Three faces of self-face recognition: Potential for a multi-dimensional diagnostic tool

Differences in own-face but not own-name discrimination between autistic and neurotypical adults: A fast periodic visual stimulation-EEG study

Self-related processing is thought to be altered in autism, with several studies reporting that autistic individuals show a diminished neural response relative to neurotypicals for their own name and face. However, evidence remains scarce and is mostly based on event-related potential studies. Here, we used EEG to measure the neural activity of autistic adults (20 for faces, 27 for names) and neurotypical adults (24 for faces, 25 for names) while they were watching rapidly alternating faces and names, through a relatively new technique called Fast Periodic Visual Stimulation. We presented strangers' faces or names at a base frequency of 5.77 Hz, while one's own, a close other's, and a specific stranger's face/name was presented at an oddball frequency of 1.154 Hz. The neurotypical group showed a significantly greater response to their own face than both close other and stranger faces, and a greater response for close other than for stranger faces. In contrast, in the autism group, own and close other faces showed stronger responses than the stranger's face, but the difference between own and close other faces was not significant in a bilateral parieto-occipital cluster. No group differences in the enhanced response to familiar names were found. These results replicate and extend results obtained using traditional electroencephalographic techniques which suggest atypical responses to self-relevant stimuli in autism.

Hypoactive Visual Cortex, Prefrontal Cortex and Insula during Self-Face Recognition in Adults with First-Episode Major Depressive Disorder

Self-face recognition is a vital aspect of self-referential processing, which is closely related to affective states. However, neuroimaging research on self-face recognition in adults with major depressive disorder is lacking. This study aims to investigate the alteration of brain activation during self-face recognition in adults with first-episode major depressive disorder (FEMDD) via functional magnetic resonance imaging (fMRI); FEMDD (n = 59) and healthy controls (HC, n = 36) who performed a self-face-recognition task during the fMRI scan. The differences in brain activation signal values between the two groups were analyzed, and Pearson correlation analysis was used to evaluate the relationship between the brain activation of significant group differences and the severity of depressive symptoms and negative self-evaluation; FEMDD showed significantly decreased brain activation in the bilateral occipital cortex, bilateral fusiform gyrus, right inferior frontal gyrus, and right insula during the task compared with HC. No significant correlation was detected between brain activation with significant group differences and the severity of depression and negative self-evaluation in FEMDD or HC. The results suggest the involvement of the malfunctioning visual cortex, prefrontal cortex, and insula in the pathophysiology of self-face recognition in FEMDD, which may provide a novel therapeutic target for adults with FEMDD.

Re-cognizing the new self: The neurocognitive plasticity of self-processing following facial transplantation

The face is a defining feature of our individuality, crucial for our social interactions. But what happens when the face connected to the self is radically altered or replaced? We address the plasticity of self-face recognition in the context of facial transplantation. While the acquisition of a new face following facial transplantation is a medical fact, the experience of a new identity is an unexplored psychological outcome. We traced the changes in self-face recognition before and after facial transplantation to understand if and how the transplanted face gradually comes to be perceived and recognized as the recipient's own new face. Neurobehavioral evidence documents a strong representation of the pre-injury appearance pre-operatively, while following the transplantation, the recipient incorporates the new face into his self-identity. The acquisition of this new facial identity is supported by neural activity in medial frontal regions that are considered to integrate psychological and perceptual aspects of the self.

Integrating mind and body: Investigating differential activation of nodes of the default mode network

BACKGROUND

The default mode network (DMN) is a large-scale brain network tightly correlated with self and self-referential processing, activated by intrinsic tasks and deactivated by externally-directed tasks.

OBJECTIVE

In this study, we aim to investigate the novel approach of default mode activation during progressive muscle relaxation and examine whether differential activation patterns result from the movement of different body parts.

METHODS

We employed neuroimaging to investigate DMN activity during simple body movements, while performing progressive muscle relaxation. We focused on differentiating the neural response between facial movements and movements of other body parts.

RESULTS

Our results show that the movement of different body parts led to deactivation in several DMN nodes, namely the temporal poles, hippocampus, medial prefrontal cortex (mPFC), and posterior cingulate cortex. However, facial movement induced an inverted and selective positive BOLD pattern in some of these areas precisely. Moreover, areas in the temporal poles selective for face movement showed functional connectivity not only with the hippocampus and mPFC but also with the nucleus accumbens.

