The intracellular domain of amyloid precursor protein induces neuron-specific apoptosis

Sex differences are often reported in spatial abilities. However, some studies show conflicting results, which can be ascribed to the complexity of the variables involved in the visuo-spatial domain. Until a few years ago, it was widely accepted that men outperformed women on almost all spatial tasks. However, recently some studies [A. Postma, G. Jager, R.P.C. Kessels, H.P.F. Koppeschaar, J. van Honk, Sex differences for selective forms of spatial memory, Brain Cogn. 54 (2004) 24-34; D.H. McBurney, S.J.C. Gaulin, T. Devineni, C. Adams, Superior spatial memory of women: stronger evidence for the gathering hypothesis, Evol. Hum. Behav. 18 (1997) 165-174; Q. Rahman, G.D. Wilson, S. Abrahams, Sexual orientation related differences in spatial memory, J. Int. Neuropsychol. Soc. 9 (2003) 376-383] found sex differences for selective forms of spatial memory and described a female advantage in specific spatial abilities. In this paper, we studied sex differences by testing object locations and route memories with the Corsi Block-Tapping test (CBT), one of the non-verbal tasks most used in clinical settings, and its modified, large-scale version. Our results showed a performance advantage for males in both tests and a more homogeneous pattern of memory in females.     

Walking in the Corsi test: Which type of memory do you need?

Sex differences are often reported in spatial abilities. However, some studies show conflicting results, which can be ascribed to the complexity of the variables involved in the visuo-spatial domain. Until a few years ago, it was widely accepted that men outperformed women on almost all spatial tasks. However, recently some studies [A. Postma, G. Jager, R.P.C. Kessels, H.P.F. Koppeschaar, J. van Honk, Sex differences for selective forms of spatial memory, Brain Cogn. 54 (2004) 24–34; D.H. McBurney, S.J.C. Gaulin, T. Devineni, C. Adams, Superior spatial memory of women: stronger evidence for the gathering hypothesis, Evol. Hum. Behav. 18 (1997) 165–174; Q. Rahman, G.D. Wilson, S. Abrahams, Sexual orientation related differences in spatial memory, J. Int. Neuropsychol. Soc. 9 (2003) 376–383] found sex differences for selective forms of spatial memory and described a female advantage in specific spatial abilities. In this paper, we studied sex differences by testing object locations and route memories with the Corsi Block-Tapping test (CBT), one of the non-verbal tasks most used in clinical settings, and its modified, large-scale version. Our results showed a performance advantage for males in both tests and a more homogeneous pattern of memory in females.     

Endogenous testosterone levels are associated with amygdala and ventromedial prefrontal cortex responses to anger faces in men but not women

Testosterone moderates behavioral and physiological responses to the emotion anger. However, little is known about the effects of testosterone in the human brain in the context of the perception of anger. We used fMRI to measure BOLD responses to anger faces in the amygdala and ventromedial prefrontal cortex (vmPFC) as a function of endogenous testosterone levels in 24 participants (10 men). In one task, participants passively viewed anger faces and neutral faces and in another task, participants engaged in an oddball task while viewing anger and neutral faces. Men's, but not women's, amygdala BOLD response to anger faces was negatively correlated with their endogenous testosterone levels in both tasks. Men's, but not women's, vmPFC BOLD response to anger faces was positively correlated with their endogenous testosterone levels in the passive-viewing task. In men, amygdala and vmPFC BOLD responses to anger faces were negatively associated. Our results extend past research by documenting associations between endogenous testosterone levels and BOLD responses to anger faces in the amygdala and vmPFC in men, and our results also support research that documents negative associations between amygdala and vmPFC activity.     

