Neural activities differentiating bodies versus non-body stimuli have been identified in the occipitotemporal cortex of both humans and nonhuman primates. However, the neural mechanisms of coding the similarity of different individuals' bodies of the same species to support their categorical representations remain unclear. Using electroencephalography (EEG) and magnetoencephalography (MEG), we investigated the temporal and spatial characteristics of neural processes shared by different individual body silhouettes of the same species by quantifying the repetition suppression of neural responses to human and animal (chimpanzee, dog, and bird) body silhouettes showing different postures. Our EEG results revealed significant repetition suppression of the amplitudes of early frontal/central activity at 180-220 ms (P2) and late occipitoparietal activity at 220-320 ms (P270) in response to animal (but not human) body silhouettes of the same species. Our MEG results further localized the repetition suppression effect related to animal body silhouettes in the left supramarginal gyrus and left frontal cortex at 200-440 ms after stimulus onset. Our findings suggest two neural processes that are involved in spontaneous categorical representations of animal body silhouettes as a cognitive basis of human-animal interactions.
Humans ; Animals ; Male ; Electroencephalography ; Magnetoencephalography ; Female ; Young Adult ; Adult ; Pattern Recognition, Visual/physiology* ; Brain Mapping ; Photic Stimulation ; Brain/physiology* ; Dogs

Previous studies have identified two group-level processes, neural representations of interracial between-group difference and intraracial within-group similarity, that contribute to the racial categorization of faces. What remains unclear is how the brain tracks race-related information that varies across different faces as an individual-level neural process involved in race perception. In three studies, we recorded functional MRI signals when Chinese adults performed different tasks on morphed faces in which proportions of pixels contributing to perceived racial identity (Asian vs White) and expression (pain vs neutral) varied independently. We found that, during a pain expression judgment task, tracking other-race and same-race-related information in perceived faces recruited the ventral occipitotemporal cortices and medial prefrontal/anterior temporal cortices, respectively. However, neural tracking of race-related information tended to be weakened during explicit race judgments on perceived faces. During a donation task, the medial prefrontal activity also tracked race-related information that distinguished between two perceived faces for altruistic decision-making and encoded the Euclidean distance between the two faces that predicted decision-making speeds. Our findings revealed task-dependent neural mechanisms underlying the tracking of race-related information during face perception and altruistic decision-making.
Adult ; Female ; Humans ; Male ; Young Adult ; Brain/diagnostic imaging* ; Brain Mapping ; Decision Making/physiology* ; Facial Recognition/physiology* ; Judgment/physiology* ; Magnetic Resonance Imaging ; Photic Stimulation ; Racial Groups ; Social Perception ; East Asian People

Social working memory (SWM)-the ability to maintain and manipulate social information in the brain-plays a crucial role in social interactions. However, research on SWM is still in its infancy and is often treated as a unitary construct. In the present study, we propose that SWM can be conceptualized as having two relatively independent components: "externally oriented SWM" (e-SWM) and "internally oriented SWM" (i-SWM). To test this external-internal hypothesis, participants were tasked with memorizing and ranking either facial expressions (e-SWM) or personality traits (i-SWM) associated with images of faces. We then examined the neural correlates of these two SWM components and their functional roles in empathy. The results showed distinct activations as the e-SWM task activated the postcentral and precentral gyri while the i-SWM task activated the precuneus/posterior cingulate cortex and superior frontal gyrus. Distinct multivariate activation patterns were also found within the dorsal medial prefrontal cortex in the two tasks. Moreover, partial least squares analyses combining brain activation and individual differences in empathy showed that e-SWM and i-SWM brain activities were mainly correlated with affective empathy and cognitive empathy, respectively. These findings implicate distinct brain processes as well as functional roles of the two types of SWM, providing support for the internal-external hypothesis of SWM.
Humans ; Memory, Short-Term/physiology* ; Male ; Female ; Empathy/physiology* ; Young Adult ; Magnetic Resonance Imaging ; Adult ; Brain/diagnostic imaging* ; Brain Mapping ; Facial Expression ; Social Behavior ; Facial Recognition/physiology* ; Social Perception ; Personality/physiology*

