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While reward associative learning has been studied extensively across different species, punishment avoidance learning has received far less attention. Of particular interest is how the two types of learning change perceptual processing of the learned stimuli. We designed a task that required participants to learn the association of emotionally neutral images with reward, punishment, and no incentive value outcomes through trial-and-error. During learning, participants received monetary reward, neutral outcomes or avoided punishment by correctly identifying corresponding images. Results showed an early bias in favor of learning reward associations, in the form of higher accuracy and fewer trials needed to reach learning criterion. We subsequently assessed electrophysiological learning effects with a task in which participants viewed the stimuli with no feedback or reinforcement. Critically, we found modulation of two early event-related potential components for reward images: the frontocentral P2 (170-230 ms) and the anterior N2/Early Anterior Positivity (N2/EAP; 210-310 ms). We suggest that reward associations may change stimuli detection and incentive salience as indexed by P2 and N2/EAP. We also reported, on an exploratory basis, a late negativity with frontopolar distribution enhanced by punishment images., Competing Interests: The authors have declared that no competing interests exist.

Vocal imitation is a phenotype that is unique to humans among all primate species, and so an understanding of its neural basis is critical in explaining the emergence of both speech and song in human evolution. Two principal neural models of vocal imitation have emerged from a consideration of nonhuman animals. One hypothesis suggests that putative mirror neurons in the inferior frontal gyrus pars opercularis of Broca's area may be important for imitation. An alternative hypothesis derived from the study of songbirds suggests that the corticostriate motor pathway performs sensorimotor processes that are specific to vocal imitation. Using fMRI with a sparse event-related sampling design, we investigated the neural basis of vocal imitation in humans by comparing imitative vocal production of pitch sequences with both nonimitative vocal production and pitch discrimination. The strongest difference between these tasks was found in the putamen bilaterally, providing a striking parallel to the role of the analogous region in songbirds. Other areas preferentially activated during imitation included the orofacial motor cortex, Rolandic operculum, and SMA, which together outline the corticostriate motor loop. No differences were seen in the inferior frontal gyrus. The corticostriate system thus appears to be the central pathway for vocal imitation in humans, as predicted from an analogy with songbirds.

Background: Patients in recovery following episodes of major depressive disorder (MDD) remain highly vulnerable to future recurrence. Although psychological determinants of this risk are well established, little is known about associated biological mechanisms. Recent work has implicated the default mode network (DMN) in this vulnerability but specific hypotheses remain untested within the high risk, recovered state of MDD., Aims: To test the hypothesis that there is excessive DMN functional connectivity during task performance within recovered-state MDD and to test for connected DMN cortical gyrification abnormalities., Method: A multimodal structural and functional magnetic resonance imaging (fMRI) study, including task-based functional connectivity and cortical folding analysis, comparing 20 recovered-state patients with MDD with 20 matched healthy controls., Results: The MDD group showed significant task-based DMN hyperconnectivity, associated with hypogyrification of key DMN regions (bilateral precuneus)., Conclusions: This is the first evidence of connected structural and functional DMN abnormalities in recovered-state MDD, supporting recent hypotheses on biological-level vulnerability.

Looking for an object that may be present in a cluttered visual display requires an advanced specification of that object to be created and then matched against the incoming visual input. Here, fast event-related fMRI was used to identify the brain networks that are active when preparing to search for a visual target. By isolating the preparation phase of the task it has been possible to show that for an identical stimulus, different patterns of cortical activation occur depending on whether participants anticipate a 'feature' or a 'conjunction' search task. When anticipating a conjunction search task, there was more robust activation in ventral occipital areas, new activity in the transverse occipital sulci and right posterior intraparietal sulcus. In addition, preparing for either type of search activated ventral striatum and lateral cerebellum. These results suggest that when participants anticipate a demanding search task, they develop a different advanced representation of a visually identical target stimulus compared to when they anticipate a nondemanding search., (© 2013 Elsevier B.V. All rights reserved.)

