The Mind and the Brain (50 page)

somatosensory reorganization in the cortices of raccoons:
Kelahan, A.M., & Doetsch, G. S. 1984. Time-dependent changes in the functional organization of somatosensory cerebral cortex following digit amputation in adult raccoons.
Somatosensory Research, 2
, pp. 49–81.
Patrick Wall’s prescient suggestion
: Wall, P. D. 1977. The presence of ineffective synapses and the circumstances which unmask them.
Philosophical Transactions of the Royal Society of London, Series B: Biological Sciences, 26
, pp. 361–372.

fifteen times as dense as those on, for instance, your shin:
Haseltine, E., 2000. How your brain sees you.
Discover
, September, p. 104.

The poor brain was hoodwinked:
Paul, R. L., Goodman, H., & Merzenich, M. 1972. Alterations in mechanoreceptor input to Brodmann’s areas 1 and 3 of the postcentral hand area of
Macaca mulatta
after nerve section and regeneration.
Brain Research, 14
, pp. 1–19.

roughly eight to fourteen square millimeters:
Merzenich, M. M., & Jenkins, W. M. 1993. Reorganization of cortical skin representations of the hand following alterations of skin inputs induced by nerve injury, skin island transfers, and experience.
Journal of Hand Therapy, 6
, pp. 89–104.

neuroscience landmark:
Ibid.

inputs from the radial and ulnar nerves:
Merzenich, M. M., Kaas, J. H., Wall, J. T., et al. 1983. Progression of change following median
nerve section in the cortical representation of the hand in areas 3b and 1 in adult owl and squirrel monkeys.
Neuroscience, 10,
pp. 639–665.

“complete topographic representation”:
Merzenich & Jenkins, 1993, p. 92.

“completely contrary to a view of sensory systems”:
Merzenich, Kass, & Wall, 1983, p. 662.

“Hubel and Wiesel’s work had shown just the opposite”:
Hubel, D. H., & Wiesel, T. N. 1970. The period of susceptibility to the physiological effects of unilateral eye closure in kittens.
Journal of Physiology, 206,
pp. 419–436; Hubel, D. H., Wiesel, T. N., & LeVay, S. 1977. Plasticity of ocular dominance columns in monkey striate cortex.
Philosophical Transactions of the Royal Society of London, Series B: Biological Sciences, 197
(26), pp. 377–409.

The representation of the hand:
Merzenich, M. M., Nelson, R. J., Kaas, J. H., et al. 1987. Variability in hand surface representations in areas 3b and 1 in adult owl and squirrel monkeys.
Journal of Comparative Neurology, 258,
pp. 281–296.

“differences in lifelong use of the hands”:
Merzenich, Nelson, & Kaas, 1987, p. 281.

amputated a single finger in owl monkeys:
Merzenich, M. M., Nelson, R. J., Stryker, M.P., et al. 1984. Somatosensory cortical map changes following digit amputation in adult monkeys.
Journal of Comparative Neurology, 224
, pp. 591–605.

a single, continuous, overlapping representation:
Clark, S. A., Allard, T., Jenkins, W. M., & Merzenich, M. M. 1988. Receptive fields in the body-surface map in adult cortex defined by temporally correlated inputs.
Nature, 332
, pp. 444–445; Allard, T., Clark, S. A., Jenkins, W. M., & Merzenich, M. M. 1991. Reorganization of somatosensory area 3b representations in adult owl monkeys after digital syndactyly.
Journal of Neurophysiology, 66
, pp. 1048–1058.
when the fused digits were separated:
Mogilner, A., Grossman, J. A., Ribary, U., et al. 1993. Somatosensory cortical plasticity in adult humans revealed by magnetoencephalography.
Proceedings of the National Academy of Sciences of the United States of America, 90,
pp. 3593–3597.

adult visual cortex seemed just as capable of reorganizing:
Kaas, J. H., Krubitzer, L. A., Chino, Y. M., et al. 1990. Reorganization of
retinotopic cortical maps in adult mammals after lesions of the retina.
Science, 248
, pp. 229–231.

experiment on four of the Silver Spring monkeys:
Pons, Garraghty, et al., 1991.

