Physiological reactions at encoding selectively predict recognition of emotional images.

The study aimed to investigate the link between physiological responses at encoding and subsequent memory of emotional stimuli, differing in two dimensions: valence and arousal. The participants (all male) freely viewed emotional images, while their pupil size and heart rate were recorded. Then, they were presented with a recognition task. Both pupil constriction and heart rate deceleration evoked by an image onset at the encoding predicted its later correct recognition. However, these effects interacted with valence and arousal. Increased pupillary constriction predicted correct recognition particularly well for low-arousing and negatively valenced images. Deeper heart rate deceleration was related to higher rate of correct recognition mainly in the case of negative images. The results show also an interaction between valence and arousal in their effect on memory. Higher arousal was linked to better recognition, but only when images were of neutral or positive valence. In contrast, negative images were remembered accurately, regardless of the level of arousal. This pattern of results supports the primacy of negative information in early memory consolidation. Overall, we demonstrate that physiological reactions at encoding - which can be linked to the depth of stimulus processing during memory formation - predict recognition accuracy. The emotional load of stimuli further modulates the prediction strength.

Restricting movements of lower face leaves recognition of emotional vocalizations intact but introduces a valence positivity bias.

Blocking facial mimicry can disrupt recognition of emotion stimuli. Many previous studies have focused on facial expressions, and it remains unclear whether this generalises to other types of emotional expressions. Furthermore, by emphasizing categorical recognition judgments, previous studies neglected the role of mimicry in other processing stages, including dimensional (valence and arousal) evaluations. In the study presented herein, we addressed both issues by asking participants to listen to brief non-verbal vocalizations of four emotion categories (anger, disgust, fear, happiness) and neutral sounds under two conditions. One of the conditions included blocking facial mimicry by creating constant tension on the lower face muscles, in the other condition facial muscles remained relaxed. After each stimulus presentation, participants evaluated sounds' category, valence, and arousal. Although the blocking manipulation did not influence emotion recognition, it led to higher valence ratings in a non-category-specific manner, including neutral sounds. Our findings suggest that somatosensory and motor feedback play a role in the evaluation of affect vocalizations, perhaps introducing a directional bias. This distinction between stimulus recognition, stimulus categorization, and stimulus evaluation is important for understanding what cognitive and emotional processing stages involve somatosensory and motor processes.

Blue blood, red blood. How does the color of an emotional scene affect visual attention and pupil size?

The function of color in the processing of emotional scenes is not entirely clear. While there are studies showing that color matters in terms of the capture of covert attention by emotional stimuli, the impact of color on fixation patterns, reflecting overt attention, is unresolved. Studies on the role of color in evoking emotional response have also produced mixed results. Here, we aimed to explore how image color and content influence pupillary response and the engagement of overt visual attention. In the first experiment, we examined the pupillary reaction to neutral images (intact and phase scrambled) in three color variants (natural, abnormal, and grayscale). In the second experiment, we investigated the pupillary changes and fixation pattern in response to images of different valence (neutral, positive, and negative), again in three color versions. The results showed that pupillary responses were influenced by both content and the color of the images. The pupillary response to phase-scrambled images did not differ between the color versions. Intact neutral and positive images, but not negative ones, evoked smaller pupil responses if they were presented in abnormal colors rather than natural ones. The initial capture of attention by emotional content depended on the color version, whereas holding of attention was affected solely by the emotional valence. Thus, color changes the physiological response to images, particularly low-arousing ones, and modulates the initial engagement of attention by image content.

Phase of the menstrual cycle affects engagement of attention with emotional images.

Changes that occur during the menstrual cycle affect various aspects of behavior, cognition, and emotion. Here, we focused on potential differences between early follicular and midluteal phases in the way women process images of behaviorally relevant content categories: children, threat, disgust, erotic scenes, low- and high-calorie food. Using eye-tracking, we examined women's engagement of attention in the key region of each image in a free-viewing condition. Specifically, we tested how quickly attention was attracted to these regions and for how long it was held there. Participants took part in two experimental sessions, one in the early follicular and one in the midluteal phase. The results showed that in the midluteal phase attention was attracted to the key region earlier than in the early follicular phase: the first fixation more often fell within the key region and there were fewer fixations preceding it. While the effect of the phase in terms of the capture of attention did not depend on the image category, the effect regarding the hold of attention was category-specific, concerning the disgust category only. Specifically, in the midluteal phase the duration of the exploration of the key region between reaching it for the first time and first exiting it was shorter, which might be due to heightened sensitivity to disgusting stimuli in this period. Overall, our results indicate the occurrence of changes in attentional processing of emotional scenes related to the menstrual cycle, which seem to differ depending on the aspect of attention deployment: in the midluteal phase the effect of enhancing orienting was general and concerned any important visual information, whereas the effect of the shortened hold of attention appeared to be limited to specific content.

