Talk:Central pattern generator

Untitled

This article requires some updating for the references which are not appropriately quoted; i.e. 27 does not exist and 26 is not the right reference. Looks like there was a shift at some point...Sebzskp (talk) 13:47, 28 October 2010 (UTC)

Feel free to improve the article in any way that seems good to you. Looie496 (talk) 16:26, 28 October 2010 (UTC)

This article is jargon and jibberish. I have read it several times and I find it incomprehensible. Is there no way to describe what's happening without resorting to terms not defined? If this was dealing with any subject other than Biology, it would be cited as too technical and more explanation be required. RDXelectric (talk) 12:03, 13 July 2018 (UTC)

Neuromodulation

In this part, the division into three subdivisions seems not to be justified, as all of them are treating quite the same, with only different accents. --77.191.235.22 (talk) 20:53, 18 December 2011 (UTC)

Formatting subheadings

Neuromechanics, with all due respect, I don't think you are familiar with the editing and formatting process of WP. Look at your latest edit and look at the current contents table. As a result of your edit, the mammalian heading is now at a higher level than the locomotion heading. I don't think this is your intention. Second, WP is NOT the place for original research WP:OR. You should be selecting references from secondary sources and summarizing their contents here. You should NOT be synthesizing information from primary sources. Please see WP:V. Many of the sources that you provided are primary sources, which may are appropriate in a peer-reviewed journal article or scholarly thesis, but not in WP. Finally, you need to resolve the copyright issue of that image that you inserted into this article. These issues must be resolved. Otherwise, the edits will be reverted. danielkueh (talk) 00:27, 13 December 2012 (UTC)

Thanks for spotting my formatting error. I saw it too and corrected it, probably just as you were putting your message together. Re. primary and secondary sources, this is confusing. How do the references I've used (articles in scientific journals) differ from all the other articles in scientific journals referenced on this page? I checked out WP:V and didn't see anything there against citing such papers. Please clarify.

Re. the figure, it's based on a figure published in the American Handbook of Physiology, but it's been extensively modified from the original, including the structure of the control loop itself.

Finally, I'm unfamiliar with the mechanism for responding to editors' criticisms. Is this the way to do it? I couldn't find any instructions on how to go about this on WP. I went to your talk page, but couldn't see how to correspond with you. Thanks v much. — Preceding unsigned comment added by Neuromechanics (talk • contribs) 00:50, 13 December 2012 (UTC)

Neuromechanics, 1) Go to WP:OR, specifically WP:primary (this section is within WP:OR). You will find WP's policies on the use of primary and secondary sources. Primary sources can be used but only under VERY limited circumstances. Your description of locomotion in mammals is quite extensive and does involve interpretation. But you have to rely on a secondary source when providing interpretations. To keep it simple, avoid primary sources when possible. 2) For the figure, you need to respond to the blue tag on the figure's page. Otherwise, that figure will be deleted on Dec 17, 2012 by WP bots. 3) Yes, all discussions about making edits to a WP article should be made on the WP article's talk page. Correspondence that are personal or that are not germane to improving or editing a WP article should be made on a user's talk page instead. Also, please indent your responses to another editor's comments by adding colons to the first sentence of each paragraph. Also, do not forget to sign your name by adding four tildes at the end of your response. Hope this helps. Regards. danielkueh (talk) 01:05, 13 December 2012 (UTC)

Danielkueh, thanks for the clarification and pointing me to WP:primary. I didn't realise that WP discourages references to regular scientific papers. I'll replace these with reviews that discuss the same material. It seems a bit odd, because in order to discuss author A's study, I have to refer to author B's interpretation of author A's study, which author A may not even agree with. Oh well, it is what it is. I may not get to this for a few days so please bear with me. Re. the figure, thanks for the warning, I'll respond to the blue tag. I'm assuming that this was the right place to respond to you. Regards, Neuromechanics (talk) 04:25, 13 December 2012 (UTC)

Neuromechanics, the easiest solution is to just avoid mentioning specific studies and just focus on basic principles. Unless of course the study is of great historical significance (e.g., Watson and Crick). Most of the time, detailed descriptions of this study and that study are overkill for a WP article. Just write it for a non-technical audience and that should be fine. Regards. danielkueh (talk) 14:21, 13 December 2012 (UTC)

I have said it before and I say it again: The rules regarding references are flawed, essentially circular logical fallacies. I can't decipher this article, as I have said, it is jargon and jibberish, so I followed the link to a reference cited here to see if it was better. And to my considerable amusement I discovered that the article states that the majority of references are wrong.

" Almost ninety years ago, Brown [1] suggested that the alternate flexion and extension of leg muscles in walking could be produced by rhythmic central circuits in which the antagonistic muscles were driven by neurons that inhibited each other. Nonetheless, the spinal reflex has dominated a century of textbooks, and many biologists labor under the misconception that rhythmic movements are produced by reflex activation, rather than by central circuits."

