Thanks for the explanation Jeff, it's a fascinating topic. Our hackathon project is going to be about motor control actually, so I've been thinking about and playing with the idea for some time now. I'm sure your talk will be very useful to us :)
On Fri, Oct 25, 2013 at 1:52 PM, Jeff Hawkins <[email protected]> wrote: > In every region of the cortex there are cells in Layer 5 that project > someplace else in the brain that is related to motor behavior. (At least in > every region people have looked.) In the classic “motor” regions the layer 5 > cells project to muscles, or spinal cord, in vision areas they project to the > superior colliculus which controls eye movement, etc. This tells us that > most (if not all) regions of the cortex are playing a role in motor behavior. > This is one reason why I think we can attack the sensorimotor problem by > initially modeling a single region. > > The axons from the layer 5 motor cells split and send a branch up the > cortical hierarchy. So the “motor command” coming from layer 5 is also an > input to the next region. When the next region learns patterns and makes > predictions part of its input is the motor commands that the lower region is > sending to motor areas. > > One twist is the feedforward motor signal is gated in the thalamus. So it > doesn’t always go to the next region. Presumably this is controlled as part > of attention. > > Remember that layer 3 is the primary feedforward inference layer, it is the > model for the CLA. My guess is that layer 5 and layer 3 are entrained by > columns and therefore layer 5 is learning a sequence similar to layer 3. > > I believe that the layer 5 cells associatively link to subcortical motor > centers. They are just like the cells in the layer 3 CLA, they represent the > state of the system, but they learn how control behavior by association. I > can explain this better but it takes more time than I have now. > > I can walk through some simple examples of how a region sits on top of a body > which has sensors and innate motor behavior. The region learns to model the > patterns of the body as it interacts with the world through its innate > behaviors. Then the region’s layer 5 cells associatively link to control the > innate behavior. Now the region is able to control behavior. If the region > learns complex patterns that result in desirable outcomes it can replay those > complex patterns (essentially new complex behaviors) to make the desired > outcome happen again. This is a form of “reinforcement learning”. > > Where I am struggling is how to set goals and how the system can adjust its > behavior as it plays back learned behaviors. > > Jeff > > Here is a paper on how the layer 5 neurons split. > http://shermanlab.uchicago.edu/files/rwg > <http://shermanlab.uchicago.edu/files/rwg&sms%20BRR%202010.pdf> > &sms%20BRR%202010.pdf > > > From: nupic [mailto:[email protected]] On Behalf Of Chetan > Surpur > Sent: Friday, October 25, 2013 10:36 AM > To: NuPIC general mailing list. > Cc: NuPIC general mailing list. > Subject: Re: [nupic-dev] motor implementation > > Hi Jeff, > > Just as briefly, would you mind describing from how region 5 helps accomplish > this? Unless you want to save it as a surprise for your talk :) > > Thanks, > Chetan > > On Fri, Oct 25, 2013 at 10:30 AM, Jeff Hawkins <[email protected]> wrote: > Aseem, > I will be giving an informal talk on this topic at the next hackathon, but > in brief, very brief... > The CLA today has no motor component. It is like an ear listening to sounds > but with no ability to interact with the world. Most sensory perception is > not like that. Most of the changes on our sensors come from our own > actions. Imagine standing in a house. If your eyes couldn't move and your > body couldn't move you would not be able to learn what the house is like. > You couldn't learn the patterns in the world. Only be moving do you > discover the structure of the house. Movement leads to sensory changes. > The brain learns sensorimotor patterns. "when I see this and turn left I > will see that". The same is true for touch. Even hearing is largely > controlled by our own motions. The only thing I am hearing right now is the > sounds of the keys on my keyboard. My cortex is predicting to hear those > sounds. If they changed even slightly I would notice the difference. > Motor behavior is how we learn most of the structure of the world. > Jeff > -----Original Message----- > From: nupic [mailto:[email protected]] On Behalf Of Aseem > Hegshetye > Sent: Friday, October 25, 2013 5:37 AM > To: [email protected] > Subject: [nupic-dev] motor implementation > Hi, > Jeff Hawkins said he is working on sensorimotor design. > How will implementation of motor layer 5 help in data prediction. > Would it be like CLA signalling anomalies like cortex gives motor commands > or are you planning on manipulating some parameters at user end based on the > predictions from given inputs. > thanks > Aseem Hegshetye > _______________________________________________ > nupic mailing list > [email protected] > http://lists.numenta.org/mailman/listinfo/nupic_lists.numenta.org > _______________________________________________ > nupic mailing list > [email protected] > http://lists.numenta.org/mailman/listinfo/nupic_lists.numenta.org >
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