Tagging cortical networks in emotion: a topographical analysis

Viewing emotional pictures is associated with heightened perception and attention, indexed by a relative increase in visual cortical activity. Visual cortical modulation by emotion is hypothesized to reflect re-entrant connectivity originating in higher-order cortical and/or limbic structures. The present study used dense-array electroencephalography and individual brain anatomy to investigate functional coupling between the visual cortex and other cortical areas during affective picture viewing. Participants viewed pleasant, neutral, and unpleasant pictures that flickered at a rate of 10 Hz to evoke steady-state visual evoked potentials (ssVEPs) in the EEG. The spectral power of ssVEPs was quantified using Fourier transform, and cortical sources were estimated using beamformer spatial filters based on individual structural magnetic resonance images. In addition to lower-tier visual cortex, a network of occipito-temporal and parietal (bilateral precuneus, inferior parietal lobules) structures showed enhanced ssVEP power when participants viewed emotional (either pleasant or unpleasant), compared to neutral pictures. Functional coupling during emotional processing was enhanced between the bilateral occipital poles and a network of temporal (left middle/inferior temporal gyrus), parietal (bilateral parietal lobules), and frontal (left middle/inferior frontal gyrus) structures. These results converge with findings from hemodynamic analyses of emotional picture viewing and suggest that viewing emotionally engaging stimuli is associated with the formation of functional links between visual cortex and the cortical regions underlying attention modulation and preparation for action.

Repetitive exposure: brain and reflex measures of emotion and attention

Effects of massed repetition on the modulation of the late positive potential elicited during affective picture viewing were investigated in two experiments. Despite a difference in the number of repetitions across studies (from 5 to 30), results were quite similar: The late positive potential continued to be enhanced when participants viewed emotional, compared to neutral, pictures. On the other hand, massed repetition did prompt a reduction in the late positive potential that was most pronounced for emotional pictures. Startle probe P3 amplitude generally increased with repetition, suggesting diminished attention allocation to repeated pictures. The blink reflex, however, continued to be modulated by hedonic valence, despite massive massed repetition. Taken together, the data suggest that the amplitude of the late positive potential during picture viewing reflects both motivational significance and attention allocation.

Scan patterns when viewing natural scenes: emotion, complexity, and repetition

Eye movements were monitored during picture viewing, and effects of hedonic content, perceptual composition, and repetition on scanning assessed. In Experiment 1, emotional and neutral pictures that were figure-ground compositions or more complex scenes were presented for a 6-s free viewing period. Viewing emotional pictures or complex scenes prompted more fixations and broader scanning of the visual array, compared to neutral pictures or simple figure-ground compositions. Effects of emotion and composition were independent, supporting the hypothesis that these oculomotor indices reflect enhanced information seeking. Experiment 2 tested an orienting hypothesis by repeatedly presenting the same pictures. Although repetition altered specific scan patterns, emotional, compared to neutral, picture viewing continued to prompt oculomotor differences, suggesting that motivationally relevant cues enhance information seeking in appetitive and defensive contexts.

The impact of anxiety on the neural processing of respiratory sensations

Previous studies demonstrated that anxiety considerably impacts the reported perceptions of respiratory sensations. A novel feature of the current study is exploring the impact of anxiety on the neural processing of respiratory sensations elicited by short inspiratory occlusions during different affective contexts. Using high-density EEG, respiratory-related evoked potentials (RREP) were recorded in 23 low and 23 matched higher anxious individuals when viewing unpleasant or neutral picture series. Low anxious individuals showed the expected pattern of reduced magnitudes of later RREP components P2 and P3 during the unpleasant compared to the neutral affective context (p<0.05 and p<0.01). In contrast, higher anxious individuals showed greater magnitudes of P2 and P3 during the unpleasant compared to the neutral affective context (p's<0.05). Moreover, higher anxiety levels were correlated with greater magnitudes for P2 (r=0.44, p<0.01) and P3 (r=0.54, p<0.001) during the unpleasant relative to the neutral affective context. Earlier components of the RREP (Nf, P1, N1) were not affected by anxiety. This study demonstrates that anxiety affects the later, higher-order neural processing of respiratory sensations, but not its earlier, first-order sensory processing. These findings might represent a neural mechanism that underlies the increased perception of respiratory sensations in anxious individuals.

Threat of suffocation and defensive reflex activation

The current study examined emotional reflex reactions of participants threatened with respiratory distress caused by imposing a resistive load at inspiration. Cues signaling threat (breathing MAY be difficult) and safe periods were intermixed while startle reflexes, heart rate, skin conductance, and facial EMG activity were measured. Compared to safe cues, threat cues elicited significant startle potentiation, enhanced skin conductance, heightened corrugator EMG changes, and pronounced "fear bradycardia" consistent with defensive activation in the context of threatened respiratory dysfunction. These data indicate that anticipating respiratory resistance activates defensive responding, which may mediate symptomatology in patients with panic and other anxiety disorders.

