Viewing artworks: Contributions of cognitive control and perceptual facilitation to aesthetic experience

When we view visual images in everyday life, our perception is oriented toward object identification. In contrast, when viewing visual images as artworks, we also tend to experience subjective reactions to their stylistic and structural properties. This experiment sought to determine how cognitive control and perceptual facilitation contribute to aesthetic perception along with the experience of emotion. Using functional MRI, we show that aesthetic perception activated bilateral insula which we attribute to the experience of emotion. Moreover, while adopting the aesthetic orientation activated the left lateral prefrontal cortex, paintings that facilitated visuospatial exploration activated the left superior parietal lobule. The results suggest that aesthetic experience is a function of the interaction between top-down orienting of attention and bottom-up perceptual facilitation.     

Effects of motor intention on the perception of somatosensory events: A behavioural and functional magnetic resonance imaging study

The intention to execute a movement can modulate our perception of sensory events, and this modulation is observed ahead of both ocular and upper limb movements. However, theoretical accounts of these effects, and also the empirical data, are often contradictory. Accounts of “active touch”, and the premotor theory of attention, have emphasized how movement intention leads to enhanced perceptual processing at the target of a movement, or on the to-be-moved effector. By contrast, recent theories of motor control emphasize how internal “forward” model (FM) estimates may be used to cancel or attenuate sensory signals that arise as a result of self-generated movements. We used behavioural and functional brain imaging (functional magnetic resonance imaging, fMRI) to investigate how perception of a somatosensory stimulus differed according to whether it was delivered to a hand that was about to execute a reaching movement or the alternative, nonmoving, hand. The results of our study demonstrate that a somatosensory stimulus delivered to a hand that is being prepared for movement is perceived to have occurred later than when that same stimulus is delivered to a nonmoving hand. This result indicates that it takes longer for a tactile stimulus to be detected when it is delivered to a moving limb and may correspond to a change in perceptual threshold. Our behavioural results are paralleled by the results of our fMRI study that demonstrated that there were significantly reduced blood-oxygen-level-dependent (BOLD) responses within the parietal operculum and insula following somatosensory stimulation of the hand being prepared for movement, compared to when an identical stimulus was delivered to a nonmoving hand. These findings are consistent with the prediction of FM accounts of motor control that postulate that central sensory suppression of somatosensation accompanies self-generated limb movements, and with previous reports indicating that effects of sensory suppression are observed in higher order somatosensory regions.     

Effects of motor intention on the perception of somatosensory events: a behavioural and functional magnetic resonance imaging study

The intention to execute a movement can modulate our perception of sensory events, and this modulation is observed ahead of both ocular and upper limb movements. However, theoretical accounts of these effects, and also the empirical data, are often contradictory. Accounts of "active touch", and the premotor theory of attention, have emphasized how movement intention leads to enhanced perceptual processing at the target of a movement, or on the to-be-moved effector. By contrast, recent theories of motor control emphasize how internal "forward" model (FM) estimates may be used to cancel or attenuate sensory signals that arise as a result of self-generated movements. We used behavioural and functional brain imaging (functional magnetic resonance imaging, fMRI) to investigate how perception of a somatosensory stimulus differed according to whether it was delivered to a hand that was about to execute a reaching movement or the alternative, nonmoving, hand. The results of our study demonstrate that a somatosensory stimulus delivered to a hand that is being prepared for movement is perceived to have occurred later than when that same stimulus is delivered to a nonmoving hand. This result indicates that it takes longer for a tactile stimulus to be detected when it is delivered to a moving limb and may correspond to a change in perceptual threshold. Our behavioural results are paralleled by the results of our fMRI study that demonstrated that there were significantly reduced blood-oxygen-level-dependent (BOLD) responses within the parietal operculum and insula following somatosensory stimulation of the hand being prepared for movement, compared to when an identical stimulus was delivered to a nonmoving hand. These findings are consistent with the prediction of FM accounts of motor control that postulate that central sensory suppression of somatosensation accompanies self-generated limb movements, and with previous reports indicating that effects of sensory suppression are observed in higher order somatosensory regions.     

