Monday, 25 November 2013
Rhythms, Pain and Consciousness in Invertebrates
This week we’d like to offer you a sort of “seafood cocktail”: links to discussions of three fundamental questions of neurobiology, as investigated using three different kinds of marine invertebrates: lobsters, crabs, and Aplysia (sea slugs).
The first link below is to an article that discusses the many rhythmic activities that can be observed in nervous systems, and in particular in that of the lobster. In neurobiology, invertebrates such as lobsters are commonly used as models, because their nervous systems are so much simpler than our own. Thus, in the stomatogastric nervous system of the lobster, researchers have identified a neural circuit that connects about 30 neurons and can generate two different patterns of rhythmic activity that are intrinsic to this circuit. This finding reminds us, first of all, that even in relatively simple organisms, the nervous system does not just passively wait for stimuli from the outside world, but instead maintains continuous, autonomous activity that will only be modulated by the environment. Second, this finding shows that complex phenomena such as circadian cycles or locomotion in humans can be better understood in light of the simpler rhythmic pattern generators found in invertebrates.
The second link below is to an article that addresses the delicate question of pain in invertebrates. There is no question that your cat or dog can feel pain, but is the same true of the lobsters and crabs that you see crammed into tanks at the fish store and that are destined to be taken home and boiled alive? Scientists long believed that because invertebrates have no cerebral cortex (a brain area that is associated with pain in humans), they could have only reflexive responses to painful stimuli. But experiments conducted at Queen’s University in Belfast, Northern Ireland, tend to prove that crustaceans such as lobsters do in fact feel pain. The researchers supported their hypothesis with a series of observations made after lobsters had been given electrical shocks, such as that they favoured the part of the body that had received the shocks and that they displayed an elevated level of stress hormones. Thus, the scientific consensus that crustaceans feel no pain is weaker than it once was.
Lastly, the third link below is to a video of a lecture given by Wayne Sossin at the 2012 Summer School on the Evolution and Function of Consciousness held in Montreal in July 2012. This lecture raises a question closely related to the preceding one, but perhaps even harder to answer: do invertebrates such as crustaceans, or the marine mollusc Aplysia used as a model in this lecture, possess consciousness? Obviously, to answer this question, we would have to know what kind of consciousness we are talking about. In this case, we probably do not mean the kind of reflexive consciousness found in humans—the impression of having a self that perceives the things in one’s environment—but rather a form of primary consciousness, or, to paraphrase the title of a famous article, a feeling of “what it is like to be an Aplysia”. As can be clearly seen from the comments that follow the video, the question of consciousness in invertebrates is far from settled.
Friday, 15 November 2013
Language as a Window into Human Nature
In previous posts in this blog, we have drawn your attention to various lectures in the RSA Animate series, in which experts is a variety of fields give online talks while cartoon illustrations are drawn in sped-up fashion to accompany their voice-over. This week we’d like to tell you about another RSA Animate lecture. This one is about language, and it is given by Harvard cognitive psychologist Steven Pinker. (more…)
Monday, 28 October 2013
Christof Koch, a Romantic Reductionist
Just in case the 2012 Summer School on the Evolution and Function of Consciousness in Montreal did not quench your ravenous thirst for knowledge on the subject, I am providing a link below to a recent Brain Science Podcast interview with Christof Koch, another great name in consciousness research.
Author of the book Confessions of a Romantic Reductionist, Koch argues that we are no longer confined to philosphical speculation about human consciousness, but instead can now make predictions and test them experimentally. In this recent interview, he reviews the progress that has been achieved since an earlier Brain Science Podcast interview on this subject with Dr. Ginger Campbell, in 2007.
Monday, 14 October 2013
Axons Play Unexpected Role in Processing Information
Recently, someone asked me whether it would be fair to say that the integration of all the information that one neuron receives from other neurons takes place in its dendrites. I replied that according to the classic model of neural communication, that is certainly the case, but that processes in living organisms are highly complex, so I probably shouldn’t make that statement categorically, if only because some integration also occurs directly in the neuron’s cell body.
And little did I know how truly I had spoken, if a study that I came across just a few days later is to be believed. That study shows that a neuron’s axon—the long extension through which it connects to other neurons—can also modulate its signal, in a certain way. That is surprising, to say the least, because neural conduction along the axon is considered an “all-or-nothing” phenomenon, which would not seem to leave much room for the possibility of signal modulation. (more…)
Tuesday, 1 October 2013
We Are All Complex Networks
Before the Harper government’s budget cuts, the CIHR Institute for Neurosciences, Mental Health and Addiction (INMHA) had been providing this web site with stable funding for over 10 years. As a result of these cuts, the INMHA had to stop funding us. Now, because of the same cuts, we have had to stop publishing new posts on the English version of this blog every week and will instead be doing so only once every two weeks. We are truly sorry, but that is the best that we can can manage on a volunteer basis. So here is this week’s post. The others will follow at two-week intervals from now until further notice.
In some previous posts in this blog, I have talked about the RSA Animate knowledge-visualization videos and the Brain Science Podcast, and I promised that I would mention other videos in these two excellent series on occasion. Well the most recent RSA Animate video and the most episode of Brain Science Podcast complement each other so well that this week I want to tell you about both of them at the same time. (more…)