[esnr] Re: AW: Re: an interesting week for neurofeedback

  • From: Wolfgang Keeser <wolfgangkeeser@xxxxxxx>
  • To: esnr@xxxxxxxxxxxxx
  • Date: Mon, 11 Oct 2004 20:34:46 +0200

thanks making this available to the list. In all my courses I enforce the importance of PRS and show them Barry's slides and motivate the participants to record simultaneously the dominant frequency (where the PRS shows up most prominent) parietally to see if what a client is doing during a session may have a lasting effect. The crux is, that most of the available software is not written or conceptualized by clinicians


Am 11.10.2004 um 20:23 schrieb reitsma:

<x-tad-bigger>Dear Group,</x-tad-bigger>

<x-tad-bigger> </x-tad-bigger>

<x-tad-bigger>Interesting doesn’t mean always important.</x-tad-bigger>

<x-tad-bigger>Please read the comments of David Kaiser on this topic</x-tad-bigger>

<x-tad-bigger> </x-tad-bigger>

<x-tad-bigger> </x-tad-bigger>

<x-tad-bigger>Newsweek featured a short article on neurofeedback this week.</x-tad-bigger>

<x-tad-bigger> Unfortunately, what caught the eye of the science writer was less science than entertainment. They featured once again a system which plays a videogame with brainwaves. Neurofeedback needs to train the brain, not entertain. Too many people feel the need to motivate the client to return with ephemoral rewards</x-tad-bigger>


<x-tad-bigger>buzz and blips-instead of the solid rewards of mental health.</x-tad-bigger>

<x-tad-bigger> A few years ago a NASA-derived company, or so they called themselves, had a similar set up, and they went belly up pretty quickly. Why? For whatever reasons they told their shareholders, but I suspect any system that simply alters gameplay of videogames cannot train the brain, at least not efficiently. Why?  Because it isn't operant conditioning (OC), at least it mightily avoids the primary goal of OC which is discrimination.</x-tad-bigger>

<x-tad-bigger> Operant conditioning increases the tendency of one and only one response in favor of all others to a stimulus. This is done by rewarding one behavior above all others, to the detriment of those near-neighbors. When a pigeon is trained to peck a light, pecking the wall nearby, or flapping a wing, or nuzzling the food magazine  -- none of these behaviors are rewarded with a pellet drop. If they were, the bird brain would continue his or her non-goal behavior. In neurofeedback, we want, say, increases in SMR, and need to reward only that.  But with an elaborate videogame going on-essentially whatever brainwaves that occur in response to any visual stimulation is being conditioned. It's jumping on the videogame addiction bandwagon to get clients into the office. We routinize poor children's brains into these inflexible states by allow such immersion into these video games. How can math and reading compete, with their slower, less frequent reward schedules. Skinner realized all of this decades ago, using rats and pigeons, but a quick primer on Operant Conditioning might help for those who missed it.</x-tad-bigger>

<x-tad-bigger> Operant conditioning works by associating reward with desired behaviors. Optimally we should place electrodes into the pleasure center of the hypothalamus and turn on the juice whenever a targeted behavior is performed and turn it off when it isn't. This on/off dichotomy is reflected in discrete exercises (not so much in continuous reward games like the ones often featured by magazines).</x-tad-bigger>

<x-tad-bigger>  </x-tad-bigger>

<x-tad-bigger>Animation, or any visual excitement prior to or after the criterion behavior is performed, undermines conditioning as it rewards non-criterion behavior, whatever the brain is doing at that moment.</x-tad-bigger>

<x-tad-bigger> Continuous reward information is only useful during shaping, when a person has difficulty eliciting or maintaining a desired behavior, and then only to successive approximations to the goal behavior. But once this obstacle is overcome, once a person can reliably perform the behavior requested of him or her, continuous reward will weaken the association between stimulus and response. As I said already, the goal of operant conditioning is discrimination. Discrimination emerges out of generalization by the means of FOCAL association, strong linkages between response and reward.</x-tad-bigger>

