Reflection and the Brain: A potential Connection between Limbic and Cortical processing circuitry

July 7, 2020 at 7:32 PM
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Reflection and the Brain: A potential Connection between Limbic and Cortical processing circuitry

By Kathleen Larsen UA ’21 and Jim Stellar

In our last blog, we discussed a conventional model developed by Kolb of the way reflection on experience could enhance learning from that experience in a cycle involving the two processes.  But, we did it from the perspective of an emotional reaction rather than just the cognitive processing of knowledge from the experience itself. This distinction may be important for the earning of soft-skills, e.g. teamwork or self confidence, especially from a complex experience like an internship or study abroad. Soft-skills stand in contrast to hard-skills, like computer coding, that can also be taught well in the classroom, as they are often more social (e.g. teamwork) and can be hard to describe.

In this blog, we want to focus on a possible neural substrate of that emotional component of experiential reflection and how it might connect to cognitive processing brain circuits, at least in theory.  We see this connection as part of a larger issue of how lower emotional brain circuits integrate with higher cognitive ones where both are changing with learning experiences.  To us, the real growth power of learning from experience occurs when the hard- and soft-skills work together.

The neuroscience part of the story begins in 1925 with the discovery in the brain of large spindle-shaped neurons by Constantin Von Economo, but we will begin this blog featuring a 2010 paper[1] by John Altman and colleagues. They showed cortical neurons (see figure below) in humans and primates that have a number of interesting properties. They have interesting shapes including a long dendrite that seems suitable for gathering inputs across many layers of cortex, and they have wide projections from, for example, from the anterior cingulate cortex (described below) to brain areas like frontal and insular cortex as well as to the limbic (emotional) brain areas like the septum and the amygdala. But what is perhaps most fascinating is that von Economo neurons appear to exist only in higher level species, including humans.

They are not found in lower animals. With their wide connections, these neurons could provide important communication and interconnection between many brain areas and some have even suggested they could underlie the somatic part of consciousness, a point made by Antonio Damasio’s seminal work as part of what he called the “convergence-divergence network” in his 2012 book, Self Comes to Mind: Constructing the Conscious Brain.

We will set aside here the issue of consciousness and focus on the interconnections that von Economo neurons could provide to link the unconscious or implicit emotional part of the learning experience with the conscious or explicit cognitive part of that and other learning experiences.  Certainly, when students do something like an internship in a rich workplace environment or study abroad, there is much learning about which even they cannot easily speak, which is why reflection is important.  That experiential growth leads to a recognized maturity level.  The student may be learning from the workplace “the mechanics feel,” a famous phrase used by the narrator in Pirsig’s book, Zen and the Art of Motorcycle Maintenance (first published in 1974). We see this phrase as referring to the kind of learning that synergizes emotional with cognitive knowledge and leads to what the book narrator calls “quality.” In students who are somewhat experienced in the workplace, we would call it professional maturity.  With more experience, we might even call it professional wisdom.

Emotion in Reflection

So how do skill or emotional learning processes in the brain connect with the conscious cognitive processes in the brain?

This question requires a brief explanation of one of the most basic principles of neuroscience – levels of function – the idea that the lower areas of the nervous system, like the spinal cord or brainstem, support simpler behaviors like pain withdrawal reflexes or automatic adjustments to breathing rate with changes in bodily activity. Indeed what makes us primates successful is the top end of the nervous system, primarily the neocortex. This extra brain matter here is said to underlie much of the difference in our intelligent symbolic processing of the world. For example, consider a classic experiment in child development where one rolls a ball behind a screen and observes where the child looks. At a younger age, the child leaves their eyes on the spot where the ball disappears and then jumps to the other side of the screen when the ball appears.  But an older child, with a bit more brain development in the neocortex, skips immediately to the other side of the screen and shows surprise if the ball appears too early or too late.  This reaction indicates something must have happened behind the screen that did not fit with the child’s automatic conceptual model of the ball’s trajectory. Neuroscientists know that in the brain stem there are areas from where the eyes can be controlled and attention can be directed (the superior colliculus). They also know that in the neocortex there is an elaborate representation of visual information that allows for all kinds of feature extraction including object motion. The lizard does not have a neocortex and cannot build conceptual models of the world even for simple matters like the trajectory of a rolling ball.

We represent these levels of function here with a simple diagram out of the 1960s by Paul Mclean.  It shows in orange the middle portion of the brain, between the higher neocortex (neomamalian) and the lower reptilian brain.  It is what Mclean called the mammalian brain. This middle part of the brain contains much of the limbic system which deals with emotion.

The question then is how does the implicit learning, perhaps occurring in the limbic system, support the explicit learning in the neocortex so the student becomes more mature in their chosen field of study?

One answer to this question may come from where the von Economo neurons are found in the brain. For example, as mentioned already, von Economo neurons are found in the anterior cingulate cortex, according to Altman, et al.’s summary this is a region that detects conflict and is involved in “risk prediction error” processing, perhaps like KL felt after her street encounter in Madrid as discussed in the previous blog.  These von Economo neurons are also found in the anterior inferior insula cortex, a brain region activated by negative feedback that KL may have given herself as described in the previous blog for not having a stronger reaction.  As KL replayed the incident in her mind, these social emotions and others returned to her cognitive experience.  She resolved to do what she thought was better the next time she had a similar encounter.

Since every part of the nervous system shows an ability to change with experience – this is called neuroplasticity – the experience KL had and her reflections on it after offer the possibility of neural change in the primate brain as part of her cognitive thinking and in her mammalian brain as part of her emotional processing.  The trick may be how these two different brain areas stay coordinated as they both change to produce the maturity in her from that study abroad incident and all of her abroad experiences. That may be due to a connection system like the von Economo neurons or others just like it.

 

[1] Note our first figure is taken from the cited Altman et al. paper, figure 5.

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