“new direction of research”
: Ramachandran, V.S., & Blakeslee, S. 1998.
Phantoms in the brain: Probing the mysteries of the human mind
. New York: William Morrow; Ramachandran, V. S., & Rogers-Ramachandran, D., 2000. Phantom limbs and neural plasticity.
Archives of Neurology
, 57, pp. 317–320.

the term
phantom limb: Herman, J. 1998. Phantom limb: From medical knowledge to folk wisdom and back.
Annals of Internal Medicine
, 128, pp. 76–78.

feel the missing appendage
: Ramachandran & Blakeslee, 1998; Ramachandran, V. S., Stewart, M., & Rogers-Ramachandran, D. 1992. Perceptual correlates of massive cortical reorganization.
Neuroreport, 3
, pp. 583–586; Ramachandran, V. S. 1993. Behavioral and magnetoencephalographic correlates of plasticity in the adult human brain.
Proceedings of the National Academy of Sciences of the United States of America, 90
, pp. 10413–10420.

invaded by nerves from the genitals
: Robertson, I. H. 1999.
Mind sculpture: Unlocking your brain’s untapped potential
. London: Bantam Press, p. 54. For excellent reviews of the clinical aspects of plasticity, see: Robertson & Murre, 1999, and Robertson, I. H., 1999. Setting goals for cognitive rehabilitation.
Current Opinion and Neurology
, 12, pp. 703–708.

double by 2050
: Taub, E., Uswatte, G., & Pidikiti, R. 1999. Constraint-induced movement therapy: a new family of techniques with broad application to physcial rehabilitation—a clinical review.
Journal of Rehabilitation Research and Development. 36
. pp. 237–251.

speed and strength of movement:
Ibid.

“neurological injury, including stroke”:
Taub, E., Miller, N. E., Novack, T. A., et al. 1993. Technique to improve chronic motor deficit after stroke.
Archives of Physical Medicine and Rehabilitation, 74
, pp. 347–354.

In just two weeks:
Robertson, I. H., & Murre, J. M. J. 1999. Rehabilitation of brain damage: Brain plasticity and principles of guided recovery.
Psychological Bulletin, 125
, pp. 544–575.

improvement on standard tests of motor ability:
Kunkel, A., Kopp, B., Muller, G., et al. 1999. Constraint-induced movement therapy for motor recovery in chronic stroke patients.
Archives of Physical Medicine and Rehabilitation, 80
, pp. 624–628.

patients who had lost the use of a leg:
Taub, Uswatte, & Pidikiti, 1999.

brain changes in six chronic stroke patients:
Liepert, J., Miltner, W. H., Bauder, H., et al. 1998. Motor cortex plasticity during constraint-induced movement therapy in stroke patients.
Neuroscience Letters, 250
, pp. 5–8.

changes in the brain’s electrical activity:
Kopp, B., Kunkel, A., Muhlnickel, W., et al. 1999. Plasticity in the motor system related to therapy-induced improvement of movement after stroke.
Neuroreport, 10
, pp. 807–810.

“induced expansion”:
Taub, Uswatte & Pidikiti, 1999.

left aphasic:
Pulvermuller, F., Neininger, B., et al. 2001. Constraint-induced therapy of chronic aphasia after stroke.
Stroke
, 32(7), pp. 1621–1626.

largely destroyed their Wernicke’s area:
Weiller, C., Isensee, C., Rijntjes, M., et al. 1995. Recovery from Wernicke’s aphasia: A positron emission tomographic study.
Annals of Neurology, 37
, pp. 723–732.

accompanied by cortical reorganization:
Liepert, J., Bauder, H., Wolfgang, H. R., et al. 2000. Treatment-induced cortical reorganization after stroke in humans.
Stroke, 6,
pp. 1210–1216.

reported a similar finding:
Buckner, R. L., Corbetta, M., Schatz, J., et al. 1996. Preserved speech abilities and compensation following prefrontal damage.
Proceedings of the National Academy of Sciences of the United States of America, 93,
pp. 1249–1253.

tactile discrimination tasks activate the visual cortex:
Sadato, N., Pascual-Leone, A., Grafman, J., et al. 1996. Activation of the primary visual cortex by Braille reading in blind subjects.
Nature, 380,
pp. 526–528.

superior tactile sense of the congenitally blind:
Cohen, L. G., Celnik P., Pascual-Leone, A., et al. 1997. Functional relevance of cross-modal plasticity in blind humans.
Nature, 389,
pp. 180–183; Musso, M., Weiller, C., Kiebel, S., et al. 1999. Training-induced brain plasticity in aphasia.
Brain, 122,
pp. 1781–1790.

for the good of millions of stroke patients:
Taub, E., & Morris, D. M. 2001. Constraint-induced movement therapy to enhance recovery after stroke.
Current Atherosclerosis Reports, 3,
pp. 279–286.

