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[0] Fetz EE, Perlmutter SI, Prut Y, Functions of mammalian spinal interneurons during movement.Curr Opin Neurobiol 10:6, 699-707 (2000 Dec)

[0] Sabelli HC, Mosnaim AD, Vazquez AJ, Giardina WJ, Borison RL, Pedemonte WA, Biochemical plasticity of synaptic transmission: a critical review of Dale's Principle.Biol Psychiatry 11:4, 481-524 (1976 Aug)[1] Sulzer D, Rayport S, Dale's principle and glutamate corelease from ventral midbrain dopamine neurons.Amino Acids 19:1, 45-52 (2000)[2] Burnstock G, Do some nerve cells release more than one transmitter?Neuroscience 1:4, 239-48 (1976 Aug)

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ref: -0 tags: Courtine PDMS soft biomaterials spinal cord e-dura date: 12-22-2017 01:29 gmt revision:0 [head]

Materials and technologies for soft implantable neuroprostheses

  • Quote: In humans, both the spinal cord and its meningeal protective membranes can experience as much as 10–20% tensile strain and
displacement (relative to the spinal canal) during normal postural movements. This motion corresponds to displacements on the order of centimetres17. The deformations relative to the spinal cord in animal models, such as rodents or non-human primates, are likely to be even larger.

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ref: -0 tags: L1 cell adhesion neural implants microglia DRG spinal cord dorsal root inflammation date: 11-19-2016 22:55 gmt revision:1 [0] [head]

PMID-22750248 In vivo effects of L1 coating on inflammation and neuronal health at the electrode-tissue interface in rat spinal cord and dorsal root ganglion.

  • Kolarcik CL1, Bourbeau D, Azemi E, Rost E, Zhang L, Lagenaur CF, Weber DJ, Cui XT.
  • Quote: With L1, neurofilament staining was significantly increased while neuronal cell death decreased.
  • These results indicate that L1-modified electrodes may result in an improved chronic neural interface and will be evaluated in recording and stimulation studies.
  • Ok, so this CAM seems to mitigate against microglia / inflammation, but how was it selected vs any of the other CAMs and surface proteins? (This domain is almost completely unknown by me..)
  • Ultimate strategy likely to be a broad combination of mechanical (size, flexibility), biochemical (inflammation, cell migration), electrochamical (surface coatings) and vasculature-avoiding approaches.

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ref: Fuentes-2009.03 tags: Nicoelis DCS spinal cord stimulation PD Fuentes Petersson 6-OHDA date: 03-03-2012 02:46 gmt revision:3 [2] [1] [0] [head]

PMID-19299613[0] Spinal cord stimulation restores locomotion in animal models of Parkinson's disease.

  • Motivation: different levels of cortical oscillation during movement and rest (LFO decreased, medium-high freq increased); PD associated with abnormal synchronous corticostriatal oscillations.
  • In epilepsy patients, stimulation of peripheral nerve afferents is effective in desychronizing low-frequency neural activity, reducing the frequency and duration of seizures (8,9,10) PMID-11050139[1] PMID-16886985[2] PMID-18188148[3]
  • DCS (dorsal column stimulation)
    • Epidural, longitudal electrodes, horizontal electrical field.
    • Upper thoracic, mice.
    • 300Hz.
    • simpler and safer than brain surgery.
    • [24] DCS induces no increase in arousal. (Wall, PD. Brain 1970; 93:505.
  • used the tyrosine hydroxyalse inhibitor AMPT
  • M1 LFP: Osc around 1.5-4Hz and 10-15Hz enhanced; osc > 25Hz subdued.
  • DCS increased locomotion by 29x in depleted animals, and 4.9x in normal animals.
  • Also titrated L-DOPA with DAT-KO mice. Without dopamine, there is no movement.
    • DCS increased L-DOPA effectiveness by 5x (1/5 the dose was required)
  • Verified in a 6-OHDA lesion model in rats.
    • Lesioned animals moved more, sham moved less.
  • Activation of locomotion is via striatal medium spiny neurons projecting to the output nuclei of the basal ganglia [26 PMID-8402406[4] ,27 PMID-1695404[5]].
  • In PD, with reduced striatal dopamine levels, the activation threshold of the projection neurons from the striatum is significantly increased [25] PMID-17916382[6].

