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Abstract

Objective: To determine if blind people have heightened tactile spatial acuity.
Background: Recently, studies using magnetic source imaging and somatosensory evoked potentials have shown that the cortical representation of the reading fingers of blind Braille readers is expanded compared to that of fingers of sighted subjects. Furthermore, the visual cortex is activated during certain tactile tasks in blind subjects but not sighted subjects. The authors hypothesized that the expanded cortical representation of fingers used in Braille reading may reflect an enhanced fidelity in the neural transmission of spatial details of a stimulus. If so, the quantitative limit of spatial acuity would be superior in blind people.
Methods: The authors employed a grating orientation discrimination task in which threshold performance is accounted for by the spatial resolution limits of the neural image evoked by a stimulus. The authors quantified the psychophysical limits of spatial acuity at the middle and index fingers of 15 blind Braille readers and 15 sighted control subjects.
Results: The mean grating orientation threshold was significantly (p = 0.03) lower in the blind group (1.04 mm) compared to the sighted group (1.46 mm). The self-reported dominant reading finger in blind subjects had a mean grating orientation threshold of 0.80 mm, which was significantly better than other fingers tested. Thresholds at non-Braille reading fingers in blind subjects averaged 1.12 mm, which were also superior to sighted subjects’ performances.
Conclusion: Superior tactile spatial acuity in blind Braille readers may represent an adaptive, behavioral correlate of cortical plasticity.

