Monthly Archives: September 2007

So, is the Mind the Brain?

brain

In 1956 Ullin Place published a paper called “Is consciousness a brain process?” in the British Journal of Philosophy.

While this was a philosophy paper, he included the following abstract and this is the first sentence:

The thesis that consciousness is a process in the brain is put forward as a reasonable scientific hypothesis, not to be dismissed on logical grounds alone.

So, is it a reasonable scientific hypothesis? Can it be falsified? I think it can, and in fact, I believe that there have already many numerous experiments where the hypothesis could have been falsified, but wasn’t, thus making the mind-brain identity theory a legitimate scientific theory, with considerable empirical support to boot.

So what were these experiments?

Binocular Rivalry

“The role of temporal cortical areas in perceptual organization”
Abstract:

…These areas thus appear to represent a stage of processing beyond the resolution of ambiguities—and thus beyond the processes of perceptual grouping and image segmentation—where neural activity reflects the brain’s internal view of objects, rather than the effects of the retinal stimulus on cells encoding simple visual features or shape primitives.

Here is another study:

“Covariation of activity in visual and prefrontal cortex associated with subjective visual perception”

Abstract:

…The coordination of activity among these regions was not linked to external sensory or motor events; rather, it reflected internal changes in perception and varied in strength with the frequency of perceptual events, suggesting that functional interactions between visual and prefrontal cortex may contribute to conscious vision…

And another:

“Perceptual flexibility after frontal or temporal lobectomy.”
Abstract:

These results indicate that the right frontal region has a particularly important role in the ability to shift visual perspective.

For more information, see:

Multistable Perception

Consciousness wikibook

Flash suppression(this is also covered in the first study listed above,with monkeys instead of humans)

“Single-neuron correlates of subjective vision in the human medial temporal lobe”
Abstract:

…Therefore, the activity of most individual neurons in the medial temporal lobe of naive human subjects directly correlates with the phenomenal visual experience.

For more info, see:

Flash Supression

These are some of the best empirical studies I could find supporting the legitimacy of the idea of Neural Correlates of Consciousness(NCC). If this sort of thing fascinates you, I highly suggest reading The Quest for Consciousness by Crick and Koch, which is mostly available for free online.

Allow me to end this post with a quote from Ullin Place:

An acceptance of inner processes does not entail dualism and [furthermore], the thesis that consciousness is a process in the brain cannot be dismissed on logical grounds.

1 Comment

Filed under Philosophy, Psychology

Change, vision, and perception

The essence of our experience is change. Change is incessant. Moment by moment life flows by and it is never the same. Perpetual alteration is the essence of the perceptual universe. A thought springs up in your head and half a second later, it is gone. In comes another one, and that is gone too. A sound strikes your ears and then silence. Open your eyes and the world pours in, blink and it is gone. People come into your life and they leave again. Friends go, relatives die. Your fortunes go up and they go down. Sometimes you win and just as often you lose. It is incessant: change, change, change. No two moments ever the same.

– Henepola Gunaratana, Mindfulness in Plain English

Now, allow me to quote from a recent scientific abstract concerning fixational eye movements:

Your eyes continually move even while we fix our gaze on an object. Although these fixational eye movements have a magnitude that should make them visible to us, we are unaware of them. If fixational eye movements are counteracted, our visual perception fades completely as a result of neural adaptation. So, our visual system has a built-in paradox — we must fix our gaze to inspect the minute details of our world, but if we were to fixate perfectly, the entire world would fade from view.

Food for thought.

References

Martinez-Conde, S., Macknik, S. L., & Hubel, D. H. (2004). The role of fixational eye movements in visual perception. Nat Rev Neurosci, 5(3), 229-240.

Leave a comment

Filed under Philosophy, Psychology

Thoughts on perception

k

This is a painting done by a congenitally blind artist named Esref Armagan.

The most obvious question is how his brain is able to perform such feats of perspective, but as the article mentions, it is well understood that “blind people… understand and can draw in three dimensions”

With that said, I think this particular “how” question is easily answered with modern paradigms of neural plasticity/pruning etc

I believe the more puzzling question to ask is not how he can perform such tasks, but rather, how his developing brain learned to generate high-order representations of three-dimensional space to such a phenomenal degree of accuracy.

Well, “I was taught, he says. Not by any formal teacher, but by casual comments by friends and acquaintances.”

This remark, combined with the fact that “it is impossible to know if he had some vision as an infant”, makes it difficult to extract any conclusive insights about whether his “mind’s eye” is purely mapped out in non-visual sensory-terms (the primary contributors likely being kinesthetic and proprioceptive), and his incredible “accuracy” is simply the result of his early peers subtlety nudging him back and forth until he got it “right”.

An alternative answer is that his brain got some “extra” reinforcement by crude visual data before his eye completely degenerated, thus making his inner conceptual space not in purely non- visual terms as is suggested by the article. This would also explain why his degree of accuracy is greater than most other congenitally blind people.

These are difficult, but fascinating problems in the psychology of perception, but regardless of Mr. Armagan’s unique skills, there seems to be an emerging consensus from all psychological disciplines that whatever “perception” is, it is realizable across many different modalities.

2 Comments

Filed under Philosophy, Psychology

Welcome to the Minds and Brains infotainment blog.

MRI brain

Leave a comment

Filed under Random