CONCLUSIONS

Our findings suggest that both conceptual and embodied self-related processes, including body movements during progressive muscle relaxation, may be mapped onto shared brain networks. This could enhance our understanding of how practices like PMR influence DMN activity and potentially offer insights to inform therapeutic strategies that rely on mindful body movements.

An Experimental Study of Subliminal Self-Face Processing in Depersonalization-Derealization Disorder

The self-perception or self-experience of patients with depersonalization/derealization disorder (DPD) is altered, leading to a profound disruption in self-awareness. The main aim of the study is to explore the characteristics of subliminal self-face processing in DPD patients. To our knowledge, this is the first experimental study that has measured and evaluated subliminal self-processing in DPD. To better understand this, we examined the ability of patients with DPD and healthy controls (HC) to identify pictures of faces using an experimental paradigm of breaking continuous flash suppression. There were 23 DPD outpatients from Beijing Anding Hospital, Capital Medical University and 23 matched HC who participated in this experiment. The time needed for a face to break into awareness was taken as the measure of participants' subliminal processing of that face. The results indicated that there were significant differences between the DPD patients and HC in subliminal reaction times to different faces. Under experimental conditions, the average reaction response of self-face recognition in the HC group was significantly faster than for a famous face. However, this difference was not observed in DPD patients, which means that DPD patients did not show the processing advantage of their own faces as did the HC. The results suggest a deficit in subliminal self-face processing in DPD.

The salience network is activated during self-recognition from both first-person and third-person perspectives

We usually observe ourselves from two perspectives. One is the first-person perspective, which we perceive directly with our own eyes, and the other is the third-person perspective, which we observe ourselves in a mirror or a picture. However, whether the self-recognition associated with these two perspectives has a common or separate neural basis remains unclear. To address this, we used functional magnetic resonance imaging to examine brain activity while participants viewed pretaped video clips of themselves and others engaged in meal preparation taken from first-person and third-person perspectives. We found that the first-person behavioral videos of the participants and others induced greater activation in the premotor-intraparietal region. In contrast, the third-person behavioral videos induced greater activation in the default mode network compared with the first-person videos. Regardless of the perspective, the videos of the participants induced greater activation in the salience network than the videos of others. On the other hand, the videos of others induced greater activation in the precuneus and lingual gyrus than the videos of the participants. These results suggest that the salience network is commonly involved in self-recognition from both perspectives, even though the brain regions involved in action observation for the two perspectives are distinct.

Spatially Adjacent Regions in Posterior Cingulate Cortex Represent Familiar Faces at Different Levels of Complexity

Extensive research has shown that perceptual information of faces is processed in a network of hierarchically-organized areas within ventral temporal cortex. For familiar and famous faces, perceptual processing of faces is normally accompanied by extraction of semantic knowledge about the social status of persons. Semantic processing of familiar faces could entail progressive stages of information abstraction. However, the cortical mechanisms supporting multistage processing of familiar faces have not been characterized. Here, using an event-related fMRI experiment, familiar faces from four celebrity groups (actors, singers, politicians, and football players) and unfamiliar faces were presented to the human subjects (both males and females) while they were engaged in a face categorization task. We systematically explored the cortical representations for faces, familiar faces, subcategories of familiar faces, and familiar face identities using whole-brain univariate analysis, searchlight-based multivariate pattern analysis (MVPA), and functional connectivity analysis. Convergent evidence from all these analyses revealed a set of overlapping regions within posterior cingulate cortex (PCC) that contained decodable fMRI responses for representing different levels of semantic knowledge about familiar faces. Our results suggest a multistage pathway in PCC for processing semantic information of faces, analogous to the multistage pathway in ventral temporal cortex for processing perceptual information of faces.SIGNIFICANCE STATEMENT Recognizing familiar faces is an important component of social communications. Previous research has shown that a distributed network of brain areas is involved in processing the semantic information of familiar faces. However, it is not clear how different levels of semantic information are represented in the brain. Here, we evaluated the multivariate response patterns across the entire cortex to discover the areas that contain information for familiar faces, subcategories of familiar faces, and identities of familiar faces. The searchlight maps revealed that different levels of semantic information are represented in topographically adjacent areas within posterior cingulate cortex (PCC). The results suggest that semantic processing of faces is mediated through progressive stages of information abstraction in PCC.

