ARTICLE UPDATE - An electrophysiological study on the interaction between emotional content and spatial frequency of visual stimuli

Luis Carretié, José A. Hinojosa, Sara López-Martín and Manuel Tapia

Neuropsychologia, in press

Previous studies suggest that the magnocellular pathway, a visual processing system that rapidly provides low spatial frequency information to fast-responding structures such as the amygdala, is more involved in the processing of emotional facial expressions than the parvocellular pathway (which conveys all spatial frequencies). The present experiment explored the spatio-temporal characteristics of the spatial frequency modulation of affect-related neural processing, as well as its generalizability to non-facial stimuli. To that aim, the event-related potentials (ERPs) elicited by low-pass filtered (i.e., high spatial frequencies are eliminated) and intact non-facial emotional images were recorded from 31 participants using a 60-electrode array. The earliest significant effect of spatial frequency was observed at 135 ms from stimulus onset: N135 component of the ERPs. In line with previous studies, the origin of N135 was localized at secondary visual areas for low-pass filtered stimuli and at primary areas for intact stimuli. Importantly, this component showed an interaction between spatial frequency and emotional content: within low-pass filtered pictures, negative stimuli elicited the highest N135 amplitudes. By contrast, within intact stimuli, neutral pictures were those eliciting the highest amplitudes. These results suggest that high spatial frequencies are not essential for the initial affect-related processing of visual stimuli, which would mainly rely on low spatial frequency visual information. According to present data, high spatial frequencies would come into play later on.

ARTICLE UPDATE - Is this happiness I see? Biases in the identification of emotional facial expressions in depression and social phobia.

Joormann J, Gotlib IH.

Journal of Abnormal Psychology, 115, 705-714.

The present study was designed to examine the operation of depression-specific biases in the identification or labeling of facial expression of emotions. Participants diagnosed with major depression and social phobia and control participants were presented with faces that expressed increasing degrees of emotional intensity, slowly changing from a neutral to a full-intensity happy, sad, or angry expression. The authors assessed individual differences in the intensity of facial expression of emotion that was required for the participants to accurately identify the emotion being expressed. The depressed participants required significantly greater intensity of emotion than did the social phobic and the control participants to correctly identify happy expressions and less intensity to identify sad than angry expressions. In contrast, social phobic participants needed less intensity to correctly identify the angry expressions than did the depressed and control participants and less intensity to identify angry than sad expressions. Implications of these results for interpersonal functioning in depression and social phobia are discussed.

ARTICLE UPDATE - Green love is ugly: Emotions elicited by synesthetic grapheme-color perceptions.

Callejas A, Acosta A, Lupianez J.

Brain Research, in press

Synesthetes who experience grapheme-color synesthesia often report feeling uneasy when dealing with incongruently colored graphemes although no empirical data is available to confirm this phenomenon. We studied this affective reaction related to synesthetic perceptions by means of an evaluation task. We found that the perception of an incorrectly colored word affects the judgments of emotional valence. Furthermore, this effect competed with the word's emotional valence in a categorization task thus supporting the automatic nature of this synesthetically elicited affective reaction. When manipulating word valence and word color-photism congruence, we found that responses were slower (and less accurate) for inconsistent conditions than for consistent conditions. Inconsistent conditions were defined as those where semantics and color-photism congruence did not produce a similar assessment and therefore gave rise to a negative affective reaction (i.e., positive-valence words presented in a color different from the synesthete's photism or negative-valence words presented in the photism's color). We therefore observed a modulation of the congruency effect (i.e., faster reaction times to congruently colored words than incongruently colored words). Although this congruence effect has been taken as an index of the true experience of synesthesia, we observed that it can be reversed when the experimental manipulations turn an incongruently colored word into a consistent stimulus. To our knowledge, this is the first report of an affective reaction elicited by the congruency between the synesthetically induced color of a word and the color in which the word is actually presented. The underlying neural mechanisms that might be involved in this phenomenon are discussed.

ARTICLE UPDATE - Recent fear is resistant to extinction

Stephen Maren and Chun-hui Chang

PNAS, 103, 18020-18025

In some individuals, fearful experiences (e.g., combat) yield persistent and debilitating psychological disturbances, including posttraumatic stress disorder (PTSD). Early intervention (e.g., debriefing) after psychological trauma is widely practiced and argued to be an effective strategy for limiting subsequent psychopathology, although there has been considerable debate on this point. Here we show in an animal model of traumatic fear that early intervention shortly after an aversive experience yields poor long-term fear reduction. Extinction trials administered minutes after aversive fear conditioning in rats suppressed fear acutely, but fear suppression was not maintained the next day. In contrast, delivering extinction trials 1 day after fear conditioning produced an enduring suppression of fear memory. We further show that the recent experience of an aversive event, not the timing of the extinction intervention per se, inhibits the development of long-term fear extinction. These results reveal that the level of fear present at the time of intervention is a critical factor in the efficacy of extinction. Importantly, our work suggests that early intervention may not yield optimal outcomes in reducing posttraumatic stress, particularly after severe trauma.

