Subcortical Discrimination of Unperceived Objects during Binocular Rivalry

Unconscious and Conscious Gaze-Triggered Attentional Orienting: Distinguishing Innate and Acquired Components of Social Attention in Children and Adults with Autistic Traits and Autism Spectrum Disorders

Typically developing (TD) individuals can readily orient attention according to others' eye-gaze direction, an ability known as social attention, which involves both innate and acquired components. To distinguish between these two components, we used a critical flicker fusion technique to render gaze cues invisible to participants, thereby largely reducing influences from consciously acquired strategies. Results revealed that both visible and invisible gaze cues could trigger attentional orienting in TD adults (aged 20 to 30 years) and children (aged 6 to 12 years). Intriguingly, only the ability to involuntarily respond to invisible gaze cues was negatively correlated with autistic traits among all TD participants. This ability was substantially impaired in adults with autism spectrum disorder (ASD) and in children with high autistic traits. No such association or reduction was observed with visible gaze cues. These findings provide compelling evidence for the functional demarcation of conscious and unconscious gaze-triggered attentional orienting that emerges early in life and develops into adulthood, shedding new light on the differentiation of the innate and acquired aspects of social attention. Moreover, they contribute to a comprehensive understanding of social endophenotypes of ASD.

Ultrahigh Field fMRI Reveals Different Roles of the Temporal and Frontoparietal Cortices in Subjective Awareness

A central question in consciousness theories is whether one is dealing with a dichotomous ("all-or-none") or a gradual phenomenon. In this 7T fMRI study, we investigated whether dichotomy or gradualness in fact depends on the brain region associated with perceptual awareness reports. Both male and female human subjects performed an emotion discrimination task (fear vs neutral bodies) presented under continuous flash suppression with trial-based perceptual awareness measures. Behaviorally, recognition sensitivity increased linearly with increased stimuli awareness and was at chance level during perceptual unawareness. Physiologically, threat stimuli triggered a slower heart rate than neutral ones during "almost clear" stimulus experience, indicating freezing behavior. Brain results showed that activity in the occipitotemporal, parietal, and frontal regions as well as in the amygdala increased with increased stimulus awareness while early visual areas showed the opposite pattern. The relationship between temporal area activity and perceptual awareness best fitted a gradual model while the activity in frontoparietal areas fitted a dichotomous model. Furthermore, our findings illustrate that specific experimental decisions, such as stimulus type or the approach used to evaluate awareness, play pivotal roles in consciousness studies and warrant careful consideration.

Perception of visual variance is mediated by subcortical mechanisms

Variance characterizes the structure of the environment. This statistical concept plays a critical role in evaluating the reliability of evidence for human decision-making. The present study examined the involvement of subcortical structures in the processing of visual variance. To this end, we used a stereoscope to sequentially present two circle arrays in a dichoptic or monocular fashion while participants compared the perceived variance of the two arrays. In Experiment 1, two arrays were presented monocularly to the same eye, dichopticly to different eyes, or binocularly to both eyes. The variance judgment was less accurate in different-eye condition than the other conditions. In Experiment 2, the first circle array was split into a large-variance and a small-variance set, with either the large-variance or small-variance set preceding the presentation of the second circle array in the same eye. The variance of the first array was judged larger when the second array was preceded by the large-variance set in the same eye, showing that the perception of variance was modulated by the visual variance processed in the same eye. Taken together, these findings provide evidence for monocular processing of visual variance, suggesting that subcortical structures capture the statistical structure of the visual world.

Impairment of unconscious emotional processing after unilateral medial temporal structure resection

The role of the amygdala in unconscious emotional processing remains a topic of debate. Past lesion studies have indicated that amygdala damage leads to impaired electrodermal activity in response to subliminally presented emotional stimuli. However, electrodermal activity can reflect both emotional and nonemotional processes. To provide behavioral evidence highlighting the critical role of the amygdala in unconscious emotional processing, we examined patients (n = 16) who had undergone unilateral resection of medial temporal lobe structures, including the amygdala. We utilized the subliminal affective priming paradigm in conjunction with unilateral visual presentation. Fearful or happy dynamic facial expressions were presented in unilateral visual fields for 30 ms, serving as negative or positive primes. Subsequently, neutral target faces were displayed, and participants were tasked with rating the valence of these targets. Positive primes, compared to negative ones, enhanced valence ratings of the target to a greater extent when they stimulated the intact hemisphere (i.e., were presented in the contralateral visual field of the intact hemisphere) than when they stimulated the resected hemisphere (i.e., were presented in the contralateral visual field of the resected hemisphere). These results suggest that the amygdala is causally involved in unconscious emotional processing.

Implicit Selective Attention: The Role of the Mesencephalic-basal Ganglia System

The ability of the brain to recognize and orient attention to relevant stimuli appearing in the visual field is highlighted by a tuning process, which involves modulating the early visual system by both cortical and subcortical brain areas. Selective attention is coordinated not only by the output of stimulus-based saliency maps but is also influenced by top-down cognitive factors, such as internal states, goals, or previous experiences. The basal ganglia system plays a key role in implicitly modulating the underlying mechanisms of selective attention, favouring the formation and maintenance of implicit sensory-motor memories that are capable of automatically modifying the output of priority maps in sensory-motor structures of the midbrain, such as the superior colliculus. The article presents an overview of the recent literature outlining the crucial contribution of several subcortical structures to the processing of different sources of salient stimuli. In detail, we will focus on how the mesencephalic- basal ganglia closed loops contribute to implicitly addressing and modulating selective attention to prioritized stimuli. We conclude by discussing implicit behavioural responses observed in clinical populations in which awareness is compromised at some level. Implicit (emergent) awareness in clinical conditions that can be accompanied by manifest anosognosic symptomatology (i.e., hemiplegia) or involving abnormal conscious processing of visual information (i.e., unilateral spatial neglect and blindsight) represents interesting neurocognitive "test cases" for inferences about mesencephalicbasal ganglia closed-loops involvement in the formation of implicit sensory-motor memories.

Invisible social grouping facilitates the recognition of individual faces

Emerging evidence suggests a specialized mechanism supporting perceptual grouping of social entities. However, the stage at which social grouping is processed is unclear. Through four experiments, here we showed that participants' recognition of a visible face was facilitated by the presence of a second facing (thus forming a social grouping) relative to a nonfacing face, even when the second face was invisible. Using a monocular/dichoptic paradigm, we further found that the social grouping facilitation effect occurred when the two faces were presented dichoptically to different eyes rather than monocularly to the same eye, suggesting that social grouping relies on binocular rather than monocular neural channels. The above effects were not found for inverted face dyads, thereby ruling out the contribution of nonsocial factors. Taken together, these findings support the unconscious influence of social grouping on visual perception and suggest an early origin of social grouping processing in the visual pathway.

