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[0] BASMAJIAN JV, Control and training of individual motor units.Science 141no Issue 440-1 (1963 Aug 2)

[0] Pleger B, Blankenburg F, Ruff CC, Driver J, Dolan RJ, Reward facilitates tactile judgments and modulates hemodynamic responses in human primary somatosensory cortex.J Neurosci 28:33, 8161-8 (2008 Aug 13)

[0] Francis JT, Influence of the inter-reach-interval on motor learning.Exp Brain Res 167:1, 128-31 (2005 Nov)

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ref: -2017 tags: human level concept learning through probabalistic program induction date: 01-20-2020 15:45 gmt revision:0 [head]

PMID-26659050 Human level concept learning through probabalistic program induction

  • Preface:
    • How do people learn new concepts from just one or a few examples?
    • And how do people learn such abstract, rich, and flexible representations?
    • How can learning succeed from such sparse dataset also produce such rich representations?
    • For any theory of learning, fitting a more complicated model requires more data, not less, to achieve some measure of good generalization, usually in the difference between new and old examples.
  • Learning proceeds bu constructing programs that best explain the observations under a Bayesian criterion, and the model 'learns to learn' by developing hierarchical priors that allow previous experience with related concepts to ease learning of new concepts.
  • These priors represent learned inductive bias that abstracts the key regularities and dimensions of variation holding actoss both types of concepts and across instances.
  • BPL can construct new programs by reusing pieced of existing ones, capturing the causal and compositional properties of real-world generative processes operating on multiple scales.
  • Posterior inference requires searching the large combinatorial space of programs that could have generated a raw image.
    • Our strategy uses fast bottom-up methods (31) to propose a range of candidate parses.
    • That is, they reduce the character to a set of lines (series of line segments), then simply the intersection of those lines, and run a series of parses to estimate the generation of those lines, with heuristic criteria to encourage continuity (e.g. no sharp angles, penalty for abruptly changing direction, etc).
    • The most promising candidates are refined by using continuous optimization and local search, forming a discrete approximation to the posterior distribution P(program, parameters | image).

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ref: Zaghloul-2009.03 tags: DBS STN reinforcement learning humans unexpected reward Baltuch date: 01-26-2012 18:19 gmt revision:1 [0] [head]

PMID-19286561[0] Human Substantia Nigra Neurons Encode Unexpected Financial Rewards

  • direct, concise.
  • 15 neurons in 11 patients -- we have far more!

____References____

[0] Zaghloul KA, Blanco JA, Weidemann CT, McGill K, Jaggi JL, Baltuch GH, Kahana MJ, Human substantia nigra neurons encode unexpected financial rewards.Science 323:5920, 1496-9 (2009 Mar 13)

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ref: Foffani-2004.07 tags: STN motor preparation human 2003 basal_ganglia DBS SMA date: 01-26-2012 17:23 gmt revision:3 [2] [1] [0] [head]

PMID-15249649 Involvement of the human subthalamic nucleus in movement preparation

  • STN receives large afferent from SMA, so it should be involved in movement planning.
  • the STN and nearby structures are active before self-paced movements in humans.
  • normal patients show a negative EEG movement-related potential (MRP) starting 1-2 seconds before the onset of self-paced movements.
  • STN also shows premovement negative MRP.
    • REquire very sensitive methods to record this MRP -- it's on the order of 1 uv.
  • the amplitude of the scalp MRP is reduced in parkinson's patients.
    • impairment of movement preparation in PD may be related to deficits in the SMA and M1, e.g. underactivity.
    • the MRP is normalized with the administration of levodopa.
  • MPTP monkeys have increased activity in the STN
  • examined the role of the STN in movement preparation and inhibition via MRP recorded from DBS electrodes in the STN + simultaneously recorded scalp electrodes.
  • their procedure has the leads externalized during the first week after surgery.

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ref: Brown-2001.12 tags: EMG ECoG motor control human coherence dopamine oscillations date: 01-19-2012 21:41 gmt revision:5 [4] [3] [2] [1] [0] [head]

PMID-11765129[0] Cortical network resonance and motor activity in humans.

