Reading and writing brain with light

Light has always been a source of inspiration to humans.

'Let there be light', our prophets have long been commanded as.

'Lead me from darkness to light', 

our seers have asked to higher existence since long ago.

And the 2015 has been proclaimed as the 

'International year of light' 

by UN's 68th general assembly.

Optics and photonics have many positive impact in fields 

as diverse as 
energy, eduction, agriculture and health.

As a child
it was bioluminescence of fireflies
which attracted us.

And as a grown up, 
humanity is just finding 

Quantum teleportation ways, 
transforming Energy into matter, 
New light to illuminate the world.

Now reading and writing brain with light.

Holographic targeting of laser beams to individual neurons in the mouse barrel cortex. 
Photograph: Lloyd Russell/Häusser Lab/UCL 
share source: http://www.theguardian.com/science/neurophilosophy/2014/dec/22/researchers-read-and-write-brain-activity-with-light

This is a case of fields combine of
Neurology and Philosophy i.e.

Neurophilosophy.

Neuroscientists of University College London 

have found out that light could be used 

for simultaneous recording and alteration of neurons impulses 

in the living brain.

The technique, described in the journal Nature Methods, combines two existing state-of-the-art neurotechnologies.

One of them is optogenetics. This involves creating genetically engineered mice expressing algal proteins called Channelrhodopsins in specified groups of neurons. This renders the cells sensitive to light, allowing researchers to switch the cells on or off, depending on which Channelrhodopsin protein they express, and which wavelength of light is used. This can be done on a millisecond-by-millisecond timescale, using pulses of laser light delivered into the animals’ brains via an optical fibre.  

The other is calcium imaging. Calcium signals are crucial for just about every aspect of neuronal function, and nerve cells exhibit a sudden increase in calcium ion concentration when they begin to fire off nervous impulses. Using dyes that give off green fluorescence in response to increases in calcium concentration, combined with two-photon microscopy, researchers can detect this signature to see which cells are activated. In this way, they can effectively ‘read’ the activity of entire cell populations in brain tissue slices or live brains. 

High-speed calcium imaging shows
simultaneous activation of six neurons
arranged in the shape of a smiley face.
Credit: Lloyd Russell, Hausser lab, UCL

To demonstrate the precision of the technique, they used a programmable device called a spatial light modulator that splits the light beam into a hologram consisting of smaller ‘beamlets’, and then simultaneously activated six neurons arranged in the shape of a smiley face.
thankfully shared/cited from:http://www.theguardian.com/science/neurophilosophy/2014/dec/22/researchers-read-and-write-brain-activity-with-light 

“We’re excited about this,” says senior author Michael Häusser. “It unites two revolutions in neuroscience and heralds a new era in which we can abandon electrodes and use light alone to probe neural circuits during behaviour.”
Links:
https://www.ucl.ac.uk/news/news-articles/1214/231214-light-brain/ 
http://www.sciencemag.org/content/346/6216/1506
http://www.ucl.ac.uk/wibr

Abstract of article from Nature Methods in original:
(thankfully shared from: http://www.nature.com/nmeth/journal/vaop/ncurrent/full/nmeth.3217.html
We describe an all-optical strategy for simultaneously manipulating and recording the activity of multiple neurons with cellular resolution in vivo. We performed simultaneous two-photon optogenetic activation and calcium imaging by coexpression of a red-shifted opsin and a genetically encoded calcium indicator. A spatial light modulator allows tens of user-selected neurons to be targeted for spatiotemporally precise concurrent optogenetic activation, while simultaneous fast calcium imaging provides high-resolution network-wide readout of the manipulation with negligible optical cross-talk. Proof-of-principle experiments in mouse barrel cortex demonstrate interrogation of the same neuronal population during different behavioral states and targeting of neuronal ensembles based on their functional signature. This approach extends the optogenetic toolkit beyond the specificity obtained with genetic or viral approaches, enabling high-throughput, flexible and long-term optical interrogation of functionally defined neural circuits with single-cell and single-spike resolution in the mouse brain in vivo.
http://www.nature.com/nmeth/journal/vaop/ncurrent/full/nmeth.3217.html 

Figure: Simultaneous fast calcium imaging and concurrent photostimulation of multiple neurons in vivo.thankfully shared from: http://www.nature.com/nmeth/journal/vaop/ncurrent/full/nmeth.3217.html

Image of pulsing motion of the electron pair in a helium atom.

