title: An Assessment of Six Muscle Spindle Models for Predicting Sensory Information during Human Wrist Movements.
abstract: BACKGROUND
  The muscle spindle is an important sensory organ for proprioceptive information, yet there have been few attempts to use Shannon information theory to quantify the capacity of human muscle spindles to encode sensory input.
  
  
  METHODS
  Computer simulations linked kinematics, to biomechanics, to six muscle spindle models that generated predictions of firing rate. The predicted firing rates were compared to firing rates of human muscle spindles recorded during a step-tracking (center-out) task to validate their use. The models were then used to predict firing rates during random movements with statistical properties matched to the ergonomics of human wrist movements. The data were analyzed for entropy and mutual information.
  
  
  RESULTS
  Three of the six models produced predictions that approximated the firing rate of human spindles during the step-tracking task. For simulated random movements these models predicted mean rates of 16.0 ± 4.1 imp/s (mean ± SD), peak firing rates <50 imp/s and zero firing rate during an average of 25% of the movement. The average entropy of the neural response was 4.1 ± 0.3 bits and is an estimate of the maximum information that could be carried by muscles spindles during ecologically valid movements. The information about tendon displacement preserved in the neural response was 0.10 ± 0.05 bits per symbol; whereas 1.25 ± 0.30 bits per symbol of velocity input were preserved in the neural response of the spindle models.
  
  
  CONCLUSIONS
  Muscle spindle models, originally based on cat experiments, have predictive value for modeling responses of human muscle spindles with minimal parameter optimization. These models predict more than 10-fold more velocity over length information encoding during ecologically valid movements. These results establish theoretical parameters for developing neuroprostheses for proprioceptive function.
authors.affiliation: Department of Biomedical Engineering, University of Alberta Edmonton, AB, Canada.
authors.forename: Puja
authors.initials: P
authors.lastname: Malik
authors.affiliation: Department of Biomedical Engineering, University of Alberta Edmonton, AB, Canada.
authors.forename: Nuha
authors.initials: N
authors.lastname: Jabakhanji
authors.affiliation: Department of Biomedical Engineering, University of AlbertaEdmonton, AB, Canada; Faculty of Physical Education and Recreation, University of AlbertaEdmonton, AB, Canada; Neuroscience and Mental Health Institute, University of AlbertaEdmonton, AB, Canada.
authors.forename: Kelvin E
authors.initials: KE
authors.lastname: Jones
keywords: Ia afferent; entropy; proprioception; sensorimotor control; spike train
references.citation: J Neurophysiol. 2006 Oct;96(4):1772-88
references.pmid: 16672301
references.citation: J Physiol. 1998 Feb 15;507 ( Pt 1):293-304
references.pmid: 9490855
references.citation: J Neurosci Methods. 2002 Jan 30;113(2):187-97
references.pmid: 11772440
references.citation: J Neurosci. 1985 Jul;5(7):1688-703
references.pmid: 4020415
references.citation: J Neurophysiol. 1988 Jun;59(6):1814-30
references.pmid: 3404206
references.citation: Nat Rev Neurosci. 2003 May;4(5):417-22
references.pmid: 12728268
references.citation: J Neurosci. 2004 Aug 4;24(31):6991-7006
references.pmid: 15295035
references.citation: J Neurophysiol. 1978 Jan;41(1):15-27
references.pmid: 146076
references.citation: Exp Brain Res. 2003 Apr;149(4):512-9
references.pmid: 12677332
references.citation: J Neurophysiol. 2005 Dec;94(6):4244-55
references.pmid: 16079196
references.citation: J Physiol. 2004 Nov 1;560(Pt 3):883-96
references.pmid: 15331686
references.citation: J Physiol. 1998 Feb 15;507 ( Pt 1):277-91
references.pmid: 9490851
references.citation: J Biomech. 1996 Mar;29(3):331-42
references.pmid: 8850639
references.citation: J Neurophysiol. 1983 Apr;49(4):989-1006
references.pmid: 6222165
references.citation: Exp Brain Res. 2002 Aug;145(4):429-36
references.pmid: 12172654
references.citation: Science. 1991 Jun 28;252(5014):1854-7
references.pmid: 2063199
references.citation: Prog Brain Res. 1999;123:133-42
references.pmid: 10635710
references.citation: J Neurosci. 1982 Nov;2(11):1527-37
references.pmid: 7143039
references.citation: Suppl Clin Neurophysiol. 2004;57:592-606
references.pmid: 16106661
references.citation: J Neurosci. 1986 Nov;6(11):3309-18
references.pmid: 3772433
references.citation: J Physiol. 2001 Oct 15;536(Pt 2):635-47
references.pmid: 11600696
references.citation: J Neurophysiol. 1999 Jan;81(1):319-33
references.pmid: 9914292
references.citation: J Neurophysiol. 1981 Jul;46(1):143-66
references.pmid: 6455505
references.citation: Ergonomics. 1999 Jul;42(7):938-51
references.pmid: 10424183
references.citation: J Neurosci. 1993 Dec;13(12):5212-27
references.pmid: 8254369
references.citation: Nature. 2000 Nov 16;408(6810):361-5
references.pmid: 11099043
references.citation: Exp Brain Res. 1994;99(1):97-111
references.pmid: 7925800
references.citation: Front Comput Neurosci. 2014 Dec 04;8:141
references.pmid: 25538613
references.citation: Exp Brain Res. 2004 Aug;157(3):359-68
references.pmid: 15007582
references.citation: J Neurophysiol. 2004 Jan;91(1):515-32
references.pmid: 13679402
references.citation: Annu Rev Neurosci. 2004;27:487-507
references.pmid: 15217341
references.citation: J Neurosci. 1990 Jan;10(1):142-52
references.pmid: 2299389
references.citation: Exp Brain Res. 2000 Oct;134(3):311-21
references.pmid: 11045356
references.citation: Trends Neurosci. 1992 Nov;15(11):428-34
references.pmid: 1281349
references.citation: Exp Brain Res. 2000 Oct;134(3):301-10
references.pmid: 11045355
references.citation: Conf Proc IEEE Eng Med Biol Soc. 2014;2014:1977-80
references.pmid: 25570369
references.citation: J Physiol. 1969 May;202(1):59-82
references.pmid: 4238988
references.citation: Science. 1999 Sep 24;285(5436):2136-9
references.pmid: 10497133
references.citation: J Neurosci. 1994 Dec;14(12):7529-40
references.pmid: 7996193
references.citation: Annu Rev Neurosci. 2001;24:1193-216
references.pmid: 11520932
references.citation: Brain Res. 1986 Mar 5;367(1-2):287-91
references.pmid: 3697703
references.citation: J Neural Eng. 2014 Jun;11(3):036007
references.pmid: 24762981