Senses & Sensory Modalities
Scientific concepts/principles which may be interesting/applicable
- Synaesthesia: Br J Psychol. 2012 Feb;103(1):1-15.Defining synaesthesia.Simner J.Source: Department of Psychology, University of Edinburgh, UK. j.simner@ed.ac.uk
Abstract:Studies investigating developmental synaesthesia have sought to describe a number of qualities that might capture in behavioural terms the definingcharacteristics of this unusual phenomenon. The task of generating a definition is made more difficult by the fact that any description of synaesthesiamust be broad enough to capture the 61 different variants of the condition already reported to date. Given these difficulties, the current literature now contains a number of conflicting assumptions about the nature of this condition. Here, I attempt to address several of these divisive areas from a set of contemporary definitions. I present evidence that might argue against previous claims that synaesthesia is (a) a 'merging of the senses', which (b) gives rise to consistent synaesthetic associations over time, with (c) synaesthetic associations that are spatially extended. I then investigate the possible benefits of moving from a behavioural definition to a neurobiological one and explore the ways in which this might force a rethink about the potential outermost boundaries of this fascinating condition
McGurk Effect: J Acoust Soc Am. 2012 Aug;132(2):1061-1077.
Binding and unbinding the auditory and visual streams in the McGurk effect. Nahorna O, Berthommier F, Schwartz JL.
Abstract: Subjects presented with coherent auditory and visual streams generally fuse them into a single percept. This results in enhanced intelligibility in noise, or in visual modification of the auditory percept in the McGurk effect. It is classically considered that processing is done independently in theauditory and visual systems before interaction occurs at a certain representational stage, resulting in an integrated percept. However, some behavioral and neurophysiological data suggest the existence of a two-stage process. A first stage would involve binding together the appropriate pieces of audio and video information before fusion per se in a second stage. Then it should be possible to design experiments leading to unbinding. It is shown here that if a given McGurk stimulus is preceded by an incoherent audiovisual context, the amount of McGurk effect is largely reduced. Various kinds of incoherent contexts (acoustic syllables dubbed on video sentences or phonetic or temporal modifications of the acoustic content of a regular sequence of audiovisual syllables) can significantly reduce the McGurk effect even when they are short (less than 4 s). The data are interpreted in the framework of a two-stage "binding and fusion" model for audiovisual speech perception.
Mirror therapy (phantom limb): Neurorehabil Neural Repair. 2009 Jul Aug;23(6):587-94. Training with virtual visual feedback to alleviate phantom limb pain. Mercier C, Sirigu A. Center for Cognitive Neuroscience, Bron, France
Abstract:
o BACKGROUND:Performing phantom movements with visual virtual feedback, or mirror therapy, is a promising treatment avenue to alleviate phantomlimb pain. However the effectiveness of this approach appears to vary from one patient to another.
o OBJECTIVE:To assess the individual response to training with visual virtual feedback and to explore factors influencing the response to that approach.
o METHODS:Eight male participants with phantom limb pain (PLP) resulting from either a traumatic upper limb amputation or a brachial plexus avulsion participated in this single case multiple baseline study. Training was performed 2 times per week for 8 weeks where a virtual image of a missing limb performing different movements was presented and the participant was asked to follow the movements with his phantom limb.
o RESULTS:Patients reported an average 38% decrease in background pain on a visual analog scale (VAS), with 5 patients out of 8 reporting a reduction greater than 30%. This decrease in pain was maintained at 4 weeks postintervention in 4 of the 5 participants. No significant relationship was found between the long-term pain relief and the duration of the deafferentation or with the immediate pain relief during exposure to the feedback.
o CONCLUSIONS:These results support the use of training with virtual feedback to alleviate phantom limb pain. Our observations suggest that between-participant differences in the effectiveness of the treatment might be related more to a difference in the susceptibility to the virtual visualfeedback, than to factors related to the lesion, such as the duration of the deafferentation.