Subcortical encoding of summary statistics in humans

Statistical encoding compresses redundant information from multiple items into a single summary metric (e.g., mean). Such statistical representation has been suggested to be automatic, but at which stage it is extracted is unknown. Here, we examined the involvement of the subcortex in the processing of summary statistics. We presented an array of circles dichoptically or monocularly while matching the number of perceived circles after binocular fusion. Experiments 1 and 2 showed that interocularly suppressed, invisible circles were automatically involved in the summary statistical representation, but only when they were presented to the same eye as the visible circles. This same-eye effect was further observed for consciously processed circles in Experiment 3, in which the estimated mean size of the circles was biased toward the information transmitted by monocular channels. Together, we provide converging evidence that the processing of summary statistics, an assumed high-level cognitive process, is mediated by subcortical structures.

Prestimulus amygdala spectral activity is associated with visual face awareness

Alpha cortical oscillations have been proposed to suppress sensory processing in the visual, auditory, and tactile domains, influencing conscious stimulus perception. However, it is unknown whether oscillatory neural activity in the amygdala, a subcortical structure involved in salience detection, has a similar impact on stimulus awareness. Recording intracranial electroencephalography (EEG) from 9 human amygdalae during face detection in a continuous flash suppression task, we found increased spectral prestimulus power and phase coherence, with most consistent effects in the alpha band, when faces were undetected relative to detected, similarly as previously observed in cortex with this task using scalp-EEG. Moreover, selective decreases in the alpha and gamma bands preceded face detection, with individual prestimulus alpha power correlating negatively with detection rate in patients. These findings reveal for the first time that prestimulus subcortical oscillations localized in human amygdala may contribute to perceptual gating mechanisms governing subsequent face detection and offer promising insights on the role of this structure in visual awareness.

Conscious awareness is necessary to assess trust and mimic facial expressions, while pupils impact trust unconsciously

People make rapid inferences about others' thoughts and intentions. For example, they observe facial movements and pupil size of others and unwittingly make use of this information when deciding whether to trust someone or not. However, whether spontaneous mimicry depends on visual awareness of the stimulus and whether these processes underlie trust decisions is still unknown. To investigate whether visual awareness modulates the relationship between emotional expressions, mimicry and trust, participants played a series of trust games and saw either their partners' faces with a neutral, happy or fearful expression, or their partners' eyes in which the pupil size was large, medium or small. Subjects' trust investments, facial movements and pupil responses were measured. In half of the trials, the stimuli were rendered invisible by continuous flash suppression. Results showed that facial expressions were mimicked and influenced trust decisions during the conscious condition, but not during the unconscious (suppressed) condition. The opposite was found for pupil size, which influenced trust decisions during states of unawareness. These results suggest that the neurobiological pathway linking the observation of facial expressions to mimicry and trust is predominantly conscious, whereas partner pupil size influences trust primarily when presented unconsciously. This article is part of the theme issue 'Cracking the laugh code: laughter through the lens of biology, psychology and neuroscience'.

Neuroscientific Evidence for Processing Without Awareness

The extent to which we are affected by perceptual input of which we are unaware is widely debated. By measuring neural responses to sensory stimulation, neuroscientific data could complement behavioral results with valuable evidence. Here we review neuroscientific findings of processing of high-level information, as well as interactions with attention and memory. Although the results are mixed, we find initial support for processing object categories and words, possibly to the semantic level, as well as emotional expressions. Robust neural evidence for face individuation and integration of sentences or scenes is lacking. Attention affects the processing of stimuli that are not consciously perceived, and such stimuli may exogenously but not endogenously capture attention when relevant, and be maintained in memory over time. Sources of inconsistency in the literature include variability in control for awareness as well as individual differences, calling for future studies that adopt stricter measures of awareness and probe multiple processes within subjects.

Holistic processing of gaze cues during interocular suppression

Direct eye contact is preferentially processed over averted gaze and has been shown to gain privileged access to conscious awareness during interocular suppression. This advantage might be driven by local features associated with direct gaze, such as the amount of visible sclera. Alternatively, a holistic representation of gaze direction, which depends on the integration of head and eye information, might drive the effects. Resolving this question is interesting because it speaks to whether the processing of higher-level social information in the visual system, such as facial characteristics that rely on holistic processing, is dependent on conscious awareness. The Wollaston Illusion is a visual illusion that allows researchers to manipulate perceived gaze direction while keeping local eye features constant. Here we used this illusion to elucidate the driving factor facilitating the direct gaze advantage during interocular suppression. Using continuous flash suppression, we rendered Wollaston faces with direct and averted gaze (initially) invisible. These faces conveyed different gaze directions but contained identical eye regions. Our results showed clear evidence for a direct gaze advantage with Wollaston faces, indicating that holistic representations of gaze direction may drive the direct gaze advantage during interocular suppression.

Neural and computational processes of accelerated perceptual awareness and decisions: A 7T fMRI study

Rapidly detecting salient information in our environments is critical for survival. Visual processing in subcortical areas like the pulvinar and amygdala has been shown to facilitate unconscious processing of salient stimuli. It is unknown, however, if and how these areas might interact with cortical regions to facilitate faster conscious perception of salient stimuli. Here we investigated these neural processes using 7T functional magnetic resonance imaging (fMRI) in concert with computational modelling while participants (n = 33) engaged in a breaking continuous flash suppression paradigm (bCFS) in which fearful and neutral faces are initially suppressed from conscious perception but then eventually ‘breakthrough’ into awareness. Participants reported faster breakthrough times for fearful faces compared with neutral faces. Drift‐diffusion modelling suggested that perceptual evidence was accumulated at a faster rate for fearful faces compared with neutral faces. For both neutral and fearful faces, faster response times were associated with greater activity in the amygdala (specifically within its subregions, including superficial, basolateral and amygdalo‐striatal transition area) and the insula. Faster rates of evidence accumulation coincided with greater activity in frontoparietal regions and occipital lobe, as well as the amygdala. A lower decision‐boundary correlated with activity in the insula and the posterior cingulate cortex (PCC), but not with the amygdala. Overall, our findings suggest that hastened perceptual awareness of salient stimuli recruits the amygdala and, more specifically, is driven by accelerated evidence accumulation in fronto‐parietal and visual areas. In sum, we have mapped distinct neural computations that accelerate perceptual awareness of visually suppressed faces.