  • good review.
  • No coherence between ECoG and eMG below 12 Hz; frequency coherence around 18 Hz.
    • This seen only in high-resolution ECoG; lower resolution signals blurs the sharp peak.
  • Striking narrowband frequency of coherence.
  • ECoG - ECoG coherence not at same frequency as EMG-ECoG.
  • Marked task-dependence of these coherences, e.g. for wrist extension and flexion they observed similar EMG/ECoG coherences; for different tasks using the same muscles, different patterns of coherence.
  • Pyramidal cell discharge tends to be phase-locked to oscillations in the local field potential (Murthy and Fetz 1996)
    • All synchronization must ultimately be through spikes, as LFPs are not transmitted down the spinal cord.
  • Broadband coherence is pathological // they note it occurred during cortical myclonus (box 2)
  • Superficial chattering pyramidal cells (!!) firing bursts of frequency at 20 to 80 Hz, interconnected to produce spike doublets (Jefferys 1996).
  • Dopamine restores coherence between EMG and ECoG in a PD patient.

____References____

[0] Brown P, Marsden JF, Cortical network resonance and motor activity in humans.Neuroscientist 7:6, 518-27 (2001 Dec)

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ref: BASMAJIAN-1963.08 tags: original BMI M1 human EMG tuning operant control Basmajian date: 01-05-2012 00:49 gmt revision:6 [5] [4] [3] [2] [1] [0] [head]

PMID-13969854[0] Control and Training of Individual Motor Units

  • humans have the ability to control the firing rate of peripheral motor units with a high resolution.
  • "The quality of control over anterior horn cells may determine the rates of learning" yup!
  • "Some learn such esquisite control that they soon can produce rhythms of contraction in one unit, imitating drum rolls etc"
  • the youngest persons were among both the best and worst learners.
  • after about 30 minutes the subject was required to learn how to repress the first unit and to recruit another one.
    • motor unit = anterior horn cell, its axon, and all the muscle fibers on which the terminal branches of the axon end. max rate ~= 50hz.
    • motor units can be discriminated, much like cortical neurons, by their shape.
    • some patients could recruit 3-5 units altogether - from one bipolar electrode!
      • in playback mode (task: trigger the queried unit), several subjects had particular difficulty in recruiting the asked-for units. "They groped around in their conscious efforts to find them sometimes, it seemed, only succeded by accident"
    • some patients could recruit motor units in the absence of feedback, but they were unable to explain how they do it.
  • 0.025 (25um) nylon-insulated Karma alloy EMG recording wire.
  • feedback: auditory & visual (oscilloscope).
  • motor units have a maximum rate, above which overflow takes place and other units are recruited (in accord with the size principle).
  • "The controls (are) learned so quickly, are so esquisite, are so well retained after the feedbacks are eliminated that one must not dismiss them as tricks"

____References____

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ref: Penfield-1937 tags: Penfield 1937 motor cortex stimulation ICMS human neurosurgery electrodes date: 01-03-2012 22:08 gmt revision:3 [2] [1] [0] [head]

No PMID / bibtex penfield-1937. Somatic motor and sensory representation in the cerebral cortex of man as studied by electrical stimulation

  • Fritsch and Hitzig (1870) [0] cited as the first paper in electrical excitation of the CNS.
  • Good review of the scientific experiments thereafter, including stimulation to S1 by Ferrier, work with apes etc.
  • Central sulcus called the 'Rolandic fissure'.
  • Interesting! quote:

The account of Bartholow (1874) is interesting to say the least and may be cited. His patient was a 30-year old-domestic. As an infant this unfortunate had chanced to fall into the fire, burning her scalp so badly that " hair was never reproduced." A piece of whale bone in the wig she was forced to wear irritated the scarred scalp and, by her statement, three months before she was admitted, an ulcer appeared. When she presented herself for relief, this had eroded the skull over a space 2 in. in diameter " where the pulsations of the brain are plainly seen." Although " rather feeble-minded " Bartholow observed that Mary returned replies to all questions and no sensory or motor loss could be made out in spite of the fact that brain substance apparently had been injured in the process of evacuation of pus from the infected area. The doctor believed, therefore, that fine insulated needles could be introduced without further damage.

