Saturday, December 1, 2012

skeptv:

New Brain Model of Earliest Primate

Researchers from the universities of Florida and Winnipeg have reconstructed the brain of Ignacius graybullianus, one of the earliest primates known, from a 54-million-year-old fossil skull. It’s the most complete brain model of its kind and casts new light on the beginnings of primate brain development.

Sunday, April 22, 2012

fuckyeahmolecularbiology:

Neuropathologist dissecting a fresh human brain. By studying the shape and structure of a brain, most brain disorders can be diagnosed. For instance, Alzheimer’s disease causes shrinkage and the fissures appear to grow. A stroke causes localised brain tissue death, and Creutzfeldt- Jakob disease gives the brain a spongy appearance with evident holes. This type of pathology is carried out not only to try to find causes of death, but also in research into all brain disorders.

(Source: neuroanatomyblog)

Friday, December 16, 2011

darkroomromance:

This is by far the most beautiful Ted Talk in existence.

Jill Bolte Taylor’s Stroke of Insight

Or, how a stroke resembles meditation. (Or drugs.)

Sunday, October 9, 2011

The Science of Significance - empathy in the amygdala

How do we know our mum is our mum? What does it mean to have ‘déjà vu’ and what makes us gaze in wonder at our surrounding universe?

The answer may lie in a small part of the brain called the amygdala.

An almond shaped region sitting close to the hippocampus, the amygdala has numerous vital neurological roles, which include interpreting social signals and controlling emotional responses.It is also thought to be involved in providing a sense of self.

Such correlative examples merely skim the surface of the amygdala’s functions, many of which we still do not know. When primate amygdalas were experimentally severed it was found that they were no longer able to respond to social cues, became withdrawn and, critically, lost their previously held positions in the social group hierarchy.

Just like monkeys, human society operates through social hierarchies. As group sizes grew in our ancestral apes, so did the evolutionary drive for social behaviours and thus the development of associated brain regions, including the amygdala. One of the vital traits that resulted from this development was the ability to empathise.

The ability to imagine oneself in another’s place is generally thought to be unique to humans and requires complex neurological processes. This includes the ability to associate significance to the behaviour of others, which means, for example, being able to appreciate instinctively what makes a laugh nervous, a glance stern, a gaze loving or a smile fake and to understand the driving force behind why another displays such behaviour. It then requires the association of an adequate response to that behaviour, such as suspicion, fear, anger or laughter. The part of the brain correlated with these functions is once again the amygdala.

(Source: bluesci.org)

Wednesday, October 5, 2011

"Neuronal recycling" - what our brains evolved to do vs what they CAN do - and whither the twain shall meet

The next giant leap in human evolution may not come from new fields like genetic engineering or artificial intelligence, but rather from appreciating our ancient brains.

[…]

This mystery mechanism of human transformation is neuronal recycling, coined by neuroscientist Stanislas Dehaene, wherein the brain’s innate capabilities are harnessed for altogether novel functions.

[…]

Neuronal recycling exploits this wellspring of potent powers. If one wants to get a human brain to do task Y despite it not having evolved to efficiently carry out task Y, then a key point is not to forcefully twist the brain to do Y. Like all animal brains, human brains are not general-purpose universal learning machines, but, instead, are intricately structured suites of instincts optimized for the environments in which they evolved. To harness our brains, we want to let the brain’s brilliant mechanisms run as intended—i.e., not to be twisted. Rather, the strategy is to twist Y into a shape that the brain does know how to process.

[…]

We have already been transformed via harnessing beyond what we once were. We’re already Human 2.0, not the Human 1.0, or Homo sapiens, that natural selection made us. We Human 2.0’s have, among many powers, three that are central to who we take ourselves to be today: writing, speech, and music (the latter perhaps being the pinnacle of the arts). […]

In this transition from Human 1.0 to 2.0, we didn’t directly do the harnessing. Rather, it was an emergent, evolutionary property of our behavior, our nascent culture, that bent and shaped writing to be right for our visual system, speech just so for our auditory system, and music a match for our auditory and evocative mechanisms.