Emotional imagery: assessing pleasure and arousal in the brain's reward circuitry

Research on emotional perception and learning indicates appetitive cues engage nucleus accumbens (NAc) and medial prefrontal cortex (mPFC), whereas amygdala activity is modulated by the emotional intensity of appetitive and aversive cues. This study sought to determine patterns of functional activation and connectivity among these regions during narrative emotional imagery. Using event-related fMRI, we investigate activation of these structures when participants vividly imagine pleasant, neutral, and unpleasant scenes. Results indicate that pleasant imagery selectively activates NAc and mPFC, whereas amygdala activation was enhanced during both pleasant and unpleasant imagery. NAc and mPFC activity were each correlated with the rated pleasure of the imagined scenes, while amygdala activity was correlated with rated emotional arousal. Functional connectivity of NAc and mPFC was evident throughout imagery, regardless of hedonic content, while correlated activation of the amygdala with NAc and mPFC was specific to imagining pleasant scenes. These findings provide strong evidence that pleasurable text-driven imagery engages a core appetitive circuit, including NAc, mPFC, and the amygdala.

Neural processing of respiratory sensations when breathing becomes more difficult and unpleasant

The accurate perception of respiratory sensations is important for the successful management and treatment of respiratory diseases. Previous studies demonstrated that external stimuli such as affective pictures and distracting films can impact the perception and neural processing of respiratory sensations. This study examined the neural processing of respiratory sensations when breathing as an internal stimulus is manipulated and becomes more difficult and unpleasant. Sustained breathing through an inspiratory resistive load was used to increase perceived breathing difficulty in 12 female individuals without respiratory disease. Using high-density EEG, respiratory-related evoked potentials (RREP) to short inspiratory occlusions were recorded at early versus late time points of sustained loaded breathing. Ratings of perceived intensity and unpleasantness of breathing difficulty showed an increase from early to late time points of loaded breathing (p < 0.01 and p < 0.05, respectively). This was paralleled by significant increases in the magnitudes of RREP components N1, P2, and P3 (p < 0.01, p < 0.05, and p < 0.05, respectively). The present results demonstrate increases in the neural processing of respiratory sensations when breathing becomes more difficult and unpleasant. This might reflect a protective neural mechanism allowing effective response behavior when air supply is at risk.

Habituation in neural processing and subjective perception of respiratory sensations

Reduced perception of respiratory sensations is associated with negative treatment outcome in asthma. We examined whether habituation in the neural processing of repeatedly experienced respiratory sensations may underlie subjective reports of reduced respiratory perception. Respiratory-related evoked potentials (RREP) elicited by inspiratory occlusions and reports of respiratory perception were compared between early and late experimental periods in healthy subjects. Reports of respiratory perception were reduced during late, compared to early, experimental periods. This was paralleled by reduced magnitudes in RREP components N1, P2, and P3 in late, compared to early, experimental periods. Habituation in the neural processing of respiratory sensations is a potential mechanism that underlies subjective reports of reduced respiratory perception and might represent a risk factor for reduced perception of respiratory sensations in asthma.

Germline CBL mutations cause developmental abnormalities and predispose to juvenile myelomonocytic leukemia

CBL encodes a member of the Cbl family of proteins, which functions as an E3 ubiquitin ligase. We describe a dominant developmental disorder resulting from germline missense CBL mutations, which is characterized by impaired growth, developmental delay, cryptorchidism and a predisposition to juvenile myelomonocytic leukemia (JMML). Some individuals experienced spontaneous regression of their JMML but developed vasculitis later in life. Importantly, JMML specimens from affected children show loss of the normal CBL allele through acquired isodisomy. Consistent with these genetic data, the common p.371Y>H altered Cbl protein induces cytokine-independent growth and constitutive phosphorylation of ERK, AKT and S6 only in hematopoietic cells in which normal Cbl expression is reduced by RNA interference. We conclude that germline CBL mutations have developmental, tumorigenic and functional consequences that resemble disorders that are caused by hyperactive Ras/Raf/MEK/ERK signaling and include neurofibromatosis type 1, Noonan syndrome, Costello syndrome, cardiofaciocutaneous syndrome and Legius syndrome.

Defensive engagement and perceptual enhancement

We tested whether visual cortical sensitivity to external cues in the context of an acute defensive reaction is heightened or attenuated. A strong cardiac defense (fear) response was elicited by presenting an abrupt, loud acoustic stimulus following a 10-min period of quiescence. Electrocortical responses to aversive and neutral pictures following defensive stimulus onset were measured using dense-array EEG. Pictures were flickered at 12.5 Hz to evoke steady-state visual evoked potentials (ssVEP), which can be reliably extracted on the basis of single trials. Visual cortical activity indexing perceptual processing was substantially heightened when pictures were shown in temporal proximity to (i.e., 5s after) the defense stimulus. Replicating previous studies, aversive visual stimuli were associated with enhanced ssVEP amplitude, compared to neutral stimuli. Acute defense facilitates visual perception of external cues and preserves accurate discrimination between threatening and safe cues.

