Connectionists: how the brain works? (UNCLASSIFIED)

[Juyang Weng]

Troy,

As far as I am aware, what we called vigilance is fully automatically
determined by the biological brain in a dynamic way, and it is not a 
single parameter and is not static either.
There are at least 5 mechanisms for each neuron in DN that affect so 
called vigilance:

(1) Goodness of match of bottom-up source:
How does the bottom-up feature of the neuron match the current sensory 
input?  ART has that.

(2) Goodness of top-down source:
How does the top-down feature of the neuron match the motor input (does 
the neuron fit the current attention)?
ART does not seems to have that.   ART uses top-down for sequential 
one-by-one search for an acceptable match.

(3) The competition through inhibitory and excitatory connections with 
other neurons.
This leads to sparse coding or a reduced number of concurrently firing 
neurons.
ART does not seem to have such fast competition.

(4) Modulation effect 1: Reinforcement (punishments and rewards):
Does the bottom-up sensory input and top-down sensory input corresponds 
to an important event?
By important, I mean, e.g., it can directly related to a past punishment 
(e.g., an electric shock) or past reward (e.g., food).
Vigilance to such a punishment or reward event will be higher.
The serotonin and dopamine systems participate such reinforcement.
ART does not seem to have that.

(5) Modulation effect 2: novelty.  E.g., How long have I attended this 
event?
This is what is called novelty, related to sensitization and 
habituation, and the sense of novelty in general.
If I attend the event for long, the novelty goes down.
The ACh and NE systems participate in such novelty evaluation.
ART does not seem to have that.

-John

On 4/8/14 9:14 AM, Kelley, Troy D CIV (US) wrote:
> Classification: UNCLASSIFIED
> Caveats: NONE
>
> Steve,
> -------
>
> In particular, during learning, a big enough mismatch can lead to hypothesis
> testing and search for a new, or previously learned, category that leads to
> an acceptable match. The criterion for what is "big enough mismatch" or
> "acceptable match" is regulated by a vigilance parameter that can itself
> vary in a state-dependent way.
>
> -------
>
> In our work with ART, we have found the vigilance to be an extremely
> sensitive parameter.  I wonder if there would be some way to change this
> calculation to keep the vigilance from being so sensitive?  There seemed to
> be a sweet spot for the parameter to work well with the learned material but
> that was sometimes difficult to find.
>
> Also, it seems to me from my work in developmental cognition that this
> parameter might benefit from being incrementally adaptive.  In other words,
> it changes from repeated exposure to learned material.  So early during
> learning, the criterion for a "big enough mismatch" is low, and as learning
> develops the criterion becomes higher - reflecting the fact that more
> information is being learned and there is less likely a chance for a big
> mismatch.
>
> Troy Kelley
> Cognitive Robotics Team Leader
> Human Research and Engineering Directorate
> Army Research Laboratory
> Aberdeen, MD, 21005
> V: 410-278-5869
>
>
>
> Classification: UNCLASSIFIED
> Caveats: NONE
>
>

-- 
--
Juyang (John) Weng, Professor
Department of Computer Science and Engineering
MSU Cognitive Science Program and MSU Neuroscience Program
428 S Shaw Ln Rm 3115
Michigan State University
East Lansing, MI 48824 USA
Tel: 517-353-4388
Fax: 517-432-1061
Email: weng at cse.msu.edu
URL: http://www.cse.msu.edu/~weng/
----------------------------------------------