Acquired Prosopagnosia with Structurally Intact and Functional Fusiform Face Area and with Face Identity-Specific Configuration Processing Deficits

Prosopagnosia or loss of face perception and recognition is still poorly understood and rare single cases of acquired prosopagnosia can provide a unique window on the behavioural and brain basis of normal face perception. The present study of a new case of acquired prosopagnosia with bilateral occipito-temporal lesions but a structurally intact FFA and OFA investigated whether the lesion overlapped with the face network and whether the structurally intact FFA showed a face selective response. We also investigated the behavioral correlates of the neural findings and assessed configural processing in the context of facial and non-facial identity recognition, expression recognition and memory, also focusing on the face-selectivity of each specific deficit. The findings reveal a face-selective response in the FFA, despite lesions in the face perception network. At the behavioural level, the results showed impaired configural processing for facial identity, but not for other stimulus categories and not for facial expression recognition. These findings challenge a critical role of the FFA for face identity processing and support a domain-specific account of configural processing.

Amygdala function in emotion, cognition, and behavior

The amygdala is a core structure in the anterior medial temporal lobe, with an important role in several brain functions involving memory, emotion, perception, social cognition, and even awareness. As a key brain structure for saliency detection, it triggers and controls widespread modulatory signals onto multiple areas of the brain, with a great impact on numerous aspects of adaptive behavior. Here we discuss the neural mechanisms underlying these functions, as established by animal and human research, including insights provided in both healthy and pathological conditions.

Visual adaptation and 7T fMRI reveal facial identity processing in the human brain under shallow interocular suppression

Face identity is represented at a high level of the visual hierarchy. Whether the human brain can process facial identity information in the absence of visual awareness remains unclear. In this study, we investigated potential face identity representation through face-identity adaptation with the adapting faces interocularly suppressed by Continuous Flash Suppression (CFS) noise, a modified binocular rivalry paradigm. The strength of interocular suppression was manipulated by varying the contrast of CFS noise. While obeservers reported the face images subjectively unperceived and the face identity objectively unrecognizable, a significant face identity aftereffect was observed under low but not high contrast CFS noise. In addition, the identity of face images under shallow interocular suppression can be decoded from multi-voxel patterns in the right fusiform face area (FFA) obtained with high-resolution 7T fMRI. Thus the comined evidence from visual adaptation and 7T fMRI suggest that face identity can be represented in the human brain without explicit perceptual recognition. The processing of interocularly suppressed faces could occur at different levels depending on how "deep" the information is suppressed.

Adult Women First Exposed to Early Adversity After 8 Years Old Show Attentional Bias to Threat

Exposure to early adversity (EA) is associated with long-lasting dysregulations in cognitive processes sustained by brain regions that are sensitive to stress hormones: the hippocampus, the amygdala, and the prefrontal cortex. The Life Cycle Model of Stress highlights the importance of considering the timing at which EA began, as these brain regions follow distinct developmental trajectories. We aimed to test this hypothesis by assessing whether adults exposed to EA exhibit different cognitive patterns as a function of the age at which they were first exposed to EA. Eighty-five healthy men and women aged 21-40 years old (y/o) exposed to EA, as assessed by the Adverse Childhood Experience Questionnaire, were grouped based on the age of first exposure to EA: 0-2 y/o ("Infancy": hippocampal development), 3-7 y/o ("Early childhood": amygdala development) and after the age of 8 ("Childhood/Adolescence": frontoamygdala connectivity development). Declarative memory, attentional bias to threat and emotion regulation were measured. Results revealed increased attentional bias to threat in women first exposed to EA after 8 years. This result is in line with the Life Cycle Model of Stress and highlights the importance of considering the age at exposure to EA when investigating the effects of EA on cognitive processes.

Analgesia for fetal pain during prenatal surgery: 10 years of progress

Some doubts on the necessity and safety of providing analgesia to the fetus during prenatal surgery were raised 10 years ago. They were related to four matters: fetal sleep due to neuroinhibitors in fetal blood, the immaturity of the cerebral cortex, safety, and the need for fetal direct analgesia. These objections now seem obsolete. This review shows that neuroinhibitors give fetuses at most some transient sedation, but not a complete analgesia, that the cerebral cortex is not indispensable to feel pain, when subcortical structures for pain perception are present, and that maternal anesthesia seems not sufficient to anesthetize the fetus. Current drugs used for maternal analgesia pass through the placenta only partially so that they cannot guarantee a sufficient analgesia to the fetus. Extraction indices, that is, how much each analgesic drug crosses the placenta, are provided here. We here report safety guidelines for fetal direct analgesia. In conclusion, the human fetus can feel pain when it undergoes surgical interventions and direct analgesia must be provided to it. IMPACT: Fetal pain is evident in the second half of pregnancy. Progress in the physiology of fetal pain, which is reviewed in this report, supports the notion that the fetus reacts to painful interventions during fetal surgery. Evidence here reported shows that it is an error to believe that the fetus is in a continuous and unchanging state of sedation and analgesia. Data are given that disclose that drugs used for maternal analgesia cross the placenta only partially, so that they cannot guarantee a sufficient analgesia to the fetus. Safety guidelines are given for fetal direct analgesia.

Frontal activation as a key for deciphering context congruity and valence during visual perception: An electrical neuroimaging study

The object-context associations and the valence are two important stimulus attributes that influence visual perception. The current study investigates the neural sources associated with schema congruent and incongruent object-context associations within positive, negative, and neutral valence during an intermittent binocular rivalry task with simultaneous high-density EEG recording. Cortical sourceswere calculated using the sLORETA algorithm in 150 ms after stimulus onset (Stim + 150) and 400 ms before response (Resp-400) time windows. No significant difference in source activity was found between congruent and incongruent associations in any of the valence categories in the Stim + 150 ms window indicating that immediately after stimulus presentation the basic visual processing remains the same for both. In the Resp-400 ms window, different frontal regions showed higher activity for incongruent associations with different valence such as the superior frontal gyrus showed significantly higher activations for negative while the middle and medial frontal gyrus showed higher activations for neutral and finally, the inferior frontal gyrus showed higher activations for positive valence. Besides replicating the previous knowledge of frontal activations in response to context congruity, the current study provides further evidence for the sensitivity of the frontal lobe to the valence associated with the incongruent stimuli.

