Summary
Here we explore contralateral tactile masking between the forearms in which tactile detection thresholds are modulated by vibration applied to a remote site. The details of which remote sites have an effect can tell us about how the body is represented in the brain.
Abstract
Masking, in which one stimulus affects the detection of another, is a classic technique that has been used in visual, auditory, and tactile research, usually using stimuli that are close together to reveal local interactions. Masking effects have also been demonstrated in which a tactile stimulus alters the perception of a touch at a distant location. Such effects can provide insight into how components of the body’s representations in the brain may be linked. Occasional reports have indicated that touches on one hand or forearm can affect tactile sensitivity at corresponding contralateral locations. To explore the matching of corresponding points across the body, we can measure the spatial tuning and effect of posture on contralateral masking. Careful controls are required to rule out direct effects of the remote stimulus, for example by mechanical transmission, and also attention effects in which thresholds may be altered by the participant’s attention being drawn away from the stimulus of interest. The use of this technique is beneficial as a behavioural measure for exploring which parts of the body are functionally connected and whether the two sides of the body interact in a somatotopic representation. This manuscript describes a behavioural protocol that can be used for studying contralateral tactile masking.
Introduction
Taktil maskering er, hvor en taktil stimulus på et sted på kroppen ændrer opfattelsen af en berøring på en anden placering. Dette er en teknik udviklet af von Bekesy 1 at afsløre nålene interaktioner, især lateral hæmning, mellem områder af huden, der grænser op på kroppens overflade. Mens taktil maskering er blevet omfattende undersøgt gennem årene, har forskningen hovedsagelig undersøgt ipsilaterale taktil maskering anvendelse af elektrisk stimulation 2, 3, tryk 4, og vibrotactile stimulering 5, 6. I modsætning hertil har nogle undersøgelser så på kontralaterale taktile maskering, hvor maskering og probe sites kan langt. Langtrækkende taktile maskering virkninger er blevet vist mellem spejl-symmetrisk punkter på hånden og arm 5 7 – 9, men disse undersøgelser har været stort set begrænset til at kigge på hænder og fingre 7, 10, med mere omfattende dele af hele kroppen bliver stort set ignoreret. Et mål af sådanne langtrækkende maskering eksperimenter er at angive, hvordan dele af kroppens repræsentation i hjernen kan være funktionelt forbundet. Her er fænomenet langtrækkende taktil maskering udforsket ved at undersøge, hvordan vibrationer påføres den ene underarm kan påvirke sensitivitetstærsklerne taktile på den modsatte underarm. Threshold refererer til den mindste stimulus, som er nødvendig for at påvise en stimulus. Vi definerer dette som intensiteten ved hvilken stimulus detekteres 75% af tiden. Vi anvendte en taktil maskering teknik, hvor berøringsfølsomhed (det reciprokke af tærskelværdien) på en underarm måles i nærværelse af en vibrerende stimulus (masken) på en anden del af kroppen. Effektiv maskering afsløres af en forhøjelse af detektionsgrænsen dvs. en reduktion i følsomhed. Teknikken kan anvendes i forbindelse med andre manipulationer såsom varierende position lemmer or bevægelse for at udforske deres virkninger på effektiviteten af maskering.
Her brugte vi vibrotactile stimuli som maskering stimulus. Fordelen ved dette er, at frekvensen og dermed receptortype, at det stimulerer kan styres. Teknikken kan udvides til at se på smerte under anvendelse af elektriske stimuli som proben eller maske eller begge. Desuden kan ethvert websted bruges som maske-webstedet tillader undersøgelse af akupunktur sites for eksempel.
Protocol
Representative Results
Discussion
Her er en detaljeret protokol for kontralateral taktile maskering beskrevet og tidligere offentliggjorte resultater ved hjælp af teknikken til at teste tærskler taktile detektion vises. Fordelen ved denne metode er, at tærsklerne måles ved anvendelse af en psychophysically streng teknik. Den tvungne valg (2AFC) procedure to-alternativ er relativt ufølsom over for respons bias og derfor fra opmærksomhedsgraden effekter. Den adaptive trappe procedure for honing i på selve tærskelværdi er meget effektiv, da de fle…
Disclosures
The authors have nothing to disclose.
Acknowledgements
LRH blev støttet af Sciences og Engineering Research Council Natural (NSERC) i Canada. SD blev delvist støttet fra NSERC CREATE programmet.
Materials
| C-2 tactor | ATAC Technology; Engineering Acoustics, Inc. | http://www.atactech.com/PR_tactors.html | |
| Magic Wand | Hitachi | http://magicwandoriginal.com/magic-wand-original/ | |
| FC5 Foot Pedals | Yamaha Corporation | http://ca.yamaha.com/en/products/music-production/accessories/footpedals/fc5/?mode=model | |
| MATLAB | The Mathworks, Inc. | http://www.mathworks.com/products/matlab/ | |
| Velcro | Velcro Industries B.V. | http://www.velcro.com/ |
References
- von Békésy, G. . Sensory Inhibition. , (1967).