Memory and event-related potentials for rapidly presented emotional pictures

Dense array event-related potentials (ERPs) and memory performance were assessed following rapid serial visual presentation (RSVP) of emotional and neutral pictures. Despite the extremely brief presentation, emotionally arousing pictures prompted an enhanced negative voltage over occipital sensors, compared to neutral pictures, replicating previous encoding effects. Emotionally arousing pictures were also remembered better in a subsequent recognition test, with higher hit rates and better discrimination performance. ERPs measured during the recognition test showed both an early (250-350 ms) frontally distributed difference between hits and correct rejections, and a later (400-500 ms), more centrally distributed difference, consistent with effects of recognition on ERPs typically found using slower presentation rates. The data are consistent with the hypothesis that features of affective pictures pop out during rapid serial visual presentation, prompting better memory performance.

Emotion and the motivational brain

Psychophysiological and neuroscience studies of emotional processing undertaken by investigators at the University of Florida Laboratory of the Center for the Study of Emotion and Attention (CSEA) are reviewed, with a focus on reflex reactions, neural structures and functional circuits that mediate emotional expression. The theoretical view shared among the investigators is that expressed emotions are founded on motivational circuits in the brain that developed early in evolutionary history to ensure the survival of individuals and their progeny. These circuits react to appetitive and aversive environmental and memorial cues, mediating appetitive and defensive reflexes that tune sensory systems and mobilize the organism for action and underly negative and positive affects. The research reviewed here assesses the reflex physiology of emotion, both autonomic and somatic, studying affects evoked in picture perception, memory imagery, and in the context of tangible reward and punishment, and using the electroencephalograph (EEG) and functional magnetic resonance imaging (fMRI), explores the brain's motivational circuits that determine human emotion.

Integrity of emotional and motivational states during the prodromal, first-episode, and chronic phases of schizophrenia

Emotional and motivational dysfunction is fundamental to schizophrenia, and yet, the nature and scope of associated deficits are not well understood. This study assessed the integrity of emotional responding from the perspective of its underlying motivational systems during different phases of schizophrenia. Evaluative, somatic, and autonomic responses were measured during viewing of pictures categorized by emotional content, including threat, mutilation, contamination, illness, pollution, mild erotica, families, food, and nature. Participants were 13 patients at ultra high risk or prodromal for psychosis, 40 first-episode schizophrenia patients, 37 chronic schizophrenia patients, and 74 healthy comparison subjects. Irrespective of phase of illness, schizophrenia patients showed a robust and normal pattern of response across multiple systems, with differential engagement of the defensive and appetitive systems as a function of the motivational significance assigned to specific emotional contexts. Although the integrity of core motivational states also appeared to be intact in prodromal patients, a less consistent pattern of response was observed. As continuing efforts are made to identify emotional and motivational abnormalities in schizophrenia, identified deficits will likely be independent of a fundamental dysfunction in basic emotion and motivation response systems and involve integration with higher order processes.

Emotion and Motivation: Toward Consensus Definitions and a Common Research Purpose

Historically, the hypothesis driving emotion research has been that emotion’s data-base—in language, physiology, and behavior— is organized around specific mental states, as reflected in evaluative language. It is suggested that this approach has not greatly advanced a natural science of emotion and that the developing motivational model of emotion defines a better path: emotion is an evolved trait founded on motivational neural circuitry shared by mammalian species, primitively prompting heightened perceptual processing and reflex mobilization for action to appetitive or threatening survival cues. As the field moves forward with increasingly sophisticated measurement technology and assessing more complex affective functioning, scientific understanding of human emotion will proceed best within the framework of this mammalian brain model.

Detecting novelty and significance

Studies of cognition often use an "oddball" paradigm to study effects of stimulus novelty and significance on information processing. However, an oddball tends to be perceptually more novel than the standard, repeated stimulus as well as more relevant to the ongoing task, making it difficult to disentangle effects due to perceptual novelty and stimulus significance. In the current study, effects of perceptual novelty and significance on ERPs were assessed in a passive viewing context by presenting repeated and novel pictures (natural scenes) that either signaled significant information regarding the current context or not. A fronto-central N2 component was primarily affected by perceptual novelty, whereas a centro-parietal P3 component was modulated by both stimulus significance and novelty. The data support an interpretation that the N2 reflects perceptual fluency and is attenuated when a current stimulus matches an active memory representation and that the amplitude of the P3 reflects stimulus meaning and significance.

Aversive imagery in posttraumatic stress disorder: trauma recurrence, comorbidity, and physiological reactivity

BACKGROUND

Posttraumatic stress disorder (PTSD) is characterized as a disorder of exaggerated defensive physiological arousal. The novel aim of the present research was to investigate within PTSD a potential dose-response relationship between past trauma recurrence and current comorbidity and intensity of physiological reactions to imagery of trauma and other aversive scenarios.

METHODS

A community sample of principal PTSD (n = 49; 22 single-trauma exposed, 27 multiple-trauma exposed) and control (n = 76; 46 never-trauma exposed, 30 trauma exposed) participants imagined threatening and neutral events while acoustic startle probes were presented and the eye-blink response (orbicularis occuli) was recorded. Changes in heart rate, skin conductance level, and facial expressivity were also indexed.