While the electrodes were in the right side Bartholow decided to try the effect of more current. ' Her countenance exhibited great distress and she began to cry. Very soon the left hand was extended as if in the act of taking hold of some object in front of her; the arm presently was agitated with clonic spasms ; her eyes became fixed with pupils widely dilated ; the lips were blue and she frothed at the mouth ; her breathing became stertorous, she lost conscious-ness and was violently convulsed on the left side. This convulsion lasted for five minutes and was succeeded by coma. She returned to consciousness in twenty minutes from the beginning of the attack and complained of some weakness and vertigo." Three days after this stimulation, following a series of right-sided seizures, the patient died.

  • Relatively modern neurosurgical procedures.
  • They observe changes to blood circulation prior epileptic procedures. wow!
  • Very careful hand-drawn maps of what they have observed. Important, as you'll probably never get this trough an IRB. It pays to be meticulous.

____References____

[0] Fritsch G, Hitzig E, Electric excitability of the cerebrum (Uber die elektrische Erregbarkeit des Grosshirns).Epilepsy Behav 15:2, 123-30 (2009 Jun)

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ref: -0 tags: abortion religion human economics date: 03-14-2011 18:19 gmt revision:1 [0] [head]

http://www.chapel.duke.edu/documents/Feb13ChoosingLifeandLivingwithChoices.pdf

This is a good sermon with a lot of good points (gasp! did an atheist just say that?), and is making me think hard -- or at least hard enough to write down how I feel on abortion.

I agree with the pastor that the community does seem at fault for not helping women whose 'unwanted' pregnancies might be wanted if there was more social support. I guess, atheist that I am, that religion has a strong and good role here by providing the impetus to make people be more cohesive and behave morally better. IMHO Thoreau-inspired mental integrity and thoughtful examination are another (better?) way to get there, but perhaps religion is a cultural shortcut to the same end, hence valuable. (As an aside, I'm irked by the repeated phrase that 'they need the church'. Seems like the church is the needy one here - if what it offers is valuable, it need not insist. A second irritation is that the church sometimes misappropriates credit/importance: things that a community of good people create (e.g. support for single mothers) the church assumes primary credit for. You preach humility, show some.)

I doubt women abort have children out of shame, as he suggests. More likely the mother understands the complex economies and timing of raising a child; presumably, in situations where an abortion is considered the mother could hope to have another child later, when she could support and raise he/she better - give he/she a happier life with more love to share to others. Are lives exchangeable in this way? You make these choices implicitly every time you choose not to have unprotected sex with someone - exchanging the possibility of creating a life presently with the possibility of creating an even better life later. This is normal and good, the point of decision has just been moved albeit utilitarian ... and of course utilitarianism is limited, because things aren't linear or monotonic. If we treat even unwanted pregnancy with 'mischievous joy' (i like that) as he suggests, perhaps the attitude of sacred life itself guarantees a happier existence than the attitude of exchangeable life. More basically: despite the logic above I intuitively and instinctively find the thought of killing anything remotely human horrific.

But, we kill things all the time. We kill (are killing..) solders in war. We kill a lot of pigs, which (this is a very iffy argument here) have as much if not more capability for suffering and pleasure than a very young fetus. And then we eat them. We, loosely and implicitly, kill people by not sending an section of our income to buy medicine, food - this to grown people with families, friends and standing importance. Is their death worse than the death of a fetus? My brain tells me that there is a continuum of existence and meaning, and in this messy realistic world, we have to admit ordering and make compromises; my soul still hates this fact.

Ultimately, human happiness and suffering, life and death, cannot be completely reduced to a utilitarian calculus. In such a calculus we should aim to optimize the total joy in the world, minus the pain and dread, integrated over lifetimes and people. To a rough and imperfect scale that is what we do, in our personal lives and more broadly. Treating all human lives as equal is an idea of both democracy and religion that makes the calculus balanced and fair, and allows us to derive usable laws and stable societies (integrated joy...), but it seems to break down in the case of abortion. This is why I think the oft myopic and special-interest swayed government should have no say in a woman's choice; if I can't come up with a solid reason either way, why should the government?

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ref: -0 tags: evolutionary psychology human mating sexuality discrimination wedlock date: 01-09-2011 18:22 gmt revision:1 [0] [head]

From Why Beautiful people have more daughters:

"Abuse, degradation, and intimidation are all part of men's unfortunate repertoire of tactics employed in competitive situations. In other words, men are not harassing women because they are treating them differently than men (which is the definition of discrimination under which harassment legally falls), but the exact opposite: men harass women because they are not discriminating between men and women."