Neural responses to facial attractiveness in the judgments of moral goodness and moral beauty

The judgments of moral goodness and moral beauty objectively refer to the perception and evaluation of moral traits, which are generally influenced by facial attractiveness. For centuries, people have equated beauty with the possession of positive qualities, but it is not clear whether the association between beauty and positive qualities exerts a similarly implicit influence on people's responses to moral goodness and moral beauty, how it affects those responses, and what is the neural basis for such an effect. The present study is the first to examine the neural responses to facial attractiveness in the judgments of moral goodness and moral beauty. We found that beautiful faces in both moral judgments activated the left ventral occipitotemporal cortices sensitive to the geometric configuration of the faces, demonstrating that both moral goodness and moral beauty required the automatic visual analysis of geometrical configuration of attractive faces. In addition, compared to beautiful faces during moral goodness judgment, beautiful faces during moral beauty judgment induced unique activity in the ventral medial prefrontal cortex and midline cortical structures involved in the emotional-valenced information about attractive faces. The opposite comparison elicited specific activity in the left superior temporal cortex and premotor area, which play a critical role in the recognition of facial identity. Our results demonstrated that the neural responses to facial attractiveness in the process of higher order moral decision-makings exhibit both task-general and task-specific characteristics. Our findings contribute to the understanding of the essence of the relationship between morality and aesthetics.

Face-Based Attention Recognition Model for Children with Autism Spectrum Disorder

Attention recognition plays a vital role in providing learning support for children with autism spectrum disorders (ASD). The unobtrusiveness of face-tracking techniques makes it possible to build automatic systems to detect and classify attentional behaviors. However, constructing such systems is a challenging task due to the complexity of attentional behavior in ASD. This paper proposes a face-based attention recognition model using two methods. The first is based on geometric feature transformation using a support vector machine (SVM) classifier, and the second is based on the transformation of time-domain spatial features to 2D spatial images using a convolutional neural network (CNN) approach. We conducted an experimental study on different attentional tasks for 46 children (ASD n=20, typically developing children n=26) and explored the limits of the face-based attention recognition model for participant and task differences. Our results show that the geometric feature transformation using an SVM classifier outperforms the CNN approach. Also, attention detection is more generalizable within typically developing children than within ASD groups and within low-attention tasks than within high-attention tasks. This paper highlights the basis for future face-based attentional recognition for real-time learning and clinical attention interventions.

The Neurological Asymmetry of Self-Face Recognition

While the desire to uncover the neural correlates of consciousness has taken numerous directions, self-face recognition has been a constant in attempts to isolate aspects of self-awareness. The neuroimaging revolution of the 1990s brought about systematic attempts to isolate the underlying neural basis of self-face recognition. These studies, including some of the first fMRI (functional magnetic resonance imaging) examinations, revealed a right-hemisphere bias for self-face recognition in a diverse set of regions including the insula, the dorsal frontal lobe, the temporal parietal junction, and the medial temporal cortex. In this systematic review, we provide confirmation of these data (which are correlational) which were provided by TMS (transcranial magnetic stimulation) and patients in which direct inhibition or ablation of right-hemisphere regions leads to a disruption or absence of self-face recognition. These data are consistent with a number of theories including a right-hemisphere dominance for self-awareness and/or a right-hemisphere specialization for identifying significant social relationships, including to oneself.

Effects of right or left face stimulation on self and other perception in enfacement illusion

Enfacement illusion is a visuo-tactile illusion elicited by being touched on one's own face while observing another face being touched at the same time, resulting in a change in self-face recognition. Left-face stimulation is usually preferred in enfacement studies. We investigated whether left or right face stimulation has any effect on the vividness of the illusion and if any relationship exists between emphatic abilities, personality traits and vividness of the illusion. The enfacement procedure included two stimuli: a cotton swab touching to face and a syringe approaching to face. We assessed subjective feeling of the illusion using a questionnaire and morphed face evaluations between self and other. Additionally, galvanic skin response (GSR) was measured. The results indicated that the syringe elicited higher GSR than that of touching and left face stimulation was much more sensitive in discriminating synchronous and asynchronous conditions. We found a significant relationship between self-to-other morph evaluations and GSR when the left side of the face was stimulated synchronously. However, a significant relationship was found between other-to-self evaluations and GSR when the right side of the face was stimulated asynchronously. We also noted significant correlations between vividness of the illusion and emphatic concern, extraversion and psychoticism traits.