C
HAPTER
S
IX

a route to cortical reorganization that is the polar opposite:
Elbert, T., Candia, V., Altenmuller, E., et al. 1998. Alteration of digital representations in somatosensory cortex in focal hand dystonia.
Neuroreport
, 9, pp. 3571–3575; Byl, N. N., McKenzie, A., & Nagarajan, S. S. 2000. Differences in somatosensory hand organization in a healthy flutist and a flutist with focal hand dystonia: A case report.
Journal of Hand Therapy, 13
, pp. 302–309; Pujol, J., Roset-Llobet, J., Rosines-Cubells, D., et al. 2000. Brain cortical activation during guitar-induced hand dystonia studied by functional MRI.
Neuroimage, 12
, pp. 257–267.

use-dependent cortical reorganization: Jenkins, W. M., Merzenich, M. M., Ochs, M.T., et al. 1990. Functional reorganization of primary somatosensory cortex in adult owl monkeys after behaviorally controlled tactile stimulation.
Journal of Neurophysiology, 63
, pp. 82–104; Nudo, R. J., Jenkins, W. M., Merzenich, M. M., et al. 1992. Neurophysiological correlates of hand preference in primary motor cortex of adult squirrel monkeys.
Journal of Neuroscience, 12
, pp. 2918–2947.

a study of the effects of motor skill learning:
Nudo, R. J., Milliken, G.W., Jenkins, W. M., Merzenich, M. M. 1996. Use-dependent alterations of movement representations in primary motor cortex of adult squirrel monkeys.
Journal of Neuroscience, 16
, pp. 785–807.

“the cortical part of the skill acquisition”:
Merzenich, M., Wright, B., Jenkins, W., et al. 1996. Cortical plasticity underlying perceptual, motor, and cognitive skill development: Implications for neu-rorehabilitation.
Cold Spring Harbor Symposia on Quantitative Biology, 61
, pp. 1–8.

the researchers made small lesions in the monkeys’ brains:
Xerri, C., Merzenich, M. M., Peterson, B. E., & Jenkins, W. 1998. Plasticity of primary somatosensory cortex paralleling sensorimotor skill recovery from stroke in adult monkeys.
Journal of Neurophysiology, 79
, pp. 2119–2148.

“the reemergence of the representation of functions”
: Merzenich, Wright, and Jenkins, 1996, p. 2.

spinning disk experiment
: Jenkins, Merzenich, & Ochs, 1990.

flutter-vibration studies
: Recanzone, G. H., Jenkins, W. M., Hradek, G.T., & Merzenich, M. M. 1992. Progressive improvement in discriminative abilities in adult owl monkeys performing a tactile frequency discrimination task.
Journal of Neurophysiology, 67
, pp. 1015–1030.

“cortical representations of the trained hands”
: Recanzone, G. H., Merzenich, M. M., Jenkins, W. M., et al. 1992. Topographic reorganization of the hand representation in cortical area 3b of owl monkeys trained in a frequency-discrimination task.
Journal of Neurophysiology
, 67, pp. 1031–1056.

only when the monkeys were attentive:
Merzenich, M., Byl, N., Wang, X., & Jenkins, W. 1996. Representational plasticity underlying learning: Contributions to the origins and expressions of neurobehavioral disabilities. In: Ono, T., et al. (Eds.)
Perception, memory, and emotion: Frontiers in neuroscience.
Oxford, U.K., and Tarrytown, N.Y.: Pergamon, pp. 45–61; Merzenich & deCharms, 1996.

discriminate small differences in the frequency of tones:
Recanzone, G. H., Schreiner, C. E., & Merzenich, M. M. 1993. Plasticity in the frequency representation of primary auditory cortex following discrimination training in adult owl monkeys.
Journal of Neuroscience, 13
, pp. 87–103.

“idiosyncratic features of cortical representation”:
Merzenich, M. M., Recanzone, G. H., Jenkins, W. M., & Grajski, K. A. 1990. Adaptive mechanisms in cortical networks underlying cortical contributions to learning and nondeclarative memory.
Cold Spring Harbor Symposia on Quantitative Biology, 55
, pp. 873–887.

fifteen proficient Braille readers:
Pascual-Leone, A., & Torres, F. 1993. Plasticity of the sensorimotor cortex representation of the reading finger in Braille readers.
Brain, 116, Part 1
, pp. 39–52.
amputation produces extensive reorganization:
Flor, H., Elbert, T., Knecht, S., et al. 1995. Phantom-limb pain as a perceptual correlate of cortical reorganization following arm amputation.
Nature, 375
, pp. 482–484.

There was no difference between the string players:
Elbert, T., Pan-tev, C., Wienbruch, C., Rockstroh, B., & Taub, E. 1995. Increased
cortical representation of the fingers of the left hand in string players.
Science, 270
, pp. 305–307.

tactile stimuli to the fingers changes the maps of the hand
: Wang, X., Merzenich, M. M., Sameshima, K., & Jenkins, W. M. 1995. Remodeling of hand representation in adult cortex determined by timing of tactile stimulation.
Nature, 378
, pp. 71–75.