ARTICLE UPDATE - Neural dynamics for facial threat processing as revealed by gamma band synchronization using MEG

Neural dynamics for facial threat processing as revealed by gamma band synchronization using MEG

Qian Luo, Tom Holroyd, Matthew Jones, Talma Hendler, and James Blair

NeuroImage, in press

Facial threat conveys important information about imminent environmental danger. The rapid detection of this information is critical for survival and social interaction. However, due to technical and methodological difficulties, the spatiotemporal profile for facial threat processing is unknown. By utilizing magnetoencephalography (MEG), a brain-imaging technique with superb temporal resolution and fairly good spatial resolution, Synthetic Aperture Magnetometry (SAM), a recently developed source analysis technique, and a sliding window analysis, we identified the spatiotemporal development of facial threat processing in the gamma frequency band. We also tested the dual-route hypothesis by LeDoux who proposed, based on animal research, that there are two routes to the amygdala: a quick subcortical route and a slower and cortical route. Direct evidence with humans supporting this model has been lacking. Moreover, it has been unclear whether the subcortical route responds specifically to fearful expressions or to threatening expressions in general. We found early event-related synchronizations (ERS) in response to fearful faces in the hypothalamus/thalamus area (10–20 ms) and then the amygdala (20–30 ms). This was even earlier than the ERS response seen to fearful faces in visual cortex (40–50 ms). These data support LeDoux's suggestion of a quick, subcortical thamalo-amygdala route. Moreover, this route was specific for fear expressions; the ERS response in the amygdala to angry expressions had a late onset (150–160 ms). The ERS onset in prefrontal cortex followed that seen within the amygdala (around 160–210 ms). This is consistent with its role in higher-level emotional/cognitive processing.

ARTICLE UPDATE - Mood Alters Amygdala Activation to Sad Distractors During an Attentional Task

Lihong Wang, Kevin S. LaBar and Gregory McCarthy

Biological Psychiatry, 60, 1139-1146

Background

A behavioral hallmark of mood disorders is biased perception and memory for sad events. The amygdala is poised to mediate internal mood and external event processing because of its connections with both the internal milieu and the sensory world. There is little evidence showing that the amygdala’s response to sad sensory stimuli is functionally modulated by mood state, however.
Methods

We investigated the impact of mood on amygdala activation evoked by sad and neutral pictures presented as distractors during an attentional oddball task. Healthy adults underwent functional magnetic resonance imaging during task runs that were preceded by sad or happy movie clips. Happy and sad mood induction was conducted within-subjects on consecutive days in counterbalanced order.
Results

Amygdala activation to sad distractors was enhanced after viewing sad movies relative to happy ones and was correlated with reaction time costs to detect attentional targets. The activation was higher in female subjects in the right hemisphere. The anterior cingulate, ventromedial and orbital prefrontal cortex, insula, and other posterior regions also showed enhanced responses to sad distractors during sad mood.
Conclusions

These findings reveal brain mechanisms that integrate emotional input and current mood state, with implications for understanding cognitive distractibility in depression.

ARTICLE UPDATE - Detecting fearful and neutral faces: BOLD latency differences in amygdala–hippocampal junction

A.A.T.S. Reinders, J. Gläscher, J.R. de Jong, A.T.M. Willemsen, J.A. den Boer and C. Büchel

NeuroImage, 33, 805-814

Evolutionary survival and procreation are augmented if an individual organism quickly detects environmental threats and rapidly initiates defensive behavioral reactions. Thus, facial emotions signaling a potential threat, e.g., fear or anger, should be perceived rapidly and automatically, possibly through a subcortical processing route which includes the amygdala. Using event-related functional magnetic resonance imaging (fMRI), we investigated the time course of the response in the amygdala to neutral and fearful faces, which appear from dynamically decreasing random visual noise. We aimed to detect differences of the amygdala response between fearful and neutral faces by estimating the latency of the blood oxygenation level-dependent (BOLD) response. We found that bilateral amygdala–hippocampal junction activation occurred earlier for fearful than for neutral faces. Our findings support the theory of a dual route architecture in which the subcortical thalamic–hippocampal–amygdala route serves fast preconscious threat perception.

ARTICLE UPDATE - A gender- and sexual orientation-dependent spatial attentional effect of invisible images

Yi Jiang, Patricia Costello, Fang Fang, Miner Huang, and Sheng He

PNAS, 103, 17048-17052

Human observers are constantly bombarded with a vast amount of information. Selective attention helps us to quickly process what is important while ignoring the irrelevant. In this study, we demonstrate that information that has not entered observers' consciousness, such as interocularly suppressed (invisible) erotic pictures, can direct the distribution of spatial attention. Furthermore, invisible erotic information can either attract or repel observers' spatial attention depending on their gender and sexual orientation. While unaware of the suppressed pictures, heterosexual males' attention was attracted to invisible female nudes, heterosexual females' attention was attracted to invisible male nudes, gay males behaved similarly to heterosexual females, and gay/bisexual females performed in-between heterosexual males and females.

ARTICLE UPDATE - Emotional modulation of pain: is it the sensation or what we recall?

Godinho F, Magnin M, Frot M, Perchet C, Garcia-Larrea L.

Journal of Neuroscience, 26, 11454-11461

Emotions modulate pain perception, although the mechanisms underlying this phenomenon remain unclear. In this study, we show that intensity reports significantly increased when painful stimuli were concomitant to images showing human pain, whereas pictures with identical emotional values but without somatic content failed to modulate pain. Early somatosensory responses (<200 ms) remained unmodified by emotions. Conversely, late responses showed a significant enhancement associated with increased pain ratings, localized to the right prefrontal, right temporo-occipital junction, and right temporal pole. In contrast to selective attention, which enhances pain ratings by increasing sensory gain, emotions triggered by seeing other people's pain did not alter processing in SI-SII (primary and second somatosensory areas), but may have biased the transfer to, and the representation of pain in short-term memory buffers (prefrontal), as well as the affective assignment to this representation (temporal pole). Memory encoding and recall, rather than sensory processing, appear to be modulated by empathy with others' physical suffering.