Threat sensitivity as assessed by automatic amygdala response to fearful faces predicts speed of visual search for facial expression

It has been argued that the amygdala represents an integral component of a vigilance system that is primarily involved in the perception of ambiguous stimuli of biological relevance. The present investigation was conducted to examine the relationship between automatic amygdala responsivity to fearful faces which may be interpreted as an index of trait-like threat sensitivity and spatial processing characteristics of facial emotions. During 3T fMRI scanning, pictures of human faces bearing fearful, angry, and happy expressions were presented to 20 healthy volunteers using a backward masking procedure based on neutral facial expressions. Subsequently, a computer-based face-in-the-crowd task using schematic face stimuli was administered. The neural response of the (right) amygdala to masked fearful faces correlated consistently with response speed to negative and neutral faces. Neither amygdala activation during the masked presentation of angry faces nor amygdala activation during the presentation of happy faces was correlated with any of the response latencies in the face-in-the-crowd task. Our results suggest that amygdala responsivity to masked facial expression is differentially related to the general visual search speed for facial expression. Neurobiologically defined threat sensitivity seems to represent an important determinant of visual scanning behaviour.     

Are two threats worse than one? The effects of face race and emotional expression on fear conditioning

Facial cues of racial outgroup or anger mediate fear learning that is resistant to extinction. Whether this resistance is potentiated if fear is conditioned to angry, other race faces has not been established. Two groups of Caucasian participants were conditioned with two happy and two angry face conditional stimuli (CSs). During acquisition, one happy and one angry face were paired with an aversive unconditional stimulus whereas the second happy and angry faces were presented alone. CS face race (Caucasian, African American) was varied between groups. During habituation, electrodermal responses were larger to angry faces regardless of race and declined less to other race faces. Extinction was immediate for Caucasian happy faces, delayed for angry faces regardless of race, and slowest for happy racial outgroup faces. Combining the facial cues of other race and anger does not enhance resistance to extinction of fear.     

Enhanced perceptual responses during visual processing of facial stimuli in young socially anxious individuals

The present study investigated whether social anxiety modulates the processing of facial expressions. Event-related potentials were recorded during an oddball task in young adults reporting high or low levels of social anxiety as evaluated by the Liebowitz Social Anxiety Scale. Repeated pictures of faces with a neutral expression were infrequently replaced by pictures of the same face displaying happiness, anger, fear or disgust. For all participants, response latencies were shorter in detecting faces expressing disgust and happiness as compared to fear or anger. Low social anxiety individuals evoked enhanced P1 in response to angry faces as compared to other stimuli while high socially anxious participants displayed enlarged P1 for all emotional stimuli as compared to neutral ones, and general higher amplitudes as compared to non-anxious individuals. Conversely, the face-specific N170 and the task-related decision P3b were not influenced by social anxiety. These results suggest increased pre-attentive detection of facial cues in socially anxious individuals and are discussed within the framework of recent models of anxiety.     

In the face of anger: Startle modulation to graded facial expressions

In the present study, the startle reflex was examined with respect to the degree of anger displayed in facial expressions. To this end, 52 participants viewed faces that were morphed to display 0, 20, 40, 60, 80, or 100% anger. As the percentage of anger in faces increased from 0 to 100%, faces were perceived as increasingly angry; however, relative to neutral facial expressions, startle amplitude was only potentiated to maximally angry faces. These data imply a non‐linear relationship between the intensity of angry faces and defensive physiological activity. This pattern of startle modulation suggests a categorical distinction between threatening (100% anger) and other facial expressions presented. These results are further discussed in terms of existing data, and how this paradigm might be utilized in psychopathology research.     

Effects of sleep loss on emotion recognition: a dissociation between face and word stimuli

Short-term sleep deprivation, or extended wakefulness, adversely affects cognitive functions and behavior. However, scarce research has addressed the effects of sleep deprivation (SD) on emotional processing. In this study, we investigated the impact of reduced vigilance due to moderate sleep deprivation on the ability to recognize emotional expressions of faces and emotional content of words. Participants remained awake for 24 h and performed the tasks in two sessions, one in which they were not affected by sleep loss (baseline; BSL), and other affected by SD, according to a counterbalanced sequence. Tasks were carried out twice at 10:00 and 4:00 am, or at 12:00 and 6:00 am. In both tasks, participants had to respond to the emotional valence of the target stimulus: negative, positive, or neutral. The results showed that in the word task, sleep deprivation impaired recognition irrespective of the emotional valence of words. However, sleep deprivation impaired recognition of emotional face expressions mainly when they showed a neutral expression. Emotional face expressions were less affected by the sleep loss, but positive faces were more resistant than negative faces to the detrimental effect of sleep deprivation. The differential effects of sleep deprivation on recognition of the different emotional stimuli are indicative of emotional facial expressions being stronger emotional stimuli than emotional laden words. This dissociation may be attributed to the more automatic sensory encoding of emotional facial content.     