Interesting argument. But in sexual discrimination cases, the women are not being treated the way they want to be treated - this is more a problem than the inequality.

The author then goes on to pose that current sexual discrimination law and policy in US corporations actually inhibits welcome sexual/romantic interest/advances. Many people do find partners at work. Again, I beg to differ: if there is passion between people, things will fall as they should; if policy and culture serves to make this more civilized (provided it's not completely inhibited, as the author suggests), then all the better.


In related news: An Analysis of Out-Of-Wedlock Births in the United States

Central hypothesis: Contraceptive technology shifted the balance of power between the sexes: prior the pill, women could force the men into promising to marry; in the case of preganancy, cultural standards forced marriage - shotgun marriage. Men accepted these terms because they were uniform across all women - sex implies pregnancy implies child rearing. When contraception became available, this was decoupled, as sex did not beget pregnancy; those women who negotiated on the old terms were likely to lose their mate, hence shotgun marriages (the result of such negotiations) gradually disappeared from culture.

The author generally approves of the idea of shotgun marriage, and suggests that a governmental body should enforce a form of it through child support payments. Presently about 40% of children in the US are born out of wedlock.


Finally, Serial monogamy increases reproductive success in men but not in women. It rests upon data, only recently gathered, that supports that having multiple partners increases reproductive success more strongly in male than in female humans. This implies that the variance of the fertility of men should be higher than that of women - again, which is borne out in the data, but only weakly: men have 10% higher variance in # of offspring than women. This effect is correlated to serial monogamy - "Compared with men with 1 spouse, men with 3 or more spouses had 19% more children in the total sample". This did not hold with women, nor did varying spouse number in men change the survival rate of their offspring.


Irregardless, this reading was spurred by someone mentioning that a genetic analysis of human populations reveals that while 80% of women reached reproductive success, only 40% of men did - implying that historically a few more successful men fathered a large fraction of children. I was unable to find evidence to support this on the internet (and indeed the Behavioral Ecology article gives much less dramatic figures), but it makes intuitive sense, especially in light of some patterns of male behavior.

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ref: Gilbert-2009.03 tags: human prediction estimation social situation neighbor advice affective forecasting date: 06-10-2009 15:13 gmt revision:2 [1] [0] [head]

PMID-19299622[0] The Surprising Power of Neighborly Advice.

  • quote (I cannot say this any better!): "People make systematic errors when attempting to predict their affective reactions to future events, and these errors have social (1–3), economic (4–8), legal (9, 10), and medical (11–22) consequences. For example, people have been shown to overestimate how unhappy they will be after receiving bad test results (23), becoming disabled (14, 19–21), or being denied a promotion (24), and to overestimate how happy they will be after winning a prize (6), initiating a romantic relationship (24), or taking revenge against those who have harmed them (3). Research suggests that the main reason people mispredict their affective reactions to future events is that they imagine those events inaccurately (25). For example, people tend to imagine the essential features of future events but not the incidental features (26–28), the early moments of future events but not the later moments (17, 24), and so on. When mental simulations of events are inaccurate, the affective forecasts that are based on them tend to be inaccurate as well."
  • solution, ala François de La Rochefoucauld: "Before we set our hearts too much upon anything," he wrote, "let us first examine how happy those are who already possess it"
    • this is surrogation ; it relies not on mental simulation, hence is immune to the associated systematic errors.
    • problem is that people differ. paper agues that, in fact, they don't all that much - the valuations & affective reactions are produced by evolutionarily ancient physiological mechanisms. Furthermore, people's neighbors, friends, and peers are likely to all be similar in personality and preference via self-selection and social reinforcement - hence their reactions to a situation will be similar.
  • They used a speed-dating scenario in their experiments, from which they observe: "Women made more accurate predictions about how much they would enjoy a date with a man when they knew how much another woman in their social network enjoyed dating the man than when they read the man's personal profile and saw his photograph."
  • Next, they employ personality-evaluation "Men and women made more accurate predictions about how they would feel after being evaluated by a peer when they knew how another person in their social network had felt after being evaluated than when they previewed the evaluation itself."
  • Conclusion: "But given people's mistaken beliefs about the relative ineffectiveness of surrogation and their misplaced confidence in the accuracy of their own mental simulations (39), it seems likely that in everyday life, La Rochefoucauld's advice—like the advice of good neighbors—is more often than not ignored.
  • Editorializing: I'm not quite convinced that 'neighborly advice' is an accurate predictor of our absolute reaction to a situation as much as it socially informs us of reaction we are *supposed* to have. Society by consensus - that's what some of my European friends dislike about (some parts of) American culture. They need to run some controls in other cultures (?)