Disentangling brain activity related to the processing of emotional visual information and emotional arousal.

Processing of emotional visual information engages cognitive functions and induces arousal. We aimed to examine the modulatory role of emotional valence on brain activations linked to the processing of visual information and those linked to arousal. Participants were scanned and their pupil size was measured while viewing negative and neutral images. The visual noise was added to the images in various proportions to parametrically manipulate the amount of visual information. Pupil size was used as an index of physiological arousal. We show that arousal induced by the negative images, as compared to the neutral ones, is primarily related to greater amygdala activity while increasing visibility of negative content to enhanced activity in the lateral occipital complex (LOC). We argue that more intense visual processing of negative scenes can occur irrespective of the level of arousal. It may suggest that higher areas of the visual stream are fine-tuned to process emotionally relevant objects. Both arousal and processing of emotional visual information modulated activity within the ventromedial prefrontal cortex (vmPFC). Overlapping activations within the vmPFC may reflect the integration of these aspects of emotional processing. Additionally, we show that emotionally-evoked pupil dilations are related to activations in the amygdala, vmPFC, and LOC.

Effects of Scene Properties and Emotional Valence on Brain Activations: A Fixation-Related fMRI Study.

Temporal and spatial characteristics of fixations are affected by image properties, including high-level scene characteristics, such as object-background composition, and low-level physical characteristics, such as image clarity. The influence of these factors is modulated by the emotional content of an image. Here, we aimed to establish whether brain correlates of fixations reflect these modulatory effects. To this end, we simultaneously scanned participants and measured their eye movements, while presenting negative and neutral images in various image clarity conditions, with controlled object-background composition. The fMRI data were analyzed using a novel fixation-based event-related (FIBER) method, which allows the tracking of brain activity linked to individual fixations. The results revealed that fixating an emotional object was linked to greater deactivation in the right lingual gyrus than fixating the background of an emotional image, while no difference between object and background was found for neutral images. We suggest that deactivation in the lingual gyrus might be linked to inhibition of saccade execution. This was supported by fixation duration results, which showed that in the negative condition, fixations falling on the object were longer than those falling on the background. Furthermore, increase in the image clarity was correlated with fixation-related activity within the lateral occipital complex, the structure linked to object recognition. This correlation was significantly stronger for negative images, presumably due to greater deployment of attention towards emotional objects. Our eye-tracking results are in line with these observations, showing that the chance of fixating an object rose faster for negative images over neutral ones as the level of noise decreased. Overall, our study demonstrated that emotional value of an image changes the way that low and high-level scene properties affect the characteristics of fixations. The fixation-related brain activity is affected by the low-level scene properties and this impact differs between negative and neutral images. The high-level scene properties also affect brain correlates of fixations, but only in the case of the negative images.

Editorial Special Issue: Neuronus.

This special issue of the 12th volume of Advances in Cognitive Psychology is devoted to the Neuronus conference that took place in Kraków in 2015. In this editorial letter, we will focus on a selection of the materials and some follow-up research that was presented during this conference. We will also briefly introduce the conference contributions that successfully passed an external reviewing process.

The color red attracts attention in an emotional context. An ERP study.

The color red is known to influence psychological functioning, having both negative (e.g., blood, fire, danger), and positive (e.g., sex, food) connotations. The aim of our study was to assess the attentional capture by red-colored images, and to explore the modulatory role of the emotional valence in this process, as postulated by Elliot and Maier (2012) color-in-context theory. Participants completed a dot-probe task with each cue comprising two images of equal valence and arousal, one containing a prominent red object and the other an object of different coloration. Reaction times were measured, as well as the event-related lateralizations of the EEG. Modulation of the lateralized components revealed that the color red captured and later held the attention in both positive and negative conditions, but not in a neutral condition. An overt motor response to the target stimulus was affected mainly by attention lingering over the visual field where the red cue had been flashed. However, a weak influence of the valence could still be detected in reaction times. Therefore, red seems to guide attention, specifically in emotionally-valenced circumstances, indicating that an emotional context can alter color's impact both on attention and motor behavior.

