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[0] Schmidt EM, McIntosh JS, Durelli L, Bak MJ, Fine control of operantly conditioned firing patterns of cortical neurons.Exp Neurol 61:2, 349-69 (1978 Sep 1)[1] Serruya MD, Hatsopoulos NG, Paninski L, Fellows MR, Donoghue JP, Instant neural control of a movement signal.Nature 416:6877, 141-2 (2002 Mar 14)[2] Fetz EE, Operant conditioning of cortical unit activity.Science 163:870, 955-8 (1969 Feb 28)[3] Fetz EE, Finocchio DV, Operant conditioning of specific patterns of neural and muscular activity.Science 174:7, 431-5 (1971 Oct 22)[4] Fetz EE, Finocchio DV, Operant conditioning of isolated activity in specific muscles and precentral cells.Brain Res 40:1, 19-23 (1972 May 12)[5] Fetz EE, Baker MA, Operantly conditioned patterns on precentral unit activity and correlated responses in adjacent cells and contralateral muscles.J Neurophysiol 36:2, 179-204 (1973 Mar)

[0] Evarts EV, Relation of pyramidal tract activity to force exerted during voluntary movement.J Neurophysiol 31:1, 14-27 (1968 Jan)

[0] Evarts EV, Activity of pyramidal tract neurons during postural fixation.J Neurophysiol 32:3, 375-85 (1969 May)[1] Evarts EV, Relation of pyramidal tract activity to force exerted during voluntary movement.J Neurophysiol 31:1, 14-27 (1968 Jan)

[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)

[0] Fromm C, Evarts EV, Relation of size and activity of motor cortex pyramidal tract neurons during skilled movements in the monkey.J Neurosci 1:5, 453-60 (1981 May)

[0] Wetts R, Kalaska JF, Smith AM, Cerebellar nuclear cell activity during antagonist cocontraction and reciprocal inhibition of forearm muscles.J Neurophysiol 54:2, 231-44 (1985 Aug)

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ref: -0 tags: NMDA spike hebbian learning states pyramidal cell dendrites date: 10-03-2018 01:15 gmt revision:0 [head]

PMID-20544831 The decade of the dendritic NMDA spike.

  • NMDA spikes occur in the finer basal, oblique, and tuft dendrites.
  • Typically 40-50 mV, up to 100's of ms in duration.
  • Look similar to cortical up-down states.
  • Permit / form the substrate for spatially and temporally local computation on the dendrites that can enhance the representational or computational repertoire of individual neurons.

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ref: Schmidt-1978.09 tags: Schmidt BMI original operant conditioning cortex HOT pyramidal information antidromic date: 04-22-2013 18:21 gmt revision:10 [9] [8] [7] [6] [5] [4] [head]

PMID-101388[0] Fine control of operantly conditioned firing patterns of cortical neurons.

  • hand-arm area of M1, 11 or 12 chronic recording electrodes, 3 monkeys.
    • but, they only used one unit at a time in the conditioning task (i think)
  • conditioning in 77% of single units and 65% of combined units (multiunits?).
  • trained to move a handle to a position indicated by 8 annular cursor lights.
    • cursor was updated at 50hz -- this was just a series of lights! talk about simple feedback...
    • Investigated different smoothing: too fast, FR does not stay in target; too slow, cursor acquires target too slowly.
    • My gamma function is very similar to their lowpass filter used for smoothing the firing rates.
    • 4 or 8 target random tracking task
    • time out of 8 seconds
    • run of 40 trials
      • the conditioning reached a significant level of performance after 2.2 runs of 40 trials (in well-trained monkeys); typically, they did 18 runs/day.
  • recordings:
    • scalar mapping of unit firing rate to cursor position.
    • filtered 600-6kHz
    • each accepted spike triggered a generator that produced a pulse of of constant amplitude and width -> this was fed into a lowpass filter (1.5 to 2.5 & 3.5Hz cutoff), and a gain stage, then a ADC, then (presumably) the PDP.
      • can determine if these units were in the pyramidal tract by measuring antidromic delay (stimulate muscles??)
    • recorded one neuron for 108 days!!
      • neuronal activity is still being recorded from one monkey 24 months after chronic implantation of the microelectrodes.
    • average period in which conditioning was attempted was 3.12 days.
  • successful conditioning was always associated with specific repeatable limb movements
    • "However, what appears to be conditioned in these experiments is a movement, and the neuron under study is correlated with that movement." YES.
    • the monkeys clearly learned to make (increasingly refined) movement to modulate the firing activity of the recorded units.
    • the monkey learned to turn off certain units with specific limb positions; the monkey used exaggerated movements for these purposes.
      • e.g. finger and shoulder movements, isometric contraction in one case.
  • Trained some monkeys or > 15 months; animals got better at the task over time.
  • PDP-12 computer!
  • Information measure: 0 bits for missed targets, 2 for a 4 target task, 3 for 8 target task; information rate = total number of bits / time to acquire targets.
    • 3.85 bits/sec peak with 4 targets, 500ms hold time
    • with this, monkeys were able to exert fine control of firing rate.
    • damn! compare to Paninski! [1]
  • 4.29 bits/sec when the same task was performed with a manipulandum & wrist movement
  • they were able to condition 77% of individual neurons and 65% of combined units.
  • Implanted a pyramidal tract electrode in one monkey; both cells recorded at that time were pyramidal tract neurons, antidromic latencies of 1.2 - 1.3ms.
    • failures had no relation to over movements of the monkey.
  • Fetz and Baker [2,3,4,5] found that 65% of precentral neurons could be conditioned for increased or decreased firing rates.
    • and it only took 6.5 minutes, on average, for the units to change firing rates!
  • Summarized in [1].