Neural correlates of beauty retouching to enhance attractiveness of self-depictions in women

Beauty filters, while often employed for retouching photos to appear more attractive on social media, when used in excess cause images to give a distorted impression. The neural mechanisms underlying this change in facial attractiveness according to beauty retouching level remain unknown. The present study used functional magnetic resonance imaging in women as they viewed photos of their own face or unknown faces that had been retouched at three levels: no, mild, and extreme. The activity in the nucleus accumbens (NA) exhibited a positive correlation with facial attractiveness, whereas amygdala activity showed a negative correlation with attractiveness. Even though the participants rated others' faces as more attractive than their own, the NA showed increased activity only for their mildly retouched own face and the amygdala exhibited greater activation in the others' faces condition than the own face condition. Moreover, amygdala activity was greater for extremely retouched faces than for unretouched or mildly retouched faces for both conditions. Frontotemporal and cortical midline areas showed greater activation for one's own than others' faces, but such self-related activation was absent when extremely retouched. These results suggest that neural activity dynamically switches between the NA and amygdala according to perceived attractiveness of one's face.

Like the back of my hand: Visual ERPs reveal a specific change detection mechanism for the bodily self

The ability to identify our own body is considered a pivotal marker of self-awareness. Previous research demonstrated that subjects are more efficient in the recognition of images representing self rather than others' body effectors (self-advantage). Here, we verified whether, at an electrophysiological level, bodily-self recognition modulates change detection responses. In a first EEG experiment (discovery sample), event-related potentials (ERPs) were elicited by a pair of sequentially presented visual stimuli (vS1; vS2), representing either the self-hand or other people's hands. In a second EEG experiment (replicating sample), together with the previously described visual stimuli, also a familiar hand was presented. Participants were asked to decide whether vS2 was identical or different from vS1. Accuracy and response times were collected. In both experiments, results confirmed the presence of the self-advantage: participants responded faster and more accurately when the self-hand was presented. ERP results paralleled behavioral findings. Anytime the self-hand was presented, we observed significant change detection responses, with a larger N270 component for vS2 different rather than identical to vS1. Conversely, when the self-hand was not included, and even in response to the familiar hand in Experiment 2, we did not find any significant modulation of the change detection responses. Overall our findings, showing behavioral self-advantage and the selective modulation of N270 for the self-hand, support the existence of a specific mechanism devoted to bodily-self recognition, likely relying on the multimodal (visual and sensorimotor) dimension of the bodily-self representation. We propose that such a multimodal self-representation may activate the salience network, boosting change detection effects specifically for the self-hand.

Amygdala Functional Connectivity During Self-Face Processing in Depressed Adolescents With Recent Suicide Attempt

OBJECTIVE

Suicide is the second leading cause of death among adolescents; however, objective biomarkers of suicide risk are lacking. Aberrant self-face amygdala activity is associated with suicide ideation, and its connectivity with neural regions that enable self-processing (eg medial prefrontal cortex) may be a suicide risk factor.

METHOD

Adolescents (aged 11-17 years; N = 120) were sorted into four groups: healthy controls (HC), depressed individuals with low suicide ideation (LS), depressed individuals with high suicide ideation (HS), and depressed suicide attempters (SA). Youth completed an emotional (Happy, Sad, Neutral) self-face recognition task in the scanner. Bilateral amygdala task-dependent functional connectivity was determined with psychophysiological interaction analysis. Connectivity was compared across groups and within Self versus Other faces across emotions and hemispheres. Voxelwise results were thresholded (p < .005, uncorrected) and corrected for multiple comparisons (p < .05, familywise error).

RESULTS

Both HS and SA displayed greater amygdala connectivity with the dorsolateral prefrontal cortex, dorsomedial prefrontal cortex, and precuneus, compared to LS, who, in turn, showed greater connectivity than HC. Greater left amygdala-rostral anterior cingulate cortex (rACC) connectivity was observed in SA compared to all other groups, whereas right amygdala-rACC connectivity was greater in HS versus LS and HC.

CONCLUSION

Greater connectivity between amygdala and other regions implicated in self-face processing differentiated suicide ideation and suicide attempt groups. A dose-dependent response showed that greater rACC-left amygdala connectivity during self-face processing was associated with a recent suicide attempt, but that a greater rACC-right amygdala connectivity was associated with suicide ideation.