ABSTRACT Smile aesthetic, known as the static and dynamic relationship of the dentition and supporting structures to the facial soft tissues, is one of the most important elements of facial attractiveness. The objective of the study was to assess the perception of smile aesthetics and attractiveness through digital image manipulation of aesthetic variables and to compare those perceptions according to diverse sociodemographic data among female Saudi laypeople attending the dental clinic. A crosssectional study of 193 female Saudi participants were randomly selected and consented to answer the study questionnaire. Nine smile photograph images were created to compare different smile aesthetic perceptions. Two groups were recruited: 120 participants in the first group (under 30 years old) and 73 participants in the second group (30 years old or above). All participants in both groups were asked to choose the attractiveness of each smile image using multiple-choice options. A statistically significant finding showed that normal buccal corridors were chosen as the most attractive smile by 42.5% of the participants in the younger group and by a significantly higher ratio of the participants with a bachelor’s degree or higher level of education at 49% (p < 0.05). Laypeople’s preferences regarding smile attractiveness vary, but a normal appearance was the ideal choice for the majority. Orthodontic treatment should consider the general sociocultural understanding of smile perception.
Esthetics, Dental--psychology ; Facial Recognition ; Saudi Arabia

How the brain perceives objects and classifies perceived objects is one of the important goals of visual cognitive neuroscience. Previous research has shown that when we see objects, the brain's ventral visual pathway recognizes and classifies them, leading to different ways of interacting with them. In this paper, we summarize the latest research progress of the ventral visual pathway related to the visual classification of objects. From the perspective of the neural representation of objects and its underlying mechanisms in the visual cortex, we summarize the current research status of the two important organizational dimensions of object animacy and real-world size, provide new insights, and point out the direction of further research.
Brain Mapping/methods* ; Magnetic Resonance Imaging ; Pattern Recognition, Visual ; Photic Stimulation ; Visual Cortex ; Visual Pathways

It is widely acknowledged that holistic processing is a key characteristic of face perception. Although holistic processing implies the automatic integration of face parts, it is unclear whether such processing requires the awareness of face parts. Here, we investigated the interactions between visible face parts and face parts rendered invisible using continuous flash suppression (CFS). In the first experiment with the upper half-face visible and the lower half-face invisible, the results showed that perceived face identity was influenced by the invisible lower half-face, suggesting that integration occurs between the visible and invisible face parts, a variant of the "composite face effect". In the second experiment, we investigated the influence of visible face parts on the processing of invisible face parts, as measured by the time it took for the invisible parts to break out from CFS. The results showed a visible-to-invisible facilitation effect, that the aligned invisible face parts broke through CFS faster than when the visible and invisible face parts were misaligned. Visible eyes had a stronger influence on the invisible nose/mouth than the other way around. Such facilitation of processing from visible to invisible parts was also found when Chinese characters were used as stimuli. These results show that information integration occurs across the consciousness boundary.
Awareness ; Consciousness ; Eye ; Face ; Facial Recognition ; Photic Stimulation

Visual object recognition in humans and nonhuman primates is achieved by the ventral visual pathway (ventral occipital-temporal cortex, VOTC), which shows a well-documented object domain structure. An on-going question is what type of information is processed in the higher-order VOTC that underlies such observations, with recent evidence suggesting effects of certain visual features. Combining computational vision models, fMRI experiment using a parametric-modulation approach, and natural image statistics of common objects, we depicted the neural distribution of a comprehensive set of visual features in the VOTC, identifying voxel sensitivities with specific feature sets across geometry/shape, Fourier power, and color. The visual feature combination pattern in the VOTC is significantly explained by their relationships to different types of response-action computation (fight-or-flight, navigation, and manipulation), as derived from behavioral ratings and natural image statistics. These results offer a comprehensive visual feature map in the VOTC and a plausible theoretical explanation as a mapping onto different types of downstream response-action systems.
Animals ; Brain Mapping ; Humans ; Magnetic Resonance Imaging ; Occipital Lobe ; Pattern Recognition, Visual ; Photic Stimulation ; Temporal Lobe ; Visual Pathways/diagnostic imaging* ; Visual Perception