RESULTS

Overall, PTSD patients exceeded control participants in startle reflex, autonomic responding, and facial expressivity during idiographic trauma imagery and, though less pronounced, showed heightened reactivity to standard anger, panic, and physical danger imagery. Concerning subgroups, control participants with and without trauma exposure showed isomorphic patterns. Within PTSD, only the single-trauma patients evinced robust startle and autonomic responses, exceeding both control participants and multiple-trauma PTSD. Despite greater reported arousal, the multiple-trauma relative to single-trauma PTSD group showed blunted defensive reactivity associated with more chronic and severe PTSD, greater mood and anxiety disorder comorbidity, and more pervasive dimensional dysphoria (e.g., depression, trait anxiety).

CONCLUSIONS

Whereas PTSD patients generally show marked physiological arousal during aversive imagery, concordant with self-reported distress, the most symptomatic patients with histories of severe, cumulative traumatization show discordant physiological hyporeactivity, perhaps attributable to sustained high stress and an egregious, persistent negative affectivity that ultimately compromises defensive responding.

The impact of emotion on respiratory-related evoked potentials

Emotion influences the perception of respiratory sensations, although the specific mechanism underlying this modulation is not yet clear. We examined the impact of viewing pleasant, neutral, and unpleasant affective pictures on the respiratory-related evoked potential (RREP) elicited by a short inspiratory occlusion in healthy volunteers. Reduced P3 amplitude of the RREP was found for respiratory probes presented when viewing pleasant or unpleasant series, when compared to those presented during the neutral series. Earlier RREP components, such as Nf, P1, N1, and P2, showed no modulation by emotion. The results suggest that emotion impacts the perception of respiratory sensations by reducing the attentional resources available for processing afferent respiratory sensory signals.

Communalities and differences in fear potentiation between cardiac defense and eyeblink startle

This study examines similarities and differences in fear potentiation between two protective reflexes: cardiac defense and eyeblink startle. Women reporting intense fear of animals but low fear of blood or intense fear of blood but low fear of animals viewed pictures depicting blood or the feared animal for 6 s in 2 separate trials in counterbalanced order. An intense burst of white noise, able to elicit both a cardiac defense response and a reflexive startle blink, was presented 3.5 s after picture onset. Both cardiac and blink responses were potentiated when highly fearful individuals viewed fearful pictures. However, differences appeared concerning picture order. This pattern of results indicates communalities and differences among protective reflexes that are relevant for understanding the dynamics of emotional reflex modulation.

Re-entrant projections modulate visual cortex in affective perception: evidence from Granger causality analysis

Re-entrant modulation of visual cortex has been suggested as a critical process for enhancing perception of emotionally arousing visual stimuli. This study explores how the time information inherent in large-scale electrocortical measures can be used to examine the functional relationships among the structures involved in emotional perception. Granger causality analysis was conducted on steady-state visual evoked potentials elicited by emotionally arousing pictures flickering at a rate of 10 Hz. This procedure allows one to examine the direction of neural connections. Participants viewed pictures that varied in emotional content, depicting people in neutral contexts, erotica, or interpersonal attack scenes. Results demonstrated increased coupling between visual and cortical areas when viewing emotionally arousing content. Specifically, intraparietal to inferotemporal and precuneus to calcarine connections were stronger for emotionally arousing picture content. Thus, we provide evidence for re-entrant signal flow during emotional perception, which originates from higher tiers and enters lower tiers of visual cortex.

Both predator and prey: emotional arousal in threat and reward

This research examined the psychophysiology of emotional arousal anticipatory to potentially aversive and highly pleasant outcomes. Human brain reactions (event-related potentials) and body reactions (heart rate, skin conductance, the probe startle reflex) were assessed along motivational gradients determined by apparent distance from sites of potential punishment or reward. A predator-prey survival context was simulated using cues that signaled possible money rewards or possible losses; the cues appeared to loom progressively closer to the viewer, until a final step when a rapid key response could ensure reward or avoid a punishing loss. The observed anticipatory response patterns of heightened vigilance and physiological mobilization are consistent with the view that the physiology of emotion is founded on action dispositions that evolved in mammals to facilitate survival by dealing with threats or capturing life-sustaining rewards.

Fear-conditioned respiration and its association to cardiac reactivity

This study aimed to investigate ventilatory correlates of conditioned fear responses. Respiratory, end-tidal carbon dioxide pressure (PetCO(2)) and heart rate changes were studied in a differential fear-conditioning paradigm. Forty-two participants viewed pictures of faces. One picture (CS+) was followed by a human scream (US) during the acquisition phase, but not in a subsequent extinction phase. Conditioning of PetCO(2) (decrease), respiratory cycle time (decrease) and inspiratory duty time (increase) was established and subsequently extinguished. When participants were clustered according to their conditioned PetCO(2) responses during acquisition, only a group showing a conditioned decrease in PetCO(2) showed also a differential cardiac acceleration, a decrease in expiratory duration and an increase in inspiratory duty time in response to the CS+. These results suggest that preparation for defensive action is characterized by a tendency towards hyperventilation and cardiac acceleration.