The neurobiology of self face recognition among depressed adolescents

OBJECTIVE

Depression is linked to alterations in both emotion and self-processing. The current study used functional magnetic resonance imaging (fMRI) to assess neural activation in healthy and depressed youth to a novel task that combined emotion processing with self-face recognition.

METHODS

An fMRI study involving 81 adolescents (50.6% females; Mage=14.61, SD=1.65) comprised of depressed (DEP, n=43), and healthy controls (HC, n=38). Participants completed a clinical interview and self-report measures during an initial assessment. In the scanner, adolescents completed a face recognition task, viewing emotional (happy, sad, neutral) images of their own face (self) or the face of another youth (other).

RESULTS

DEP youth showed higher activity in the cuneus (F=26.29) and post and precentral gyri (F=20.76), across all conditions compared to HC. Sad faces elicited higher posterior cingulate cortex, precuneus (F=10.36) and inferior parietal cortex activity (F=11.0), and self faces elicited higher precuneus, fusiform (F=16.39), insula and putamen (F=16.82) activity in all youth. DEP showed higher middle temporal activity to neutral faces but lower activity to sad faces compared to HC, who showed the opposite pattern (F=12.86). DEP also showed hypoactive mid-temporal limbic activity relative to controls when identifying their self happy face vs. neutral face, yet showed hyperactivity when identifying the other happy face vs. neutral face, and HC showed the opposite pattern (F=10.94).

CONCLUSIONS

The neurophysiology of self-face recognition is altered in adolescent depression. Specifically, depression was associated with decreased activity in neural areas that support emotional and associative processing for positive self-faces and increased processing for neutral self-faces. These results suggest that depression in adolescents is associated with hypoactive emotional processing and encoding of positive self-related visual information. This abnormal neural activity at the intersection of reward and self-processing among depressed youth might have long lasting impact in self-formation and future adult self-representations, given that adolescence is a sensitive period for self-development.

Strange-face Illusions During Interpersonal-Gazing and Personality Differences of Spirituality

Strange-face illusions are produced when two individuals gaze at each other in the eyes in low illumination for more than a few minutes. Usually, the members of the dyad perceive numinous apparitions, like the other's face deformations and perception of a stranger or a monster in place of the other, and feel a short lasting dissociation. In the present experiment, the influence of the spirituality personality trait on strength and number of strange-face illusions was investigated. Thirty participants were preliminarily tested for superstition (Paranormal Belief Scale, PBS) and spirituality (Spiritual Transcendence Scale, STS); then, they were randomly assigned to 15 dyads. Dyads performed the intersubjective gazing task for 10 minutes and, finally, strange-face illusions (measured through the Strange-Face Questionnaire, SFQ) were evaluated. The first finding was that SFQ was independent of PBS; hence, strange-face illusions during intersubjective gazing are authentically perceptual, hallucination-like phenomena, and not due to superstition. The second finding was that SFQ depended on the spiritual-universality scale of STS (a belief in the unitive nature of life; e.g., "there is a higher plane of consciousness or spirituality that binds all people") and the two variables were negatively correlated. Thus, strange-face illusions, in particular monstrous apparitions, could potentially disrupt binding among human beings. Strange-face illusions can be considered as 'projections' of the subject's unconscious into the other's face. In conclusion, intersubjective gazing at low illumination can be a tool for conscious integration of unconscious 'shadows of the Self' in order to reach completeness of the Self.

Mirror self-face perception in individuals with schizophrenia: Feelings of strangeness associated with one's own image

Self-face recognition is crucial for sense of identity and for maintaining a coherent sense of self. Most of our daily life experiences with the image of our own face happen when we look at ourselves in the mirror. However, to date, mirror self-perception in schizophrenia has received little attention despite evidence that face recognition deficits and self abnormalities have been described in schizophrenia. Thus, this study aims to investigate mirror self-face perception in schizophrenia patients and its correlation with clinical symptoms. Twenty-four schizophrenia patients and twenty-five healthy controls were explicitly requested to describe their image in detail during 2min whilst looking at themselves in a mirror. Then, they were asked to report whether they experienced any self-face recognition difficulties. Results showed that schizophrenia patients reported more feelings of strangeness towards their face compared to healthy controls (U=209.5, p=0.048, r=0.28), but no statistically significant differences were found regarding misidentification (p=0.111) and failures in recognition (p=0.081). Symptoms such as hallucinations, somatic concerns and depression were also associated with self-face perception abnormalities (all p-values>0.05). Feelings of strangeness toward one's own face in schizophrenia might be part of a familiar face perception deficit or a more global self-disturbance, which is characterized by a loss of self-other boundaries and has been associated with abnormal body experiences and first rank symptoms. Regarding this last hypothesis, multisensorial integration might have an impact on the way patients perceive themselves since it has an important role in mirror self-perception.