Three-dimensional coherence of the conscious body image

We experience our body as a coherent object in the three-dimensional (3-D) world. In contrast, the body is represented in somatosensory cortex as a fragmented collection of two-dimensional (2-D) maps. Recent results have suggested that some forms of higher level body representations maintain this fragmentation, for example by showing different patterns of distortion for two surfaces of a single body part, such as the palmar and dorsal hand surfaces. This study investigated the 3-D coherence of the conscious body image of the hand by comparing perceptual biases of perceived hand shape on the dorsal and palmar surfaces. Participants made forced-choice judgements of whether observed hand images were thinner or wider than their own left or right hand, and perceptual distortions of the hand image were assessed by fitting psychometric functions. The results suggested that the hand is consciously represented as a fully coherent, 3-D object. Specifically: (a) Similar overall levels of distortion were found on the palmar and dorsal hand surfaces, (b) comparable laterality effects were found on both surfaces (left hand represented as wider than right hand), and (c) the magnitude of distortions were strongly correlated across the two surfaces. Whereas other recent results have suggested that perceptual abilities such as position sense, tactile size perception, and tactile localization may rely on fragmented, 2-D representations of individual skin surfaces, the present results suggest that, in striking contrast, the conscious body image represents the body (or, at least the hand) as a coherent, 3-D object.     

Neural correlates of viewing paintings: Evidence from a quantitative meta-analysis of functional magnetic resonance imaging data

Many studies involving functional magnetic resonance imaging (fMRI) have exposed participants to paintings under varying task demands. To isolate neural systems that are activated reliably across fMRI studies in response to viewing paintings regardless of variation in task demands, a quantitative meta-analysis of fifteen experiments using the activation likelihood estimation (ALE) method was conducted. As predicted, viewing paintings was correlated with activation in a distributed system including the occipital lobes, temporal lobe structures in the ventral stream involved in object (fusiform gyrus) and scene (parahippocampal gyrus) perception, and the anterior insula—a key structure in experience of emotion. In addition, we also observed activation in the posterior cingulate cortex bilaterally—part of the brain’s default network. These results suggest that viewing paintings engages not only systems involved in visual representation and object recognition, but also structures underlying emotions and internalized cognitions.     

自我面孔识别的脑机制

自我面孔识别是自我参照加工的一种研究范式, 反映了人们通过自我与他人的区分识别出自我面孔的过程。自我面孔识别的脑区定位涉及前额叶、脑岛、扣带回、颞叶和顶叶等脑区的协同作用, 其认知加工有三个阶段：低水平的感觉处理阶段, 对自我参照的面孔信息的处理阶段和身份辨别阶段。在今后的研究中, 应该在时程上区分自我面孔识别的各个加工过程, 并且结合脑区定位结果, 明确自我面孔识别的各加工阶段及认知成分。     

Grasping with the eyes: The role of elongation in visual recognition of manipulable objects

Processing within the dorsal visual stream subserves object-directed action, whereas visual object recognition is mediated by the ventral visual stream. Recent findings suggest that the computations performed by the dorsal stream can nevertheless influence object recognition. Little is known, however, about the type of dorsal stream information that is available to assist in object recognition. Here, we present a series of experiments that explored different psychophysical manipulations known to bias the processing of a stimulus toward the dorsal visual stream in order to isolate its contribution to object recognition. We show that elongated-shaped stimuli, regardless of their semantic category and familiarity, when processed by the dorsal stream, elicit visuomotor grasp-related information that affects how we categorize manipulable objects. Elongated stimuli may reduce ambiguity during grasp preparation by providing a coarse cue to hand shaping and orientation that is sufficient to support action planning. We propose that this dorsal-stream-based analysis of elongation along a principal axis is the basis for how the dorsal visual object processing stream can affect categorization of manipulable objects.     

