1

From 1:37 to 3:22 in this video, the claim is made that

we can clearly see that brain chemistry cannot give rise to unified subjective experience and cannot explain how our experiences emerge. The core issue of the mind, our subjective experience, cannot be explained by looking at the brain alone. Thus we cannot conclude the brain gives rise to the mind if it cannot be responsible for subjective experience in unified perceptions.

The video cites an article in the journal of Cognitive Neurodynamics, quoting the following passage from page 3 (emphasis in original):

There is now overwhelming biological and behavioral evidence that the brain contains no stable, high-resolution full field representation of a visual scene, even though that is what we subjectively experience (Martinez-Conde et al. 2008). The structure of the primate visual system has been mapped in detail (Kaas and Collins 2003) and there is no area that could encode this detailed information. The subjective experience is thus inconsistent with the neural circuitry.

  • Are the results of the article generally accepted?
  • Are there notable conflicting opinions?
  • Is the conclusion drawn in the video supported by the article's results?
Sam Estep
  • 113
  • 6

2 Answers2

4

The information in the video is incomplete, outdated, and the cited journal is not popular among neuroscientists (every publication in "Cognitive Neurodynamics" gets cited close to 2 times per year. The impact factor is 1.828 according to the publisher: https://link.springer.com/journal/11571). The first citation of the quote has only been cited 7 times. The second citation only refers to that the visual system has been thoroughly mapped. Although the latter is true, the author is making a sweeping statement that

there is no area that could encode this detailed information.

Now, to some extent this is true. A single region of the brain is an unlikely candidate for a complex phenomenon such as subjective experience. This is an old idea, dating back to at least Decartes, who guessed that the soul was seated in the pineal gland, at the very center of the brain. However, one needs to take into account the entire brain, which contemporary theories of consciousness also do (see Dehaene and Naccache's paper from 2001 also listed below, which has been cited more than 1800 times).

Regarding the details of the paper from 2013, the evidence for phase coding is more limited than for frequency coding, so perhaps the model in the paper should be taken with a grain of salt. In addition, the model is fairly abstract and lacks biological detail. The paper does try to explain binding with the help of neuronal activity.

Today, neuroscientists can stimulate the motor cortex to cause reflex-like movement of the arms. This is done using transcranial magnetic stimulation (TMS). Even subjectively, but not "objectively present", experienced phosphenes can be induced by stimulating visual area V1 using the same technique.

There is more to experience than the processing in the visual cortex. For example, in front of - anterior to - the occipital lobe, activity in the intraparietal sulcus (IPS) has been implied in various processes. In addition, activity in early visual areas have even been linked to basic semantic processing. Activity in the prefrontal cortex has been associated with short-term memory and planning, including prospective memory. The hippocampus, a subcortical structure, has been strongly implied (since 1957 and onwards) in memory, spatial navigation, and pattern related processing. These are just some examples of areas that are involved in our day-to-day moment of what it is like to be.

In summary:

  • There are no results in the paper. It describes a theoretical model. The type of model is not popular among neuroscientists.

  • There appears to be more consensus today on how to approach a science of consciousness, compared to 1994, when the first conference Towards a Science of Consciousness, was held in Tuscon Arizona (see Dehaene & Naccache, 2001).

  • The words are taken out of context. The author seeks to explain binding using a theory that refers to neuronal activity, in this case spiking.

Does current research imply that unified perception cannot be physical?

Quite the contrary. Current neuroscience research aims to build models of cognition, including consciousness (subjective experience, awareness, wakefulness, etc.). To some extent, sensation has been dealt with, but perception is more complex and cognition even more so.

For more reading, see:

Baars, B. http://www.scholarpedia.org/article/Consciousness

Dehaene, S. & Naccache, L. (2001). Towards a cognitive neuroscience of consciousness: basic evidence and a workspace framework

Eds. Bourget, D., Chalmers, D. [maintainers], & Isham, E. A. (Ed.) Papers Related to the Science of Consciousness

noumenal
  • 693
  • 3
  • 8
-1

Re "...there is no area that could encode this detailed information...", if you don't understand how computers work, you would quite possibly think that there's no way that little chunk of impure silicon could encode the detailed audio & video information of a movie - or indeed, of this discussion forum. But it seems fairly obvious that it does, and some people do understand how it works.

However, we don't really understand how the brain works, but saying that "we don't understand how it works" is a very different thing from a proof, or even reasonably strong evidence, that the brain can't do it. Indeed, we have no positive evidence that there's anything but brain chemistry at work.

In short, this is just trying to parlay a lack of knowledge into a justification for an unsupported theory.

jamesqf
  • 817
  • 1
  • 7
  • 11