____References____

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ref: Evarts-1968.01 tags: Evarts motor control pyramidal tract M1 PTN tuning date: 01-16-2012 18:59 gmt revision:4 [3] [2] [1] [0] [head]

PMID-4966614[] Relation of pyramidal tract activity to force exerted during voluntary movement

  • PTNs with high conduction velocity tend to be silent during motor quiescence and show phasic activity with movement.
  • PTNs with lower axonal conduction velocities are active in the absence of movement; with movement they show both upward and downward modulations of the resting discharge.
  • many PTNs responded to a conditional stimulus before the movement.
  • in this study, they wanted to determine if phasic response was more correlated with displacement or with force.
    • did this with two different motions (flexion and extension) in two different force loads (opposing flexion and opposing extransion)
      • movements were slow (or at least nonballistic) and somewhat controlled - they had to last between 400 and 700ms.
      • monkeys usually carried out 3,000 cycles of the movement daily !!
  • "prior to the experiment, hte authour was biased to think that the displacement model (where the cortex commands a location/movement of the arm, which is then accomplished through feedback & feedforward mechanisms e.g. in the spinal cord) was correct; experimental results seem to indicate that force is very strongly represented in PTN population.
  • many PTN firing rates reflected dF/dt very strongly.
  • old, good paper. made with 'primitive' technology - but why do we need to redo this?

____References____

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ref: Wyler-1980.08 tags: Wyler operant conditioning fast slow pyramidal tract neurons BMI date: 01-07-2012 22:09 gmt revision:3 [2] [1] [0] [head]

PMID-7409057[0] Operant control of precentral neurons: comparison of fast and slow pyramidal tract neurons.

  • Slow PTN (neurons with antidromic latency > 2ms) are pratically all well controlled in his operant-conditioning task;
  • Fast (< 2ms, mean 1.2ms latency) have a more highly variable firing rates and ISIs.
  • "[I]t appears that the majority of error from fast PT cells was generated by ISIS less than 30 ms, whereas the majority of error for slow PT cells was represented in ISIS greater than 60 ms."
    • Ok, trivial observation, but still interesting.

____References____

[0] Wyler AR, Burchiel KJ, Robbins CA, Operant control of precentral neurons: comparison of fast and slow pyramidal tract neurons.Exp Neurol 69:2, 430-3 (1980 Aug)

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ref: notes-0 tags: clementine operant conditioning 041707 pyramidal tract tlh24 date: 01-06-2012 03:12 gmt revision:4 [3] [2] [1] [0] [head]

It appears that operant/feedback training of one neuron (channel 29, in SMA region) works fine (not great, but fine). In the experiment performed prior to visiting Seattle, on April 10 2007, I was not convinced that the neuron was controlling anything. Now, it is apparent that the monkey has some clue as to what he is doing. Today I made a simple change: I made the filtering function sum (all spikes) 1/12 * x*(x-1)^2, where x = time - time_of_spike. In comparison to a butterworth filter, this has no rebound oscillation & makes the estimation of firing rate much more transparent. It averages over approximately 500ms ~= lowcut of 1.5hz? I see no reason to change this filtering function much, as it works fine. Spikes were binned at 100hz as input to this function, but that should be equivalent to binning at 1khz etc.

Next time, i want to do 2d, where channel 62 controls the Y-axis. really should try to determine the approximate tunings of these cells. I'm somewhat concerned as this channel seems to have a much lower mean firing rate than channel 29. According to the literature, PTNs have high firing rates and strong tuning...

for reference, here is the channel used for the one-neuron BMI, recorded April 10. It has not changed much in the last 7 days.

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ref: Evarts-1969.05 tags: Evarts pyramidal tract motor control M1 tuning date: 01-03-2012 23:08 gmt revision:2 [1] [0] [head]

PMID-4977837[0] Activity of Pyramidal Tract neurons during postural fixation

  • Force was thus dissociated from displacement, and it was possible to determine whether PTN discharges were related to position or force.
  • for the majority of PTNs discharge frequency was related to to the magnitude and rate of change of force rather than to the joint position or the speed of joint movement (same as the MUA in the Kinarm data!!)
  • task was simple: just try to avoid joint movement.
  • in comparison to [1] where PTN were related to force under joint displacement, this task shows they are still related to force even when the joint angle is fixed.
  • used sharpened tungsten electrodes to record 102 pyramidal tract neurons.
  • monkeys were trained to do the tasks in their home cages (obviously weren't recorded there - need to be headposted)
  • I'm not sure how he determined if it was or was not a pyramidal tract neuron.

