Friday, April 15, 2011

Dynamic Hierarchies

So the brain is a dynamic system, if Sporns is correct. How does this dynamism arise?

I've just reread the chapter, and I confess that I am not yet ready to talk confidently about the physiology of the brain, but I think I have gleaned enough to make some general statements that might be useful. The brain's dynamics rest on heterogenous coupling and multiscale dynamics, both of which Sporns says are "ubiquitous features of the brain" (258).

Heterogenous coupling suggests that any given neuron, cluster of neurons, or brain region will connect to (couple with) most any other neuron, cluster, or region, and multiscale dynamics suggests that the neural activity at any neural level – neuron, cluster, or region – affects the activity of the enclosed and enclosing levels. Sporns says:
Brain connectivity is organized on a hierarchy of scales from local circuits of neurons to modules of functional brain systems. Distinct dynamic processes on local and global scales generate multiple levels of segregation and integration and give rise to spatially differentiated patterns of coherence …. Neural dynamics at each scale is determined not only by processes at the same sale but also by the dynamics at smaller and larger scales. (258)
Just as neural dynamics unfold across different spatial scales, they also unfold across different time scales "from fast synaptic processes in the millisecond range to dynamic states that can persist for several seconds to long-lasting changes in neural interactions due to plasticity" (262). As a neural pattern is created or expressed (or blooms, ripples, or flashes) across the spatial and temporal structures of the brain, it is invariably modified by endogenous brain activity and by external inputs. All neural "brain dynamics is inherently variable and 'labile,' consisting of sequences of transient spatiotemporal patterns that mediate perception and cognition" (262). Sporns calls these brain dynamics "that are neither entirely stable  nor completely unstable" metastable.

If I understand this correctly, then, all thoughts and emotions are metastable, always expressed somewhere on a scale between completely stable and completely unstable. To use my two bands model of the brain (left: orchestra, right: jazz band), each time I sound the thought Connectivism, I sound a recognizable but variable musical motif. Like Jimi Hendrix, I never quite play the song riff the same way, even if, like a classical guitarist, I'm trying to. And  even if I managed to play it exactly the same twice, it would still sound different if I were playing at the Fillmore East, at Woodstock, or in the studio.

It just won't ever be exactly the same. Thoughts, concepts, and emotions are dynamic, metastable expressions. So what's the point for education? Our effort to impart the same knowledge to 30 different students in a single class is pointless and impossible, so let's give it up. Let's shift gears and devise a different goal. Thirty students cannot learn the same thing, so let's quit teaching as if they can.

Okay, you rightfully ask, if we don't teach them all the same thing in the same way, then what do we teach them and how? I thought you might ask that. Fortunately, I've run out of time for writing today. Later.

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