____References____

[0] Fuentes R, Petersson P, Siesser WB, Caron MG, Nicolelis MA, Spinal cord stimulation restores locomotion in animal models of Parkinson's disease.Science 323:5921, 1578-82 (2009 Mar 20)
[1] Fanselow EE, Reid AP, Nicolelis MA, Reduction of pentylenetetrazole-induced seizure activity in awake rats by seizure-triggered trigeminal nerve stimulation.J Neurosci 20:21, 8160-8 (2000 Nov 1)
[2] DeGiorgio CM, Shewmon A, Murray D, Whitehurst T, Pilot study of trigeminal nerve stimulation (TNS) for epilepsy: a proof-of-concept trial.Epilepsia 47:7, 1213-5 (2006 Jul)
[3] George MS, Nahas Z, Bohning DE, Lomarev M, Denslow S, Osenbach R, Ballenger JC, Vagus nerve stimulation: a new form of therapeutic brain stimulation.CNS Spectr 5:11, 43-52 (2000 Nov)
[4] Brudzynski SM, Wu M, Mogenson GJ, Decreases in rat locomotor activity as a result of changes in synaptic transmission to neurons within the mesencephalic locomotor region.Can J Physiol Pharmacol 71:5-6, 394-406 (1993 May-Jun)
[5] DeLong MR, Primate models of movement disorders of basal ganglia origin.Trends Neurosci 13:7, 281-5 (1990 Jul)
[6] Grillner S, Wallén P, Saitoh K, Kozlov A, Robertson B, Neural bases of goal-directed locomotion in vertebrates--an overview.Brain Res Rev 57:1, 2-12 (2008 Jan)

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ref: -0 tags: locomotion decerebrated monkeys spinal cord section STN stimulation date: 03-01-2012 23:53 gmt revision:0 [head]

PMID-7326562 Locomotor control in macaque monkeys

  • Were not able to induce walking with in monkeys with a sectioned spinal cord
  • Were able to induce walking motion by pulsed stimulation of the STN, with varying walking speed with varying currents!
  • Detailed, informative report, more than I have time to record here today.

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ref: Hagbarth-1983.02 tags: piper rhythm oscillations feedback proprioception spinal reflex date: 01-19-2012 21:41 gmt revision:2 [1] [0] [head]

PMID-6869036[0] The Piper rhythm--a phenomenon related to muscle resonance characteristics?

  • Piper rhythm: the tendency towards rhytmical 40-60 Hz grouping of motor unit potentials in steadily contracting human muscles.
  • Recording of nerves in muscles did not support the idea that the Piper rhythm is dependent on afferent spindle pulses causing reflex entrainment. (loop too slow).
  • TThis wouldn't make sense anyway, as the same rhythm appears in different muscles with markedly different mechanical properties.
  • Likkely cause is the cerebrum, upper oscillations. Interesting!
  • See also: PMID-9862895[1] Cortical correlate of the Piper rhythm in humans.
    • MEG data is consistent with the cortex being the origin of the Piper rhythm.
  • And PMID-10203308[2] Rhythmical corticomotor communication.
    • The rhythmic modulation may form a tool for efficient driving of motor units but we express some reservations about the assumed binding and attention-related roles of the rolandic brain rhythms.
  • PMID-10622378[3] Cortical drives to human muscle: the Piper and related rhythms.
    • Alternately, oscillations may be a form of holding state.
    • They think gamma frequencies are a means of binding together simultaneously activated isometric muscles.
    • Inadequate output from the basal ganglia leads to a disappearance of the beta and piper drives to muscle.
    • Did we see and piper band osc activity? Did not look.

____References____

[0] Hagbarth KE, Jessop J, Eklund G, Wallin EU, The Piper rhythm--a phenomenon related to muscle resonance characteristics?Acta Physiol Scand 117:2, 263-71 (1983 Feb)
[1] Brown P, Salenius S, Rothwell JC, Hari R, Cortical correlate of the Piper rhythm in humans.J Neurophysiol 80:6, 2911-7 (1998 Dec)
[2] Hari R, Salenius S, Rhythmical corticomotor communication.Neuroreport 10:2, R1-10 (1999 Feb 5)
[3] Brown P, Cortical drives to human muscle: the Piper and related rhythms.Prog Neurobiol 60:1, 97-108 (2000 Jan)

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ref: Moritz-2008.12 tags: FES BMI Fetz Moritz Perlmutter spinal cord date: 01-08-2012 05:18 gmt revision:1 [0] [head]

PMID-18923392[0] Direct control of paralysed muscles by cortical neurons.

  • FES BMI: route signals around a broken spinal cord.
  • Found that "neurons could control functional stimulation equally well regardless of any prior association to movement". interesting. consistent with previous work. Wonder if I can duplicate this result.
  • Another relatively straightforward (?) paper where most of the difficulty is technology (!!). I mean, what new knowledge was needed to do this? Compare this with the technology that was needed. One of these was very challenging. now, as it come in for my stuff: what does technology let you do? Have to motivate.