____References____

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ref: -0 tags: Evarts force pyramidal tract M1 movement monkeys conduction velocity tuning date: 01-03-2012 03:25 gmt revision:3 [2] [1] [0] [head]

PMID-4966614 Relation of pyramidal tract activity to force exerted during voluntary movement.

  • One of the pioneering studies of electrophysiology in awake behaving animals; single electrode juice reward headposting: many followed.
  • {960} looked at conduction velocity, which we largely ignore now -- most highly mylenated axons are silent during motor quiescence and show phasic activity during movement.
    • Lower conduction velocity PTNs show + and - FR modulations. Again from [5]
  • [6] showed that PTN activity preceded EMG activity, implying that it was efferent rather than afferent feedback that was controlling the fr. as expected.
  • task: wrist flexion & extension under load.
  • task in monkey's home cage for a period of three months; monkeys carried out 3000 trials or more of the task (must have had strong wrists!)
  • Head fixated the monkeys for about 10 days prior unit recordings; "The monkeys learned to be quite cooperative in reentering the chair in the morning, since entrance to the chair was rewarded by the fruit juice of their choice (grape, apple, or orange). Indeed, some monkeys continued to work even in the presence of free water!
    • Maybe I should give mango some Hawaiian punch as well?
  • Mesured antidromic responses with a permanent electrode in the ipsilateral medullary pyramid.
  • Used glass insulated platinum-iridium electrodes [11]
  • traces are clean, very clean. I wonder if good insulation (in this case, glass) has anything to do with it?
  • controlled for displacement by varying the direction of load; PTNs seem to directly control muscles.
    • Fire during acceleration and movement for no load
    • Fire during load and co-contraction when loaded.
  • FR also related to δF/δt : FR higher during a low but rising force than a high but falling force.
  • more than 100 PTN recorded from the precentral gyrus, but only 31' had clear and consistent relation to performance on the task.
    • 16 units on extension loads, 7 units flexion loads
    • It was only one joint afterall..
  • Cells responding to the same movement (flexion or extension) were often founf on the same vertical electrode tract.
  • Very little response to joint position.
  • Very clean moculations -- neurons are almost silent if there is no force production; FR goes up to 50-80Hz.
  • Prior to the exp Evart expected a position tuning model, but saw clear evidence of force tuning.
  • Group 1 muscle afferents have now been shown to project to the motor cortex of both monkey [1] and cat [9]. Make sense, as if the ctx is to control force, it needs feedback regarding its production.
  • Caveats: many muscles were involved in the study, mainly due to postural effects, and having one or two controls poorly delineates what is going on in the motor ctx.
    • Plus, all the muscles controlling the figers come into play -- the manipulandum must be gripped firmly, esp to resist extension loads.

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ref: Tehovnik-2006.08 tags: ICMS cortical microstimulation pyramidal neurons date: 12-20-2011 06:08 gmt revision:1 [0] [head]

PMID-16835359[0] Direct and indirect activation of cortical neurons by electrical microstimulation.

  • looked at ICMS via single-cell recording, behavior, and fMRI.
  • These properties suggested that microstimulation activates the most excitable elements in cortex, that is, by and large the fibers of the pyramidal cells.
    • this is a useful result to perhaps reference..

____References____

[0] Tehovnik EJ, Tolias AS, Sultan F, Slocum WM, Logothetis NK, Direct and indirect activation of cortical neurons by electrical microstimulation.J Neurophysiol 96:2, 512-21 (2006 Aug)

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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____

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ref: Fromm-1981.05 tags: Evarts pyramidal tract size principle movements date: 04-23-2007 04:25 gmt revision:2 [1] [0] [head]

PMID-6809905[0] Relation of size and activity of motor cortex pyramidal tract neurons during skilled movements in the monkey

  • there did not seem to be a "size principle" in the strict sense that this term has been used with reference to spinal cord motoneurons.

____References____

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ref: Wetts-1985.08 tags: Kalaska isometric motor control dentate cerebellum purkinje M1 pyramidal tract direction tuning date: 04-09-2007 19:54 gmt revision:0 [head]

PMID-3928831[0] Cerebellar nuclear cell activity during antagonist cocontraction and reciprocal inhibition of forearm muscles. by kalaska concering the interpositus dentate & isometric task.

  • the dentate nucleus sends afferents to the premotor areas. GABAergic inhibition from purkinje cells.
  • not so much tuning in the dentate nucleus as M1, but positive correlation was found.
  • Purkinje cells had a general low-order negative tuning to muscle activations.

____References____