These paradigms allow representing stimuli through a computer (Figure 1) and to record participants responses, such as the percentage of correct answers or the response latency. Stimuli can be scenes, faces, bodies, words, anything that your brain can process. The presentation of stimuli coupled with brain stimulation allows to infer which brain areas (or brain networks) are involved in a given function.
|Figure 1||Example of behavioural paradigm|
|Stimuli (original dataset here: http://www.beatricedegelder.com/beast.html) presented through a computer, thanks to a dedicated software (OpenSesame: http://osdoc.cogsci.nl/).|
Other paradigms available at the Lab include:
A) the Size Weight Illusion and sensorimotor control equipment- thanks to the collaboration with Dr Gavin "SWI" Buckingham https://sites.google.com/site/obintlab/
In the size-weight illusion (SWI), the person lifts objects with the same mass and of different size, and 5 perceives the small object to be heavier than the big object (Charpentier, 1891).
Various stimuli for the SWI
ATI Nano17 force transducers for recording fingertip forces and torques
A TrakStar magnetic motion tracker for the recording of kinematic data
A 3-Camera ProReflex optical tracking system for the wireless recording of kinematic data
Buckingham G. 2014. Getting a grip on heaviness perception: a review of weight illusions and their probable causes. Exp Brain Res. 232:1623–1629.
Buckingham G, Bieńkiewicz M, Rohrbach N, Hermsdörfer J. 2015. The impact of unilateral brain damage on weight perception, sensorimotor anticipation, and fingertip force adaptation. Vision Res, Perception of Material Properties (Part II). 115, Part B:231–237.
Charpentier, A. (1891). Analyse experimentale quelques elements de la sensation de poids [Experimental study of some aspects of weight perception]. Arch. Physiol. Normales Pathologiques, 3, 122–135.
B) the famous Rubber Limbs Illusions (see below)
Through this illusion is possible to foster a sense of ownership of fake limbs, such as a hand (i.e. Botvinick et al. 1998) and a foot (i.e. Lenggenhager et al., 2015)
Rubber Hand Illusion (RHI)
Visuo-tactile version (Botvinick et al. 1998)
Synchronous visuo-tactile stimulation of a rubber hand and tactile stimulation of a real hand induce the illusion of perceiving the rubber hand as one’s own. Moreover, subjects perceive a drift of the perceived location of the real hand towards the rubber hand, this phenomenon being named proprioceptive drift (Botvinick et al., 1998).
Tactile version (Ehrsson, Holmes & Passingham, 2005)
Ehrsson, Holmes & Passingham (2005) proposed a variant of the classic version of the RHI (Botvinick & Cohen, 1998), a tactile version. In this version of the RHI, authors were able to elicit the sense of ownership of the fake hand in participants using only tactile and proprioceptive integration. Participants are blindfolded and, while their left index is moved by the experimenter over the right rubber hand, at the same time, the experimenter touches the participant’s right hand. The synchronous stimulation condition fosters the illusion.
Rubber Foot Illusion (RFI)
Visuo-tactile version (Lenggenhager et al., 2015)
As well as for the RHI, even in the RFI participants perceive the rubber foot as one’s own, due to synchronous visuo-tactile stimulation of both real and fake foot.
None explored the RFI with a tactile version, one of our lab projects wants to apply this version on the foot (see Lab Projects).
Useful references on guidelines:
Botvinick, M., & Cohen, J. (1998). Rubber hands ‘feel’touch that eyes see. Nature, 391(6669), 756.
Ehrsson, H. H., Holmes, N. P., & Passingham, R. E. (2005). Touching a rubber hand: feeling of body ownership is associated with activity in multisensory brain areas. Journal of Neuroscience, 25(45), 10564-10573.
Lenggenhager, B., Hilti, L., & Brugger, P. (2015). Disturbed body integrity and the “rubber foot illusion”. Neuropsychology, 29(2), 205.