The anxiety disorder spectrum: fear imagery, physiological reactivity, and differential diagnosis

This review considers recent research assessing psychophysiological reactivity to fear imagery in anxiety disorder patients. As in animal subjects, fear cues prompt in humans a state of defensive motivation in which autonomic and somatic survival reflexes are markedly enhanced. Thus, a startle stimulus presented in a fear context yields a stronger (potentiated) reflex, providing a quantitative measure of fearful arousal. This fear potentiation is further exaggerated in specific or social phobia individuals when viewing pictures or imagining the phobic object. Paradoxically, fear imagery studies with more severe anxiety disorder patients--panic disorder with agoraphobia, generalized anxiety disorder, or anxious patients with comorbid depression--show a blunted, less robust fear potentiated response. Furthermore, this reflex blunting appears to systematically be more pronounced over the anxiety disorder spectrum, coincident with lengthier chronicity, worsening clinician-based judgments of severity and prognosis, and increased questionnaire-based indices of negative affectivity, suggesting that normal defensive reactivity may be compromised by an experience of long-term stress.

The pupil as a measure of emotional arousal and autonomic activation

Pupil diameter was monitored during picture viewing to assess effects of hedonic valence and emotional arousal on pupillary responses. Autonomic activity (heart rate and skin conductance) was concurrently measured to determine whether pupillary changes are mediated by parasympathetic or sympathetic activation. Following an initial light reflex, pupillary changes were larger when viewing emotionally arousing pictures, regardless of whether these were pleasant or unpleasant. Pupillary changes during picture viewing covaried with skin conductance change, supporting the interpretation that sympathetic nervous system activity modulates these changes in the context of affective picture viewing. Taken together, the data provide strong support for the hypothesis that the pupil's response during affective picture viewing reflects emotional arousal associated with increased sympathetic activity.

The pupil as a measure of emotional arousal and autonomic activation

Pupil diameter was monitored during picture viewing to assess effects of hedonic valence and emotional arousal on pupillary responses. Autonomic activity (heart rate and skin conductance) was concurrently measured to determine whether pupillary changes are mediated by parasympathetic or sympathetic activation. Following an initial light reflex, pupillary changes were larger when viewing emotionally arousing pictures, regardless of whether these were pleasant or unpleasant. Pupillary changes during picture viewing covaried with skin conductance change, supporting the interpretation that sympathetic nervous system activity modulates these changes in the context of affective picture viewing. Taken together, the data provide strong support for the hypothesis that the pupil's response during affective picture viewing reflects emotional arousal associated with increased sympathetic activity.

Gender differences in reported dental fear and fear of dental pain

OBJECTIVES

Gender differences in dental fear have been of increasing interest among clinicians and researchers. The objectives of this study were to assess: (i) gender differences in reports of global dental fear, global fear of dental pain, and specific fear of dental pain; (ii) how the wording of questions about specific fear of dental pain influences a subjective report, and (iii) the interactions between gender differences and wording effects in the reports of specific fear of dental pain.

METHODS

A telephonic survey of 504 adult Floridians was conducted in 2004. Data collected included six measures of specific fear of dental pain, one measure of global fear of dental pain, one measure of global dental fear, and demographic information.

RESULTS

Women were more likely to report global dental fear, global fear of dental pain, and specific fear of dental pain than men, and both women and men were more likely to report 'dread' of dental pain than 'fear' of dental pain.

CONCLUSIONS

Our findings suggest that: (i) there are gender differences in reports of dental fear and fear of dental pain; and (ii) both men and women are more willing to express their fearful feelings regarding dentistry using a more socially acceptable term.

Affective picture perception: emotion, context, and the late positive potential

Event-related potentials (ERP) were measured when pleasant, neutral or unpleasant pictures were presented in the context of similarly valenced stimuli, and compared to ERPs elicited when the same pictures were viewed in an intermixed context. An early ERP component (150-300 ms) measured over occipital and fronto-central sensors was specific to viewing pleasant pictures and was not affected by presentation context. Replicating previous studies, emotional pictures prompted a larger late positive potential (LPP, 400-700 ms) and a larger positive slow wave (1-6 s) over centro-parietal sensors that also did not differ by presentation context. On the other hand, ERPs elicited when viewing neutral pictures varied as a function of context, eliciting somewhat larger LPPs when presented in blocks, and prompting smaller slow waves over occipital sensors. Taken together, the data indicate that emotional pictures prompt increased attention and orienting that is unaffected by its context of presentation, whereas neutral pictures are more vulnerable to context manipulations.

Rapid picture processing: affective primes and targets

In rapid serial visual presentation of pictures, an early ERP component shows enlarged negativity over occipital regions for emotional, compared to neutral, pictures. The present study examined the processing of emotional target pictures as a function of the hedonic valence of a preceding prime picture. Dense sensor ERPs were measured while subjects viewed a continuous stream of pleasant, neutral, and unpleasant pictures, presented for 335 ms each. Two main findings were observed: First, replicating previous results, emotional target pictures were associated with a larger posterior negativity, compared to neutral pictures. Second, the emotional content of the preceding prime picture affected target processing, with pleasant or unpleasant primes resulting in reduced negativity of the following picture, irrespective of its emotional valence. These findings are discussed within a framework of competition among successive pictures.

