Category Archives: learning

Plasticity through feedback

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Most people know that the best and fastest way to learn something is to have excellent and instant feedback. In fact it is almost impossible, maybe always impossible, to learn something without any feedback. In general, we cannot control anything that does not provide feedback and we are much better at learning to control something if the feedback reaches consciousness.

Researchers at the University of Western Ontario (citation below) have used alpha wave feedback at enable changes in the brain and behavior.

our results indicate that at around 30 min after training, NFB (neurofeedback) induced a statistically significant up-regulation of functional connectivity within the dACC/MCC (dorsal anterior cingulate/mid-cingulate cortex) of the salience network in the experimental but not in the SHAM group. Hence utilizing fMRI and a placebo-control group we extend the findings of Ros et al. (2010) demonstrating that the adult cortex is sufficiently plastic that a mere half-hour of targeted volitional activity (i.e. NFB) is capable of intrinsically reconfiguring the brain’s functional activity to last above and beyond – and at least as long as – the time period of training itself.

This results in reductions in mind-wandering and increases in attention to a task – much as meditation does. There is a hope that this technique can be used to help some medical conditions that seem to be associated with abnormal alpha waves.

Here is the abstract:

Neurofeedback (NFB) involves a brain–computer interface that allows users to learn to voluntarily control their cortical oscillations, reflected in the electroencephalogram (EEG). Although NFB is being pioneered as a noninvasive tool for treating brain disorders, there is insufficient evidence on the mechanism of its impact on brain function. Furthermore, the dominant rhythm of the human brain is the alpha oscillation (8–12 Hz), yet its behavioral significance remains multifaceted and largely correlative. In this study with 34 healthy participants, we examined whether during the performance of an attentional task, the functional connectivity of distinct fMRI networks would be plastically altered after a 30-min session of voluntary reduction of alpha rhythm (n = 17) versus a sham-feedback condition (n = 17). We reveal that compared to sham-feedback, NFB induced an increase of connectivity within the salience network (dorsal anterior cingulate focus), which was detectable 30 min after termination of training. This increase in connectivity was negatively correlated with changes in ‘on-task’ mind-wandering as well as resting state alpha rhythm. Crucially, there was a causal dependence between alpha rhythm modulations during NFB and at subsequent resting state, not exhibited by the SHAM group. Our findings provide neurobehavioral evidence for a temporally direct, plastic impact of NFB on a key cognitive control network of the brain, suggesting a promising basis for its use to treat cognitive disorders under physiological conditions.

 

 

ResearchBlogging.org

Ros, T., Théberge, J., Frewen, P., Kluetsch, R., Densmore, M., Calhoun, V., & Lanius, R. (2012). Mind over chatter: Plastic up-regulation of the fMRI salience network directly after EEG neurofeedback NeuroImage DOI: 10.1016/j.neuroimage.2012.09.046

Play

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Sam Wang and Sandra Aamodt have an article in Dana Cerebrum (here), Play, Stress, and the Learning Brain.

They define play.

First, play resembles a serious behavior, such as hunting or escaping, but is done by a young animal or is exaggerated, awkward, or otherwise altered. Second, play has no immediate survival purpose. It appears to be done for its own sake and is voluntary and pleasurable. Third, play occurs when an animal is not under stress and does not have something more pressing to do.

If that is play then it occurs among many animals: mammals, birds, some other vertebrates and even some invertebrates (octopus, squid, honeybee). This wide spread points to a very long history and suggests it serves a vital purpose. Another indication of usefulness is that play is fun; enjoyment is a sign of survival traits. Play is rewarded with dopamine. It is tailored to the lifestyle of the animal. Depending on the typical behavior of the animal there are three types of play. Playing with objects is typical of species that hunt, scavenge or eat a variety of foods. Locomotor play is usual in active animals who run, swim, fly, climb trees. Social play (fighting, chasing, wrestling) uses pretending in animals who have important social encounters. It is the species with the bigger brains for their body size who most engage in social play.

So play has an adaptive purpose or purposes. What would they be?

play is practice that prepares animals for the real activity later—when it matters. … In mammals, play is necessary for forming normal social connections. Rats and cats raised in social isolation become incompetent in dealing with others of their kind and typically react with aggression. In our species, abnormal play as children often presages dysfunction in adults. A notable feature of psychopaths is that their childhoods lacked in play. … Play also transmits culture. … Risk taking in children’s play may be an important developmental process. It tests boundaries and establishes what is safe and what is dangerous. … play also helps children learn what they like and don’t like.

Interesting, playing is a low stress activity (either play lowers stress or stress interferes with play). This is important for learning during play.

Play activates other brain signaling systems as well, including the neurotransmitter

norepinephrine. … Norepinephrine is also involved in rousing us to attention and action, but by acting as a neurotransmitter. Norepinephrine facilitates learning mechanisms at synapses as well. In some neurons, norepinephrine improves brain plasticity, such that change becomes possible when this chemical is present in elevated amounts. The same is true for dopamine, which accounts for how reward leads to long-term changes to make us want more—neural plasticity mechanisms are strongly facilitated when reward occurs. … Though real-life stressors trigger the release of both epinephrine and cortisol, play does not increase cortisol. Cortisol is a stress hormone that helps us in genuinely dangerous situations by redirecting resources to the most urgent needs, such as repairing a wound or fighting an infection.

For humans, play continues into adulthood.

work in adult life is often most effective when it resembles play. Indeed, total immersion in an activity often indicates that the activity is intensely enjoyable; this is the concept of flow, or what athletes call being in the zone. Flow occurs during active experiences that require concentration but are also highly practiced, where the goals and boundaries are clear but leave room for creativity. This describes many adult hobbies, from skiing to music, as well as careers like surgery and computer programming. Such immersion can make solving a great challenge as easy as child’s play.

And not just humans play as adults. Dogs do and they have a special signal to commence play so that their actions are not misunderstood. It is a similar signal in many animals and young of different species have been seen playing together.

What has this to do with consciousness? It seems to me that play is like a type of consciousness – a way of experiencing the world that can be turned on and off. We are able to experience a low tension, enjoyable, somewhat pretend world in which we actively experiment, discover and learn.

Two old ways of learning

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The common ancestor of mollusks, arthropods and chordates (sea snail, fruit fly and mouse) was about 530 million years ago. Bjorn Brembs posts on two learning systems that appear to be this old. (here)

Synaptic plasticity which changes the connectivity between neurons seems to have two different chemical routes: (1) neural transmitter, rutabaga adenylyl cyclase, cAMP, PKA, CREB, DNA to give long-term memory (2) similar but a different cyclase enzyme instead of rutabaga, PKC instead of PKA, FoxP instead of CREB.

The two chemical routes can be separated by either a PKC inhibitor or interfering with the FoxP gene. The research has been done on the sea snail, fruit fly and mouse. By killing the PKC route it appears that the PKA route is likely to be used for classical conditioning which relies on external cues and is thought similar to declarative memory. And it appears that the PKC route is likely to be used for operant conditioning which relies on self motion and is thought similar to procedural memory.

If this turns out to be confirmed, it would mean that our two basic memory systems are as distinct as they appear and are very old indeed. It is interesting that the FoxP gene is involved procedural memory – this is a gene that in humans and song birds appears to help facilitate learning language and song. Also interesting is that there may be a link between classic conditioning and declarative (passing through consciousness) memory.