- Uttal, W. R. Inhibitory interaction of responses to electrical stimuli in the fingers. J. Comp. Physiol. Psych. 53 (1), 47-51 (1960).
- Schmid, E. Temporal aspects of cutaneous interaction with two-point electrical stimulation. J. Exp. Psychol. Gen. 61, 400-409 (1961).
- Abramsky, O., Carmon, A., Bentontt, A. L. Masking of and by tactile pressure stimuli. Percept. Psychophys. 10 (5), 353-355 (1971).
- Sherrick, C. E. Effects of double simultaneous stimulation of the skin. Am. J. Psychol. 77, 42-53 (1964).
- Gilson, R. D. Vibrotactile masking: effects of multiple maskers. Percept. Psychophys. 95 (4), 2213-2220 (1969).
- Braun, C., Hess, H., Burkhardt, M., Wühle, A., Preissl, H. The right hand knows what the left hand is feeling. Exp. Brain. Res. 162 (3), 366-373 (2005).
- Tamè, L., Farnè, A., Pavani, F. Spatial coding of touch at the fingers: Insights from double simultaneous stimulation within and between. Neurosci. Lett. 487 (1), 78-82 (2011).
- Tamè, L., Moles, A., Holmes, N. P. Within but not between hands interactions in vibrotactile detection thresholds reflect somatosensory receptive field organization. Front. Psychol. 5, 1-9 (2014).
- Harris, J. A., Diamond, M. E. Ipsilateral and contralateral transfer of tactile learning. Neuroreport. 11 (2), 263-266 (2000).
- Fechner, G. T. . Elemente der Psychophysik . , (1860).
- Watson, A., Pelli, D. QUEST-A Bayesian adaptive psychophysical method. Percept. Psychophys. 33, 113-120 (1983).
- D’Amour, S., Harris, L. R. Contralateral tactile masking between forearms. Exp. Brain. Res. 232 (3), 821-826 (2014).
- D’Amour, S., Harris, L. R. Vibrotactile masking through the body. Exp. Brain. Res. 232 (9), 2859-2863 (2014).
- Gescheider, G. A., Herman, D. D., Phillips, J. N. Criterion shifts in the measurement of tactile masking. Percept. Psychophys. 8, 433-436 (1970).
- Iwamura, Y., Tanaka, M., Iriki, A., Taoka, M., Toda, T. Processing of tactile and kinesthetic signals from bilateral sides of the body in the postcentral gyrus of awake monkeys. Behav. Brain. Res. 135 (1-2), 185-190 (2002).
- Killackey, H. P., Gould, H. J., Cusick, C. G., Pons, T. P., Kaas, J. H. The relation of corpus callosum connections to architectonic fields and body surface maps in sensorimotor cortex of new and old world monkeys. J. Comp. Neurol. 219 (4), 384-419 (1983).
- Reed, J. L., Qi, H. X., Kaas, J. H. Spatiotemporal properties of neuron response suppression in owl monkey primary somatosensory cortex when stimuli are presented to both hands. J. Neurosci. 31 (10), 3589-3601 (2011).
- Hlushchuk, Y., Hari, R. Transient suppression of ipsilateral primary somatosensory cortex during tactile finger stimulation. J. Neurosci. 26 (21), 5819-5824 (2006).
- Nihashi, T., et al. Contralateral and ipsilateral responses in primary somatosensory cortex following electrical median nerve stimulation–an fMRI study. Clin. Neurophysiol. 116 (4), 842-848 (2005).
- Tamè, L., et al. The contribution of primary and secondary somatosensory cortices to the representation of body parts and body sides: an fMRI adaptation study. J. Cognitive. Neurosci. 24 (12), 2306-2320 (2012).
- Tamè, L., Farnè, A., Pavani, F. Vision of the body and the differentiation of perceived body side in touch. Cortex. 49 (5), 1340-1351 (2013).
- Tamè, L., Pavani, F., Papadelis, C., Farnè, A., Braun, C. Early integration of bilateral touch in the primary somatosensory cortex. Hum. Brain. Mapp. 36 (4), 1506-1523 (2015).
- Gilson, R. D. Vibrotactile masking: Some spatial and temporal aspects. Percept. Psychophys. 5 (3), 176-180 (1969).
- Alliusi, E., Morgan, B., Hawkes, G. R. Masking of cutaneous sensations in multiple stimulus presentations. Percept. Motor. Skill. 20, 39-45 (1965).
- Geldard, F. A., Sherrick, C. E. Multiple cutaneous stimulation: The discrimination of vibratory patterns. J. Acoust. Soc. Am. 37, 797-801 (1965).
- Craig, J. C. Vibrotactile loudness addition. Percept. Psychophys. 1, 185-190 (1966).
