Encephalon - The Vertebrate Brain

Thanks to Mindhacks, I could find a treasure trove of information related to neuroscience and psychology. There is a community of neuroscience and psychology bloggers and they collect the best posts in the past fortnight and post it on one of their blogs. It is one of the peer-recommended, peer-hosted magazines around. It seems interesting. There have been many such issues, I thought why shouldn’t the information and links be got from one page. So here it is….

1. Issue 1
2. Issue 2
3. Issue 3
4. Issue 4
5. Issue 5
6. Issue 6
7. Issue 7
8. Issue 8
9. Issue 9
10. Issue 10
11. Issue 11
12. Issue 12
13. Issue 13
14. Issue 14
15. Issue 15
16. Issue 16
17. Issue 17
18. Issue 18
19. Issue 19
20. Issue 20
21. Issue 21
22. Issue 22
23. Issue 23
24. Issue 24
25. Issue 25
26. Issue 26
27. Issue 27
28. Issue 28
29. Issue 29
30. Issue 30
    
31. Issue 31
32. Issue 32
33. Issue 33
34. Issue 34
35. Issue 35
36. Issue 36
37. Issue 37
38. Issue 38
39. Issue 39
40. Issue 40
41. Issue 41
42. Issue 42

Most links due to Neurophilosophy, Sharpbrains. Thanks to the new Neurophilosophy for starting all this.

Mindhacks has a reading list for students

Update:- Another Blog carnival that has been temporarily suspended now is Synapse

Different views

These are some of the views about a video by ‘The Singin’ Scientist’. I strongly recommend you checkout the video at TED

•  ”some fascinating insights into the experience of having a stroke” - Deric Bownd
• “You can almost hear the sound of a thousand cognitive scientists gritting their teeth” - Vaughan
• “it’s eerily fascinating to hear this brain scientist describing what it was like” - The Thinking Meat
• “The language …. to relate her experience is very much like … describing a mystical or religious experience” - Learning Computation

It is one of the most talked about videos in TED 2008. A neuroanatomist, Jill Bolte Taylor, had a stroke in 1996 and lived on to tell her experiences in a book(amazon, lulu), a radio interview and a video.

Isn’t it amazing to see so many views?

• Deric’s View
  
• Vaughan’s view
• Thinking Meat’s View
• Kurt’s View
• Zuckerman’s commentary
• The Press

Can we see what we want or hate?

Recently there have been many articles about Mind reading devices, based on fMRI. Though there are many ethical issues around such a device. But lets us imagine such a device exists, Is it possible to find out what we really want or hate? Maybe..

An excerpt from the release at Princeton University

A team of scientists from Princeton University has devised a new experimental technique that produces some of the best functional images ever taken of the human brainstem, the most primitive area of the brain.

This region of the brain is sometimes referred to as Reptilian Brain, based on evolutionary view of looking at the brain regions. It is involved in many important human brain functions required for survival including decision making.

Some of the difficulties in looking at this region of the brain are its size, movement effects due to heart pulse, existing experimental and analysis methods.

“For a long time, scientists have tried looking at this area of the brain and have been unsuccessful — it’s just too small,” said Kimberlee D’Ardenne, the lead author on the paper.

The article by Kimberlee D’Ardenne, Samuel M. McClure, Leigh E. Nystrom, and Jonathan D. Cohen appeared in February Issue of Science Magazine. They overcome the above difficulties combining a number of techniques including synchronizing the fMRI with heart rate, using novel pulse sequences, novel algorithms for processing the data.

They look at brain activity of thirsty humans when drops of juice/water/money are given and find that the activity in the brain stem encodes positive reward prediction error, error when an unexpected reward is given, and the probability of getting any reward. But they couldn’t find the negative reward prediction error, error when expected reward is not given.

So they can find what you want but not what you hate. But the take home is the ability to look at brain stem activity.

• An Article on Mind Reading
• About fMRI
• Article at Princeton.
• Princeton link from The Thinking Meat
• About Reptilian Brain
• Article abstract at Science

D’Ardenne K, McClure SM, Nystrom LE, Cohen JD (200 BOLD responses reflecting dopaminergic signals in the human ventral tegmental area. Science 319: 1264-1267 link

A few interesting blog articles..

Along came few nice stories..

• How irrational are we? - Proof to our complexity
• A vote for extra-curricular activities - Hurray for the rolling stones
• A few more Options wastes your resources - Take action
• Uncommon Knowledge - Modern Myths
• Shot at Hypertension - Progress
• How efficiently use Caffeine? - A suggestion
• Effective emotion Control - Some help
• How cruel can we be? - Retrospect

Enjoy your time with these enlightening views.

Artifacts of Decision Making in the Brain

We take decisions all the time from the most simple(food) to the most complex(invest, career, friends).

Ever wondered

• Where in the brain does this all happen?
• How do we make these decisions?
• How good are we at making these decisions?
• and many more…

One of the decision making theories is based on learning to decide better simply based on rewards and punishments. It has been extensively studied in machine learning, statistics, control communities under the guise of Reinforcement Learning. Temporal Difference learning is one of the simplest models of reinforcement learning used to explain learning from rewards. The learning in the model is based on difference in the expected future reward and actual reward, Temporal Prediction Error.

Decision making behavior of animals was extensively studied and models of their behavior were proposed. Conditioned response to an object in the presence/absence of reward was one of the widely studied behaviors. When animals were repeatedly presented by the object followed by reward, animals started expecting reward on presenting the object.

Models of animal behavior were developed conditioned on just the object and actions taken by the animal. Rescorla-Wagner(RW) model was one of the models used to explain the conditioned reward animal behavior. This model is based on increasing/decreasing the association strength between reward and preceding object presentation. Come to think of it temporal difference learning is very similar to RW model and maybe its offshoot.

Significant amount of work in understanding decision making regions of the brain started after the seminal paper by Wolfram Schultz, Peter Dayan and Read Montague which showed that Dopamine neurons(DA) in Ventral Tegmental Area(VTA) encode the temporal prediction error.

This has led to a new field of research - Neuro-economics - for studying the decision-making aspects of the brain.

Schultz, W., Dayan, P., Montague, P.R. (1997) A Neural substrate of prediction and reward. Science, 275: 5306, 1593-1599. link