Where does fear originate in the brain? A coordinate-based meta-analysis of explicit and implicit fear processing

Processing of fear is of crucial importance for human survival and it can generally occur at explicit and implicit conditions. It is worth noting that explicit and implicit fear processing produces different behavioral and neurophysiological outcomes. The present study capitalizes on the Activation Likelihood Estimation (ALE) method of meta-analysis to identify: (a) the "core" network of fear processing in healthy individuals; (b) common and specific neural activations associated with explicit and implicit processing of fear. Following PRISMA guidelines, a total of 92 fMRI and PET studies were included in the meta-analysis. The overall analysis show that the core fear network comprises the amygdala, pulvinar, and fronto-occipital regions. Both implicit and explicit fear processing activated amygdala, declive, fusiform gyrus, and middle frontal gyrus, suggesting that these two types of fear processing share a common neural substrate. Explicit fear processing elicited more activations at the pulvinar and parahippocampal gyrus, suggesting visual attention/orientation and contextual association play important roles during explicit fear processing. In contrast, implicit fear processing elicited more activations at the cerebellum-amygdala-cortical pathway, indicating an 'alarm' system underlying implicit fear processing. These findings have shed light on the neural mechanism underlying fear processing at different levels of awareness.

Perceptual rivalry across animal species

This review in memoriam of Jack Pettigrew provides an overview of past and current research into the phenomenon of multistable perception across multiple animal species. Multistable perception is characterized by two or more perceptual interpretations spontaneously alternating, or rivaling, when animals are exposed to stimuli with inherent sensory ambiguity. There is a wide array of ambiguous stimuli across sensory modalities, ranging from the configural changes observed in simple line drawings, such as the famous Necker cube, to the alternating perception of entire visual scenes that can be instigated by interocular conflict. The latter phenomenon, called binocular rivalry, in particular caught the attention of the late Jack Pettigrew, who combined his interest in the neuronal basis of perception with a unique comparative biological approach that considered ambiguous sensation as a fundamental problem of sensory systems that has shaped the brain throughout evolution. Here, we examine the research findings on visual perceptual alternation and suppression in a wide variety of species including insects, fish, reptiles, and primates. We highlight several interesting commonalities across species and behavioral indicators of perceptual alternation. In addition, we show how the comparative approach provides new avenues for understanding how the brain suppresses opposing sensory signals and generates alternations in perceptual dominance.

Dynamic face mask enhances continuous flash suppression

In continuous flash suppression (CFS), an image presented to one eye is suppressed from awareness by a dynamic image masker presented to the other eye. Previous studies report that face stimuli break out of CFS more readily when they are oriented upright and contain ecologically relevant information such as facial expressions or direct eye gaze, potentially implicating face processing in the mechanisms of interocular competition. It is unknown, however, whether face content helps to drive interocular suppression when incorporated into the dynamic masker itself, either by engaging higher-level visual mechanisms that underlie face detection or due to lower-level image features that the faces happen to contain. To investigate this, we devised a dynamic mask composed of upright faces and tested how well it suppressed detection of face or grating targets presented to the other eye. Relative contributions of higher-level and lower-level features were compared by manipulating the image properties of the mask. Results show that the dynamic face mask is strikingly effective at suppressing sensory input presented to the opposing eye, but its effectiveness is largely attributable to image texture, which can be quantified in terms of image entropy and edge density. This is because strong suppression was still observed following phase-scrambling or spatial inversion of the face elements, and while a target-selective effect was observed for the face mask, inverting the face elements to interfere with configural processing did not significantly diminish this effect. Thus, visual properties of faces, such as their image entropy and complex phase structure, predominate in driving interocular suppression rather than face detection per se.

Effects of Language on Visual Perception

Does language change what we perceive? Does speaking different languages cause us to perceive things differently? We review the behavioral and electrophysiological evidence for the influence of language on perception, with an emphasis on the visual modality. Effects of language on perception can be observed both in higher-level processes such as recognition and in lower-level processes such as discrimination and detection. A consistent finding is that language causes us to perceive in a more categorical way. Rather than being fringe or exotic, as they are sometimes portrayed, we discuss how effects of language on perception naturally arise from the interactive and predictive nature of perception.

Adaptation to transients disrupts spatial coherence in binocular rivalry

When one eye is presented with an image that is distinct from the image presented to the other eye, the eyes start to rival and suppress each other's image. Binocular rivalry leads to perceptual alternations between the images of each eye, during which only one of the images is perceived at a time. However, when the eyes exert weak and shallow suppression, participants tend to perceive both images intermixed more often. A recent study proposed that the precedence of mixed percepts positively correlates with the degree of adaptation to conflict between the eyes. However, this study neglected the role of visual transients, which covaried with the degree of conflict in the stimulus design. Here we report that not the conflict between the eyes but prolonged and repeated observations of strong visual transients cause participants to report more mixed percepts. We conclude that visual transients, such as sudden changes in contrast, draw attention, strengthen both eyes' image representations, and facilitate the adaptation to interocular suppression, which consequentially disrupts the spatial coherence in binocular rivalry. This finding is relevant to virtual- and augmented reality for which it is crucial to design stereoscopic environments in which binocular rivalry is limited.

Intranasal Oxytocin Increases Perceptual Salience of Faces in the Absence of Awareness

OBJECTIVE

The neuropeptide oxytocin has been found to improve human social cognition and promote prosocial behavior. However, it is still unclear about the mechanisms underlying these effects of oxytocin on neural processes, such as visual perception and awareness. Especially, it is still unclear whether oxytocin influences perceptual salience of social stimuli in the absence of awareness.

METHODS

In a randomized double-blind, placebo-controlled trial we applied an interocular suppression paradigm and eye tracking methods to investigate the influence of intranasally administered oxytocin on perceptual salience of social stimuli. Suppression times and pupillometric data were measured during subjects being presented with gradually introduced pictures of social stimuli (neutral expression faces) or nonsocial stimuli (grayscale watch pictures) that were suppressed and invisible in 10 men who were administered 24 IU oxytocin and 10 men who were administered a placebo.

RESULTS

The results demonstrated that the oxytocin group perceived social stimuli more quickly accompanied by subsequent larger increasing pupil diameter than nonsocial stimuli, indicating an increased unconscious salience of social stimuli.

CONCLUSION

These findings provided new insights into oxytocin's modulatory role to social information processing, suggesting that oxytocin might enhance attentional bias to social stimuli even after removal of awareness.