The spatiotemporal dynamics of the hedonic response to chocolate images was investigated in healthy participants high and low in trait-chocolate craving employing high-density ERPs. There were two sessions: (1) before and (2) after satiety for chocolate. Among cravers, chocolate stimuli evoked a positive amplitude ERP enhancement over the anterior frontal scalp (250-350 ms) that was not modified by satiety and that source localized to the left lateral orbitofrontal cortex. Chocolate stimuli also elicited a later LPP over the posterior scalp (360-560 ms) which was of similar amplitude for high and low chocolate cravers, independent of satiety. Unexpectedly, in non-cravers, chocolate stimuli elicited an earlier (100-250 ms) negative ERP modulation over the frontomedial scalp, which disappeared after eating chocolate to satiety. These results confirm the role of OFC in unrestrained appetitive responses to chocolate in cravers, and suggest top-down influences from cognitive control mechanisms when attempting to restrain the urge to eat chocolate in non-cravers., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

We present here the most comprehensive analysis to date of neuroaesthetic processing by reporting the results of voxel-based meta-analyses of 93 neuroimaging studies of positive-valence aesthetic appraisal across four sensory modalities. The results demonstrate that the most concordant area of activation across all four modalities is the right anterior insula, an area typically associated with visceral perception, especially of negative valence (disgust, pain, etc.). We argue that aesthetic processing is, at its core, the appraisal of the valence of perceived objects. This appraisal is in no way limited to artworks but is instead applicable to all types of perceived objects. Therefore, one way to naturalize aesthetics is to argue that such a system evolved first for the appraisal of objects of survival advantage, such as food sources, and was later co-opted in humans for the experience of artworks for the satisfaction of social needs., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Local alpha-band synchronization has been associated with both cortical idling and active inhibition. Recent evidence, however, suggests that long-range alpha synchronization increases functional coupling between cortical regions. We demonstrate increased long-range alpha and beta band phase synchronization during short-term memory retention in children 6-10 years of age. Furthermore, whereas alpha-band synchronization between posterior cortex and other regions is increased during retention, local alpha-band synchronization over posterior cortex is reduced. This constitutes a functional dissociation for alpha synchronization across local and long-range cortical scales. We interpret long-range synchronization as reflecting functional integration within a network of frontal and visual cortical regions. Local desynchronization of alpha rhythms over posterior cortex, conversely, likely arises because of increased engagement of visual cortex during retention.

Executive function and working memory deficits are not only present in ADHD, but also in reading disorder (RD). Here, high-density ERPs were recorded during the Stop Signal Task in 53 children and adolescents: An ADHD-combined type group, a group with RD, and a healthy control group. The ADHD-C group displayed unique abnormalities of the frontal N200. Both healthy controls and RD groups showed a success-related right frontal N200 modulation, which was absent in the ADHD group. Second, for Success Inhibition trials, the ADHD-C had smaller right frontal N200 waves relative to healthy controls, while the RD group did not. In contrast, NoGo-P3 abnormalities were present both in the ADHD-C and RD groups. Impaired early response inhibition mechanisms, indexed by the frontal N200, appear to be limited to ADHD-C. In contrast, deficits in later cognitive control and error monitoring mechanisms, indexed by the NoGo-P3, appear to be present in both conditions., (Copyright 2009 Elsevier Inc. All rights reserved.)

Objective: To determine if there are differences in the volume of the caudate and anterior cingulate cortex (ACC) between children with attention deficit hyperactivity disorder (ADHD) and controls, and if such differences are related to the subjects' history of stimulant treatment., Methods: We performed a case-control study in an academic medical center. Twenty-one healthy controls, 16 children with ADHD, combined type with a history of stimulant treatment, and 14 children with ADHD, combined type treatment naïve, underwent structural MRI. All children with ADHD were medication-free at the time of the MRI. Regional hemispheric volumes (in cm3) of caudate and anterior cingulate cortex were determined., Results: There were significant differences bilaterally on caudate volume for both ADHD groups vs controls, with no difference between the ADHD groups on either side. In contrast, the right ACC was significantly smaller for the ADHD-treatment naïve (ADHD/TN) group compared to the ADHD-treated (ADHD/Rx) and control group. The volume of left ACC approached significance contrast between ADHD/RX and ADHD/TN. There were no differences found between the ADHD/Rx and controls on the ACC volumes bilaterally., Conclusions: The results from this study indicate a relationship of previous treatment history with caudate and anterior cingulate volumetric changes in children with attention deficit hyperactivity disorder-combined type.

