices have been a focus in memory research because they supply highly processed, polymodal sensory information to the hippocampus, both directly and via the entorhinal cortex. Available evidence indicates that these cortices receive different complements of cortical information, which are then forwarded to the hippocampus via parallel pathways. Here we have summarized the cortical, subcortical, and hippocampal connections of the perirhinal and postrhinal cortices in order to provide further insight into the nature of the information that is processed by these regions prior to arriving in the hippocampus. As has been previously described, the cortical afferents of the rodent postrhinal cortex are dominated by structures known to be involved in the processing of visual and spatial information, whereas the cortical afferents of the perirhinal cortex result in remarkable convergence of polymodal sensory information. The two regions are also differentiated by their cortical efferents. The perirhinal cortex projects more strongly to piriform, frontal, and insular regions, whereas the postrhinal cortex projects preferentially to visual and visuospatial regions. The subcortical connections of the two regions provide further evidence that they have different functions. For example, the perirhinal cortex has strong reciprocal connections with the amygdala, which suggest involvement in processing affective stimuli. Subcortical input to the postrhinal cortex is dominated by projections from dorsal thalamic structures, particularly the lateral posterior nucleus. Although the perirhinal and postrhinal cortices are considered to contribute to the episodic memory system, many questions remain about their particular roles. A detailed description of the anatomical connections of the perirhinal and postrhinal cortices will permit the generation of new, anatomically guided, hypotheses about their role in episodic memory and other cognitive processes.

Neural Dynamics of Rejection Sensitivity

Rejection sensitivity (RS) is the tendency to anxiously expect, readily perceive, and intensely react to rejection. This study used functional magnetic resonance imaging to explore whether individual differences in RS are mediated by differential recruitment of brain regions involved in emotional appraisal and/or cognitive control. High and low RS participants were scanned while viewing either representational paintings depicting themes of rejection and acceptance or nonrepresentational control paintings matched for positive or negative valence, arousal and interest level. Across all participants, rejection versus acceptance images activated regions of the brain involved in processing affective stimuli (posterior cingulate, insula), and cognitive control (dorsal anterior cingulate cortex; medial frontal cortex). Low and high RS individuals' responses to rejection versus acceptance images were not, however, identical. Low RS individuals displayed significantly more activity in left inferior and right dorsal frontal regions, and activity in these areas correlated negatively with participants' self-report distress ratings. In addition, control analyses revealed no effect of viewing negative versus positive images in any of the areas described above, suggesting that the aforementioned activations were involved in rejection-relevant processing rather than processing negatively valenced stimuli per se. Taken together, these findings suggest that responses in regions traditionally implicated in emotional processing and cognitive control are sensitive to rejection stimuli irrespective of RS, but that low RS individuals may activate prefrontal structures to regulate distress associated with viewing such images.

Reward‐Related Responses in the Human Striatum

Much of our knowledge of how reward information is processed in the brain comes from a rich animal literature. Recently, the advancement of neuroimaging techniques has allowed researchers to extend such investigations to the human brain. A common finding across species and methodologies is the involvement of the striatum, the input structure of the basal ganglia, in a circuit responsible for mediating goal-directed behavior. Central to this idea is the role of the striatum in the processing of affective stimuli, such as rewards and punishments. The goal of this article is to probe the human reward circuit, specifically the striatum and its subdivisions, with an emphasis on how the affective properties of outcomes or feedback influence the underlying neural activity and subsequent decision making. Discussion will first focus on anatomical and functional considerations regarding the striatum that have emerged from animal models. The rest of the article will center on how human neuroimaging studies map to findings from the animal literature, and how more recently, this research can be extended into the social and economic domains.