Atypical Amygdala-Neocortex Interaction During Dynamic Facial Expression Processing in Autism Spectrum Disorder

Atypical reciprocal social interactions involving emotional facial expressions are a core clinical feature of autism spectrum disorder (ASD). Previous functional magnetic resonance imaging (fMRI) studies have demonstrated that some social brain regions, including subcortical (e.g., amygdala) and neocortical regions (e.g., fusiform gyrus, FG) are less activated during the processing of facial expression stimuli in individuals with ASD. However, the functional networking patterns between the subcortical and cortical regions in processing emotional facial expressions remain unclear. We investigated this issue in ASD (n = 31) and typically developing (TD; n = 31) individuals using fMRI. Participants viewed dynamic facial expressions of anger and happiness and their corresponding mosaic images. Regional brain activity analysis revealed reduced activation of several social brain regions, including the amygdala, in the ASD group compared with the TD group in response to dynamic facial expressions vs. dynamic mosaics (p < 0.05, ηp2 = 0.19). Dynamic causal modeling (DCM) analyses were then used to compare models with forward, backward, and bi-directional effective connectivity between the amygdala and neocortical networks. The results revealed that: (1) the model with effective connectivity from the amygdala to the neocortex best fit the data of both groups; and (2) the same model best accounted for group differences. Coupling parameter (i.e., effective connectivity) analyses showed that the modulatory effects of dynamic facial processing were substantially weaker in the ASD group than in the TD group. These findings suggest that atypical modulation from the amygdala to the neocortex underlies impairment in social interaction involving dynamic facial expressions in individuals with ASD.

New insights into fetal pain

Fetal pain is difficult to assess, because the main feature needed to spot pain, is the subject's capability of declaring it. Nonetheless, much can be affirmed about this issue. In this review we first report the epochs of the development of human nociceptive pathways; then we review since when they are functioning. We also review the latest data about the new topic of analgesia and prenatal surgery and about the scarce effect on fetal pain sentience of the natural sedatives fetuses produce. It appears that pain is a neuroadaptive phenomenon that emerges in the middle of pregnancy, at about 20-22 weeks of gestation, and becomes more and more evident for bystanders and significant for the fetus, throughout the rest of the pregnancy.

Brief facial emotion aftereffect occurs earlier for angry than happy adaptation

Prolonged exposure to an emotional face biases our judgement of subsequent face stimulus toward the opposite emotion. This emotion aftereffect has been suggested to occur as early as 35 ms exposure duration in cartoon faces. In the current study, we are interested in investigating the time-course of brief emotional face adaptation, and the relationship between brief emotional face adaptation and prolonged emotional face adaptation. We adapted the subjects from 17 ms to 1000 ms with a happy or angry adapting face. We found that a facial emotion adaptation aftereffect started from 17 ms adapting duration for angry face adaptation, and from 50 ms for happy face adaptation. Factor analysis on the adaptation effects highlighted three different components: brief angry adaptation (17 ms, 34 ms, and 50 ms), prolonged angry adaptation (100 ms and 1000 ms), and happy face adaptation (from 17 ms to 1000 ms). We found that the brief angry face adaptation was negatively associated with the awareness of the adapting face, and the prolonged angry face adaptation was stronger in subjects who perceived the angry adapting face as more negative in valence. Together, these findings suggest that (1) facial emotion adaptation can be induced by brief (17 ms) adapting face presentation; (2) brief angry face adaptation may be related to early visual processing, whereas prolonged angry face adaptation may be related to adaptation at later and higher-level visual emotional processing; and (3) brief and prolonged adaptations may adapt different neural populations. Our findings thus shed light on the current understanding of the neural mechanisms of emotional face adaptation.

Widespread and lateralized social brain activity for processing dynamic facial expressions

Dynamic facial expressions of emotions constitute natural and powerful means of social communication in daily life. A number of previous neuroimaging studies have explored the neural mechanisms underlying the processing of dynamic facial expressions, and indicated the activation of certain social brain regions (e.g., the amygdala) during such tasks. However, the activated brain regions were inconsistent across studies, and their laterality was rarely evaluated. To investigate these issues, we measured brain activity using functional magnetic resonance imaging in a relatively large sample (n = 51) during the observation of dynamic facial expressions of anger and happiness and their corresponding dynamic mosaic images. The observation of dynamic facial expressions, compared with dynamic mosaics, elicited stronger activity in the bilateral posterior cortices, including the inferior occipital gyri, fusiform gyri, and superior temporal sulci. The dynamic facial expressions also activated bilateral limbic regions, including the amygdalae and ventromedial prefrontal cortices, more strongly versus mosaics. In the same manner, activation was found in the right inferior frontal gyrus (IFG) and left cerebellum. Laterality analyses comparing original and flipped images revealed right hemispheric dominance in the superior temporal sulcus and IFG and left hemispheric dominance in the cerebellum. These results indicated that the neural mechanisms underlying processing of dynamic facial expressions include widespread social brain regions associated with perceptual, emotional, and motor functions, and include a clearly lateralized (right cortical and left cerebellar) network like that involved in language processing.

Amygdala activation during unconscious visual processing of food

Hedonic or emotional responses to food have important positive and negative effects on human life. Behavioral studies have shown that hedonic responses to food images are elicited rapidly, even in the absence of conscious awareness of food. Although a number of previous neuroimaging studies investigated neural activity during conscious processing of food images, the neural mechanisms underlying unconscious food processing remain unknown. To investigate this issue, we measured neural activity using functional magnetic resonance imaging while participants viewed food and mosaic images presented subliminally and supraliminally. Conjunction analyses revealed that the bilateral amygdala was more strongly activated in response to food images than to mosaic images under both subliminal and supraliminal conditions. Interaction analyses revealed that the broad bilateral posterior regions, peaking at the posterior fusiform gyrus, were particularly active when participants viewed food versus mosaic images under the supraliminal compared with the subliminal condition. Dynamic causal modeling analyses supported the model in which the subcortical visual pathway from the pulvinar to the amygdala was modulated by food under the subliminal condition; in contrast, the model in which both subcortical and cortical (connecting the primary visual cortex, fusiform gyrus, and the amygdala) visual pathways were modulated by food received the most support under the supraliminal condition. These results suggest the possibility that unconscious hedonic responses to food may exert an effect through amygdala activation via the subcortical visual pathway.

Category-selective processing in the two visual pathways as a function of stimulus degradation by noise

Understanding the organising principles and functional properties of the primate brain's numerous visually responsive cortical regions is one of the major goals in cognitive neuroscience. Functional magnetic resonance imaging (fMRI) studies have revealed that neural responses in higher-order visual cortex are shaped by object categories, task context, and spatiotemporal regularities. Beyond these properties, visual processing in the ventral pathway has been shown to be tightly linked to perceptual awareness, while the evidence regarding dorsal visual processing and awareness is mixed. Most previous studies targeting the dorsal pathway have used dichotomous "visible versus invisible" experimental designs and interocular suppression paradigms to modulate stimulus visibility. In this fMRI study, we sought to investigate category-selective processing of faces and tools in the ventral and dorsal visual streams as a function of parametric stimulus degradation by noise. Both frequentist and Bayesian statistics provide strong evidence for a linear relationship between category-selective processing and stimulus information in both visual pathways. Overall, multivariate category decoding accuracies turned out to be lower in the dorsal pathway. We discuss our results within the context of the emerging notion of highly interconnected visual streams, and provide an outlook on how future studies may help to further refine our understanding of the functional role of the dorsal pathway in visual object processing.

