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Functional magnetic resonance imaging (fMRI) is a powerful tool for imaging somatosensory cortex, providing a means to non-invasively measure cortical activity in awake and behaving humans. Notably, this technique has permitted the homunculus – a hallmark of primary somatosensory cortex (S1) organization – to be examined with unprecedented detail....
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... does limit options; however, an increasing number of compatible devices are being manufactured -both by small groups of scientists as well as by specialized companies (e.g., Dancer Design in the UK and QuaeroSys in Germany). As outlined in Table 1, over the years there have been a wide-range of various stimulation methods safely used in the MR environment. The simplest of these involves a researcher brushing or otherwise manually stimulating some body part of a research participant lying in the scanner. ...Similar publications
Neurons in the cerebral cortex fire coincident action potentials during ongoing activity and in response to sensory inputs. These synchronized cell assemblies are fundamental to cortex function, yet basic dynamical aspects of their size and duration are largely unknown. Using 2-photon imaging of neurons in the superficial cortex of awake mice, we s...
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Interactions with the world and between our own body parts often result in motion across the skin, and sensory processing of this motion is of interest to both basic and applied researchers. We describe motion cues and common approaches to creating tactile motion to help researchers make choices for their study, and we give two illustrative examples.Major cues that inform about direction and speed of tactile motion are displacement over the skin, skin stretch, and skin vibration. The most common approach for creating tactile motion relies on apparent motion, the motion sensation arising from discrete—often vibrating—stimuli presented in quick succession to simulate object displacement. Other methods rely on real displacement of objects such as plates and brushes. They create friction and skin stretch, allowing the study of that cue and resulting in a richer motion experience. Friction can also be implemented in devices that rely on apparent motion, but this is still very rare. Some recent solutions, such as movement-contingent air turbulation, are driven by the desire to create immersive tactile experience in virtual reality.Illusions abound in perception of motion, as in any other aspect of perception. They include mislocalization of discrete motion stimuli known as sensory saltation, and filling-in of non-stimulated skin area with the sensation of continuous motion—the two effects we focus on in the Methods section. We use them to illustrate two manners of motion delivery (discrete stimulation vs real object displacement) and a variety of ways to measure perception of the moving stimulus.Key wordsTouch Tactile motion Motion cues Motion perception Apparent motion Numb spots Filling-in Sensory saltation Cutaneous rabbit Somatosensory experiments
Illusions arouse interest in the layperson and researcher alike. The layperson learns that perception is fallible, and the researcher wants to better understand mechanisms of perception and implement illusions in various applications. We are accustomed to visual illusions, but less so to their somatosensory sisters, some of which summon fresh amazement bordering on disbelief. What can possibly make us feel that our tongue is split in two, or that a brush touching an artificial hand touches us? How do we study such experiences? This chapter directs the reader to sources describing a variety of somatosensory illusions. We also outline methodological issues in studying them, and describe methods used to study the well-known rubber hand illusion, and the recently described whose hand illusion.Key wordsHaptic illusions Tactile illusions Illusions of touch Somatosensory illusions Bodily illusions Rubber hand illusion Whose hand illusion Proprioceptive illusions Kinesthetic illusions