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References

1.
Pascual–Leone A, Torres F. Plasticity of the sensorimotor cortex representation of the reading finger in Braille readers. Brain 1993;16:39–52.
2.
Sterr A, Muller MM, Elbert T, Rockstroh B, Pantev C, Taub E. Perceptual correlates of changes in cortical representation of fingers in blind multifinger Braille readers. J Neurosci 1998;18:4417–4423.
3.
Sadato N, Pascual–Leone A, Grafman J, et al. Activation of the primary visual cortex by Braille reading in blind subjects. Nature 1996;380:526–528.
4.
Cohen LG, Celnik P, Pascual–Leone A, et al. Functional relevance of cross-modal plasticity in blind humans. Nature 1997;389:180–183.
5.
Buchel C, Price C, Frackowiak RSJ, Friston K. Different activation patterns in the visual cortex of late and congenitally blind subjects. Brain 1998;121:409–419.
6.
Rauschecker JP. Compensatory plasticity and sensory substitution in the cerebral cortex. Trends Neurosci 1995;18:1:36–43.
7.
Johnson KO, Van Boven RW, Hsiao SS. The perception of two points is not the spatial resolution threshold. In: Boivie J, Hansson P, Lindblom U, eds. Touch, temperature, and pain in health and disease: mechanisms and assessments, progress in pain research and management, vol 3.Seattle, WA:IASP Press; 1994:389–404.
8.
Van Boven RW, Johnson KO. The limit of tactile spatial resolution in humans: grating orientation discrimination at the lip, tongue, and finger. Neurology 1994;44:2361–2366.
9.
Van Boven RW, Hamilton RH, Pascual–Leone A. Spatial acuity thresholds in blind humans are lower than in sighted subjects. Neurology 1998;50 (suppl 4):A162. Abstract.
10.
Schachter SC, Ransil BJ, Geschwind N. Associations of handedness with hair color and learning disabilities. Neuropsychologia 1987;25:269–276.
11.
Van Boven RW, Johnson KO. A psychophysical study of the mechanisms of sensory recovery following nerve injury in humans. Brain 1994;117:149–167.
12.
Johnson KO, Phillips JR. Tactile spatial resolution. I. Two-point discrimination, gap detection, grating resolution, and letter recognition. J Neurophysiol 1981;46:1177–1191.
13.
Vega–Bermudez F, Johnson KO. SA1 and RA receptive fields, response variability, and population responses mapped with a probe array. J Neurophysiol 1999;81:2701–2710.
14.
Sathian K, Zangaladze A, Green J, Vitek JL, DeLong MR. Tactile spatial acuity and roughness discrimination: impairments due to aging and Parkinson’s disease. Neurology 1997;49:168–177.
15.
Hollins M. Understanding blindness. Hillsdale, NJ:L. Erlbaum Associates, Inc., 1989:43–63.
16.
Heinrichs RW, Moorhouse JA. Touch-perception thresholds in blind diabetic subjects in relation to the reading of Braille type. N Engl J Med 1969;280:72–75.
17.
Stevens JC, Foulke E, Patterson MQ. Tactile acuity, aging, and Braille reading in long-term blindness. J Exp Psychol Appl 1996;2:91–106.
18.
Tilney F. A comparative sensory analysis of Helen Keller and Laura Bridgman. II. Its bearing on the further development of the human brain. Arch Neurol Psychiatr 1929;21:1237–1269.
19.
Axelrod S. Effects of early blindness: performance of blind and sighted children on tactile and auditory tasks. New York, NY:American Foundation for the Blind, 1959.
20.
Vega–Bermudez F, Johnson KO. Surround suppression in the responses of primate SA1 and RA mechanoreceptive afferents mapped with a probe array. J Neurophysiol 1999;81:2711–2719.
21.
Grant AC, Thiagarajah MC, Sathian K. Tactile perception in blind braille readers: a psychophysical study of acuity and hyperacuity using gratings and dot patterns. Percept Psychophys 2000;62:301–312.
22.
Craig JC. The role of experience in tactual pattern perception: a preliminary report. Int J Rehab Res 1988;11:167–183.
23.
Sathian K, Zangaladze A. Tactile learning is task specific but transfers between fingers. Percept Psychophys 1997;59:119–128.
24.
Gardner EP, Palmer CI. Simulation of motion on the skin. III. Mechanisms used by rapidly adapting cutaneous mechanoreceptors in the primate hand for spatiotemporal resolution and two-point discrimination. J Neurophysiol 1990;63:841–859.
25.
Phillips JR, Johnson KO. Tactile spatial resolution. II. Neural representation of bars, edges, and gratings in monkey primary afferents. J Neurophysiol 1981;46:1192–1203.
26.
Phillips JR, Johansson RS, Johnson KO. Responses of human mechanoreceptive afferents to embossed dot arrays scanned across fingerpad skin. J Neurosci 1992;12:827–839.
27.
Phillips JR, Johnson KO, Hsiao SS. Spatial pattern representation and transformation in monkey somatosensory cortex. Proc Natl Acad Sci 1988;85:1317–1321.
28.
Penfield W, Rasmussen T. The cerebral cortex of man: a clinical study of localization of function. New York, NY:Macmillan, 1950.
29.
Johansson RS, Vallbo AB. Tactile sensibility in the human hand: relative and absolute densities of four types of mechanoreceptive units in glabrous skin. J Physiol (Lond) 1979;286:283–300.
30.
Weinstein S. Intensive and extensive aspects of tactile sensitivity as a function of body part, sex, and laterality. In: Kenshalo DR, ed. The skin senses. Springfield, IL:CC Thomas; 1968:195–222.
31.
Sur M, Merzenich MM, Kaas JH. Magnification, receptive field area, and “hypercolumn” size in areas 3b and 1 of somatosensory cortex in owl monkeys. J Neurophysiol 1980;44:295–311.
32.
Jenkins WM, Merzenich MM, Ochs MT, Allard T, Guic–Robles E. Functional reorganization of primary somatosensory cortex in adult owl monkeys after behaviorally controlled tactile stimulation. J Neurophysiol 1990;63:82–104.
33.
Recanzone GH, Merzenich MM, Jenkins WM, Grajski KA, Dinse HR. Topographic reorganization of the hand representation in cortical area 3b of owl monkeys trained in a frequency-discrimination task. J Neurophysiol 1992;67:1031–1056.
34.
Xerri C, Merzenich MM, Jenkins WM, Santucci S. Representational plasticity in cortical area 3b paralleling tactual-motor skill acquisition in adult monkeys. Cereb Cortex 1999;9:264–276.
35.
Hsiao SH, O’Shaughnessy DM, Johnson KO. Effects of selective attention on spatial form processing in monkey primary and secondary somatosensory cortex. J Neurophysiol 1993;70:444–447.
36.
Kilgard MP, Merzenich MM. Cortical map reorganization enabled by nucleus basalis activity. Science 1998;279:1714–1718.
37.
Elbert T, Pantev C, Wienbruch C, Rockstroh B, Taub E. Increased cortical representation of the fingers of the left hand in string players. Science 1995;270:305–307.
38.
Ahissar M, Hochstein S. Task difficulty and the specificity of perceptual learning. Nature 1997;387:401–406.
39.
Recanzone GH, Jenkins WM, Hradek GT, Merzenich MM. Progressive improvement in discriminative abilities in adult owl monkeys performing a tactile frequency discrimination task. J Neurophysiol 1992;67:1015–1030.
40.
Sampaio E, Philip J. Influences of age at onset of blindness on Braille reading performances with left and right hands. Percept Mot Skills 1995;81:131–141.
41.
Semenza C, Zoppello M, Gidiuli O, Borgo F. Dichaptic scanning of Braille letters by skilled blind readers: lateralization effects. Percept Mot Skills 1996;82:1071–1074.
42.
Nagarajan SS, Blake DT, Wright BA, Byl N, Merzenich MM. Practice-related improvements in somatosensory interval discrimination are temporally specific but generalize across skin location, hemisphere, and modality. J Neurosci 1998;18:1559–1570.
43.
Summers DC, Lederman SJ. Perceptual asymmetries in the somatosensory system: a dichaptic experiment and critical review of the literature from 1929 to 1986. Cortex 1990;26:201–226.
44.
Sathian K, Zangaladze A. Tactile spatial acuity at the human fingertip and lip: bilateral symmetry and interdigit variability. Neurology 1996;46:1464–1466.
45.
Vega–Bermudez F, Johnson KO, Hsiao SS. Human tactile pattern recognition: active versus passive touch, velocity effects, and patterns of confusion. J Neurophysiol 1991;65:531—546.
46.
Supa M, Cotzin M, Dallenbach KM. “Facial vision”: the perception of obstacles by the blind. Am J Psychol 1944;57:133–183.
47.
Merzenich MM, Wright B, Jenkins W, et al. Cortical plasticity underlying perceptual, motor, and cognitive skill development: implications for neurorehabilitation. Cold Spring Harb Symp Quant Biol 1996;61:1–8.
48.
Zangaladze A, Epstein CM, Grafton ST, Sathian K. Involvement of visual cortex in tactile discrimination of orientation. Nature 1999;401:587–590.

