Wednesday, May 21, 2014

The real Phineas Gage?

This Slate article is worth a read. Gage may not have been the man we make him out to be. Take home lesson: don't believe what you read in textbooks or review articles, especially if there is strong consensus. Question everything and check original sources for yourself.

Monday, May 19, 2014

All time best historical models of language and brain

If you were going to put together a highlight reel of the best, most influential models of language and brain, what would they be?  You gotta start with the single-node model of Broca, then Wernicke's two-node, dual stream "connectionist" model.  But what then?  Lichtheim I suppose (although I think he ended up doing more harm than good despite his good intentions).  Any Freud fans?  Not very influential, though.  Geschwind for sure.  Anything in between?

Friday, May 16, 2014

Talking Brains turns 7!

Today is the 7-year anniversary of the birth of Talking Brains.  I thought it would be fun to repost our first blog entry:


The Cortical Organization of Speech Processing

Our new article, "The Cortical Organization of Speech Processing" has recently been published in Nature Reviews Neuroscience, 8393-402(May 2007). Although it is an extension of the model we proposed in our 2000 TICS and 2004 Cognition papers, there are several new features in the current proposal. One is the claim that within the ventral stream there are parallel routes from acoustic input to lexical access. Another is that within the dorsal stream, there are also parallel circuits, one supporting auditory-motor integration at the phoneme level, and another supporting auditory-motor integration at the level of sequences of phonemes or syllables. We also suggest that the dorsal auditory-motor integration system may be fundamentally organized around the vocal tract effector system, rather than the auditory-system per se. More on these recent claims in future posts. Let us know what you think of the new paper!
I guess you *have* let us know.  That 2007 paper has done better than I could have imagined--over 1300 citations at last check according to Google Scholar.  As David pointed out to me recently, we seem to have become the establishment now, rather than the kids with the crazy ideas.  We started working together back when we were both post-docs, me at the Salk Institute and David at UCSF (we knew each other from MIT where David got his Ph.D. and I did a post-doc stint with Pinker, but didn't interact much).  We generated two empirical papers together, our only two:
  • Hickok, G., Poeppel, D., Clark, K., Buxton, R.B., Roberts, T.P.L., & Rowley, H.A. (1997). Sensory mapping in a congenitally deaf subject:  MEG and fMRI studies of cross-modal non-plasticity.  Human Brain Mapping, 5, 437-444.
  • Gage, N., Poeppel, D., Roberts, T.P.L., & Hickok, G.  (1998).  Auditory evoked M100 reflects onset acoustics of speech sounds.  Brain Research, 814, 236-239.
Then, once we felt reasonably secure in our careers having landed faculty positions (me at UCI in 1996 and David at UCSF in 1997) we quickly turned to working on theory development.  What started as a simple position piece pointing out that speech perception is more bilateral that most people appreciated (Hickok & Poeppel, rejected 1999, Neuron), morphed into the dual stream model presented in 3 installments: 2000 TICS (nearly rejected), which focused on speech perception being bilateral and task-dependent; 2004 Cognition (nearly rejected) which explicitly tied the model to dorsal and ventral streams and showed how it explained aspects of aphasia; and finally 2007, by which that time we had done enough empirical work on the dorsal stream (my Spt-related stuff) and the ventral stream (David's AST stuff) to back up the claims with hard data.  I still believe most of what we said in that 2007 paper. 
Thanks for reading and contributing to Talking Brains! 

Thursday, May 8, 2014

The Myth of Mirror Neurons

(Warning: A bit of shameless self-promotion follows, but you might be interested anyway.)

My forthcoming book, The Myth of Mirror Neurons: The Real Neuroscience of Communication and Cognition is now available for pre-order on Amazon.

You had to know this was coming given my obsession with, and frustrated rantings about mirror neuron theory in many posts on this blog.  Writing this book (my first) was a really fun and interesting experience.  It forced me to look deeply not only into data and theory concerning mirror neurons and the human mirror system but well beyond it in areas that the mirror neuron phenomenon has touched: imitation, embodied cognition, theory of mind, autism, empathy, and lots more.  I actually learned quite a lot.  In the end, the book is about the cognitive neuroscience of communication and cognition more broadly, using mirror neuron theory as a theme.

For those of you who think this might be nothing more than a destructive barn-kicking exercise, rest-assured, it's more than that (although I do my share of kicking).  I spend a good deal of space in the book developing alternative's to the Parma story using their own data and talking about a lot of other relevant phenomena and theoretical ideas.

The book is written to be accessible to a broad audience but I wanted it to be a serious book and was pretty anal about being scientifically rigorous with lots of detail and citations for practicing scientists. I hope that the endorsements from Steve Pinker, Gary Marcus, and Pat Churchland mean that the book has academic value. On the general audience side the one early review from the trade book world has been positive (whew!), although it highlights only the barn-kicking aspect (oh well).  From Publishers Weekly: 
Hickok, professor cognitive science at the University of California, Irvine, frames his book around a straightforward question: "How is it possible that a cell in the motor cortex of a monkey can provide the neural blueprint for human language, empathy, autism, and more?" His answer, presented with great clarity and detail, is equally straightforward: it can't. Hickok balances his exploration of the hype surrounding the importance of mirror neurons with a careful analysis of the scientific literature, always attempting to ensure that conclusions are well supported by available data.  In fact, he firmly believes that conclusions have far outpaced data. When he take on the assertion that problems with mirror neurons are the cause of autism, he does not sugarcoat his finding that "the broken mirror hypothesis does not fare well in light of empirical facts." He is equally confident that mirror neurons have not provided clues to the evolution of language, empathy, or theory of mind. Hickok's skepticism toward the claims associated with mirror neurons began when he taught a course on the subject, and thanks to those origins his impressive handling of basic neuroscience makes a complex topic understandable to the general reader as he delves into cutting-edge science.  -Publishers Weekly, May 5 2014, p. 50
As always, I welcome feedback from the blogosphere.  In fact, my ideas were shaped to some extent by interactions with people commenting on my many posts, so I owe all you commenters a big thank you.