What is the fallacy of who said it rather than what they said? That's what the WP rules do, value that someone (anyone) has said it rather than IS IT TRUE. And another thing: I own a set of the Encyclopedia Britannica and I have had occasion to read articles in it, including one on the U.S. State of Texas. What is interesting about it is this: that article is ORIGINAL RESEARCH. Yes it refers to other sources for specific statistical facts and such but the bulk of the article is one man's scholarly work. Why does WP seek to cripple itself with misguided, pedantic or half-baked rules? Isn't there something called the Bonehead Award? We have a candidate. RDXelectric (talk) 05:52, 18 July 2018 (UTC)

Useful source

A useful source for updating information, freely available, may be Marder, E & Bucher, D (2001). Central pattern generators and the control of rhythmic movements. Current Biology, 11, R986-996. http://www.cell.com/current-biology/abstract/S0960-9822(01)00581-4 TristramWyatt (talk) 12:15, 10 December 2015 (UTC)

That's a bit antiquated but, yes, still possibly useful. Looie496 (talk) 13:42, 10 December 2015 (UTC)

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I just tried clinking the link, http://www.bio.brandeis.edu/biomath/mike/network.html and it failed. RDXelectric (talk) 06:01, 18 July 2018 (UTC)

Introduction

This article begins with the following:

Central pattern generators (CPGs) are biological neural circuits that produce rhythmic outputs in the absence of rhythmic input.[1][2] They are the source of the tightly-coupled patterns of neural activity that drive rhythmic motions like walking, breathing, or chewing. Importantly, the ability to function without input from higher brain areas does not mean that CPGs don’t receive modulatory inputs, or that their outputs are fixed. Flexibility in response to sensory input is a fundamental quality of CPG driven behavior. [1][2]

However, this implies that CPGs are identifiable as such, but in fact CPGs cannot be found and may not exist as separate entities but rather are functions of the spinal nerves or other ganglia.

As far as being tightly-coupled patterns, there are alternative models which suggest that CPGs are "a filter for processing sensory information rather than a generator of commands." If we consider walking as an example, the question arises, "What determines the periodicy of the gait?" If a purely feed-forward, command driven system is assumed then there is no way to synchronize with the natural mechanical period of the legs. If these two systems are not synchronized, energy is lost in forcing the legs to conform to the driven cycle. Logically, wasting energy should not happen, so the CPGs must be receiving sensory input to set the timing of the motor commands.

Kuo also argues that a feedforward command function behaves poorly in cases of unexpected disturbances to the rhythm, adding that a feedback component is necessary to deal with such occurrences. The feedforward function is necessary to generate the fictive movements that are known to arise from CPGs and to keep the rhythm going when the feedback information is noisy and the feedback function is necessary to respond to stumbles and other physical interruptions to the gait.

In the simplest case of one CPG controlling one motor neuron, it would be possible to identify a small set of neurons comprising the CPG. However in the actual situation there are many muscles being driven in synchronized sequences in different phases of the cycle suggesting there are many neurons contributing to the CPG and making localization impossible. Dr. Peggy Mason, professor of Neurobiology at the University of Chicago, describes "Central Pattern Generator" as a conceptual term and one of the reasons is that they cannot be found. It may be that all of this distributed network is working together as a unit. This configuration could easily adjust to different demands (running vs. walking) where the precise phasing and strength of the muscle contraction would differ but the basic neural circuits remain the same.

All in all, looking at the subject of CPGs from an engineering point of view adds understanding because while biology can describe the what and where of the subject, engineering casts light on the how.

RDXelectric (talk) 21:53, 21 July 2018 (UTC)

References

Proposed addition at the end of the "Locomotion" section

Network of coupled non-linear oscillators implementing an artificial pattern generator for controlling the locomotion of an insect-like robot. The connections within the CPG encode certain canonical gaits, and the LPGs realize the transformation from the gait information to the leg trajectories.

The design of artificial, mainly electronic, implementations of CPGs has received considerable attention in the community of bio-inspired robotics. The interest stems mainly from the fact that CPG-like circuits and architectures can solve complex problems, such as the adaptive generation of trajectories for insect-like robots, at a much lower computational cost compared to conventional approaches based on forward and inverse kinematic models. A wide variety of such locomotion controllers have been realized, adapted to biped, quadruped, hexapod and even swimming robots. One possible approach is predicated on the notions of connectionism and emergence, and hinges around creating a network of coupled non-linear oscillators, whose connections are modulated to obtain the sustained generation of a locomotion pattern of interest. Similarly to their biological counterparts, such circuits intrinsically oscillate in a periodic manner, namely generate limit cycles, under the influence of afferences from sensory inputs and "higher areas". One example of a small-sized but versatile generator for controlling an insect-like robot was demonstrated based on 24 non-linear electronic oscillators.

( Lminati (talk) 15:25, 12 March 2019 (UTC) )

References