<x-tad-bigger> BF Skinner figured this all out 50 years ago: punishment and reinforcement, both positive and negative, reinforcement schedules, contingencies, informative signals, noninformative ones, primary reinforcers, secondary reinforcers, spontaneous recovery, shaping, extinction curves. Positive reinforcement is when an appetitive stimulus (a rewarding one like food) is provided. Negative reinforcement, despite the oxymoronic name, is also a good thing-an aversive stimulus is removed (and thus rewarded). We drop a coin into a vending machine and receive an item: that's positive reinforcement. We fasten our seat belts when we get into the car to stop an annoying buzzer: that's negative reinforcement. I know the wording is perverse, but it's Skinnerian. There is also negative punishment (withholding a positive reward) and positive punishment (providing an aversive one) although I don't think, of all the aspects of learning theory we have, that scientists have fully understand all the components and aftermath of punishment. I tell my students how the environment includes the punisher for punishment but not for reinforcement, so that the behavioral tendency is increased universally with reward but only diminished in the presence of the punisher or ones like him or her for punishment.  Maybe I'm wrong, but I have yet to read a convincing case for the converse equality of reinforcement and punishment.</x-tad-bigger>

<x-tad-bigger> The most effective reinforcement schedule for task acquisition is to reward every instance. Unfortunately this is also the schedule which is most easy to snuff out once the reward is withheld. So if you reward your kids every time they clean their rooms, for instamce, once you stop paying them, they will stop cleaning. But if you work on a partial reinforcement schedule, and reward them after every third or fourth cleaning, they will continue to work much longer after the reward has stopped. This is called resistance to extinction and it's one goal of neurofeedback because the bells and blips will not be available forever to the client.</x-tad-bigger>

<x-tad-bigger> There are four partial reinforcement schedules: variable ratio and variable interval, and fixed ratio and fixed interval. The variable ratio schedule (VR) is the best. More than any reinforcement schedule, VR speeds task acquisition and tasks acquired with it resist extinction. VR built Las Vegas out there in the desert, and it is quite visible in slot machines. For VR, the individual is rewarded on average after some amount of behavior. In slot machines VR may be set to every 50 or 100 pulls. As long as the payoff is appropriate for the schedule rate, an individual will repeat the behavior indefinitely. Slot machines layer multiple VR schedules on top of each other to produce behavior quickly acquired and extremely resistant to extinction. Large payoffs occur infrequently (but predictably in a statistical sense) and smaller payoffs occur frequently (and predictably again, in a statistical sense).</x-tad-bigger>

<x-tad-bigger> Predictably in the sense that a $1 million payoff occurs on average after every 100 million pulls or so. All games should incorporate multiple reinforcement schedules by the use of multiple layers of reward, be it screen completion, bonus scores, or sudden completion of task. More important than the schedule is reward delivery, which should be discrete like the hypothalamic shocks to rats I mentioned above. Those rats literally died from starvation because they stimulated their brain rather than sought food. That is the best advertisement and evidence of the power of discrete rewards. Had the shocks come about regardless of their actions, with peaks and valleys of activity perhaps as they came near the bar they were suppose to press, then food consumption would have been option. But they all died, because the rewards were discrete and focal.</x-tad-bigger>

<x-tad-bigger> Finally, one last aspect of operant conditioning is the stage of immediate consolidation, the sensory pause after a reinforcement has been given in order to strengthen the linkages between behavior and response, and presumably to weaken the linkages with other behaviors in this context). Thirty years ago, Sterman, Clemente, Marczynski (a decade later) and colleagues quite clearly revealed the presence of a consolidation period immediately after response and rewards. Few if any learning theorists seemed to be aware of their discovery, however. I reviewed the operant conditioning literature and except for those mentioned above, I find nothing about immediate consolidation, probably because outside of this field few scientists investigate EEG during operant conditioning.</x-tad-bigger>

<x-tad-bigger> In 1981 Ted Marczynski and colleagues identified how blocked consolidation led to slower learning in cats. Kaiser (1994) documented this process in humans, perhaps for the first time. Learning is a two-step discrete process that involves sampling of the environment followed by consolidation of associations. This consolidation period is evident in one's EEG as a post-response synchronization, i.e., a dominant frequency burst after response and reinforcement. The beep and visual reward signals to the client that the desired behavior was performed, now it is time to consolidate. The next couple of seconds are spent strengthening the internal linkages, an unconscious process that can be derailed when the environment prods the client for more behaviors.  When there is no break in training, either the client makes one him or herself, or a client continues to sample the environment even after the behavioral criteria is met, which is essentially informing them that the goal behavior was not the goal.</x-tad-bigger>

<x-tad-bigger> In my study, subjects who failed to alpha burst, missed the material they needed to process as shown by missing the items on later recognition tests. It's strange that so little is understand about this part of learning, despite Skinner's work.</x-tad-bigger>

<x-tad-bigger> But of course Skinner didn't use electrodes.</x-tad-bigger>

<x-tad-bigger> </x-tad-bigger>

<x-tad-bigger>Ben Reitsma</x-tad-bigger>

<x-tad-bigger> </x-tad-bigger>


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