____References____

[0] Gilbert DT, Killingsworth MA, Eyre RN, Wilson TD, The surprising power of neighborly advice.Science 323:5921, 1617-9 (2009 Mar 20)

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ref: Shadmehr-1997.01 tags: Shadmehr human long term memory learning motor M1 cortex date: 03-25-2009 15:29 gmt revision:2 [1] [0] [head]

PMID-8987766[0] Functional Stages in the Formation of Human Long-Term Motor Memory

  • We demonstrate that two motor maps may be learned and retained, but only if the training sessions in the tasks are separated by an interval of ~5 hr.
  • Analysis of the after-effects suggests that with a short temporal distance, learning of the second task leads to an unlearning of the internal model for the first.
  • many many citations!

____References____

[0] Shadmehr R, Brashers-Krug T, Functional stages in the formation of human long-term motor memory.J Neurosci 17:1, 409-19 (1997 Jan 1)

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ref: Mamassian-2008.06 tags: overconfidence human motor learning date: 02-17-2009 17:51 gmt revision:0 [head]

PMID-18578851 Overconfidence in an objective anticipatory motor task.

  • Participants were asked to press a key in synchrony with a predictable visual event and were rewarded if they succeeded and sometimes penalized if they were too quick or too slow.
  • If they had used their own motor uncertainty in anticipating the timing of the visual stimulus, they would have maximized their gain.
  • However, they instead displayed an overconfidence in the sense that they underestimated the magnitude of their uncertainty and the cost of their error.
  • Therefore, overconfidence is not limited to subjective ratings in cognitive tasks, but rather appears to be a general characteristic of human decision making. interesting! but is overconfidence really so bad?

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ref: Pleger-2008.08 tags: S1 reward fMRI human date: 10-07-2008 23:06 gmt revision:1 [0] [head]

PMID-18701678[0] Reward facilitates tactile judgments and modulates hemodynamic responses in human primary somatosensory cortex.

  • "Remarkably, primary somatosensory cortex contralateral to the judged hand was reactivated at the point of reward delivery, despite the absence of concurrent somatosensory input at that time point."
    • hence, it is probably rostral to the central sulcus too.
  • the same as http://m8ta.com/index.pl?pid=630
  • rewarded humans with $
  • people had to discriminate the frequency of electrical stimulation to their left/right index fingers. i guess a vibrator would have been hard in the magnet of an MRI machine.
  • reward cue was visually instructed.
  • reference Janaina's paper. http://www.jneurosci.org/cgi/content/full/27/39/10608

____References____

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ref: Francis-2005.11 tags: Joe_Francis motor_learning reaching humans delay intertrial interval date: 04-09-2007 22:48 gmt revision:1 [0] [head]

PMID-16132970[0] The Influence of the Inter-Reach-Interval on Motor Learning.

Previous studies have demonstrated changes in motor memories with the passage of time on the order of hours. We sought to further this work by determining the influence that time on the order of seconds has on motor learning by changing the duration between successive reaches (inter-reach-interval IRI). Human subjects made reaching movements to visual targets while holding onto a robotic manipulandum that presented a viscous curl field. We tested four experimental groups that differed with respect to the IRI (0.5, 5, 10 or 20 sec). The 0.5 sec IRI group performed significantly worse with respect to a learning index than the other groups over the first set of 192 reaches. Each group demonstrated significant learning during the first set. There was no significant difference with respect to the learning index between the 5, 10 or 20 sec IRI groups. During the second and third set of 192 reaches the 0.5 sec IRI group's performance became indistinguishable from the other groups indicating that fatigue did not cause the initial poor performance and that with continued training the initial deficit in performance could be overcome.

____References____