Discrimination thresholds for recognizing facial emotions: mostly higher among the elderly

Elderly people have lower ability for recognizing facial emotions than younger people. Previous studies showed that older adults had difficulty in recognizing anger, sadness and fear, but there were no consistent results for happiness, surprise and disgust. Most of these studies used a small number of stimuli, and tabulated the number of correct responses for facial expressions. These characteristics of the task might be the source of the discrepancy in the findings. The present study used a task which measures participants' discrimination thresholds for six basic emotions using psychophysical measurement methods. The results showed that the thresholds for elderly participants (74.8 +/- 6.5 yrs) were significantly higher than for younger participants (20.1 +/- 1.6 yrs) for sadness, surprise, anger, disgust and fear. There was no significant difference for happiness. Since the task that we developed was sufficiently sensitive, it is a useful tool for assessing individuals' ability to perceive emotion.     

Natural facial motion enhances cortical responses to faces

The ability to perceive facial motion is important to successfully interact in social environments. Previously, imaging studies have investigated neural correlates of facial motion primarily using abstract motion stimuli. Here, we studied how the brain processes natural non-rigid facial motion in direct comparison to static stimuli and matched phase-scrambled controls. As predicted from previous studies, dynamic faces elicit higher responses than static faces in lateral temporal areas corresponding to hMT+/V5 and STS. Interestingly, individually defined, static-face-sensitive regions in bilateral fusiform gyrus and left inferior occipital gyrus also respond more to dynamic than static faces. These results suggest integration of form and motion information during the processing of dynamic faces even in ventral temporal and inferior lateral occipital areas. In addition, our results show that dynamic stimuli are a robust tool to localize areas related to the processing of static and dynamic face information. J. Schultz and K. S. Pilz have contributed equally to this work.     

Are facial expressions contagious in the Japanese?

Previous studies, mainly with Caucasian samples, have shown that facial expressions of emotion are contagious, a phenomenon known as facial mimicry. This study examined facial mimicry using a Japanese sample. Participants were shown a series of Japanese faces (from Matsumoto and Ekman, 1988) on a computer screen expressing "happiness", "sadness", "anger", or "disgust". While viewing the facial expressions, electoromyograms (EMG) of the participants' faces were recorded to see whether their own facial muscles corresponding to the stimulus faces were activated. Consistent with the previous studies using Caucasian samples, all four facial expressions were mimicked. The peak time of mimicry of angry or happy faces was later, while that of disgusted faces was relatively sooner. The potential relation of facial mimicry to "emotional contagion", a social phenomenon whereby subjective feelings transfer between people, is discussed.     

The relationship between the categorical perception of facial expressions and semantic distances]

It has been argued whether the facial expression is recognized categorically or dimensionally. We investigated this issue using three sets of morphed photographic facial images (happiness to anger, surprise, and sadness). Our interest is whether the experimental data of categorical perception can be explained by the dimensional point of view. Experiment 1 examined the facial stimuli generated by FACS. In Experiment 2, subjects were asked to discriminate some pairs of faces and to categorize the emotion shown one at a time. The discrimination accuracy between categories was better than that within each category. In Experiment 3, subjects were asked to rate those stimuli following the semantic differential technique. Then we examined the relationship between the discrimination accuracy obtained in Experiment 2 and the semantic distances obtained in Experiment 3, defined by Euclidean distances between pairs of stimuli in the factor space that was constituted two factors interpreted as "pleasantness" and "activities". Discrimination accuracy within each category increased as a function of the semantic distances, whereas discrimination accuracy between categories remained high irrespective of the different semantic distances.     

