Dammit, Jim, I'm a blogger not a scientist!

frickyeah1990s: Trent Lane… me

Tue, 21 May 2013 17:02:23 -0400

frickyeah1990s:

Trent Lane…

holmies. [x] #no gang signs #i don’t want to see this on your...

Tue, 21 May 2013 14:07:23 -0400

holmies.

[x]

#no gang signs #i don’t want to see this on your myspace page #just kidding throw it up there

They didn’t choose the thug life

the thug life chose them

inchells: No one messes with this hobbit.

Tue, 21 May 2013 13:40:30 -0400

inchells:

No one messes with this hobbit.

neurosciencestuff: Complex brain function depends on...

Tue, 21 May 2013 13:32:49 -0400

neurosciencestuff:

Complex brain function depends on flexibility

Over the past few decades, neuroscientists have made much progress in mapping the brain by deciphering the functions of individual neurons that perform very specific tasks, such as recognizing the location or color of an object.

However, there are many neurons, especially in brain regions that perform sophisticated functions such as thinking and planning, that don’t fit into this pattern. Instead of responding exclusively to one stimulus or task, these neurons react in different ways to a wide variety of things. MIT neuroscientist Earl Miller first noticed these unusual activity patterns about 20 years ago, while recording the electrical activity of neurons in animals that were trained to perform complex tasks.

“We started noticing early on that there are a whole bunch of neurons in the prefrontal cortex that can’t be classified in the traditional way of one message per neuron,” recalls Miller, the Picower Professor of Neuroscience at MIT and a member of MIT’s Picower Institute for Learning and Memory.

In a paper appearing in Nature on May 19, Miller and colleagues at Columbia University report that these neurons are essential for complex cognitive tasks, such as learning new behavior. The Columbia team, led by the study’s senior author, Stefano Fusi, developed a computer model showing that without these neurons, the brain can learn only a handful of behavioral tasks.

“You need a significant proportion of these neurons,” says Fusi, an associate professor of neuroscience at Columbia. “That gives the brain a huge computational advantage.”

Lead author of the paper is Mattia Rigotti, a former grad student in Fusi’s lab.

Multitasking neurons

Miller and other neuroscientists who first identified this neuronal activity observed that while the patterns were difficult to predict, they were not random. “In the same context, the neurons always behave the same way. It’s just that they may convey one message in one task, and a totally different message in another task,” Miller says.

For example, a neuron might distinguish between colors during one task, but issue a motor command under different conditions.

Miller and colleagues proposed that this type of neuronal flexibility is key to cognitive flexibility, including the brain’s ability to learn so many new things on the fly. “You have a bunch of neurons that can be recruited for a whole bunch of different things, and what they do just changes depending on the task demands,” he says.

At first, that theory encountered resistance “because it runs against the traditional idea that you can figure out the clockwork of the brain by figuring out the one thing each neuron does,” Miller says.

For the new Nature study, Fusi and colleagues at Columbia created a computer model to determine more precisely what role these flexible neurons play in cognition, using experimental data gathered by Miller and his former grad student, Melissa Warden. That data came from one of the most complex tasks that Miller has ever trained a monkey to perform: The animals looked at a sequence of two pictures and had to remember the pictures and the order in which they appeared.

During this task, the flexible neurons, known as “mixed selectivity neurons,” exhibited a great deal of nonlinear activity — meaning that their responses to a combination of factors cannot be predicted based on their response to each individual factor (such as one image).

Expanding capacity

Fusi’s computer model revealed that these mixed selectivity neurons are critical to building a brain that can perform many complex tasks. When the computer model includes only neurons that perform one function, the brain can only learn very simple tasks. However, when the flexible neurons are added to the model, “everything becomes so much easier and you can create a neural system that can perform very complex tasks,” Fusi says.

The flexible neurons also greatly expand the brain’s capacity to perform tasks. In the computer model, neural networks without mixed selectivity neurons could learn about 100 tasks before running out of capacity. That capacity greatly expanded to tens of millions of tasks as mixed selectivity neurons were added to the model. When mixed selectivity neurons reached about 30 percent of the total, the network’s capacity became “virtually unlimited,” Miller says — just like a human brain.

Mixed selectivity neurons are especially dominant in the prefrontal cortex, where most thought, learning and planning takes place. This study demonstrates how these mixed selectivity neurons greatly increase the number of tasks that this kind of neural network can perform, says John Duncan, a professor of neuroscience at Cambridge University.

“Especially for higher-order regions, the data that have often been taken as a complicating nuisance may be critical in allowing the system actually to work,” says Duncan, who was not part of the research team.

Miller is now trying to figure out how the brain sorts through all of this activity to create coherent messages. There is some evidence suggesting that these neurons communicate with the correct targets by synchronizing their activity with oscillations of a particular brainwave frequency.

“The idea is that neurons can send different messages to different targets by virtue of which other neurons they are synchronized with,” Miller says. “It provides a way of essentially opening up these special channels of communications so the preferred message gets to the preferred neurons and doesn’t go to neurons that don’t need to hear it.”

Photo

Tue, 21 May 2013 13:17:14 -0400

Hard-hitting news

Tue, 21 May 2013 12:57:18 -0400

Hard-hitting news

willietheplaidjacket: John Watson painted using my shiny new...

Tue, 21 May 2013 12:55:48 -0400

willietheplaidjacket:

John Watson painted using my shiny new tablet.

My eyes hurt from staring at my laptop for so long. I think it was worth it. The things I can achieve when it involves Martin Freeman… and I have a good image as a reference.