Transhumanism - Neurocosmetics, transhumanism and eliminative materialism: toward new ways of eugenics].Echarte Alonso LE.Instituto Cultura y Sociedad /Departamento de Humanidades Biomédicas, Facultad de Medicina, Universidad de Navarra, Navarre, Spain. lecharte@unav.es 2012 Jan-Apr;23(77):37-51
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Abstract: In this paper I present similarities and connections between Transhumanism and Eliminative Materialism. Concretely, I study the arguments with which in both positions it is defended a merely instrumental idea of human body and, because of that, one infinitely mouldable. First, I show the social relevance of this idea and its projections in phenomena as medicalization of human condition and, especially, cosmetic psychopharmacology. Besides, I denounce that such influences are caused by illegitimate transference of authority between philosophical and scientific forums. Second, according to my analysis, these new postmodern fashions of chemical sentimentalism (related with radical changes on personal identity and human nature) drive to new eugenic forms what I name autoeugenics. Finally, I call attention to the important role of utopian speeches about the science of tomorrow and super-human civilization in a Carpe Diem society. In my conclusions, I claim that historical reasoning or warnings about what is coming are not efficient strategies to control neither new psychopharmacological habits nor passivity generated by them. Returning social confidence in the power of reason to achieve reality (and other human beings) is, in my opinion, the best way to rehabilitate a more and more devalued human action.
Tactile information as visual information
Brain Res Bull. 2010 Jul 30;82(5-6):264-70. Epub 2010 May 11.
o Beyond visual, aural and haptic movement perception: hMT+ is activated by electrotactile motion stimulation of the tongue in sighted and in congenitally blind individuals. Matteau I, Kupers R, Ricciardi E, Pietrini P, Ptito M. Ecole d'Optométrie, Université de Montréal, Montréal, QC, Canada H3C 3J7.
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Abstract: The motion-sensitive middle temporal cortex (hMT+ complex) responds also to non-visual motion stimulation conveyed through the tactile and auditory modalities, both in sighted and in congenitally blind individuals. This indicates that hMT+ is truly responsive to motion-related information regardless of visual experience and the sensory modality through which such information is carried to the brain. Here we determined whether the hMT+ complex responds to motion perception per se, that is, motion not perceived through the visual, haptic or aural modalities. Using functional magnetic resonance imaging (fMRI), we investigated brain responses in eight congenitally blind and nine sighted volunteers who had been trained to use the tongue display unit (TDU), a sensory substitution device which converts visual information into electrotactile pulses delivered to the tongue, to resolve a tactile motion discrimination task. Stimuli consisted of either static dots, dots moving coherently or dots moving in random directions. Both groups learned the task at the same rate and activated the hMT+ complex during tactile motion discrimination, although at different anatomical locations. Furthermore, the congenitally blind subjects showed additional activations within the dorsal extrastriate cortical pathway. These results extend previous data in support of the supramodal functional organization of hMT+ complex by showing that this cortical area processes motion-related information per se, that is, motion stimuli that are not visual in nature and that are administered to body structures that, in humans, are not primarily devoted to movement perception or spatial location, such as the tongue. In line with previous studies, the differential activations between sighted and congenitally blind individuals indicate that lack of vision leads to functional rearrangements of these supramodal cortical areas.
Philosophical theories of sensory modalities
What is visual information as opposed to tactile information?
- How do we perceive the world (metaphysical claims which may entail or conceal empirical positions)
- Epistemological claims – how do we come to know things through our senses?
-What constitutes an appropriate connection between my beliefs and the world/my perceptions of the world?
Beyond vision: The vertical integration of sensory substitution devices Ophelia Deroy & Malika Auvray In M. Matthen & D. Stokes (eds.), Perception and Its Modalities
− Abstract: What if a blind person could 'see' with her ears? Thanks to Sensory Substitution Devices (SSDs), blind people now have access to out-of-reach objects, a privilege reserved so far for the sighted. In this paper, we show that the philosophical debates have fundamentally been mislead to think that SSDs should be fitted among the existing senses or that they constitute a new sense. Contrary to the existing assumption that they get integrated at the sensory level, we present a new thesis according to which they are not sensory, and get vertically integrated on the top of existing sensory abilities, from which they should be theoretically distinguished.
Substituting the Senses Julian Kiverstein, Mirko Farina & Andy Clark In Mohan Matthen (ed.), The Oxford Handbook of the Philosophy of Perception. Oxford University Press
Abstract:Sensory substitution devices are a type of sensory prosthesis that (typically) convert visual stimuli transduced by a camera into tactile or auditory stimulation. They are designed to be used by people with impaired vision so that they can recover some of the functions normally subserved by vision. In this chapter we will consider what philosophers might learn about the nature of the senses from the neuroscience of sensory substitution. We will show how sensory substitution devices work by exploiting the cross-modal plasticity of sensory cortex: the ability of sensory cortex to pick up some types of information about the external environment irrespective of the nature of the sensory inputs it is processing. We explore the implications of cross-modal plasticity for theories of the senses that attempt to make distinctions between the senses on the basis of neurobiology.