Subcortical visual pathway may be a new way for early diagnosis of glaucoma

Glaucoma is the leading cause of irreversible blindness worldwide, which is now viewed as a disease of brain with pathogenesis not fully understood. The main diagnostic methods are examining the retinal nerve fiber layer through optical coherence tomography and investigating visual field defect, but these methods present disadvantages in clinical practice. Studies have shown that patients with glaucoma often suffer negative emotion like anxiety and depression which is related to abnormal or reduced amygdala. Moreover, selective reduction of fMRI responses to transient achromatic stimuli in the superficial layer of the superior colliculus was found in the early glaucoma patients. By summarizing previous studies, we developed a hypothesis: superior colliculus-pulvinar-amygdala subcortical visual pathway may be involved in the incidence or progression of glaucoma. Validating this hypothesis would further clarify the mechanism of glaucoma and lead to the development of a more sensitive method for making an early diagnosis of glaucoma.

Trypophobic images gain preferential access to early visual processes

Trypophobia is a common but unusual phobia that is induced by viewing many clustered objects. Previous studies suggested that this trypophobia is caused by the specific power spectrum of the images; this idea has not been fully investigated empirically. In the present study, we used breaking continuous flash suppression (b-CFS) to clarify whether the trypophobic images affect access to visual awareness, and what features of trypophobic images contribute to rapid access of awareness. In the b-CFS paradigms, a dynamic masking pattern presented to one eye suppresses the target images shown to the other eye. The participants' task was to indicate where the target image appeared in a dichoptic display through a mirror stereoscope. The target images consisted of trypophobic, fear-related, clusters or neutral images. The trypophobic images emerged into awareness faster than the other types of images. However, the phase-scrambled versions of the trypophobic images did not show any differences across the image types, suggesting that the trypophobic power spectra themselves did not affect access to awareness. Moreover, the phase-scrambled trypophobic images without CFS tended to be detected earlier than the phase-scrambled fearful and neutral images. These findings indicate that trypophobic power spectra might affect post-perceptual processing, such as response production.

Preschool negative emotionality predicts activity and connectivity of the fusiform face area and amygdala in later childhood

Negative emotionality (NE) refers to individual differences in the propensity to experience and react with negative emotions and is associated with increased risk of psychological disorder. However, research on the neural bases of NE has focused almost exclusively on amygdala activity during emotional face processing. This study broadened this framework by examining the relationship between observed NE in early childhood and subsequent neural responses to emotional faces in both the amygdala and the fusiform face area (FFA) in a late childhood/early adolescent sample. Measures of NE were obtained from children at age 3 using laboratory observations, and functional magnetic resonance imaging (fMRI) data were collected when these children were between the ages of 9 and 12 while performing a visual stimulus identity matching task with houses and emotional faces as stimuli. Multiple regression analyses revealed that higher NE at age 3 is associated with significantly greater activation in the left amygdala and left FFA but lower functional connectivity between these two regions during the face conditions. These findings suggest that those with higher early NE have subsequent alterations in both activity and connectivity within an extended network during face processing.

The automaticity of face perception is influenced by familiarity

In this study, we explore the automaticity of encoding for different facial characteristics and ask whether it is influenced by face familiarity. We used a matching task in which participants had to report whether the gender, identity, race, or expression of two briefly presented faces was the same or different. The task was made challenging by allowing nonrelevant dimensions to vary across trials. To test for automaticity, we compared performance on trials in which the task instruction was given at the beginning of the trial, with trials in which the task instruction was given at the end of the trial. As a strong criterion for automatic processing, we reasoned that if perception of a given characteristic (gender, race, identity, or emotion) is fully automatic, the timing of the instruction should not influence performance. We compared automaticity for the perception of familiar and unfamiliar faces. Performance with unfamiliar faces was higher for all tasks when the instruction was given at the beginning of the trial. However, we found a significant interaction between instruction and task with familiar faces. Accuracy of gender and identity judgments to familiar faces was the same regardless of whether the instruction was given before or after the trial, suggesting automatic processing of these properties. In contrast, there was an effect of instruction for judgments of expression and race to familiar faces. These results show that familiarity enhances the automatic processing of some types of facial information more than others.

The dissociations of visual processing of "hole" and "no-hole" stimuli: An functional magnetic resonance imaging study

INTRODUCTION

"Where to begin" is a fundamental question of vision. A "Global-first" topological approach proposed that the first step in object representation was to extract topological properties, especially whether the object had a hole or not. Numerous psychophysical studies found that the hole (closure) could be rapidly recognized by visual system as a primitive property. However, neuroimaging studies showed that the temporal lobe (IT), which lied at a late stage of ventral pathway, was involved as a dedicated region. It appeared paradoxical that IT served as a key region for processing the early component of visual information. Did there exist a distinct fast route to transit hole information to IT? We hypothesized that a fast noncortical pathway might participate in processing holes.

METHODS

To address this issue, a backward masking paradigm combined with functional magnetic resonance imaging (fMRI) was applied to measure neural responses to hole and no-hole stimuli in anatomically defined cortical and subcortical regions of interest (ROIs) under different visual awareness levels by modulating masking delays.

RESULTS

For no-hole stimuli, the neural activation of cortical sites was greatly attenuated when the no-hole perception was impaired by strong masking, whereas an enhanced neural response to hole stimuli in non-cortical sites was obtained when the stimulus was rendered more invisible.

CONCLUSIONS

The results suggested that whereas the cortical route was required to drive a perceptual response for no-hole stimuli, a subcortical route might be involved in coding the hole feature, resulting in a rapid hole perception in primitive vision.

Developmental effects of androgens in the human brain

Neuroendocrine theories of brain development posit that androgens play a crucial role in sex-specific cortical growth, although little is known about the differential effects of testosterone and dehydroepiandrosterone (DHEA) on cortico-limbic development and cognition during adolescence. In this context, the National Institutes of Health Study of Normal Brain Development, a longitudinal study of typically developing children and adolescents aged 4-24 years (n=433), offers a unique opportunity to examine the developmental effects of androgens on cortico-limbic maturation and cognition. Using data from this sample, our group found that higher testosterone levels were associated with left-sided decreases in cortical thickness (CTh) in post-pubertal boys, particularly in the prefrontal cortex, compared to right-sided increases in CTh in somatosensory areas in pre-pubertal girls. Prefrontal-amygdala and prefrontal-hippocampal structural covariance (considered to reflect structural connectivity) also varied according to testosterone levels, with the testosterone-related brain phenotype predicting higher aggression levels and lower executive function, particularly in boys. By contrast, DHEA was associated with a pre-pubertal increase in CTh of several regions involved in cognitive control in both boys and girls. Covariance within several cortico-amygdalar structural networks also varied as a function of DHEA levels, with the DHEA-related brain phenotype predicting improvements in visual attention in both boys and girls. DHEA-related cortico-hippocampal structural covariance, on the other hand, predicted higher scores on a test of working memory. Interestingly, there were significant interactions between testosterone and DHEA, such that DHEA tended to mitigate the anti-proliferative effects of testosterone on brain structure. In sum, testosterone-related effects on the developing brain may lead to detrimental effects on cortical functions (ie, higher aggression and lower executive function), whereas DHEA-related effects may optimise cortical functions (ie, better attention and working memory), perhaps by decreasing the influence of amygdalar and hippocampal afferents on cortical functions.

