Methamphetamine use is on the rise (Drug Enforcement Administration 2015). And so are crystal-meth-related drug convictions (see “State Sentencing…”). So what do we know about crystal meth? In particular, what does crystal meth do to your body and brain? The South Shore Recovery Center has some answers. In fact, they’ve done us the favor of turning those answers into the infographic below.
Continue reading Crystal Meth & Your Brain: An Infographic
Michael Bishop outlines a network theory of well-being in which well-being is constituted by positive causal networks and their fragments (2012, 2015). ‘Positive’ refers to — among other things — experiences that have positive hedonic tones, the affirmation or fulfilment of one’s values, and success in achieving goals. So according to Bishop’s view, we flourish when certain positive causal networks are robust and self-reinforcing. For example, something good happens to us and that improves our motivation and mood, which then helps us achieve more, which improves our motivation and mood even more, and so on.
Bishop’s network account musters philosophical rigor by providing a systematic and coherent account of wellbeing that satisfies many common sense judgments about well-being. But lots of philosophical accounts can do that. So Bishop’s account does even more. It unifies and makes sense of a huge swath of the science. This provides some reason to think that Bishop’s account is superior to its competition.
So what’s this got to do with exercise and neuroscience?
I am largely persuaded by Bishop’s arguments for the network account of well-being, so I will skip my criticism of the project. Rather, I will add to it. Specifically, I will show how well is makes sense of the neuroscience. While I will not be able to review all of neuroscience, I can accomplish a more modest goal. I can review one part of neuroscience: the effect of exercise on the brain.
There is a wealth of evidence suggesting that regular physical activity and exercise forms an important part of one’s positive causal network of well-being by, among other things, increasing positive affect (Harte, Eifert, and Smith 1995), increasing confidence (Klem, Wing, McGuire, Seagle, and Hill 1997), reducing stress, relieving depression (Blumenthal et al 1999; Motl et al 2005) and preventing more than a dozen chronic diseases (Booth, Gordon, Carlson and Hamilton 2000; see also Biddle, Fox and Boutcher 2000 for a review of relationships between exercise and well-being). The mechanisms for all of these results are not entirely clear. But neuroscience is providing, in broad strokes at least, some clues about the mechanisms that can explain, in part, why exercise produces a series of positive effects in a well-being network (e.g., Meeusen 1995, Farooqui 2014).
The Positive Effects in the Brain
Let’s start with how exercise produces direct positive effects in the brain. Firstly, exercise and regular physical activity directly improve the brain’s synaptic structure by improving potentiating synaptic strength (Cotman, Berchtold, Christie 2007). Secondly, exercise and regular physical activity strengthen systems that underlie neural plasticity—e.g., neurogenesis, the growth of new neural tissue (ibid., Praag et al 2014). These changes in the brain cause “growth factor cascades” which improve overall “brain health and function” (ibid.; Kramer and Erickson 2007).
Now consider how exercise has indirect positive effects in the brain by producing ancillary positive circumstances. Generally speaking, “exercise reduces peripheral risk factors for cognitive decline” by preventing—among other things—neurodegeneration, neurotrophic resistance, hypertension, and insulin resistance (ibid.; see also Mattson 2014). By preventing these threats to neural and cognitive health, exercise is, indirectly, promoting brain health and function.
Positive Causal Networks
It requires no stretch of the imagination to see how these positive effects will reinforce positive causal networks and thereby increase well-being. Even so, I will do you a favor by trying to demonstrate a connection between exercise, the brain, and the larger network of well-being.
We have already seen how exercise results in, among other things, increased plasticity. And increased plasticity results in improved learning (Geinisman 2000; Rampon and Tsien 2000). Also, the increased plasticity that results in improved learning can produce other positive outcomes: increased motivation, increased opportunities for personal relationships in learning environments, etc. (Zelazo and Carlson 2012, 358). Further, increased motivation and social capital can — coming full circle — result in further motivation (Wing and Jeffery 1999).
That right there is what we call a self-reinforcing positive causal network or positive feedback loop. And that, according to Bishop, is how we increase well-being (see figure 1).
This causal model shows how the neuroscience we just discussed implies a causal network. The nodes and causal connections in this model show how well-being is a matter of positive causal networks.
3. What about Ill-being?
Obviously, I’ve only mentioned the neuroscience of well-being. But if we want to promote well-being, then we also have to decrease ill-being, right? Right. And once again, the network theory of well-being will fit nicely with the research on ill-being. For example, the research on emotion regulation (see Livingston et al 2015) implies some causal networks that can inhibit ill-being. The same can be said of the research about using deep brain stimulation in treatment-resistance depression (Bewernick et al 2010; Lozano et al 2008; Mayberg et al 2005; Neuner et al 2010).