Emotional content of an image attracts attention more than visually salient features in various signal-to-noise ratio conditions.

Emotional images are processed in a prioritized manner, attracting attention almost immediately. In the present study we used eye tracking to reveal what type of features within neutral, positive, and negative images attract early visual attention: semantics, visual saliency, or their interaction. Semantic regions of interest were selected by observers, while visual saliency was determined using the Graph-Based Visual Saliency model. Images were transformed by adding pink noise in several proportions to be presented in a sequence of increasing and decreasing clarity. Locations of the first two fixations were analyzed. The results showed dominance of semantic features over visual saliency in attracting attention. This dominance was linearly related to the signal-to-noise ratio. Semantic regions were fixated more often in emotional images than in neutral ones, if signal-to-noise ratio was high enough to allow participants to comprehend the gist of a scene. Visual saliency on its own did not attract attention above chance, even in the case of pure noise images. Regions both visually salient and semantically relevant attracted a similar amount of fixation compared to semantic regions alone, or even more in the case of neutral pictures. Results provide evidence for fast and robust detection of semantically relevant features.

Editorial to the special issue Neuronus.

Did you visit the Neuronus conferences in the years 2012 and 2013 in Kraków? If not, then you certainly should have a close examination of this special issue including this introduction to at least have a glimpse of an idea of the highly interesting topics in the field of cognitive neuroscience that were presented at these conferences. If you were there, it is for sure a good choice to focus on this special issue as well, first to refresh your minds (we know our memories are far from perfect), but especially to see what happened with research of the presenters at these conferences.

The left visual-field advantage in rapid visual presentation is amplified rather than reduced by posterior-parietal rTMS.

In the present task, series of visual stimuli are rapidly presented left and right, containing two target stimuli, T1 and T2. In previous studies, T2 was better identified in the left than in the right visual field. This advantage of the left visual field might reflect dominance exerted by the right over the left hemisphere. If so, then repetitive transcranial magnetic stimulation (rTMS) to the right parietal cortex might release the left hemisphere from right-hemispheric control, thereby improving T2 identification in the right visual field. Alternatively or additionally, the asymmetry in T2 identification might reflect capacity limitations of the left hemisphere, which might be aggravated by rTMS to the left parietal cortex. Therefore, rTMS pulses were applied during each trial, beginning simultaneously with T1 presentation. rTMS was directed either to P4 or to P3 (right or left parietal cortex) either as effective or as sham stimulation. In two experiments, either one of these two factors, hemisphere and effectiveness of rTMS, was varied within or between participants. Again, T2 was much better identified in the left than in the right visual field. This advantage of the left visual field was indeed modified by rTMS, being further increased by rTMS to the left hemisphere rather than being reduced by rTMS to the right. It may be concluded that superiority of the right hemisphere in this task implies that this hemisphere is less irritable by external interference than the left hemisphere.

On how the motor cortices resolve an inter-hemispheric response conflict: an event-related EEG potential-guided TMS study of the flankers task.

An important aspect of human motor control is the ability to resolve conflicting response tendencies. Here we used single-pulse transcranial magnetic stimulation (TMS) to track the time course of excitability changes in the primary motor hand areas (M1(HAND)) while the motor system resolved response conflicts. Healthy volunteers had to respond fast with their right and left index fingers to right- and left-pointing arrows. These central target stimuli were preceded by flanking arrows, inducing premature response tendencies which competed with correct response activation. The time point of maximum premature activation was individually measured as peak latency of the lateralized readiness potential (LRP) in the EEG. In the subsequent TMS experiment, single pulses were applied to left or right M1(HAND) during the same flanker task. The amplitude of the motor evoked potentials in the contralateral first dorsal interosseus muscle was taken as an index of corticospinal excitability. Guided by the previous LRP measurement, magnetic stimuli were applied 0-90 ms after the individual LRP peak, to cover the epoch of conflict resolution. When flankers were incompatible with the target, excitability of the prematurely activated M1(HAND) gradually decreased during this 90 ms period. This decrease was paralleled by a mirror-symmetrical increase in excitability in the other M1(HAND). These results show that the inappropriate response tendency is cancelled in one M1(HAND) simultaneously with activation of the correct response in the other. This integrated implementation of response activation and cancellation at the level of the M1(HAND) presumably represents a downstream effect orchestrated by premotor brain regions.

Facing facts: neuronal mechanisms of face perception.