And culture’s trick? It was to shape these artifacts to look and sound like things from our natural environment, just what our sensory systems evolved to expertly accommodate.

There are characteristic sorts of contour conglomerations occurring among opaque objects strewn about in three dimensions (like our natural Earthly habitats), and writing systems have come to employ many of these naturally common conglomerations rather than the naturally uncommon ones. Sounds in nature, in particular among the solid objects that are most responsible for meaningful environmental auditory stimuli, follow signature patterns, and speech also follows these patterns, both in its fundamental phoneme building blocks and in how phonemes combine into morphemes and words. And we humans, when we move and behave, make sounds having a characteristic animalistic signature, something we surely have specialized auditory mechanisms for sensing and processing; music is replete with these characteristic sonic signatures of animal movements, harnessing our auditory mechanisms that evolved for recognizing the actions of other large mobile creatures like ourselves.

[Mark Changizi Humans, Version 3.0 in Seed Magazine. Emphasis added.]

Yes, yes, fascinating, great point, hmmm, and yes.

I’ve always been intrigued by the difference between (inherent) capability as opposed to (expressed) ability - especially when it comes to primate (and human) behaviour.

Let’s take language in extant primates. Chimpanzees, when taught, can become reasonably fluent (I’m using that word broadly) in sign language. They have been known to teach it to each other. After becoming familiar and comfortable with speaking, they are distressed when they are placed with chimps who cannot speak - to the point that they refuse to acknowledge, refuse to identify, those other chimps.

And, yet: it is an indisputable fact that, had they not been taught sign language, had they not been taught a language, they would not have invented one on their own. They didn’t “evolve” to speak - and yet, they can. They don’t regularly express the ability, yet they are nonetheless capable.

Language isn’t the best example, because there is good reason to believe that the ability was under direct selective pressure (which is to say that those individuals with better lingustic facilities were indeed more capable of survial and reproduction).

On the other hand, we’re also beginning to realize that, no matter how good at language the brain is, the portions of the brain that are primarily concerned with language not only had to come from somewhere (which is to ask, what were they doing before they were helping us talk) - but, they might have been shaped by a pressure to do something other than talk - at least, at first. (Visual processing, spacial awareness, and mental imaging being surprisingly and intriguingly related to language. One of the theories suggests that mental modeling and visualization - building, forming, and holding a mental reconstruction of, say, the landscape - was the mental “facility” that was, primarily, providing a survival benefit - and that language was a side-effect, a symptom, of the same constructs which enabled “mapping”.)

An even worse analogy would be to compare it to a disease vs its symptoms: we’re increasingly well aware of what we do (the symptoms) but unfortunately ignorant of the mechanisms and the causes and how we came to do it (the disease).

What else can a (primate) brain do - that it hasn’t yet been asked to? That it wasn’t, five million years ago as the forests began to withdraw and the savanna spread, immediately advantageous to do - but that might be related, use the same mechanisms?

Tuesday, October 4, 2011

eudaimonist:

2,500-Year-Old Brain Examined:

First dug up in 2008 by archaeologists in York, England, the well-preserved brain prompted experts to investigate how the tissue had stayed in such good shape. Above, a computer-generated scan of the 2,500-year-old human skull shows brain matter in dark gray. The lighter gray colors in the skull represent soil. Protein analysis confirmed the ancient brain matter—dated to between 673 and 482 B.C.—belonged to a human, said study co-author Matthew Collins, an archaeologist at the University of York.

“The majority of the mass of the brain is still there, but it’s quite reduced in volume—it’s lost a lot of water,” he said. A new study released in March suggests that the skull had been quickly buried in a pit full of thick, wet clay—among several factors that may have helped prevent the brain from decomposing. The cool, low-oxygen conditions of the soil may have aided in the brain’s preservation, according to the study, published in the Journal of Archaeological Science. Analyses of the tissue and remains of the surrounding skull suggest the Iron Age brain belonged to a male between 26 and 45 who was hanged and then ritually decapitated. The rest of the man’s body hasn’t been located.