4. A Concern: Fitness
You might object by positing that Bishop’s theory of well-being will not fit neuroscience as well as it fits positive psychology. This objection can be dismissed in a few ways. Here are two ways.
First, we can safely accept that Bishop’s network theory of well-being will not fit neuroscience as well as it fits positive psychology. After all, Bishop’s network theory was designed to fit positive psychology, not neuroscience. It’s hardly a fault for a theory to not do what is was not intended to do.
Second, neuroscience is a larger domain than positive psychology. So of course it is harder for a theory to fit it. Allow me to explain. As the domain of discourse increases in scope, it becomes increasingly difficult for us to find a theory that fits all of it. So, because neuroscience is a larger domain than positive psychology, the challenge of providing a theory that fits neuroscience is always more difficult than providing a theory that fits positive psychology. So the fitness objection doesn’t necessarily reflect badly on Bishop’s theory. It might only reflect a difference between positive psychology and neuroscience.
Let me summarize. I mentioned a few cases in which Bishop’s theory of well-being can unifies and makes sense of neuroscience. Then I proposed a few more cases in which Bishop’s theory might do the same. And then I addressed a skeptical worry about the project I propose. So Bishop’s theory of well-being can accomplish even more than Bishop intended.
‘Bottom-up’ and ‘top-down’ are staple concepts in cognitive science. These terms refer to more than one set of concepts, depending on the context. In this post, I want to talk about one version of ‘bottom-up’ and try to pin down what is at the “bottom” of cognition.
First, I should single out the meaning of ‘bottom-up’ that I have in mind. It is the one in which ‘bottom’ refers to the deterministic hardware and pre-conscious processes from which “higher level” processes like meaning, affect, and perhaps conscious awareness emerge. Continue reading Where Does “Bottom-up” Bottom Out?
Randy O’Reilly gave a talk at CU Boulder yesterday entitled “Goal-driven Cognition in the Brain:….” It was an excellent look at how goals have emerged in cognitive science and psychology and how goal-based models have improved upon previous behaviorist models. He also told a story about how goal-driven cognitive models can be grounded in neurobiology.1 There are two reasons I mention this talk. First, Randy’s talk convinced me that “goals” have a valuable place in the ontology of mental states. Second, his talk helped me realize an example that shows how goals and desires are dissociable. In this post, I will talk about this second item. Continue reading Goals & Desires
Kouider et al have recently reported that infants’ cortical activity (when viewing faces) is isomorphic to that of adults who consciously perceive faces. They conclude that conscious perception develops between 5 and 15 months of age. After reading their paper, I want to consider a different conclusion. Perhaps Kouider et al didn’t find a marker of conscious perception. Maybe they found a marker of unconscious perception.
A couple month’s ago, I was at a conference where Anthony Jack proposed a very interesting theory: maybe we have two neural systems (Task Positive Network [TPN] and Default Mode Network [DMN]) that produce conflicting intuitions about some age-old philosophical puzzles. These conflicting intuitions lead us to get stuck when thinking about these puzzles (e.g. the hard problem of consciousness, the explanatory gap, or qualitative consciousness) are the result of conflicting intuitions (Jack et al 2013).
I was struck by Jack’s presentation for two reasons: (1) I was presenting a poster with a similar motivation at the same conference and (2) I have long been interested in a biological examination of (academic) philosophers.
This link is a poster about philosophers’ brains that I presented at the Towards a Science of Consciousness Conference in Tuscon—I gave a talk based on this poster at University of Utah. Use the link to see a full-size PDF that will allow you to zoom ad nauseum without the blurriness—vector graphics are so cool!
We should not be surprised if some of the differences between philosophers views correlate with differences between philosophers’ brains. I list a handful of neurobiological differences that already correlate with philosophical differences among non-philosophers. It’s not obvious what we should glean from the possibility that philosophers’ brains could differ as a function of their views. After all, it might be that studying certain views changes our brain. That would not be surprising or concerning, really. But if it were the other way around — e.g., that structural/functional differences in brains predisposed us towards some views and away from other views — then that might be concerning. What if academic philosophy is just an exercise of post hoc rationalization of the views that philosophers’ brains are predisposed toward? Of course, it’s entirely possible that causation works in both directions. But even that could be concerning because that is compatible with self-reinforcing feedback loops. For instance, perhaps we are neurally predisposed to certain views, so we study those views which further predisposes us toward that view (and away from its alternatives). But these questions are getting ahead of the evidence. Hopefully, the neuroscience of philosophy will provide some answers. Until then, check out the poster to see what questions the research has already answered.