The influence of stimulus valence on perceptual processing of facial expressions and subsequent response inhibition

The constant interplay between affective processing and cognitive control supports emotion regulation and appropriate social functioning. Even when affective stimuli are processed implicitly, threat-related stimuli are prioritized in the earliest stages of processing; yet, it remains unclear how implicit attention to affect influences subsequent cognitive control functions. The present study evaluated the influence of affective valence on early perceptual processes and subsequent response inhibition in a context where affective properties of the stimuli (facial expressions) were not critical for performing the task. Participants (N = 32) completed an affective stop-signal task (SST) while their scalp EEGs were recorded. The SST assessed response inhibition while participants implicitly attended to happy and afraid facial expressions that were matched for level of arousal. Behavioral performance was measured via response time and accuracy while physiological response was measured via the P100, N170, and N200/P300 ERP components. Decreased gender discrimination accuracy, delayed P100 latency, and more negative N170 amplitude were observed for afraid faces compared to happy faces, suggesting a shift in processing with respect to face valence. However, differences in stopping accuracy or N200/P300 ERP components during response inhibition were not observed, pointing to top-down cognitive processes likely being recruited to override the early automatic response to prioritize threat-related stimuli. Findings highlight that, in this implicit affective attention task, threat-related stimuli are prioritized early during processing, but implicitly attending to differentially valenced stimuli did not modulate subsequent cognitive control functions.     

Time course of attentional bias in social anxiety: The effects of spatial frequencies and individual threats

Hypervigilance and attentional bias to threat faces with low-spatial-frequency (LSF) information have been found in individuals with social anxiety. The vigilance–avoidance hypothesis posits that socially anxious individuals exhibit initial vigilance and later avoidance to threatening cues. However, the temporal dynamics of these two processes in response to various LSF threats in social anxiety remain unclear. In the current study, we presented faces containing anger, disgust, and fear in high and low spatial frequencies and compared the neural correlates with sensory perception and attention in individuals with high versus low social anxiety (HSA/LSA, n = 24). A visual search task was used to investigate the attentional effects of threats and spatial frequencies, and event-related potentials, particularly, the visual components of P1 and P250, were measured to index visual perceptual and attentional processes, respectively. We found that HSA individuals showed pronounced P1 and reduced P250 to LSF (vs. HSF) faces, regardless of emotion type, suggesting a general pattern of initial vigilance and later avoidance to LSF faces in social anxiety. Furthermore, while LSA individuals showed enhanced P250 to both fear and disgust (vs. neutral) faces, HSA individuals showed pronounced P250 to disgust faces alone. Our results, thus, elucidate the temporal profile of early vigilance and later avoidance in social anxiety, highlighting its broad implication for all faces and predominance in the low spatial frequency. Considering individual threats, our results demonstrate specific attentional avoidance of fear faces in social anxiety.     

Attention bias to faces in Asperger Syndrome: a pictorial emotion Stroop study

BACKGROUND: Emotional Stroop tasks have shown attention biases of clinical populations towards stimuli related to their condition. Asperger Syndrome (AS) is a neuropsychiatric condition with social and communication deficits, repetitive behaviours and narrow interests. Social deficits are particularly striking, including difficulties in understanding others. METHOD: We investigated colour-naming latencies of adults with and without AS to name colours of pictures containing angry facial expressions, neutral expressions or non-social objects. We tested three hypotheses: whether (1) controls show longer colour-naming latencies for angry versus neutral facial expressions with male actors, (2) people with AS show differential latencies across picture types, and (3) differential response latencies persist when photographs contain females. RESULTS: Controls had longer latencies to pictures of male faces with angry compared to neutral expressions. The AS group did not show longer latencies to angry versus neutral expressions in male faces, instead showing slower latencies to pictures containing any facial expression compared to objects. When pictures contained females, controls no longer showed longer latencies for angry versus neutral expressions. However, the AS group still showed longer latencies to all facial picture types, compared to objects, providing further evidence that faces produce interference effects for this clinical group. CONCLUSIONS: The pictorial emotional Stroop paradigm reveals normal attention biases towards threatening emotional faces. The AS group showed Stroop interference effects to all facial stimuli regardless of expression or sex, suggesting that faces cause disproportionate interference in AS.     