Brain electrical activity associated with inhibitory control was recorded in ten ADHD and ten healthy children using high density event related potentials (ERPs) during the Stop Signal Task (SST). SST is a two-choice reaction time (RT) paradigm, in which subjects are required, on 25% of the trials, to withdraw their response upon presentation of a "Stop Signal". In the healthy children, the ERP evoked by the Stop Signal differed for successful inhibitions (SI) compared to failed inhibitions (FI), with greater amplitude of a positive wave peaking around 320 msec over anterior medial frontal scalp (P3a). Such success-related P3a activity was significantly reduced in amplitude in the ADHD group. In addition, the error related negativity (ERN), a sharp negative wave that is present selectively on error trials in choice RT experiments, peaking 100 ms after motor onset, and distributed over anterior medial frontal scalp, was also markedly reduced in the ADHD group. The scalp distribution of the group differences in P3a and the ERN is consistent with a reduction of activity of sources in dorsal anterior cingulate cortex (dACC), suggesting a global deficit in cognitive control operations subserved by dACC in ADHD.

Objective: Remitted major depressive disorder is a vulnerable clinical state, suggesting persistence of an underlying disease diathesis between episodes. To investigate neural correlates of such risk and to identify potential depression trait markers, euthymic unipolar patients in remission, acutely depressed patients, and never-depressed volunteers were studied before and after transient sad mood challenge., Method: Common and differential changes in regional blood flow among the groups relative to the baseline state were examined with [(15)O]H(2)O positron emission tomography after provocation of sadness with autobiographical memory scripts., Results: Mood provocation in both depressed groups resulted in regional cerebral blood flow (rCBF) decreases in medial orbitofrontal cortex Brodmann's area 10/11, which were absent in the healthy group. In the remitted group, mood provocation produced a unique rCBF decrease in pregenual anterior cingulate 24a. The main effects in healthy subjects, an rCBF increase in subgenual cingulate Brodmann's area 25 and a decrease in right prefrontal cortex Brodmann's area 9, were not present in the depressed groups., Conclusions: Mood challenge in unipolar euthymic patients in full remission unmasks an apparent depression trait marker. The pattern of acute CBF changes is distinct from that seen in euthymic healthy volunteers and mirrors the untreated depressed state seen during a major depressive episode and the pattern of change seen in depressed patients. These findings suggest that disease-specific modifications of pathways mediating transient mood changes are present in unipolar depression independent of clinical illness status. These findings have implications for understanding the vulnerability of remitted patients for illness relapse.

In a positron emission tomography (PET) study, a very large visual display was used to simulate continuous observer roll, yaw, and linear movement in depth. A global analysis based on all three experiments identified brain areas that responded to the three conditions' shared characteristic of coherent, wide-field motion versus incoherent motion. Several areas were identified, in the posterior-inferior temporal cortex (Brodmann area 37), paralimbic cortex, pulvinar, and midbrain tegmentum. In addition, occipital region KO was sensitive to roll and expansion but not yaw (i.e., coherent displays containing differential flow). Continuous ambient motion did not activate V5/MT selectively. The network of sites responding specifically to coherent motion contrasted with the extensive, contiguous activation that both coherent and incoherent motion elicited in visual areas V1, V2, and V3. The coherent motion mechanisms, furthermore, extended beyond the traditional dorsal pathway proposed to account for visual motion processing, and included subcortical and limbic structures, which are implicated in polysensory processing, posture regulation, and arousal.