I thought this was a photograph.

Would you mind talking about the processes a little? Do you start with a blunt concept? Does it change as the words come out? Do you tend to have a set "step by step" process, so to speak, that you lean on with writing?

Tue, 21 May 2013 12:39:18 -0400

There’s very little actual process for my poetry (as opposed to my prose, which I tend to structure more before I even write it). I’ll have a vague idea or emotion in mind and just write what that thing is. I know that doesn’t make a lot of sense. It’s hard enough for me to understand myself, let alone explain. I ‘receive’ (that word doesn’t seem right but I’ll use it anyway) a lot of mental imagery and physical sensation when I feel an emotion. I try to write what those things are. Sometimes it works, sometimes it doesn’t.

How long does it take you to write a poem? Is it as effortless as you make it seem or straight revision, revision, revision?

Tue, 21 May 2013 12:30:00 -0400

I cranked out that one I just posted like an hour before it was due and it turned out sort of okay. If it’s a poem I actually sort of like, I might churn it out quickly to establish a sort of skeleton then go back and add the flesh and circulatory system and genitalia. That might take a total of two hours or so.

the-lonely-scottish-guy: ‘stop being overdramatic’ they say ‘i dont know whaat you mean’ i say as i...

Tue, 21 May 2013 12:27:26 -0400

the-lonely-scottish-guy:

‘stop being overdramatic’ they say

‘i dont know whaat you mean’ i say as i descend from the ceiling, surrounded by mist

Photo

Tue, 21 May 2013 11:52:31 -0400

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Tue, 21 May 2013 11:52:16 -0400

Lucifer and Visitor

Tue, 21 May 2013 11:34:00 -0400

I wrote this poem for a class then proceeded to completely forget about it, so here it is.

The Devil mourned his homeland lost

Upon a stone in exile deep

Beneath the great earth’s hardened crust

Where fires rage inside the sea

Much too far for father sky

To see the rock where The Devil lie

As he lamented, sullen, weary

Expression that of sorrow true

A Thing appeared, and very clearly

Cracked the gates of Lucifer’s tomb

The grin that danced upon his face

Found hell to be the quaintest place

The thing approached and asked him kindly,

“Why do you mourn your banishment?

All the land above I see

But I’ve never seen an armament

So well hidden from my mighty eyes

Which see all things as they live and die

For I grow restless by the day

When I see the angels serve

And humans so engaged in play

Unaware that they deserve

For my wrathful hand to crush them quick

And maintain that they had asked for it

I was there for heaven’s birth

A burst of light in infinity

I’d have watched it grow, but- for what it’s worth-

I found the whole thing uninteresting

That rampant Lord and all his fleet

Like insects underneath my feet

The rancid things, they can’t compare

To all of my eternities

The nebulas I birthed in air

The stars I created in my dreams

Infinity and nothingness

From Chaos I created this

Some billion has this Sheppard high

Within the fences of His keep

Now I; don’t bother asking, I

Think but a fool can count his sheep

Human, land, the weeping sea

All this and more belongs to me

The steely grass of Serbia

The golden waves of deserts vast

Broken bone and melancholia

All contained within my grasp

What good exists and soothes your thirst

Exists for I did not kill it first

I’ve come to them as famine then

The mercy of the summer rain

Play after plague, and time again

I relieved them from my wanton pain

The murder, the cry, the whispered plea

All this and more commanded by me

I am the sun, the single eye

And should it flutter but one time

All of human and the earth should die

My cosmos would pay you not a mind

So when you speak of evil deeds

I laugh, for you have heard of me

So one day out of ennui I

Took him down from out the sky

I snapped his neck and broke his spine

And wore his skin for quite some time

I think it funny how rather odd

The humans never knew their god

I caused the most brilliant wars in his name!

Ah- I shudder how to think

Whenever I killed, he took the blame

Endless blood I had to drink

Humans are so simple that

For millennia they worshipped a marionette.”

He laughed and like a tolling bell

It rang through every corridor,

Off every wall of raging Hell

And flung itself upon the floor,

The lake, the castle, the mighty throne

And claimed the palace as its own

He spoke again, his voice as sweet

As Eve’s last fruit in paradise

And Lucifer could not help but eat

The knowledge would be worth the price

To posses all this creature’s mind

If only he had been this kind:

“Please don’t weep, future god

I find you lovely beyond compare

In your corruption of all right and good

And so, in kindness, you I’ll spare

You’ll never fear your Lord again

God is dead, I’ve eaten him.”

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Tue, 21 May 2013 10:13:36 -0400

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Tue, 21 May 2013 10:01:52 -0400

If they could improve the writing in that Hannibal show, I might enjoy it more. I think it should be...

Tue, 21 May 2013 10:01:08 -0400

If they could improve the writing in that Hannibal show, I might enjoy it more. I think it should be renewed for another season, but they have to sack whoever’s doing most of the writing because they always make it like 75 percent of the way to great but never quite get there. The focus should be on good storytelling, not how macabre you can make something while still playing it on TV.

Photo

Tue, 21 May 2013 09:56:14 -0400

Photo

Tue, 21 May 2013 09:39:07 -0400

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Tue, 21 May 2013 01:24:19 -0400

lonelywhiteasian: lay nudes at my gravestone, not flowers. flowers will wither away, but a bomb ass...

Tue, 21 May 2013 00:39:50 -0400

lonelywhiteasian:

lay nudes at my gravestone, not flowers. flowers will wither away, but a bomb ass booty is forever