The Significance of the Modular Organization of Entorhinal Grid Cells

Enthusiastic and Excited┬áresponse to the publication of “The entorhinal grid map is discretized” (Stensola, et al, Nature, 492, 72-78; 2012)

Background

The hippocampal formation is an amazing place, populated by strange characters called place cells, head-direction cells and grid cells. Hippocampal place cells exhibit “location-specific firing” (see figure). A single place cell willtwo grid cell2 “fire” only when the rat crosses a restricted region of space. The figure below is an overhead-view map of the firing of a single place cell averaged over a 16-minute recording session (the animal was in a cylindrical enclosure; that’s why the map is round). John O;Keefe, followed by many others, has suggested that the collective firing of hippocampal place cells forms the rat’s “cognitive map”, and permits efficient navigation.

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Rules and Values for Moral Robots

I’d like to start by thanking Gary Marcus for starting a terrific series of Neuroscience discussions from his post as New Yorker’s Neuroscience Blogger. Each topic has been juicy, and each perspective fresh.auto-man2

This is a continued discussion from Gary’s first post: Moral Machines. As with Gary, I’m going to focus on the design strategy for programming moral behavior into a robot.

Gary’s post focuses on Isaac Asimov’s rules for programming moral behavior into robots. The most prominent commandment is the first:

A robot may not injure a human being or, through inaction, allow a human being to come to harm.

Gary explores whether this is sufficient.

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Was Cajal a Newton?

Over the past few days the question has been raised: “Does Neuroscience Need a Newton?”. Gary Marcus says yes. Scicurious says “no”.neuron doctrine

I think Neuroscience has aready had one: Cajal. Read Gordon Shepherd’s 1991 book Foundations of the Neuron Doctrice. The 19th century scientists were lost, arguing about which of the artifacts seen under the microscope were which. Cajal, in remote Spain, peered through his microscope and saw neurons.

Living on the current side of this revolution, its hard to imagine the 19th century image of neural function. Were juices flowing down tubes? Were strings being pulled?

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What’s wrong with Neuroscience (fMRI)?

Gary Marcus has a marvelous article in this week’s New Yorker that points out the over-reach the media has imposed on Neuroscience. Neuroscience has progressed, but is still in its infancy. I have no disagreement with Marcus. This post is part of a conversation.place cell

A major culprit has been functional imaging (fMRI) as presented in the media. Functional imaging has been a wonderful advance that permits a glimpse of the activity in regions of the normal human brain. A wonderful tool, but it is a tool with serious limitations. It doesn’t lead to direct understanding how the brain works. Let me explain.

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A Fan’s Notes: Ray Rice’s amazing run and what it says about conscious decision making

I’m a big Ray Rice fan. Last Sunday Ray made an amazing run on 4th and 29; some have called it the play of the season. I watched re-runs many times (he said, sheepishly).ray

A few hours later I watched the press conference interview, where he describes what was going thru his mind. Fascinating.

There is debate in Neuroscience about free will and conscious decision making. When we think we are making a deliberative choice, are we fooling ourselves? I believe, generally not.

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Great Book on Memory

memorybookI just finished reading Memory: Fragments of Modern History by Alison Winter. Simply, its a great book. My only problem was that I spent most of yesterday reading it when I had other stuff to do. I read about the book yesterday morning from a TLS review by Jonathan Sutton. In this web era, I read the review yesterday morning, bought the kindle book for about $5 a few minutes later and started reading within minutes. As noted, my day was redirected.

Sutton’s review is mixed and, I think, grossly unfair. “Memory” is about 250 pages long. A serious, complete, encyclopedic treatise on memory would be 10s of thousands of pages (I have one such book: Encyclopedia of Memory. Unreadable). What Alison Winter does, and what she says she is going to do, is take a few jumping off points and proceed. While these are clearly linked, they can be read as independent essays. I loved two of the topics (Penfield and Bartlett) and liked the rest. This is not because these two are better, but because I’m just not as interested in PTSD or childhood sexual abuse.

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