The neurobiology of self-face recognition in depressed adolescents with low or high suicidality

This study sought to test whether the neurobiology of self-processing differentiated depressed adolescents with high suicidality (HS) from those with low suicidality (LS) and healthy controls (HC; N = 119, MAGE = 14.79, SD = 1.64, Min = 11.3, Max = 17.8). Participants completed a visual self-recognition task in the scanner during which they identified their own or an unfamiliar adolescent face across 3 emotional expressions (happy, neutral or sad). A 3-group (HS, LS, HC) by 2 within-subject factors (2 Self conditions [self, other] and 3 Emotions [happy, neutral, sad]) GLM yielded (a) a main effect of Self condition with all participants showing higher activity in the right occipital, precuneus and fusiform during the self- versus other-face conditions; (b) a main effect of Group where all depressed youth showed higher dorsolateral prefrontal cortex activity than HC across all conditions, and with HS showing higher cuneus and occipital activity versus both LS and HC; and (c) a Group by Self by Emotion interaction with HS showing lower activity in both mid parietal, limbic, and prefrontal areas in the Happy self versus other-face condition relative to the LS group, who in turn had less activity compared to HC youth. Covarying for depression severity replicated all results except the third finding; In this subsequent analysis, a Group by Self interaction showed that although HC had similar midline cortical structure (MCS) activity for all faces, LS showed higher MCS activity for the self versus other faces, whereas HS showed the opposite pattern. Results suggest that the neurophysiology of emotionally charged self-referential information can distinguish depressed, suicidal youth versus nonsuicidal depressed and healthy adolescents. Neurophysiological differences and implications for the prediction of suicidality in youth are discussed. (PsycINFO Database Record

Processing of self-related kinematic information embedded in static handwritten characters

Handwritten characters are generated by our own motor actions, and previous studies have shown that the manner in which such characters are perceived and generated is related. However, the temporal course of the neural activation involved in the processing of self-related kinematic information embedded in static handwritten characters remains to be identified. We applied event-related potential (ERP) recording while participants judged whether handwritten characters were self- or non-self-generated. To test the effects of the self-related kinematic characteristics of static handwritten characters, we conducted two experiments in which the styles or familiarity of characters were manipulated. The ERP results indicated differences in brain activation between self- and non-self-written characters for the P250 component (250-350ms after stimulus onset) in right posterior regions and for the late positive component (LPC; 350-500ms after stimulus onset) in anterior midline regions; this was the case even when the handwritten characters were not generated in their usual form or were written for the first time. Therefore, our data indicate that self-information embedded in handwritten characters involves both right-lateralized brain activation associated with bodily self-processing and anterior midline brain activation related to self-referential processing.

The Role of Familiarity on Viewpoint Adaptation for Self-Face and Other-Face Images

An adaptation method was used to investigate whether self-face processing is dissociable from general face processing. We explored the viewpoint aftereffect with face images having different degrees of familiarity (never-before-seen faces, recently familiarized faces, personally familiar faces, and the participant’s own face). A face viewpoint aftereffect occurs after prolonged viewing of a face viewed from one side, with the result that the perceived viewing direction of a subsequently presented face image shown near the frontal view is biased in a direction which is the opposite of the adapting orientation. We found that (1) the magnitude of the viewpoint aftereffect depends on the level of familiarity of the adapting and test faces, (2) a cross-identity transfer of the viewpoint aftereffect is found between all categories of faces, but not between an unfamiliar adaptor face and the self-face test, and (3) learning affects the processing of the self-face in greater measure than any other category of faces. These results highlight the importance of familiarity on the face aftereffects, but they also suggest the possibility of separate representations for the self-face, on the one side, and for highly familiar faces, on the other.