Treatment of developmental stress disorder: mind, body and brain - analysis and pharmacology coupled

The schism between psychiatry, psychology and analysis, while long present, has widened even more in the past half-century with the advances in psychopharmacology. With the advances in electronic brain imaging, particularly in developmental and post-traumatic stress disorders, there has emerged both an understanding of brain changes resulting from severe, chronic stress and an ability to target brain chemistry in ways that can relieve clinical symptomatology. The use of alpha-1 adrenergic brain receptor antagonists decreases many of the manifestations of PTSD. Additionally, this paper discusses the ways in which dreaming, thinking and the analytic process are facilitated with this concomitant treatment and hypervigilence and hyper-arousal states are signficiantly decreased.

Basic Emotions in Human Neuroscience: Neuroimaging and Beyond

The existence of so-called ‘basic emotions’ and their defining attributes represents a long lasting and yet unsettled issue in psychology. Recently, neuroimaging evidence, especially related to the advent of neuroimaging meta-analytic methods, has revitalized this debate in the endeavor of systems and human neuroscience. The core theme focuses on the existence of unique neural bases that are specific and characteristic for each instance of basic emotion. Here we review this evidence, outlining contradictory findings, strengths and limits of different approaches. Constructionism dismisses the existence of dedicated neural structures for basic emotions, considering that the assumption of a one-to-one relationship between neural structures and their functions is central to basic emotion theories. While these critiques are useful to pinpoint current limitations of basic emotions theories, we argue that they do not always appear equally generative in fostering new testable accounts on how the brain relates to affective functions. We then consider evidence beyond PET and fMRI, including results concerning the relation between basic emotions and awareness and data from neuropsychology on patients with focal brain damage. Evidence from lesion studies are indeed particularly informative, as they are able to bring correlational evidence typical of neuroimaging studies to causation, thereby characterizing which brain structures are necessary for, rather than simply related to, basic emotion processing. These other studies shed light on attributes often ascribed to basic emotions, such as automaticity of perception, quick onset, and brief duration. Overall, we consider that evidence in favor of the neurobiological underpinnings of basic emotions outweighs dismissive approaches. In fact, the concept of basic emotions can still be fruitful, if updated to current neurobiological knowledge that overcomes traditional one-to-one localization of functions in the brain. In particular, we propose that the structure-function relationship between brain and emotions is better described in terms of pluripotentiality, which refers to the fact that one neural structure can fulfill multiple functions, depending on the functional network and pattern of co-activations displayed at any given moment.

Object Localization Does Not Imply Awareness of Object Category at the Break of Continuous Flash Suppression

In continuous flash suppression (CFS), a dynamic noise masker, presented to one eye, suppresses conscious perception of a test stimulus, presented to the other eye, until the suppressed stimulus comes to awareness after few seconds. But what do we see breaking the dominance of the masker in the transition period? We addressed this question with a dual-task in which observers indicated (i) whether the test object was left or right of the fixation mark (localization) and (ii) whether it was a face or a house (categorization). As done recently Stein et al. (2011a), we used two experimental varieties to rule out confounds with decisional strategy. In the terminated mode, stimulus and masker were presented for distinct durations, and the observers were asked to give both judgments at the end of the trial. In the self-paced mode, presentation lasted until the observers responded. In the self-paced mode, b-CFS durations for object categorization were about half a second longer than for object localization. In the terminated mode, correct categorization rates were consistently lower than correct detection rates, measured at five duration intervals ranging up to 2 s. In both experiments we observed an upright face advantage compared to inverted faces and houses, as concurrently reported in b-CFS studies. Our findings reveal that more time is necessary to enable observers judging the nature of the object, compared to judging that there is “something other” than the noise which can be localized, but not recognized. This suggests gradual transitions in the first break of CFS. Further, the results imply that suppression is such that no cues to object identity are conveyed in potential “leaks” of CFS (Gelbard-Sagiv et al., 2016).

Negative Valence in Autism Spectrum Disorder: The Relationship Between Amygdala Activity, Selective Attention, and Co-occurring Anxiety

BACKGROUND

A critical agenda of the National Institutes of Health Research Domain Criteria (RDoC) initiative is establishing whether domains within the RDoC matrix are truly transdiagnostic. Rates of anxiety disorders are elevated in autism spectrum disorder (ASD), but it is unclear whether the same mechanisms contribute to anxiety in individuals with and without ASD. As changes in selective attention are a hallmark of anxiety disorders in non-ASD samples, the identification of these changes in ASD would support the transdiagnostic nature of anxiety.

METHODS

This functional magnetic resonance imaging study focused on the negative valence domain from RDoC (manifest as anxiety symptoms) in youth with ASD (n = 38) and typically developing control participants (n = 25). The task required selective attention toward and away from social information (faces) with negative and neutral affect. Participants underwent in-depth characterization for both anxiety and ASD symptoms.

RESULTS

Dimensional and categorical measures of anxiety were significantly related to increased amygdala activation-evidence of enhanced attentional capture by social information.

CONCLUSIONS

This pattern fits with decades of research among non-ASD samples using selective attention and attentional bias paradigms, suggesting that anxiety in ASD shares mechanisms with anxiety alone. Overall, results from this study support the transdiagnostic nature of the negative valence domain from RDoC and increase the likelihood that anxiety in ASD should be responsive to interventions targeting maladaptive responses to negative information.