There are defined medullary, mesencephalic, hypothalamic, and thalamic functions in regulation of respiration, but knowledge of cortical control and the elements subserving the consciousness of breathlessness and air hunger is limited. In nine young adults, air hunger was produced acutely by CO(2) inhalation. Comparisons were made with inhalation of a N(2)/O(2) gas mixture with the same apparatus, and also with paced breathing, and with eyes closed rest. A network of activations in pons, midbrain (mesencephalic tegmentum, parabrachial nucleus, and periaqueductal gray), hypothalamus, limbic and paralimbic areas (amygdala and periamygdalar region) cingulate, parahippocampal and fusiform gyrus, and anterior insula were seen along with caudate nuclei and pulvinar activations. Strong deactivations were seen in dorsal cingulate, posterior cingulate, and prefrontal cortex. The striking response of limbic and paralimbic regions points to these structures having a singular role in the affective sequelae entrained by disturbance of basic respiratory control whereby a process of which we are normally unaware becomes a salient element of consciousness. These activations and deactivations include phylogenetically ancient areas of allocortex and transitional cortex that together with the amygdalar/periamygdalar region may subserve functions of emotional representation and regulation of breathing.

Little is known about the physiological mechanisms subserving the experience of air hunger and the affective control of breathing in humans. Acute hunger for air after inhalation of CO(2) was studied in nine healthy volunteers with positron emission tomography. Subjective breathlessness was manipulated while end-tidal CO(2-) was held constant. Subjects experienced a significantly greater sense of air hunger breathing through a face mask than through a mouthpiece. The statistical contrast between the two conditions delineated a distributed network of primarily limbic/paralimbic brain regions, including multiple foci in dorsal anterior and middle cingulate gyrus, insula/claustrum, amygdala/periamygdala, lingual and middle temporal gyrus, hypothalamus, pulvinar, and midbrain. This pattern of activations was confirmed by a correlational analysis with breathlessness ratings. The commonality of regions of mesencephalon, diencephalon and limbic/paralimbic areas involved in primal emotions engendered by the basic vegetative systems including hunger for air, thirst, hunger, pain, micturition, and sleep, is discussed with particular reference to the cingulate gyrus. A theory that the phylogenetic origin of consciousness came from primal emotions engendered by immediate threat to the existence of the organism is discussed along with an alternative hypothesis by Edelman that primary awareness emerged with processes of ongoing perceptual categorization giving rise to a scene [Edelman, G. M. (1992) Bright Air, Brilliant Fire (Penguin, London)].

An automated coordinate-based system to retrieve brain labels from the 1988 Talairach Atlas, called the Talairach Daemon (TD), was previously introduced [Lancaster et al., 1997]. In the present study, the TD system and its 3-D database of labels for the 1988 Talairach atlas were tested for labeling of functional activation foci. TD system labels were compared with author-designated labels of activation coordinates from over 250 published functional brain-mapping studies and with manual atlas-derived labels from an expert group using a subset of these activation coordinates. Automated labeling by the TD system compared well with authors' labels, with a 70% or greater label match averaged over all locations. Author-label matching improved to greater than 90% within a search range of +/-5 mm for most sites. An adaptive grey matter (GM) range-search utility was evaluated using individual activations from the M1 mouth region (30 subjects, 52 sites). It provided an 87% label match to Brodmann area labels (BA 4 & BA 6) within a search range of +/-5 mm. Using the adaptive GM range search, the TD system's overall match with authors' labels (90%) was better than that of the expert group (80%). When used in concert with authors' deeper knowledge of an experiment, the TD system provides consistent and comprehensive labels for brain activation foci. Additional suggested applications of the TD system include interactive labeling, anatomical grouping of activation foci, lesion-deficit analysis, and neuroanatomy education.

