In recent years, the bidirectional communication between the gut microbiome and the brain has emerged as a factor that influences immunity, metabolism, neurodevelopment and behaviour. Cross-talk between the gut and brain begins early in life immediately following the transition from a sterile in utero environment to one that is exposed to a changing and complex microbial milieu over a lifetime. Once established, communication between the gut and brain integrates information from the autonomic and enteric nervous systems, neuroendocrine and neuroimmune signals, and peripheral immune and metabolic signals. Importantly, the composition and functional potential of the gut microbiome undergoes many transitions that parallel dynamic periods of brain development and maturation for which distinct sex differences have been identified. Here, we discuss the sexually dimorphic development, maturation and maintenance of the gut microbiome–brain axis, and the sex differences therein important in disease risk and resilience throughout the lifespan.
A neuron that encircles the mouse brain emanates from the claustrum (an on/off switch for awareness) and has dense links with both brain hemispheres. Scientists including Francis Crick and Christoph Koch have speculated that the claustrum may play a role in enabling conscious thought.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1569501/ (Crick and Koch academic article)
We’ve frequently discussed how self-aware consciousness likely arises not from any single brain structure or signal, but from complex, recursive (reentrant), synchronized signaling among many structures organized into functional regions. (Did I get close to accurate there?) That a giant neuron provides another connection path among such regions can be taken to align with the reentrant signaling and coordination view of consciousness (ala Edelman and Tononi).
It’s common for brain functions to be described in terms of digital computing, but this metaphor does not hold up in brain research. Unlike computers, in which hardware and software are separate, organic brains’ structures embody memories and brain functions. Form and function are entangled.
Rather than finding brains to work like computers, we are beginning to design computers–artificial intelligence systems–to work more like brains.
Caltech researchers have identified the brain mechanisms that enable primates to quickly identify specific faces. In a feat of efficiency, surprisingly few feature-recognition neurons are involved in a process that may be able to distinguish among billions of faces. Each neuron in the facial-recognition system specializes in noticing one feature, such as the width of the part in the observed person’s hair. If the person is bald or has no part, the part-width-recognizing neuron remains silent. A small number of such specialized-recognizer neurons feed their inputs to other layers (patches) that integrate a higher-level pattern (e.g., hair pattern), and these integrate at yet higher levels until there is a total face pattern. This process occurs nearly instantaneously and works regardless of the view angle (as long as some facial features are visible). Also, by cataloging which neurons perform which functions and then mapping these to a relatively small set of composite faces, researchers were able to tell which face a macaque (monkey) was looking at.
These findings seem to correlate closely with Ray Kurzweil’s (Google’s Chief Technology Officer) pattern-recognition theory of mind.
Scientific American article
BMCAI library file (site members only)
New Scientist article: Applying the mathematical field of topology to brain science suggests gaps in densely connected brain regions serve essential cognitive functions. Newly discovered densely connected neural groups are characterized by a gap in the center, with one edge of the ring (cycle) being very thin. It’s speculated that this architecture evolved to enable the brain to better time and sequence the integration of information from different functional areas into a coherent pattern.
Aspects of the findings appear to support Edelman’s and Tononi’s (2000, p. 83) theory of neuronal group selection (TNGS, aka neural Darwinism).
Edelman, G.M. and Tononi, G. (2000). A Universe of Consciousness: How Matter Becomes Imagination. Basic Books.
In preparation for the March meeting topic, Your Political Brain, please recommend any resources you have found particularly enlightening about why humans evolved political thinking. Also, please share references about how brain functions lead to political perceptions. I’m assuming political perceptions result from more fundamental cognitive orientations, and that those arise in part from one’s genetics and in part from environment (during development and afterward).
Let’s use the following description from Wikipedia:
Politics is the process of making decisions applying to all members of each group. More narrowly, it refers to achieving and exercising positions of governance— organized control over a human community, particularly a state. Furthermore, politics is the study or practice of the distribution of power and resources within a given community (this is usually a hierarchically organized population) as well as the interrelationship(s) between communities. (Wikipedia)
This description places political thinking in the realm of the brain’s/mind’s social processing.
Following are some candidate resources for our discussion preparation:
Brain imaging research indicates some aspects of individual political orientation correlate significantly with the mass and activity of particular brain structures including the right amygdala and the insula. This correlation may derive in part from genetics, but is also influenced by environment and behavior.
“there’s a critical nuance here. Schreiber thinks the current research suggests not only that having a particular brain influences your political views, but also that having a particular political view influences and changes your brain. The causal arrow seems likely to run in both directions—which would make sense in light of what we know about the plasticity of the brain. Simply by living our lives, we change our brains. Our political affiliations, and the lifestyles that go along with them, probably condition many such changes.”
Thanks to member, Edward, for recommending this article: http://www.motherjones.com/politics/2013/02/brain-difference-democrats-republicans
In a similar vein, Bob Altemeyer conducted and reported on some seminal social science research and theory on political dispositions. See http://home.cc.umanitoba.ca/~altemey/. Note the free book link on the left.
“When something is memorable, it tends to be the thing you think of first, and then it has an outsize influence on your understanding of the world. After the movie Jaws came out, a generation of people was afraid to swim in the sea—not because shark attacks were more likely but because all those movie viewers could more readily imagine them.”
“Until recently, scientists had thought that most synapses of a similar type and in a similar location in the brain behaved in a similar fashion with respect to how experience induces plasticity,” Friedlander said. “In our work, however, we found dramatic differences in the plasticity response, even between neighboring synapses in response to identical activity experiences.”
“Individual neurons whose synapses are most likely to strengthen in response to a certain experience are more likely to connect to certain partner neurons, while those whose synapses weaken in response to a similar experience are more likely to connect to other partner neurons,” Friedlander said. “The neurons whose synapses do not change at all in response to that same experience are more likely to connect to yet other partner neurons, forming a more stable but non-plastic network.”
Read more at: https://medicalxpress.com/news/2016-02-scientists-brain-plasticity-assorted-functional.html#jCp