Head-Direction Cell Assembies have Attractor Properties During Locomotion and Sleep

Poster: Organization of the neuronal assemblies in the anterior thalamus coding for head direction   326.14 (Mon Morning)
Authors: A. Peyrache, M. Lacorix, P. Petersen, G. Buzsaki; NYU

Head-direction cells are neurons that fire when ever a rat’s head is pointed in a particular direction. Discovered by Jim Ranck and first reported at SfN 29 years ago today’s findings are a major update, confirming and extending the cohesive properties of head-direction cell networks.

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Passive Versus Active Movement in Grid Cells and Head Direction Cells

Poster: Passive Transport Disrupts Grid Cell Firing Patterns. Shawn Winter and Jeff Taube.

rat in cartBoth Grid Cells and Head Direction Cells are thought to be path integrators. That is, each cell type is thought to be driven as a function of the animal’s movement. For head-direction cells firing is thought to be driven by rotational movement; for grid cells a combination of rotation and translation. There are distinct sources of self-movement information: motor action plans, proprioception, and feedback from the environment. Winter and Taube sought to dissect these by removing “action plans” (and some proprioception) by comparing firing in these cell types during passive and active movement. Continue reading

How Cognitive Processing is Implemented at Pixar

photo 3Ed Catmull’s lecture.

Each year SfN invites a prominent non-neuroscientist to speak in the series: Dialog Between Neuroscience and Society.  These talks are given on the first day of the meeting, in large, ballroom format. Today’s dialog was given by Ed Catmull, a trained mathematician-physicist whose career has been in developing computer-animation techniques and producing great pictures. Dr. Catmull is president of Pixar the animation component at Disney Pictures. Pixar made Toy Story, the first full-length computer-animated film. Toy Story was, of course, a huge creative and financial success.  It has been followed by a string of animated films remarkable in their complexity, creativity and financial returns. How was this done? How can a huge team work for years with one goal, to create a single creative product? What’s the magic formula?  Dr. Catmull suggested some answers in his lecture, “The Culture of Creativity“. Continue reading

Bob Muller, loose-fish

Drs J Kubie & R Muller 4x_1 mirror

Bob and me in ’83

Bob Muller, close friend and colleague, died last Monday (Sept 16, 2013). His life was remarkable in breadth, richness and the number of people he loved and influenced. Bob occupied space, lots of space,  now a vacuum. Not a vacuum, really; we have memories, achievements and the influence Bob had on so many.  Alex, Bob’s daughter, read an email he sent while she was struggling as a novice marine biologist, trying to tag and collect tagged fish. Bob’s email was what we had come to expect: funny (very funny), warm, insightful and wise (although minus the scatological humor regularly heard from Bob).* Continue reading

The Humanities: Leon Wieseltier wants to protect his turf

A science versus humanities war is brewing. Triggered by Steven Pinker’s excellent article in the New Republic (Science is not the Enemy), Leon Weiseltier, a “Humanist” and literary editor of the New Republic, retorted “Science is the Enemy” (rough translation; Crimes Against Humanities: Science wants to invade the liberal arts. Don’t let that happen). I am not the first to complain about Weiseltier’s screed. Daniel Dennett does an excellent job in the Edge (Dennett on Wieseltier v. Pinker in the New Republic. Lets Start With A Respect For Truth).

But I want to make one simple point. Weiseltier is not making an argument, he is making an assertion.

For example, Wieseltier states,

… the differences between the various realms of human existence, and between the disciplines that investigate them, are final.

Huh? who said so?

For all his complex words, Wieseltier is a dualist.

Pinker rejects the momentous distinction between the study of the natural world and the study of the human world

It is fine for Wieseltier to be a dualist. Dualism is a respectable framework. But one cannot assert that it is true, just as one cannot assert that materialism is true. Assertions are not arguments, they are articles of faith.

The advantage of the scientific/materialist framework is that it can expand. Gradually, it can explain more of the natural world. With the rise of Neuroscience, materialism is beginning to explain and understand aspects of the mental (human) world. As truth-seekers we should rejoice in this. But Neuroscience is not alone. I interpret much of the work in the liberal arts as a search for truth that is not a conflict with materialism.

Will there be convergence? Will we understand the mind — the “hard problem”? I don’t know. But simply to assert the impossibility of the task — and to attack those who attempt to bridge the divide — is turf protection and the opposite of scholarship.

Personal Identity and Agency


“I act therefore I am” — anonymous

In previous blog posts I’ve supported John Locke’s account of Personal identity. Briefly, identity is the awareness of a continuous conscious experience extending from birth to the present and extending into the future (links: here, here, here).  Locke’s conception is old, but is, I believe, consistent with modern mind-based views of identity.

Although I believe this conception is powerful, and an essential component of identity, it doesn’t seem complete. Perhaps an additional critical component is a person’s concept of his or her agency. Continue reading

Grid Cells, Place Cells and Navigation

grid module small I’ve made a posting on the BrainsFacts Blog site on Grid Cells and Path Integration. Aimed at High School and College students, but I think it gets complicated. Write your comments here!

Also, planning a third post or the Modular organization of Grid Cells. Based on new paper “Specific evidence of low-dimensional continuous attractor dynamics in grid cells” (Yoon et al) published in Nature Neuroscience.