Fear of pain and defensive activation

Fear of pain and its relationship to dental fear was investigated by measuring autonomic reactions (skin conductance and heart rate) in individuals reporting high and low dental fear when in the presence of a cue that threatened the presentation of electric shock ("threat") or not ("safe"). Acoustic startle probes were also presented during both threat and safe periods, and the reflexive eye blink, the skin conductance response, and cardiac changes to the startle probe measured. All participants reacted with greater defensive reactivity, including potentiated startle blinks, heightened skin conductance, and cardiac deceleration in the context of threat, compared to safe, cues. Individuals reporting high dental fear were significantly more reactive during threat periods, compared to low fear individuals, showing larger blink reflexes and heightened electrodermal activity, as well as heightened autonomic responses to the startle probe itself. Individual differences in defensive reactivity persisted even after participants received a single mild shock halfway through the experiment. The data indicate that threat of shock elicits heightened defensive reactivity in those reporting high dental fear, consistent with the hypothesis that fear of potentially painful events may be a potent mediator of the anxiety involved in anticipated medical and dental treatment.

Effect of fear on dental utilization behaviors and oral health outcome

OBJECTIVES

This paper assesses the effect of fear on a number of dental utilization behaviors and oral heath outcome in a sample of adult Floridians.

METHODS

A telephone survey was conducted in 2004 among 504 adult Floridians. Data collected included sociodemographic factors, specific fear of dental pain (FDP), global FDP, global dental fear, three measures of dental utilization behaviors, and one measure of oral health outcome. Chi-squared tests and logistic regression analyses were conducted to quantify the individual and multivariate associations between fear factors and four behavior and outcome measures.

RESULTS

Global FDP was significantly associated with putting off making a dental appointment and approach to dental treatment. Global dental fear showed an independent negative impact on all four behavior and outcome measures; reports regarding specific fear of painful dental events were not significantly associated with four behavior and outcome measures.

CONCLUSIONS

Our findings suggest that: (i) dental fear and FDP have independent negative effects on dental utilization behaviors and oral health outcome after controlling for other sociodemographic and general health factors; and (ii) global dental fear encompasses broader components than FDP.

Immunosuppressive total lymphoid irradiation-based reconditioning regimens enable engraftment after graft rejection or graft failure in patients treated with allogeneic hematopoietic stem cell transplantation

PURPOSE

To retrospectively evaluate the efficacy of total lymphoid irradiation (TLI)-based reconditioning regimens in patients with graft failure or graft rejection after allogeneic hematopoietic stem cell transplantation.

METHODS AND MATERIALS

The results of 14 patients (7 adults and 7 children) with a variety of hematologic malignant diseases treated with a TLI-based reconditioning regimen with 7-Gy single-dose application plus anti-T-lymphocyte antibody OKT3 (n = 11) and/or antithymocyte globulin (n = 7)/fludarabine (n = 9), followed by an infusion of peripheral blood stem cells (n = 13) or bone marrow stem cells (n = 1) from related or unrelated donors, were retrospectively analyzed.

RESULTS

Of the 14 recipients, the data from 11 were evaluable for engraftment after TLI-based reconditioning because 3 adults died early (at Day 2, 5, and 15) after the second transplantation of infectious complications. Engraftment in 4 adults was seen after a median of 12 days (range, 10-18) and occurred after a median of 10 days (range, 9-32) in the 7 children. TLI-based reconditioning was well-tolerated with no severe toxicity. The median overall survival and disease-free survival for the whole cohort was 140 days (range, 5-1,268). After a median follow-up of 681 days, the disease-free survival and overall survival rate was 85.7% and 85.7%, respectively, in the children. Despite engraftment in the 4 remaining adults, 1 died of fatal graft-vs.-host disease, 1 of infectious complications, 1 of disease relapse, and 1 of acute respiratory distress syndrome.

CONCLUSIONS

In patients with graft failure or graft rejection after allogeneic hematopoietic stem cell transplantation, TLI-based reconditioning regimens allow sustained engraftment, paralleled by a favorable toxicity profile, potentially leading to long-term survival.

Pleasure rather than salience activates human nucleus accumbens and medial prefrontal cortex

Recent human functional imaging studies have linked the processing of pleasant visual stimuli to activity in mesolimbic reward structures. However, whether the activation is driven specifically by the pleasantness of the stimulus, or by its salience, is unresolved. Here we find in two studies that free viewing of pleasant images of erotic and romantic couples prompts clear, reliable increases in nucleus accumbens (NAc) and medial prefrontal cortex (mPFC) activity, whereas equally arousing (salient) unpleasant images, and neutral pictures, do not. These data suggest that in visual perception, the human NAc and mPFC are specifically reactive to pleasant, rewarding stimuli and are not engaged by unpleasant stimuli, despite high stimulus salience.

Brain potentials in perception: Picture complexity and emotional arousal

Event-related potentials (ERPs) were measured while participants viewed affectively arousing and neutral pictures depicting either simple figure-ground compositions or more complex scenes to assess the timing and topography of perceptual and emotional modulation. Emotional pictures elicited a larger late positive potential than neutral pictures in a 400-700-ms window over centro-parietal sensors both for pictures with simple figure-ground composition and for more complex scenes. Picture composition affected ERPs beginning earlier (around 150 ms), with simple figure-ground compositions eliciting less positivity over posterior sensors and less negativity over frontal sensors. Emotionality had little effect on modulation of these early ERPs. These data suggest that the late centro-parietal positive potential primarily reflects motivational relevance, and that earlier posterior (and anterior) components reflect, at least in part, differences in a picture's perceptual organization.

