Rubber Hand Illusions and Size–Weight Illusions: Self-Representation Modulates Representation of External Objects

Perception ◽  
10.1068/p6399 ◽  
2009 ◽  
Vol 38 (12) ◽  
pp. 1796-1803 ◽  
Author(s):  
Patrick Haggard ◽  
Shyma Jundi
2021 ◽  
Author(s):  
Tzu-Yu Hsu ◽  
Ji-Fan Zhou ◽  
Georg Northoff ◽  
Su-Ling Yeh ◽  
Timothy Joseph Lane

Susceptibility to the rubber hand illusion (RHI) varies. Thus far, however, there is no consensus as regards how to explain this variation. Previous studies, focused on the role of multisensory integration, have searched for neural correlates of the illusion. Those studies, however, have failed to identify a sufficient set of functionally specific neural correlates. An alternative explanation of the illusion is that it results from demand characteristics, chiefly variability in the disposition to respond to imaginative suggestion: the degree to which intrinsic neural activity allows for a blurring of boundaries between self and external objects. Some evidence suggests that frontal alpha power is one means of tracking neural instantiations of self; therefore, we hypothesized that the higher the frontal alpha power during eyes-closed resting state, the more stable the self. As a corollary, we infer that the more stable the self, the less susceptible are participants to a blurring of boundaries, to feeling that the rubber hand belongs to them. Indeed, we found that frontal alpha amplitude oscillations negatively correlate with susceptibility. Moreover, since alpha and delta oscillations seem to be associated in pathological states that allow for a blurring of boundaries between self and external objects, we conjectured that the high frontal alpha power observed in low-RHI participants is modulated by delta frequency oscillations. Indeed, we found this to be the case. Based on our findings we propose that the two explanatory frameworks might be complementary: that is, the neural correlates of multisensory integration might be necessary for the RHI, but a sufficient explanation requires investigation of variable intrinsic neural activity that acts to modulate how the brain responds to incompatible sensory stimuli.


2018 ◽  
Vol 44 (7) ◽  
pp. 1012-1021 ◽  
Author(s):  
Dominika Radziun ◽  
H. Henrik Ehrsson

Author(s):  
Ann-Sophie Barwich

How much does stimulus input shape perception? The common-sense view is that our perceptions are representations of objects and their features and that the stimulus structures the perceptual object. The problem for this view concerns perceptual biases as responsible for distortions and the subjectivity of perceptual experience. These biases are increasingly studied as constitutive factors of brain processes in recent neuroscience. In neural network models the brain is said to cope with the plethora of sensory information by predicting stimulus regularities on the basis of previous experiences. Drawing on this development, this chapter analyses perceptions as processes. Looking at olfaction as a model system, it argues for the need to abandon a stimulus-centred perspective, where smells are thought of as stable percepts, computationally linked to external objects such as odorous molecules. Perception here is presented as a measure of changing signal ratios in an environment informed by expectancy effects from top-down processes.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Caleb Liang ◽  
Wen-Hsiang Lin ◽  
Tai-Yuan Chang ◽  
Chi-Hong Chen ◽  
Chen-Wei Wu ◽  
...  

AbstractBody ownership concerns what it is like to feel a body part or a full body as mine, and has become a prominent area of study. We propose that there is a closely related type of bodily self-consciousness largely neglected by researchers—experiential ownership. It refers to the sense that I am the one who is having a conscious experience. Are body ownership and experiential ownership actually the same phenomenon or are they genuinely different? In our experiments, the participant watched a rubber hand or someone else’s body from the first-person perspective and was touched either synchronously or asynchronously. The main findings: (1) The sense of body ownership was hindered in the asynchronous conditions of both the body-part and the full-body experiments. However, a strong sense of experiential ownership was observed in those conditions. (2) We found the opposite when the participants’ responses were measured after tactile stimulations had ceased for 5 s. In the synchronous conditions of another set of body-part and full-body experiments, only experiential ownership was blocked but not body ownership. These results demonstrate for the first time the double dissociation between body ownership and experiential ownership. Experiential ownership is indeed a distinct type of bodily self-consciousness.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Michael Schaefer ◽  
Anja Kühnel ◽  
Franziska Rumpel ◽  
Matti Gärtner

AbstractPrevious research revealed an active network of brain areas such as insula and anterior cingulate cortex when witnessing somebody else in pain and feeling empathy. But numerous studies also suggested a role of the somatosensory cortices for state and trait empathy. While recent studies highlight the role of the observer’s primary somatosensory cortex when seeing painful or nonpainful touch, the interaction of somatosensory cortex activity with empathy when receiving touch on the own body is unknown. The current study examines the relationship of touch related somatosensory cortex activity with dispositional empathy by employing an fMRI approach. Participants were touched on the palm of the hand either by the hand of an experimenter or by a rubber hand. We found that the BOLD responses in the primary somatosensory cortex were associated with empathy personality traits personal distress and perspective taking. This relationship was observed when participants were touched both with the experimenter’s real hand or a rubber hand. What is the reason for this link between touch perception and trait empathy? We argue that more empathic individuals may express stronger attention both to other’s human perceptions as well as to the own sensations. In this way, higher dispositional empathy levels might enhance tactile processing by top-down processes. We discuss possible implications of these findings.


Author(s):  
Akihiro Maehigashi ◽  
Akira Sasada ◽  
Miki Matsumuro ◽  
Fumihisa Shibata ◽  
Asako Kimura ◽  
...  

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