Synaesthesia: supernormal integration?

Synaesthesia has been known to scientific research for over 100 years but has undergone something of a renaissance recently as new investigations begin to uncover its neurological basis. Rather than being an anomaly, it might offer beneficial insights into the basis of normal perception. A new study by Esterman et al. epitomises this current trend and claims to show that the posterior parietal cortex is a crucial locus of synaesthetic experience. As the posterior parietal cortex is commonly linked to normal sensory integration, Esterman et al.'s finding might lend support to the claim that synaesthesia is an extension of the normal perceptual processes assumed to occur in binding.     

Mental body representations retain homuncular shape distortions: Evidence from Weber’s illusion

Mental body representations underlying tactile perception do not accurately reflect the body’s true morphology. For example, perceived tactile distance is dependent on both the body part being touched and the stimulus orientation, a phenomenon called Weber’s illusion. These findings suggest the presence of size and shape distortions, respectively. However, whereas each morphological feature is typically measured in isolation, a complete morphological characterization requires the concurrent measurement of both size and shape. We did so in three experiments, manipulating both the stimulated body parts (hand; forearm) and stimulus orientation while requiring participants to make tactile distance judgments. We found that the forearm was significantly more distorted than the hand lengthwise but not widthwise. Effects of stimulus orientation are thought to reflect receptive field anisotropies in primary somatosensory cortex. The results of the present study therefore suggest that mental body representations retain homuncular shape distortions that characterize early stages of somatosensory processing.     

Metaphorically feeling: comprehending textural metaphors activates somatosensory cortex

Conceptual metaphor theory suggests that knowledge is structured around metaphorical mappings derived from physical experience. Segregated processing of object properties in sensory cortex allows testing of the hypothesis that metaphor processing recruits activity in domain-specific sensory cortex. Using functional magnetic resonance imaging (fMRI) we show that texture-selective somatosensory cortex in the parietal operculum is activated when processing sentences containing textural metaphors, compared to literal sentences matched for meaning. This finding supports the idea that comprehension of metaphors is perceptually grounded.     

Neural correlates of object indeterminacy in art compositions

Indeterminate art invokes a perceptual dilemma in which apparently detailed and vivid images resist identification. We used event-related fMRI to study visual perception of representational, indeterminate and abstract paintings. We hypothesized increased activation along a gradient of posterior-to-anterior ventral visual areas with increased object resolution, and postulated that object resolution would be associated with visual imagery. Behaviorally, subjects were faster to recognize familiar objects in representational than in both indeterminate and abstract paintings. We found activation within a distributed cortical network that includes visual, parietal, limbic and prefrontal regions. Representational paintings, which depict scenes cluttered with familiar objects, evoked stronger activation than indeterminate and abstract paintings in higher-tier visual areas. Perception of scrambled paintings was associated with imagery-related activation in the precuneus and prefrontal cortex. Finally, representational paintings evoked stronger activation than indeterminate paintings in the temporoparietal junction. Our results suggest that perception of familiar content in art works is mediated by object recognition, memory recall and mental imagery, cognitive processes that evoke activation within a distributed cortical network.     

Potential perceptual bases for successful use of a vibrotactile speech perception aid

This paper examines the possibility that perception of vibrotactile speech stimuli is enhanced in adults with early and life-long use of hearing aids. We present evidence that vibrotactile aid benefit in adults is directly related to the age at which the hearing aid was fitted and the duration of its use. The stimulus mechanism responsible for this effect is hypothesized to be long-term vibrotactile stimulation by high powered hearing aids. We speculate on possible mechanisms for enhanced vibrotactile speech perception as the result of hearing aid use: (1) long-term experience receiving degraded or impoverished speech stimuli results in a speech processing system that is more effective for novel stimuli, independent of perceptual modality; and/or (2) long-term sensory/perceptual experience causes neural changes that result in more effective delivery of speech information via somatosensory pathways.     