____References____

[0] Moritz CT, Perlmutter SI, Fetz EE, Direct control of paralysed muscles by cortical neurons.Nature 456:7222, 639-42 (2008 Dec 4)

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ref: Fetz-2000.12 tags: motor control spinal neurons interneurons movement primitives Fetz review tuning date: 01-03-2012 23:08 gmt revision:4 [3] [2] [1] [0] [head]

PMID-11240278[0] Functions of mammalian spinal interneurons during movement

  • this issue of current opinion in neuro has many reviews of motor control
  • points out that the Bizzi results (they microstimulated & observed a force-field-primitive type organization)
    • others have found that this may be a consequence of decerebration + the structure of the biomechanical groupings of muscles. (see 'update').
  • intraspinal electrodes in the cat provide a secure and reliable method of eliciting forces and movements.
  • CM (corticomotor) cells more often represent synergistic groups of muscles, whereas premotor spinal interneurons are organized to target specific muscles.
    • CMs are therefore more strictly recruited for particular movements.
  • interneurons (IN) are, of course, arrayed in such a way so that antagonist and agonist muscles cross-inhibit eachother (for efficiency)
    • however, we are still able to control the endpoint impedance of the arm - how?
  • spinal interneurons modulate activity during wait period prior to movement!
    • there might be substantial interaction between the cortex and spinal cord.. subjects asked to imagine pressing a foot pedal showed enhanced reflexes in the involved soleus muscle.
      • cognitive priming?
  • spinal reflexes are strongly modulated in movement.

____References____

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ref: Thevathasan-2010.04 tags: DCS DBS spinal cord stimulation PD date: 12-28-2011 20:43 gmt revision:4 [3] [2] [1] [0] [head]

PMID-20404313[0] Spinal cord stimulation failed to relieve akinesia or restore locomotion in Parkinson disease.

  • motivated by [1]
  • Implanted two PD patients with commercial DBS stimulators and electrodes; observed no therapeutic effect.
  • Electric field was axial rather than transverse, hence likely did not activate the same way or same ammount as in the Nicolelis study.
  • Not sure if anyone has tried with other eletrodes... spinal cord stimulation would be great for inductive powering.

____References____

[0] Thevathasan W, Mazzone P, Jha A, Djamshidian A, Dileone M, Di Lazzaro V, Brown P, Spinal cord stimulation failed to relieve akinesia or restore locomotion in Parkinson disease.Neurology 74:16, 1325-7 (2010 Apr 20)
[1] Fuentes R, Petersson P, Siesser WB, Caron MG, Nicolelis MA, Spinal cord stimulation restores locomotion in animal models of Parkinson's disease.Science 323:5921, 1578-82 (2009 Mar 20)

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ref: -0 tags: M1 Evarts PTN conduction velocity monkey electrophysiology spinal cord date: 12-25-2011 04:25 gmt revision:0 [head]

PMID-14283057 Relation of Discharge Frequency to conduction velocity in pyramidal tract neurons

  • Not all PTN arise from the giant Betz cells -- there are too many pyramical tract axons, and not enough betz cells.
  • Most axons come from smaller cortical neurons [8,11,12].
  • Large cells have large axons hence the highest conduction velocity. (cite the squid studies...)
  • Estimate conduction velocity my stimulating in the medullary pyramid (e.g. the pyramidal tract at the level of the medulla)
  • Conduction velocity, in m/s, is six times diameter in microns (roughly; he lists no source here)
  • Mean frequency for 28 rapidly conductin units was 4.1 Hz;
    • These had a non-moving FR of fractional Hz.
    • Showed bursts with sleep, a few spikes when drowsy, very quiet when not moving.
  • MFR for 34 slower cells was 15.6 Hz.
    • Resting rate was higher in these cells.
    • Also showed bursts / more irregular firing with sleep.
  • Amazingly clean recordings. envy.
  • Some cells have much more irregular / more
  • Brookhart [2] concluded that large, rapidly conducting pyramidal fibers are probably responsible for the phasic element of movement control, whereas the smaller slower neurons are responsible for the tonic element.
  • Also true in the spinal cord: large afferents of the nuclear bag fibers in the muscle spindle carry transient info; group II are smaller and carry steady-state info.
  • ref Mountcastle [14] regarding reciprocal pairs of neurons being (surprise) reciprocally activated during joint movements.

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ref: Sabelli-1976.08 tags: anatomy of the spinal cord interneurons pyramidal tract commissure reflexes date: 04-23-2007 05:12 gmt revision:1 [0] [head]

Anatomy of the spinal cord

  • wow! detailed!!
  • the spinal cord is remarkably complex (of course, considering how old it is and how important it is for structuring movement and locomotion..well..most animals)
  • there is a lot of well-organized circuitry in the spinal cord mediating adaptive phenomena and reflexes like the clasp knife reflex (upper motoneuron disease where the resistance to flexion abruptly melts away when the joint is fully flexed)

____References____