neuroscience – Australian Science

Connectomics: a window to the mind

Kevin Orrman-Rossiter — Mon, 26 Aug 2013 00:08:44 +0000

Connectomics as a 3D graph. Cell types with stronger connections are positioned closer to each other, using an algorithm. Three spatially segregated groups are observed that closely match the pathways identified through clustering (colouring of spheres). The dominant direction of signal flow is oriented into the page.

The human brain has 100 billion neurons, connected to each other in networks that allow us to interpret the world around us, plan for the future, and control our actions and movements. Mapping those networks, creating a wiring diagram of the brain could help scientists learn how we each become our unique selves. Understanding the brain and all its connections is Connectomics – a word soon to become as familiar as ‘genetics’.

In three papers appearing in Nature, scientists report their first step toward this goal: Firstly using a combination of human and artificial intelligence, they have mapped all the wiring among 950 neurons within a tiny patch of the mouse retina. While a second group look at a classic problem of neural computation – the detection of visual motion – in the eye of a fruitfly.

The eye of the mouse

The retina is technically part of the brain, as it is composed of neurons that process visual information. Neurons come in many types, and the retina is estimated to contain 50 to 100 types, but they’ve never been exhaustively characterised. Their connections are even less well known. Neurons in the retina are classified into five classes: photoreceptors, horizontal cells, bipolar cells, amacrine cells and ganglion cells. Within each class are many types, classified by shape and by the connections they make with other neurons.

In this study, the research team focused on a section of the retina known as the inner plexiform layer, which is one of several layers sandwiched between the photoreceptors, which receive visual input, and the ganglion cells, which relay visual information to the brain via the optic nerve. The neurons of the inner plexiform layer help to process visual information as it passes from the surface of the eye to the optic nerve.

By mapping all of the neurons in a 117-micrometre-by-80-micrometre patch of tissue, researchers were able to classify most of the neurons they found, based on their patterns of wiring. They also identified a new type of retinal cell that had not been seen before. To map all of the connections in this small patch of retina, the researchers first took electron micrographs of the targeted section generating high-resolution three-dimensional images of biological samples.

Cite this article:
Orrman-Rossiter K (2013-08-26 00:08:44). Connectomics: a window to the mind. Australian Science. Retrieved: May 07, 2024, from http://australianscience.com.au/science-2/connectomics-a-window-to-the-mind/

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From fables to Facebook: Why do we tell stories?

Lauren — Tue, 18 Jun 2013 00:33:20 +0000

Cave painting, Lascaux, France, 15,000-10,000 BC

Throughout human history, stories have existed across all cultures in all forms, from ballads, poems, songs to oral history, plays, novels. Some narratives have evolved along with the human species—we are consistently drawn back to ancient parables, fables and fairytales, constantly reworking them into modern contexts.

Narrative is a gift unique to the human species, but how as it survived for so long? Is it a by-product of evolution or essential to survival? What drove us to painstakingly inscribe portraits on rocky walls in ochre and charcoal, to compose and listen to lengthy ballads of heroes’ tales, to nosily read people’s Facebook statuses about their day, to devour novels and films like we’re hungry for fictional worlds? Neuroscience and developmental psychology have begun to answer these questions, embarking on the ambitious task of explaining why we tell stories.

Storytelling is one of our most fundamental communication methods, for an obvious reason: narrative helps us cognise information. Telling intelligible, coherent stories to both ourselves and others helps our brains to organise data about our lives and our world. But when we ask why stories are so effective at helping us cognise information, the answers are surprising: it seems that somewhere in the otherwise ruthless process of natural selection, evolution has wired our brains to prefer storytelling over other forms of communication.

Good stories engage us. When we hear plain, bloodless facts, the language processing centres of our brain light up and we decode words into meaning—but when we’re told a story, not only are language processing centres lit up, but also a vast array of other regions distinct from those centres. For example, if you tell a friend a story about a dinner party at which you ate delicious roast pork, their sensory cortex will light up; or if you tell them about the game of football, their motor cortex will become active. The parts of the brain they would use if actually experiencing the event light up, even though they are only being told about it.

This is particularly interesting when considering the effect that literary techniques have on our brain activity. In a 2006 study published in NeuroImages, Spanish researchers asked participants to read both neutral words (such as chair and key) as well as words with strong odour associations (such as coffee, perfume, lavender and soap). Brain scans using an fMRI machine showed that when they read the odour-associated words, their primary olfactory cortex lit up; but when they read the neutral words, that region remained dark. In another study at Emory University, texture metaphors such as “the singer had a velvet voice

Cite this article:
Fuge L (2013-06-18 00:33:20). From fables to Facebook: Why do we tell stories?. Australian Science. Retrieved: May 07, 2024, from http://australianscience.com.au/psychology/from-fables-to-facebook-why-do-we-tell-stories/

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Tricks of the mind

amy.r — Mon, 14 Jan 2013 03:36:35 +0000

Have you ever experienced a sudden feeling of familiarity while in a completely new place? Or the feeling you’ve had the exact same conversation with someone before?

This feeling of familiarity is, of course, known as déjà vu (a French term meaning “already seen

Cite this article:
Reichelt A (2013-01-14 03:36:35). Tricks of the mind. Australian Science. Retrieved: May 07, 2024, from http://australianscience.com.au/psychology/tricks-of-the-mind/

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Remembering to forget

amy.r — Mon, 07 Jan 2013 00:34:16 +0000

Memories influence our behaviour for better or worse. A traumatic incident, experienced once, can darken our lives for ever more. Drug or alcohol addiction – driven by remembered rewards – can render the idea of “normal life

Cite this article:
Reichelt A (2013-01-07 00:34:16). Remembering to forget. Australian Science. Retrieved: May 07, 2024, from http://australianscience.com.au/research-2/remembering-to-forget/

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Tasting colours and seeing sound: Synaesthesia

Lauren — Wed, 07 Nov 2012 00:30:18 +0000

Kandinsky: “Composition 8”

“One hears a sound but recollects a hue, invisible the hands that touch your heartstrings,

Cite this article:
Fuge L (2012-11-07 00:30:18). Tasting colours and seeing sound: Synaesthesia. Australian Science. Retrieved: May 07, 2024, from http://australianscience.com.au/history/tasting-colours-and-seeing-sound-synaesthesia/

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