Cross-modal attention capture by affective stimuli: Evidence from event-related potentials

The P3 component of the event-related potential (ERP) to an acoustic startle probe is modulated during picture viewing, with reduced P3 amplitude when participants view either pleasant or unpleasant, as opposed to neutral, pictures. We have interpreted this as reflecting capture of attentional resources by affective pictures, with fewer resources available for processing the secondary startle probe. In the present study, we tested this resource allocation hypothesis by presenting either pictures or sounds as foreground stimuli, with the prediction that P3 amplitude in response to secondary startle probes would be reduced for affectively engaging foregrounds regardless of modality. Using dense-array electroencephalography and a source estimation procedure, we observed that P3 amplitude was indeed smaller when startle probes were presented during emotional, as opposed to neutral, stimuli for both sound and picture foregrounds. Source modeling indicated a common frontocentral maximum of P3 modulation by affect. The data support the notion that emotionally arousing stimuli transmodally attract resources, leading to optimized processing of the affective stimuli at the cost of the processing of concurrent stimuli.

A multi-process account of startle modulation during affective perception

Modulation of the startle reflex by sensory, attentional, and emotional processes was explored by presenting acoustic startle probes at various delays following picture onset. Within 500 ms of onset, blinks were first greatly facilitated and then inhibited, indicating prepulse facilitation and prepulse inhibition that did not vary with affect. Attention allocation to the picture continued across the viewing interval and was most pronounced for emotional pictures, as determined by attenuation of the P3 component to the startle probe. Startle potentiation for unpleasant pictures occurred later in the viewing interval and was strongest for highly arousing pictures. Taken together, the startle reflex during picture viewing is modulated by sequential and sometimes concurrent processes of prepulse facilitation, prepulse inhibition, attentional inhibition, and affective modulation, with reflex magnitude reflecting the net effect of multiple processes.

Emotional Perception: Correlation of Functional MRI and Event-Related Potentials

Dense-array electrocortical and functional hemodynamic measures of human brain activity were collected to assess the relationship between 2 established neural measures of emotional reactivity. Recorded in parallel sessions, the slow-wave late positive potential (LPP) and visual cortical blood oxygen level-dependent (BOLD) signals were both modulated by the rated intensity of picture arousal. The amplitude of the LPP correlated significantly with BOLD intensity in lateral occipital, inferotemporal, and parietal visual areas across picture contents. Estimated strength of modeled regional sources did not correlate significantly with regional BOLD intensity. These data suggest that the enhanced positive slow wave seen over posterior sites during emotional picture processing represents activity in a circuit of visual cortical structures, reflecting a perceptual sensitivity to the motivational relevance of visual scenes.

Panic and fear induced by deep brain stimulation

BACKGROUND

Mood, cognitive, and behavioural changes have been reported with deep brain stimulation (DBS) in the thalamus, globus pallidus interna, and anterior limb of the internal capsule/nucleus accumbens region.

OBJECTIVE

To investigate panic and fear resulting from DBS.

METHODS

Intraoperative DBS in the region of the right and then left anterior limb of the internal capsule and nucleus accumbens region was undertaken to treat a 52 year old man with treatment refractory obsessive-compulsive disorder (OCD). Mood, anxiety, OCD, alertness, heart rate, and subjective feelings were recorded during intraoperative test stimulation and at follow up programming sessions.

RESULTS

DBS at the distal (0) contact (cathode 0-, anode 2+, pulse width 210 ms, rate 135 Hz, at 6 volts) elicited a panic attack (only seen at the (0) contact). The patient felt flushed, hot, fearful, and described himself as having a "panic attack." His heart rate increased from 53 to 111. The effect (present with either device) was witnessed immediately after turning the device on, and abruptly ceased in the off condition

CONCLUSIONS

DBS of the anterior limb of the internal capsule and nucleus accumbens region caused severe "panic." This response may result from activation of limbic and autonomic networks.

Fleeting images: rapid affect discrimination in the visual cortex

Converging electrophysiological and hemodynamic findings indicate sensory processing of emotional pictures is preferred to that of neutral pictures. Whereas neuroimaging studies of emotional picture perception have employed stimulus durations lasting several seconds, recent electrocortical investigations report early visual cortical discrimination between emotionally arousing and neutral picture processing. Here, we use a hybrid picture presentation paradigm covering a range of rapid presentation rates (0.75-6 Hz), while visual system activity is recorded with functional magnetic resonance imaging. Results demonstrate widespread sensitivity to emotional arousal in the secondary and inferior temporal visual cortex. Furthermore, activity in the lateral inferior occipital and medial inferior temporal visual cortex revealed equivalent emotion-sensitive activation across all presentation rates. Results further support the notion that attention and perceptual processing are in part directed by underlying motivational systems.

