Hmm, where to start... this was a very fascinating talk. The part related to cephalopods did not have too much new detail I was unaware of, but was a fantastic introduction to the capabilities and style of the ceph nervous system, and why it these are great animals to study to as a comparative consciousness study, and it seemed to get the attention of a lot of the neuroscientists who attended. I spoke briefly with the speaker, David Edelman, afterwards, but since he had a lot of real neuroscientists waiting to talk to him, I said I'd follow up with him later by email. He was well aware of TONMO, and gave some high praise, and I encouraged him to stop by and participate. (That being said, I'm all nervous about trying to do his wonderful talk justice in this summary-- I tried to take good notes, but some of the slides went by pretty fast... I saw hallucigenia there, who can perhaps correct any gaffs or omissions, hint hint.)
The talk covered a number of interesting areas, starting with a brief discussion of "what is consciousness" (a popular topic around Caltech, since it's a favorite topic of
Christof Koch) and the history of that question. Behaviorists like Skinner have guided neuroethology and the like away from asking questions about things like "mind" and "consciousness," so for a lot of the 20th century it was more studied by philosophers than neuroscientists. There also have been serious technical hurdles on the subject, since it's hard to measure, describe, monitor, and so forth. Much of what modern studies of consciousness have been based on in humans is their own reports of what they're subjectively experiencing about their state of mind ("metacognition"), which, of course, can't be done with most non-human animals (with the possible exception of great apes like Koko and the late Alex the parrot.)
He had a slide of a long list of things related to consciousness that I didn't fully copy, but they range from purely subjective to very physiological but rather primate-oriented (the reference is Seth et. al. 2005 Consciousness & Cognition 14:119-139, where Edelman is part of et.al., I'm going to see if I can download that one shortly.) We understand some of the parts of the brain, like cortex and thalamus, that seem to be involved in human consciousness, but we see what appears to be consciousness in animals that don't have those brain parts at all.
Consciousness seems to involve the ability to integrate multiple modalities of sensory input with memory, learning, and behavior, and the sorts of things that he thinks we should be looking for as general mechanisms for consciousness include this cross-modal sensory input, feed forward signaling across the cortex (or the equivalent part) and "reentrant signaling." It also seems that consciousness often involves regional long-term potentiation as a form of memory, and widespread, fast, low-amplitude electrical activity in the brain, which is sort of a fancy way of saying "thinking and memory of what was thought" if I understand it correctly. In any case, he believes we should be looking for analogs of the mammal thalamocortical system in other animals, such as birds and cephalopods.
He also touched on some ecological aspects that I'll mention since I can look clever for mentioning some in my post before the talk
-- a heterogeneous ecology, predator/prey arms races, and hierarchical social ecologies all seem to be ecological pressures to develop consciousness. He also noted that octopuses are interesting in that last one, in that they are generally solitary and don't communicate so much with others of their own species.
The next part of the talk discussed various animals that have been studied: vocal learning has been shown in marine mammals (both cetaceans and pinnipeds), birds, and bats, and manual learning (like sign language) has been shown in primates. There was then a history of trained primates, like Koko the signing gorilla and Alex the parrot, which I'll skip the details of.
Then he mentioned that animals with "simpler" nervous systems show quite sophisticated behaviors, mentioning fruit flies, bees, jumping spiders, and octos-- I'm sure Roy would encourage him to add stomatopods to the list, too. He also discussed some robots that could do things like play soccer or navigate mazes with thousands of neurons and millions of connections, which sounds like a lot but is far less than are present in all but the simplest animals... in particular, the maze-solving "Darwin Machine" robot has its nervous system connectivity modeled roughly on the hippocampus.
The next section was about birds, with some emphasis on ravens, which show some rather sophisticate behavior like solving puzzles involving pulleys and ropes to get their food, and keeping track of which other ravens may have seen where they stashed their food and which ones haven't, which they use to decide how to defend their hidden snacks ("I can't let that guy get close; he knows where I hid my lunch!") which is surprising in that it suggests the raven has an idea of what the other raven is thinking.
(The reference for the Raven stuff is Scientific American, 2007, Heinrich & Bugnyar
preview here and a book by Heinrich.)
To me, although the bird part was interesting, one of the observations made it less so than for cephs: although bird brains look anatomically somewhat different than mammal brains, when one studies the homeotic gene expression in their development, it suggests that there are a lot of homologies between parts of bird brains and parts of mammal brains that seem to have the same function, suggesting that their original form, including primitive consciousness, were probably common in a shared ancestor.
There was a bit of discussion of Alex the parrot, too.
Then, finally, on to the cephalopods!
He mentioned a number of the "classic" results, including J.Z. Young, Wells, and such, and discussed the recent work on the shoulders of those giants by Fiorito & Chichery and Hochner. He has been working with Fiorito in particular, it would appear, and he also had quite a number of excellent videos from Hanlon, several of which I hadn't seen before. There's also a video from Fiorito I'd love to track down of an octo doing the classic "crab in a plexiglass box" trick but with the twist that there are 3 lids it could unscrew, but only one opens (and one with no crab, where the octo decides to open it and check anyway, not trusting its eyesight, cause the researcher wouldn't be so mean is to give the box without a crab, would they?)
Several of the interesting studies mentioned, some of which we've discussed before around TONMO, include Hochner's studies of arm behavior (including amputated arms
) and using the bend of an "elbow" to "reel in" prey captured at the tip (I didn't know that the bend is generally at the same place even in a severed arm, suggesting the decision is made in the arm's nervous system more than the brain.)
Also, Fiorito has now apparently developed a technique for neural recording from an electrode in the brain of a free-swimming octopus, and has found some interesting results there: a brain region that may be a hippocampus analog (I think it was in or next to the vertical lobe, but I need to look it up) and that there are single sites in the brain that respond to multiple tactile sites for stimulating the octo's body (like poking it), and that electrically stimulating brain regions can elicit a lot of behaviors-- primitive stuff compared to mammal electrophysiology, but starting to get on the right track of reproducing what's been done in fish and mammals. So far, there's no evidence that octos have a somatoropic map the way that mammal motor and somatosensory coretex works, but that might be more because we don't know what we're looking at than because it's not there (in fact, it's hard to imagine how a cuttlefish could map its visual world onto its chromatophores without a map from the optic lobes a somatotropic map on the cromatophore lobes.)
Apparently, there is also a laminar (layered) organization to the vertical lobes that might be similar to that in mammal cortex in some ways, and the connectivity around there is similar to the thalamus and cortex (and maybe hippocampus?) in mammals in some ways. Also, Fiorito has found long-term potentiation, an important building block of memory and learning in mammals, in the vertical lobes of octopus in vitro, in prepared slices. There is some evidence that this is convergent evolution rather than something present in the shared ancestor, since it's physiologically similar, but biochemically isn't NMDA-dependent as it is in vertebrates (essentially, it's doing the same thing but with different chemicals.)
(cont)
But I hope it's thought-provoking reading, at least...