The face is one of the most important stimuli carrying social meaning. Thanks to the fast analysis of faces, we are able to judge physical attractiveness and features of their owners' personality, intentions, and mood. From one's facial expression we can gain information about danger present in the environment. It is obvious that the ability to process efficiently one's face is crucial for survival. Therefore, it seems natural that in the human brain there exist structures specialized for face processing. In this article, we present recent findings from studies on the neuronal mechanisms of face perception and recognition in the light of current theoretical models. Results from brain imaging (fMRI, PET) and electrophysiology (ERP, MEG) show that in face perception particular regions (i.e. FFA, STS, IOA, AMTG, prefrontal and orbitofrontal cortex) are involved. These results are confirmed by behavioral data and clinical observations as well as by animal studies. The developmental findings reviewed in this article lead us to suppose that the ability to analyze face-like stimuli is hard-wired and improves during development. Still, experience with faces is not sufficient for an individual to become an expert in face perception. This thesis is supported by the investigation of individuals with developmental disabilities, especially with autistic spectrum disorders (ASD).

The P3 produced by auditory stimuli presented in a passive and active condition: modulation by visual stimuli.

The aim of this study was to investigate how the processing of auditory stimuli is affected by the simultaneous presentation of visual stimuli. This was approached in an active and passive condition, during which a P3 was elicited in the human EEG by single auditory stimuli. Subjects were presented tones, either alone or accompanied by the simultaneous exposition of pictures. There were two different sessions. In the first, the presented tones demanded no further cognitive activity from the subjects (passive or 'ignore' session), while in the second session subjects were instructed to count the tones (active or 'count' session). The central question was whether inter-modal influences of visual stimulation in the active condition would modulate the auditory P3 in the same way as in the passive condition. Brain responses in the ignore session revealed only a small P3-like component over the parietal and frontal cortex, however, when the auditory stimuli co-occurred with the visual stimuli, an increased frontal activity in the window of 300-500 ms was observed. This could be interpreted as the reflection of a more intensive involuntary attention shift, provoked by the preceding visual stimulation. Moreover, it was found that cognitive load caused by the count instruction, resulted in an evident P3, with maximal amplitude over parietal locations. This effect was smaller when auditory stimuli were presented on the visual background. These findings might support the thesis that available resources were assigned to the analysis of visual stimulus, and thus were not available to analyze the subsequent auditory stimuli. This reduction in allocation of resources for attention was restricted to the active condition only, when the matching of a template with incoming information results in a distinct P3 component. It is discussed whether the putative source of this effect is a change in the activity of the frontal cortex.

Central control of heart rate changes during visual affective processing as revealed by fMRI.

In the present study we addressed the question of central control of heart rate (HR) in emotions. Parallel measurement of HR changes and changes of local intensity of blood flow as indexed by fMRI in a procedure eliciting emotions allowed us to pinpoint areas of the brain responsible for HR variations during emotional arousal. In condition eliciting positive emotions we detected activation of occipito-temporal regions, anterior insula, and hypothalamus. In condition eliciting negative emotions we also detected activation of occipito-temporal regions and additionally activation of bilateral anterior insulae, right amygdala and right superior temporal gyrus. The results show that structures constituting neural network involved in HR control during emotional arousal are affect specific. Particularly the central circuit controlling HR in negative affect includes the amygdala, while central circuit controlling HR in positive affect includes the hypothalamus. Additionally activation of bilateral occipito-temporal cortex proves enhancement of visual processing of emotional material as compared to neutral material in both positive and negative affect. This might be attributed to top-down processes originating in the frontal lobe and related to shifting attention to the emotionally relevant stimuli. Activation of insular cortex is probably related to autonomic arousal accompanying watching emotional content (e.g. sweating, heart-rate changes etc.). Activation of the amygdala in the negative condition supports the well documented engagement of this structure in processing of fear and disgust.

Correlation between long latency evoked potentials from amygdala and evoked cardiac response to fear conditioned stimulus in rats.

We investigated relation between activity of central nucleus of amygdala (CE) and phasic heart rate deceleration during differential fear conditioning. We found that P2 component of long-lasting event potential (EP) to CS+ but not to CS- correlated strongly with HR deceleration in the 1st second after stimulus onset. The obtained results are discussed in the light of LeDoux's and Kapp's findings showing crucial role of amygdala in processing of emotionally relevant stimulation and it's involvement in initiating autonomic responses.