Rapid picture presentation and affective engagement

Emotional reactions were assessed to pictorial stimuli presented in a continuous stream at rapid speeds that compromise conceptual memory and the processing of specific picture content. Blocks of unpleasant, neutral, or pleasant pictures were presented at the rate of either three pictures per second or seven pictures per second. Even with rapid presentation rates, startle reflexes, corrugator muscle activity, and skin conductance responses were heightened when viewing unpleasant pictures. These effects were stronger later in the aversive block, suggesting that cumulative exposure increasingly activates the defense system. The findings suggest that, despite conceptual masking inherent in rapid serial visual presentation, affective pictures prompt measurable emotional engagement.

The neural basis of narrative imagery: emotion and action

It has been proposed that narrative emotional imagery activates an associative network of stimulus, semantic, and response (procedural) information. In previous research, predicted response components have been demonstrated through psychophysiological methods in peripheral nervous system. Here we investigate central nervous system concomitants of pleasant, neutral, and unpleasant narrative imagery with functional magnetic resonance imaging. Subjects were presented with brief narrative scripts over headphones, and then imagined themselves engaged in the described events. During script perception, auditory association cortex showed enhanced activation during affectively arousing (pleasant and unpleasant), relative to neutral imagery. Structures involved in language processing (left middle frontal gyrus) and spatial navigation (retrosplenium) were also active during script presentation. At the onset of narrative imagery, supplementary motor area, lateral cerebellum, and left inferior frontal gyrus were initiated, showing enhanced signal change during affectively arousing (pleasant and unpleasant), relative to neutral scripts. These data are consistent with a bioinformational model of emotion that considers response mobilization as the measurable output of narrative imagery.

Emotion, motivation, and the brain: Reflex foundations in animal and human research

This review will focus on a motivational circuit in the brain, centered on the amygdala, that underlies human emotion. This neural circuitry of appetitive/approach and defensive/avoidance was laid down early in our evolutionary history in primitive cortex, sub-cortex, and mid-brain, to mediate behaviors basic to the survival of individuals and the propagation of genes to coming generations. Thus, events associated with appetitive rewards, or that threaten danger or pain, engage attention and prompt information gathering more so than other input. Motive cues also occasion metabolic arousal, anticipatory responses, and mobilize the organism to prepare for action. Findings are presented from research with animals, elucidating these psychophysiological (e.g., cardiovascular, neuro-humoral) and behavioral (e.g., startle potentiation, "freezing") patterns in emotion, and defining their mediating brain circuits. Parallel results are described from experiments with humans, showing similar activation patterns in brain and body in response to emotion cues, co-varying with participants' reports of affective valence and increasing emotional arousal.

Parafoveal semantic processing of emotional visual scenes

The authors investigated whether emotional pictorial stimuli are especially likely to be processed in parafoveal vision. Pairs of emotional and neutral visual scenes were presented parafoveally (2.1 degrees or 2.5 degrees of visual angle from a central fixation point) for 150-3,000 ms, followed by an immediate recognition test (500-ms delay). Results indicated that (a) the first fixation was more likely to be placed onto the emotional than the neutral scene; (b) recognition sensitivity (A') was generally higher for the emotional than for the neutral scene when the scenes were paired, but there were no differences when presented individually; and (c) the superior sensitivity for emotional scenes survived changes in size, color, and spatial orientation, but not in meaning. The data suggest that semantic analysis of emotional scenes can begin in parafoveal vision in advance of foveal fixation.

When good things go bad: the reflex physiology of defense

For humans, the threat of painful shock greatly potentiates the reflexive startle blink. Moreover, viewing unpleasant, compared with pleasant, pictures also prompts heightened startle reflexes, suggesting that the startle reflex indexes general defensive activation. In this study, pleasant or unpleasant pictures were used to signal shock threat in order to explore how previous affective associations modulate new defensive reactions. When cuing threat of shock, pleasant and unpleasant pictures prompted physiological profiles consistent with defensive activation, indicating that threat of shock renders previously pleasant cues aversive. For unpleasant pictures only, defensive startle was potentiated even when these cues signaled safety. Taken together, the data indicate that (a) regardless of their intrinsic affective meaning, cues signaling shock threat prompt somatic and autonomic reactions consistent with defense, and that (b) intrinsically unpleasant cues continue to prompt defensive activation even when the context of their presentation is specifically non-threatening.

Affective reactions to pictures of ingroup and outgroup members

A pervasive form of social categorization among humans is between us and them. In this study, we assessed emotional reactions when people viewed pictures depicting members of the same or different ethnic group. African American and European American participants viewed a series of pleasant and unpleasant pictures portraying either ingroup or outgroup members, while physiological, behavioral, and evaluative judgments were measured. Two hypotheses were assessed. The outgroup antipathy hypothesis predicts that people will respond to outgroup pictures with more negative affect than to ingroup pictures. In contrast, the ingroup empathy hypothesis predicts that people will show exaggerated (pleasant and unpleasant) affective responses to pictures of ingroup members, due to group identification or personal relevance. The data provided no support for the antipathy hypothesis, whereas facial EMG, skin conductance, rating, and viewing time data lent support to the ingroup empathy hypothesis, in which greater pleasure and displeasure were apparent when viewing ingroup pictures.