Stroke me for longer this touch feels too short: The effect of pleasant touch on temporal perception

Negative, painful, somatosensory stimulation lengthens the perceived duration of time. However, to date, no research has explored the influence of positive, pleasant, somatosensory stimulation on temporal perception. Here we asked whether gentle stroking touch influences perceptions of duration. Pleasant (gentle) and mildly unpleasant (rough) tactile stimulation was delivered whilst participants estimated the duration of a neutral visual stimulus. Pleasant touch resulted in shorter estimates of duration than unpleasant touch. There was no difference in duration perception in the unpleasant and control conditions. Taken together with the results of previous research (Ogden, Moore, Redfern, & McGlone, 2015), the results of this study suggest that pleasant and painful somatosensory stimulation have opposing effects on temporal perception, and additionally that pleasant touch can alter aspects of perceptual and attentional processing outside the purely affective domain.     

Sustained attention to spontaneous thumb sensations activates brain somatosensory and other proprioceptive areas

The present experiment was designed to test if sustained attention directed to the spontaneous sensations of the right or left thumb in the absence of any external stimuli is able to activate corresponding somatosensory brain areas. After verifying in 34 healthy volunteers that external touch stimuli to either thumb effectively activate brain contralateral somatosensory areas, and after subtracting attention mechanisms employed in both touch and spontaneous-sensation conditions, fMRI evidence was obtained that the primary somatosensory cortex (specifically left BA 3a/3b) becomes active when an individual is required to attend to the spontaneous sensations of either thumb in the absence of external stimuli. In addition, the left superior parietal cortex, anterior cingulate gyrus, insula, motor and premotor cortex, left dorsolateral prefrontal cortex, Broca’s area, and occipital cortices were activated. Moreover, attention to spontaneous-sensations revealed an increased connectivity between BA 3a/3b, superior frontal gyrus (BA 9) and anterior cingulate cortex (BA 32), probably allowing top-down activations of primary somatosensory cortex. We conclude that specific primary somatosensory areas in conjunction with other left parieto-frontal areas are involved in processing proprioceptive and interoceptive bodily information that underlies own body-representations and that these networks and cognitive functions can be modulated by top-down attentional processes.     

Contributions of the Insula to Cognition and Emotion

Historically, the insula was considered primary gustatory cortex. Now it is known to play a more comprehensive role in the processing of sensory information, including acting as primary cortex for interoceptive information, including autonomic nervous system mediated changes. As such, it is critical for emotional feeling in accord with the James-Lange theory, a role previously ascribed to the limbic system. Neuroimaged abnormal grey matter volumes or activity levels in the insula have been associated with schizophrenia, eating disorders, anxiety and mood disorders, conduct disorder, autism, addiction, and chronic pain. The significance of these abnormal activity patterns remains theoretical. Neuropsychological studies have linked dominant insula injury with various symptoms of aphasia, but its exact role in language processing remains uncertain as most cases involve lesions that extend into perisylvian language zones. Functional neuroimaging studies have found insula hyper-activations, typically in conjunction with anterior cingulate cortex, for all manner of experimental tasks including those involving perception, intentional action, and consciousness. Such neuroimaged activity is unlikely to be task-specific, but rather reflective of generic changes in autonomic activity in response to salience, homeostatic incongruence, or cognitive challenge.     