Amygdala Response to Emotional Stimuli without Awareness: Facts and Interpretations

Over the past two decades, evidence has accumulated that the human amygdala exerts some of its functions also when the observer is not aware of the content, or even presence, of the triggering emotional stimulus. Nevertheless, there is as of yet no consensus on the limits and conditions that affect the extent of amygdala’s response without focused attention or awareness. Here we review past and recent studies on this subject, examining neuroimaging literature on healthy participants as well as brain-damaged patients, and we comment on their strengths and limits. We propose a theoretical distinction between processes involved in attentional unawareness, wherein the stimulus is potentially accessible to enter visual awareness but fails to do so because attention is diverted, and in sensory unawareness, wherein the stimulus fails to enter awareness because its normal processing in the visual cortex is suppressed. We argue this distinction, along with data sampling amygdala responses with high temporal resolution, helps to appreciate the multiplicity of functional and anatomical mechanisms centered on the amygdala and supporting its role in non-conscious emotion processing. Separate, but interacting, networks relay visual information to the amygdala exploiting different computational properties of subcortical and cortical routes, thereby supporting amygdala functions at different stages of emotion processing. This view reconciles some apparent contradictions in the literature, as well as seemingly contrasting proposals, such as the dual stage and the dual route model. We conclude that evidence in favor of the amygdala response without awareness is solid, albeit this response originates from different functional mechanisms and is driven by more complex neural networks than commonly assumed. Acknowledging the complexity of such mechanisms can foster new insights on the varieties of amygdala functions without awareness and their impact on human behavior.

Invisible own- and other-race faces presented under continuous flash suppression produce affective response biases

One triumph of the human mind is the ability to place the multitudinous array of people we encounter into in- and out-group members based on racial characteristics. One fundamental question that remains to be answered is whether invisible own- and other-race faces can nevertheless influence subsequent affective judgments. Here, we employed continuous flash suppression (CFS) to render own- and other-race faces unperceivable in an affective priming task. Both on-line and off-line awareness checks were employed to provide more stringent control of partial awareness. Results revealed that relative to own-race faces, imperceptible other-race faces significantly facilitated participants' identification of negative words, suggesting an other-race derogation bias. When faces were presented consciously, we found that not only other-race faces facilitated detection of negative words, but also own-race faces facilitated detection of positive words. These findings together provide novel and strong evidence suggesting that invisible racial faces can bias affective responses.

Subliminal Impending Collision Increases Perceived Object Size and Enhances Pupillary Light Reflex

Fast detection of ambient danger is crucial for the survival of biological entities. Previous studies have shown that threatening information can bias human visual perception and enhance physiological reactions. It remains to be delineated whether the modulation of threat on human perceptual and physiological responses can take place below awareness. To probe this issue, we adopted visual looming stimuli and created two levels of threat by varying their motion trajectories to the observers, such that the stimuli could move in a path that either collided with the observers' heads or just nearly missed. We found that when the observers could not explicitly discriminate any difference between the collision and the near-miss stimuli, the visual stimuli on the collision course appeared larger and evoked greater pupil constrictions than those on the near-miss course. Furthermore, the magnitude of size overestimation was comparable to when the impending collision was consciously perceived. Our findings suggest that threatening information can bias human visual perception and strengthen pupil constrictions independent of conscious representation of the threat, and imply the existence of the subcortical visual pathway dedicated to automatically processing threat-related signals in humans.

The Attentional Dependence of Emotion Cognition Is Variable with the Competing Task

The relationship between emotion and attention has fascinated researchers for decades. Many previous studies have used eye-tracking, ERP, MEG, and fMRI to explore this issue but have reached different conclusions: some researchers hold that emotion cognition is an automatic process and independent of attention, while some others believed that emotion cognition is modulated by attentional resources and is a type of controlled processing. The present research aimed to investigate this controversy, and we hypothesized that the attentional dependence of emotion cognition is variable with the competing task. Eye-tracking technology and a dual-task paradigm were adopted, and subjects’ attention was manipulated to fixate at the central task to investigate whether subjects could detect the emotional faces presented in the peripheral area with a decrease or near-absence of attention. The results revealed that when the peripheral task was emotional face discrimination but the central attention-demanding task was different, subjects performed well in the peripheral task, which means that emotional information can be processed in parallel with other stimuli, and there may be a specific channel in the human brain for processing emotional information. However, when the central and peripheral tasks were both emotional face discrimination, subjects could not perform well in the peripheral task, indicating that the processing of emotional information required attentional resources and that it is a type of controlled processing. Therefore, we concluded that the attentional dependence of emotion cognition varied with the competing task.

[Recovery time as a potential new progression parameter for patients with advanced glaucomatous optic atrophy]

BACKGROUND

Functional tests in glaucoma diagnosis can monitor a potential perimetric progression. However white-on-white perimetry is limited in advanced glaucoma, whereas contrasts were detected reproducibly. Especially when stressing (i. e. adapting) the visual system, subsequent measurements yielded different results-the visual system needs a "recovery time". In the present study the recovery time was investigated in patients with advanced glaucoma. Additionally correlation analysis was done with standard perimetric parameters.

MATERIAL AND METHODS

Temporal contrast sensitivity (TCS) and recovery time (RT) were measured using the Erlanger Flicker Test in 61 probands (15 normals, 25 primary open-angle glaucomas, 17 secondary open-angle glaucomas, 4 narrow-angle glaucoma). Additionally, ophthalmological examinations and perimetry (Octopus G1) was done.

RESULTS

(1) TCS was significantly reduced in patients with advanced glaucoma (p < 0.001). (2) Test stimuli with 3 and 5 % contrast showed a large variability in contrast to higher contrasts (12 %, 25 %, 35 %). (3) RT_12%, RT_25% and RT_35% were significantly prolonged in advanced glaucoma (p < 0.001). (4) RT_25% correlated significantly with mean defect (p = 0.015).

CONCLUSION

Recovery time seems to be a potential parameter in advanced glaucoma follow-up, as it is reproducible, independently of cataract and fixation.

Differential Visual Processing of Animal Images, with and without Conscious Awareness

The human visual system can quickly and efficiently extract categorical information from a complex natural scene. The rapid detection of animals in a scene is one compelling example of this phenomenon, and it suggests the automatic processing of at least some types of categories with little or no attentional requirements (Li et al., 2002, 2005). The aim of this study is to investigate whether the remarkable capability to categorize complex natural scenes exist in the absence of awareness, based on recent reports that “invisible” stimuli, which do not reach conscious awareness, can still be processed by the human visual system (Pasley et al., 2004; Williams et al., 2004; Fang and He, 2005; Jiang et al., 2006, 2007; Kaunitz et al., 2011a). In two experiments, we recorded event-related potentials (ERPs) in response to animal and non-animal/vehicle stimuli in both aware and unaware conditions in a continuous flash suppression (CFS) paradigm. Our results indicate that even in the “unseen” condition, the brain responds differently to animal and non-animal/vehicle images, consistent with rapid activation of animal-selective feature detectors prior to, or outside of, suppression by the CFS mask.