Wednesday, September 28, 2011
jtotheizzoe:

A brief history of the brain
An amazing feature in New Scientist explores how brains came into being, from the days of single-celled organisms and chemical signals to the modern human brain and its capacity for abstract artistic thought. Don’t miss this one.

How did we acquire our beautiful brains? How did the savage struggle for survival produce such an extraordinary object? This is a difficult question to answer, not least because brains do not fossilise. Thanks to the latest technologies, though, we can now trace the brain’s evolution in unprecedented detail, from a time before the very first nerve cells right up to the age of cave art and cubism.

(via New Scientist, image via foxtongue on Flickr)

jtotheizzoe:

A brief history of the brain

An amazing feature in New Scientist explores how brains came into being, from the days of single-celled organisms and chemical signals to the modern human brain and its capacity for abstract artistic thought. Don’t miss this one.

How did we acquire our beautiful brains? How did the savage struggle for survival produce such an extraordinary object? This is a difficult question to answer, not least because brains do not fossilise. Thanks to the latest technologies, though, we can now trace the brain’s evolution in unprecedented detail, from a time before the very first nerve cells right up to the age of cave art and cubism.

(via New Scientist, image via foxtongue on Flickr)

Wednesday, September 21, 2011
How can a few black marks on a white page evoke an entire universe of sounds and meanings? Our cortex is the product of millions of years of evolution in a world without writing, so how did it adapt to recognize words? Stanislas Dehaene, Reading in the Brain (via smilebehindthemadness)
Sunday, September 18, 2011

degig:

The Brain’s Silent Majority: How the Other 90 Percent of Your Brain Works

Neurons are the brain’s rock stars. But without the glial cells — astrocytes, microglia and oligodendrocytes — there would be no show at all.

VERY interesting. One of my favorite articles I’ve read about neuroscience. Definitely worth reading.

Saturday, September 17, 2011 Wednesday, September 14, 2011
What is the self? How does the activity of neurons give rise to the sense of being a conscious human being? Even this most ancient of philosophical problems, I believe, will yield to methods of empirical science. It now seems increasingly likely that the self is not a holistic property of the entire brain; it arises from the activity of specific sets of interlinked brain circuits. But we need to know which circuits are critically involved and what their functions might be. It is the ‘turning inward’ aspect of the self — its recursiveness — that gives it its peculiar paradoxical quality.

John Brockman gathers 15 years of seminal thinking on understanding the mind (via curiositycounts)

And, for my to-read-list… jumping straight to the top.

eudaimonist:

Brain casts of the hominid fossil Australopithecus:
Found in the limestone caves at Sterkfontein, South Africa in 1936, endocasts are formed when petrified sediments fill the cranium after death. They are casts of the brain case and represent fossil brains. The australopithecines are thought to be the oldest known group of hominids. They date from 3.7 to 1.6 million years ago & were widely distributed through Africa. Three species are known & two distinct types, gracile & robust are apparent; the former lightly-built & omnivorous, the latter heavily built and vegetarian.

eudaimonist:

Brain casts of the hominid fossil Australopithecus:

Found in the limestone caves at Sterkfontein, South Africa in 1936, endocasts are formed when petrified sediments fill the cranium after death. They are casts of the brain case and represent fossil brains. The australopithecines are thought to be the oldest known group of hominids. They date from 3.7 to 1.6 million years ago & were widely distributed through Africa. Three species are known & two distinct types, gracile & robust are apparent; the former lightly-built & omnivorous, the latter heavily built and vegetarian.

Wednesday, August 31, 2011
Intriguingly, cephalopod ink sometimes contains dopamine. In our own brains, dopamine is a neurotransmitter that produces euphoria. It’s central to our reward system and involved in sex and drug addiction. The presence of the same molecular compound in squid ink is mysterious. Does a predator get high on the dopamine in the squid ink and give up its hunt? No one knows, but dopamine’s presence in cephalopods implies that the molecule has been around, in one role or another, since the earliest days of evolution. If we ever come to understand its role in squid ink, perhaps we’ll understand something more about our own predilections for addictive behavior. Wendy Williams - Kraken: The Curious, Exciting, & Slightly Disturbing Science of Squid (via therecipe)