Information & Authors

Information

Published In

Neurology®
Volume 54Number 12June 27, 2000
Pages: 2230-2236
PubMed: 10881245

Publication History

Received: April 4, 1999
Accepted: April 7, 2000
Published online: June 27, 2000
Published in print: June 27, 2000

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Authors

Affiliations & Disclosures

R.W. Van Boven, MD, DDS
From the Department of Neurology (Dr. Van Boven)Northwestern University Medical School, Chicago, IL; and the Laboratory for Magnetic Brain Stimulation (Drs. Keenan and Pascual–Leone, R.H. Hamilton and T. Kauffman), Behavioral Neurology Unit, Department of Neurology, Beth Israel-Deaconess Medical Center and Harvard Medical School, Boston, MA.
R.H. Hamilton, BS
From the Department of Neurology (Dr. Van Boven)Northwestern University Medical School, Chicago, IL; and the Laboratory for Magnetic Brain Stimulation (Drs. Keenan and Pascual–Leone, R.H. Hamilton and T. Kauffman), Behavioral Neurology Unit, Department of Neurology, Beth Israel-Deaconess Medical Center and Harvard Medical School, Boston, MA.
T. Kauffman, BS
From the Department of Neurology (Dr. Van Boven)Northwestern University Medical School, Chicago, IL; and the Laboratory for Magnetic Brain Stimulation (Drs. Keenan and Pascual–Leone, R.H. Hamilton and T. Kauffman), Behavioral Neurology Unit, Department of Neurology, Beth Israel-Deaconess Medical Center and Harvard Medical School, Boston, MA.
J.P. Keenan, PhD
From the Department of Neurology (Dr. Van Boven)Northwestern University Medical School, Chicago, IL; and the Laboratory for Magnetic Brain Stimulation (Drs. Keenan and Pascual–Leone, R.H. Hamilton and T. Kauffman), Behavioral Neurology Unit, Department of Neurology, Beth Israel-Deaconess Medical Center and Harvard Medical School, Boston, MA.
A. Pascual–Leone, MD, PhD
From the Department of Neurology (Dr. Van Boven)Northwestern University Medical School, Chicago, IL; and the Laboratory for Magnetic Brain Stimulation (Drs. Keenan and Pascual–Leone, R.H. Hamilton and T. Kauffman), Behavioral Neurology Unit, Department of Neurology, Beth Israel-Deaconess Medical Center and Harvard Medical School, Boston, MA.

Notes

Address correspondence and reprint requests to Dr. Robert W. Van Boven, Laboratory of Brain and Cognition, NIMH, Building 10, Room 4C104, 10 Center Drive, MSC 1366, Bethesda, MD 20892-1366; e-mail: [email protected]; or Dr. Alvaro Pascual–Leone, Department of Neurology, Beth Israel-Deaconess Medical Center, 330 Brookline Avenue, KS452, Boston, MA 02215; e-mail: [email protected]

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