Many tasks require rapid and fine-tuned adjustment of motor performance based on incoming sensory information. This process of sensorimotor adaptation engages two parallel subcorticocortical neural circuits, involving the cerebellum and basal ganglia, respectively. How these distributed circuits are functionally coordinated has not been shown in humans. The cerebellum and basal ganglia show very similar convergence of input-output organization, which presents an ideal neuroimaging model for the study of parallel processing at a systems level. Here we used functional magnetic resonance imaging to measure the temporal coherence of brain activity during a tactile discrimination task. We found that, whereas the prefrontal cortex maintained a high level of activation, output activities in the cerebellum and basal ganglia showed different phasic patterns. Moreover, cerebellar activity significantly correlated with the activity of the supplementary motor area but not with that of the primary motor cortex; in contrast, basal ganglia activity was more strongly associated with the activity of the primary motor cortex than with that of the supplementary motor area. These results demonstrate temporally partitioned activity in the cerebellum and basal ganglia, implicating functional independence in the parallel subcortical outputs. This further supports the idea of task-related dynamic reconfiguration of large-scale neural networks.

Subjective and physiologic effects of 33% inhaled Xe were measured with 15O-water positron emission tomography (PET) in 3 subjects at rest and during visual stimulation. The procedure was well tolerated. Robust functional activations of the visual cortex were obtained after xenon (Xe) inhalation as well as air breathing. However, Xe inhalation was followed by smaller size, but significant decreases of regional cerebral blood flow (rCBF) in visual cortex relative to the air-breathing baseline, both during visual stimulation and at rest. No such decreases were found in other sensory or motor regions.

University students in either an optimistic or pessimistic mood state read brief stories of daily life events as event-related brain potentials were collected during the final word of each story. For subjects in a pessimistic mood, a bias to expect negative outcomes was seen as an N400/P300 effect over posterior scalp regions. For subjects in an optimistic mood, a differentiation between good and bad outcomes was also observed, but it was specific to medial frontal areas. Analysis of single-trial P300 latencies suggested that semantically incongruent and mood-incongruent outcome words resulted in increased median latency of the late positive complex (LPC) and resulted in increased variability of LPC latency across trials.

Positron emission tomography (PET) provides an unprecedented opportunity to study the organization of cognitive functions in the working brain of normal individuals. A number of PET experiments, based on well-established paradigms derived from cognitive psychology, have investigated several aspects of language processing. These studies show that word processing is carried out by a distributed network of cortical areas with functional specificity. Results of this research sometimes confirm--sometimes clearly contradict--classic axioms of language organization. This article illustrates some of the methodological issues in PET research, then provides an overview of the most relevant studies using PET. Integrated with other functional imaging methodologies and with behavioral data from cognitive psychology and lesion studies, PET will certainly continue to represent a precious tool to enhance our knowledge of the functional organization of language.

Several lines of evidence suggest impaired right hemisphere function in depression. In order to further investigate this phenomenon, simple reaction times (RTs) to lateralized visual stimuli were studied in patients with mild unipolar depression, in patients with chronic anxiety, and in medical patients free of psychiatric symptoms. The results showed a marked slowing of RTs to left visual field (right hemisphere) stimuli in depressed patients. Anxious patients showed a trend toward an opposite asymmetry, with slower responses to right field (left hemisphere) stimuli. In the nonpsychiatric group no visual field differences were present. The results are discussed in light of two alternative interpretations: depression may engage the right hemisphere's mechanisms, interfering with its functioning at a premotor level, or it may influence the regulation of performance by arousal and vigilance mechanisms lateralized to the right hemisphere, possibly operating at an earlier sensory stage.

Simple reaction times (RTs) to lateralized unstructured visual stimuli were measured in normal subjects while they were carrying out concomitant oculomotor tasks. Four tasks were used. In the first task, subjects had to find the correct path in a maze presented at the centre of a screen; in the second task, subjects had to follow a bright dot moved on a screen with variable direction, trajectory and velocity with their eyes; in the third task, the subjects had to follow a bright dot moved back and forth either horizontally or vertically along the same trajectory and at a constant velocity; in the fourth task, the subjects had to monitor the movement of a bright dot moved with variable direction, trajectory and velocity without moving the eyes. In all tasks, with the exception of the third, there was a selective lengthening of RTs mediated by the right hemisphere. It is concluded that the right hemisphere is dominant in programming eye movements.