Attachment state of mind and perceptual processing of emotional stimuli

This study aimed to investigate the relationship between attachment state of mind and perceptual processing of social and non-social, affective, and neutral material. A total of 57 young adults completed the Adult Attachment Interview (AAI) plus an experimental task in which their perceptual thresholds to different types of pictures were assessed. Significant correlations were found between the AAI dimensions and perceptual thresholds for social stimuli such as social interactions or human faces displaying emotional expressions. As expected, no relationships were found between the AAI and perception of neutral stimuli. The pattern of correlations was especially clear for the dismissing dimension. The results suggest that higher vigilance to social stimuli is related to dismissing attachment tendencies and, to a milder degree, to preoccupied tendencies.     

Attachment state of mind and perceptual processing of emotional stimuli

This study aimed to investigate the relationship between attachment state of mind and perceptual processing of social and non-social, affective, and neutral material. A total of 57 young adults completed the Adult Attachment Interview (AAI) plus an experimental task in which their perceptual thresholds to different types of pictures were assessed. Significant correlations were found between the AAI dimensions and perceptual thresholds for social stimuli such as social interactions or human faces displaying emotional expressions. As expected, no relationships were found between the AAI and perception of neutral stimuli. The pattern of correlations was especially clear for the dismissing dimension. The results suggest that higher vigilance to social stimuli is related to dismissing attachment tendencies and, to a milder degree, to preoccupied tendencies.     

Early glycinergic axon contact with the Mauthner neuron during zebrafish development

One important aspect of empathy is a “resonance mechanism”, which includes emotional cue detection, facial mimicry (measured by electromyography, EMG) and a specific cortical response. This study explored the convergence of these three measures of affective empathy. The twenty students who took part in the study were required to empathise with the situation by entering into the other person's situation. The four emotions portrayed were anger, fear, happiness, and neutral, and the subjects were instructed to make a two-alternative response (emotion or no emotion) to each emotion. A repeated transcranial magnetic stimulation was used to produce a temporary inhibition of the medial prefrontal cortex (MPFC). The results support the hypothesis that there is a direct relationship between emotional cue recognition, EMG-measured facial response and prefrontal activity. First, both facial expression detection and autonomic mimicry in reaction to emotional faces were systematically modulated in response to inhibition of the MPFC. Second, the MPFC was implicated in facial cue detection and the subsequent autonomic response because an impaired performance on both measures was observed when this brain area was inhibited. Third, this effect increased when negative-valenced stimuli (angry and fearful faces) were presented to the subjects. These results revealed a significant effect of the MPFC on both cue detection and facial mimicry that was distinctly related to different types of emotions.     

Gender differences in facial reactions to facial expressions

This study explored whether males and females differ in facial muscle reactivity when exposed to facial expressions. The study also examined whether the sex of the stimulus faces differentially influences the response patterns to facial stimuli. Thus, the sex was manipulated in a 2 x 2 factorial design by exposing males and females to slides of angry and happy faces displayed by both sexes. Facial electromyographic (EMG) activity was measured from the corrugator and zygomatic muscle regions. The subjects were also required to rate the stimuli on different dimensions. The results showed that angry faces evoked increased corrugator activity whereas happy faces evoked increased zygomatic activity. As predicted, these effects were more pronounced for females, particularly for the response to happy faces. Interestingly, there were no facial EMG effects for gender of stimulus. It was further found that males and females perceived the stimuli similarly. The results are consistent with previous findings indicating that females are more facially reactive than are males.     

What facial features activate face neurons in the inferotemporal cortex of the monkey?

Summary Single neurons were recorded in the inferotemporal cortex (IT) of a monkey trained to discriminate three selected human faces from a large number of different faces. Neurons which were not responsive to non-face visual stimuli used in the task but were responsive to certain sets of faces were found in the gyrus of the IT. The correlation analysis between the quantified facial features and the responses has revealed that face neurons detect the combination of the distances between facial parts such as eyes, mouth, eyebrows, hair, and so on. One of the face neurons detected the combination of the degree that the forehead above the left eye covered with hair and the distance between the eyes and the mouth. The results of this analysis have given appropriate reason for naming the neurons as the face neurons.