Brain activity for visual judgment of lifted weight

It is well established that humans can recognize high-level aspects from point-light biological motion, such as gender and mood. If the task is to judge the manipulated weight we expected that sensorimotor regions should be recruited in the brain. Moreover, we have recently shown that chronic pain in a limb that is involved in the presented movement disturbs the weight judgment. We therefore hypothesized that some cortical regions usually activated during the processing of pain will also be activated while viewing point-light biological motion with the instruction to judge the manipulated weights. We investigated point-light biological motion of two types of movements performed with different weights in a blocked fMRI experiment in healthy subjects. In line with our a priori hypothesis, we found strong activity in the regions known as the neuromatrix of pain, such as the anterior cingulate (ACC), insula, as well as primary and secondary somatosensory regions. We also found activation in the occipital and temporal regions that are typical for biological motion, as well as regions in the cerebellum and prefrontal cortex. The activation of the somatosensory regions probably serves the judgment of the biological motion stimuli. Activation of the anterior cingulate and the insula might be explained by their role in the integration of behaviorally relevant information. Alternatively, these structures are known to be involved in the processing of nociceptive information and pain. So it seems possible that the interference between judgment of weights and perception of pain in chronic pain patients occurs in the somatosensory areas, anterior cingulate and/or insula. This finding provides important information as to the underlying mechanisms used for the weight judgment task, but also why chronic pain interferes with this task.     

Recalibrating color categories using world knowledge

ABSTRACT— When the perceptual system uses color to facilitate object recognition, it must solve the color-constancy problem: The light an object reflects to an observer's eyes confounds properties of the source of the illumination with the surface reflectance of the object. Information from the visual scene ( bottom-up information) is insufficient to solve this problem. We show that observers use world knowledge about objects and their prototypical colors as a source of top-down information to improve color constancy. Specifically, observers use world knowledge to recalibrate their color categories. Our results also suggest that similar effects previously observed in language perception are the consequence of a general perceptual process.     

“有声有色”的触觉体验：来自多感觉通道整合的线索

虚拟现实技术通过提供视觉、听觉和触觉等信息为用户创造身临其境的感知体验, 其中触觉反馈面临诸多技术瓶颈使得虚拟现实中的自然交互受限。基于多感官错觉的伪触觉技术可以借助其他通道的信息强化和丰富触觉感受, 是目前虚拟现实环境中优化触觉体验的有效途径。本文聚焦于触觉中最重要的维度之一——粗糙度, 试图为解决虚拟现实中触觉反馈的受限问题提供新思路。探讨了粗糙度感知中, 视、听、触多感觉通道整合的关系, 分析了视觉线索(表面纹理密度、表面光影、控制显示比)和听觉线索(音调/频率、响度)如何影响触觉粗糙度感知, 总结了当下调控这些因素来改变粗糙度感知的方法。最后, 探讨了使用伪触觉反馈技术时, 虚拟现实环境中视、听、触觉信息在呈现效果、感知整合等方面与真实世界相比可能存在的差异, 提出可借鉴的改善触觉体验的适用方法和未来待研究的方向。     

Altering sensorimotor feedback disrupts visual discrimination of facial expressions

Looking at another person’s facial expression of emotion can trigger the same neural processes involved in producing the expression, and such responses play a functional role in emotion recognition. Disrupting individuals’ facial action, for example, interferes with verbal emotion recognition tasks. We tested the hypothesis that facial responses also play a functional role in the perceptual processing of emotional expressions. We altered the facial action of participants with a gel facemask while they performed a task that involved distinguishing target expressions from highly similar distractors. Relative to control participants, participants in the facemask condition demonstrated inferior perceptual discrimination of facial expressions, but not of nonface stimuli. The findings suggest that somatosensory/motor processes involving the face contribute to the visual perceptual—and not just conceptual—processing of facial expressions. More broadly, our study contributes to growing evidence for the fundamentally interactive nature of the perceptual inputs from different sensory modalities.     

Developmental changes in the discrimination of dynamic human actions in infancy

Recent evidence suggests that adults selectively attend to features of action, such as how a hand contacts an object, and less to configural properties of action, such as spatial trajectory, when observing human actions. The current research investigated whether this bias develops in infancy. We utilized a habituation paradigm to assess 4-month-old and 10-month-old infants' discrimination of action based on featural, configural, and temporal sources of action information. Younger infants were able to discriminate changes to all three sources of information, but older infants were only able to reliably discriminate changes to featural information. These results highlight a previously unknown aspect of early action processing, and suggest that action perception may undergo a developmental process akin to perceptual narrowing.