The human visual system efficiently extracts local elements from cluttered backgrounds and integrates these elements into meaningful contour perception. This process is a critical step before object recognition, in which contours often play an important role in defining the shapes and borders of the to-be-recognized objects. However, the neural mechanism of the contour integration is still under debate. The investigation of the neural mechanism underlying contour integration could deepen our understanding of perceptual grouping in the human visual system and advance the development of the algorithms for image grouping and segmentation in computer vision. Here, we review two theoretical frameworks that were proposed over the past decades. The first framework is based on hardwired horizontal connection in primary visual cortex, while the second one emphasizes the role of recurrent connections within intra- and inter-areas. At the end of review, we also raise the unsolved issues that need to be addressed in future studies.
Form Perception ; Humans ; Models, Neurological ; Pattern Recognition, Visual ; Visual Cortex ; physiology ; Visual Perception

This study evaluated the feasibility of using texture analysis and machine learning to distinguish radiographic lung patterns. A total of 1200 regions of interest (ROIs) including four specific lung patterns (normal, alveolar, bronchial, and unstructured interstitial) were obtained from 512 thoracic radiographs of 252 dogs and 65 cats. Forty-four texture parameters based on eight methods of texture analysis (first-order statistics, spatial gray-level-dependence matrices, gray-level-difference statistics, gray-level run length image statistics, neighborhood gray-tone difference matrices, fractal dimension texture analysis, Fourier power spectrum, and Law's texture energy measures) were used to extract textural features from the ROIs. The texture parameters of each lung pattern were compared and used for training and testing of artificial neural networks. Classification performance was evaluated by calculating accuracy and the area under the receiver operating characteristic curve (AUC). Forty texture parameters showed significant differences between the lung patterns. The accuracy of lung pattern classification was 99.1% in the training dataset and 91.9% in the testing dataset. The AUCs were above 0.98 in the training set and above 0.92 in the testing dataset. Texture analysis and machine learning algorithms may potentially facilitate the evaluation of medical images.
Animals ; Area Under Curve ; Cats ; Classification ; Dataset ; Dogs ; Fourier Analysis ; Fractals ; Lung ; Machine Learning ; Neural Networks (Computer) ; Pattern Recognition, Visual ; Radiography, Thoracic ; Residence Characteristics ; ROC Curve

BACKGROUND: The facial expression of medical staff has been known to greatly affect the psychological state of patients, making them feel uneasy or conversely, cheering them up. By clarifying the characteristics of facial expression recognition ability in patients with Lewy body disease, the aim of this study is to examine points to facilitate smooth communication between caregivers and patients with the disease whose cognitive function has deteriorated. METHODS: During the period from March 2016 to July 2017, we examined the characteristics of recognition of the six facial expressions of "happiness," "sadness," "fear," "anger," "surprise," and "disgust" for 107 people aged 60 years or more, both outpatient and inpatient, who hospital specialists had diagnosed with Lewy body diseases of Parkinson's disease, Parkinson's disease with dementia, and dementia with Lewy bodies. Based on facial expression recognition test results, we classified them by cluster analysis and clarified features of each type. RESULTS: In patients with Lewy body disease, happiness was kept unaffected by aging, age of onset, duration of the disease, cognitive function, and apathy; however, recognizing the facial expression of fear was difficult. In addition, due to aging, cognitive decline, and apathy, the facial expression recognition ability for sadness and anger decreased. In particular, cognitive decline reduced recognition of all of the facial expressions except for happiness. The test accuracy rates were classified into three types using the cluster analysis: "stable type," "mixed type," and "reduced type". In the "reduced type", the overall facial recognition ability declined except happiness, and in the mixed type, recognition ability of anger particularly declined. CONCLUSION There were several facial expressions that the Lewy body disease patients were unable to accurately identify. Caregivers are recommended to make an effort to compensate for such situations with language or body contact, etc., as a way to convey correct feeling to the patients of each type.
Aged ; Aged, 80 and over ; Cluster Analysis ; Cognition ; physiology ; Emotions ; Facial Expression ; Facial Recognition ; physiology ; Female ; Humans ; Lewy Body Disease ; physiopathology ; psychology ; Male ; Middle Aged