Electronic pas de deux

 

The motion of the two electrons in the helium atom can be imaged and controlled with attosecond-timed laser flashes

Physicists in Heidelberg have filmed the pulsing motion of the electron pair 
in a helium atom.
At 15.3 femtoseconds (fs) the two electrons are close to the nucleus (centre of image) 
and then move away from it. 
The colour indicates the probability of finding one electron at position A (vertical axis) 
and the second electron at position B (horizontal axis) 
on a line drawn through the atom (along the polarisation direction of the laser). 
At 16.3 femtoseconds they arrive back at their original position again; 
they thus move with a beat of around one femtosecond.

(Christian Ott, Andreas Kaldun, Luca Argenti, Philipp Raith, Kristina Meyer, Martin Laux, Yizhu Zhang, Alexander Blättermann, Steffen Hagstotz, Thomas Ding, Robert Heck, Javier Madroñero, Fernando Martín, Thomas Pfeifer. Reconstruction and control of a time-dependent two-electron wave packet.) 

Nature, 2014; 516 (7531): 374 DOI: 10.1038/nature14026

Credit: © MPI for Nuclear Physics

Electrons are hard to get a hold of. Physicists cannot determine their precise location in an atom, but they can narrow down the region where the charge carriers are most probably located. When electrons move, this brings about a change to the regions where the electrons have the highest probability of being located. In some electronic states -- physicists call them superposition states -- this motion manifests itself as a pulsing with a regular beat.

"Although we do not directly image where the electrons are," explains Thomas Pfeifer, "the visible pulse provides us with the relative phase of the superposition state." The phase describes the to and fro of an oscillation, and hence the rhythmic motion of the electron pair. In this case it tells the physicists at which point of their natural pas de deux around the helium atom the electrons are at a given moment.

At this point, at the latest, attosecond physics would create new tools for chemistry as well.

#thankfully shared and cited:http://www.sciencedaily.com/releases/2014/12/141218103219.htm 

Light of fireflies

Bioluminescence in fireflies: Fireflies used rapid light flashes to communicate. This "bioluminescence" is an intriguing phenomenon that has many potential applications, from drug testing and monitoring water contamination, and even lighting up streets using glow-in-dark trees and plants.

Mechanism: Fireflies emit light when a compound called luciferin breaks down. We know that this reaction needs oxygen, but what we don't know is how fireflies actually supply oxygen to their light-emitting cells.

The firefly's light-producing organ is called the "lantern," and it is located in the insect's abdomen. It looks like a series of tubes progressing into smaller ones and so one, like a tree's branches growing into twigs. The function of these tubes, called, is to supply oxygen to the cells of the lantern, which contain luciferase and can produce light.

Latest studies: Scientists from Switzerland and Taiwan have determined how fireflies control oxygen distribution to light up their cells.

The imaging showed that the firefly diverts oxygen from other cellular functions and puts it into the reaction that breaks up luciferin. Specifically, the researchers found that oxygen consumption in the cell decreased, slowing down energy production. At the same time, oxygen supply switched to light-emission.

This detailed microimage shows 

larger channels branching into smaller ones, 

supplying oxygen for the firefly's light emission. 

The smallest channels are ten thousand times smaller than a millimeter 

and therefore invisible to other experimental probes.

Credit: Giorgio Margaritondo/EPFL

#Yueh-Lin Tsai, Chia-Wei Li, Tzay-Ming Hong, Jen-Zon Ho, En-Cheng Yang, Wen-Yen Wu, G. Margaritondo, Su-Ting Hsu, Edwin B. L. Ong, and Y. Hwu. Firefly light flashing: Oxygen supply mechanism. Physical Review Letters, 2014 [link]
#thankfully cited and shared from:http://www.sciencedaily.com/releases/2014/12/141217074508.htm

Energy into matter

Science and mythologies: The Latin phrase "creatio ex nihilo" means "creation out of nothing," and it's largely the domain of theology, philosophy and mythology* for a reason.
The first law of thermodynamics, which is actually a conservation of energy equation, is that energy can neither be created nor destroyed. (http://science.howstuffworks.com/)

Vedic hymns: Rig Vedic hymns (of Indus valley civilization* period) are less dogmatic, more a kind of postulate or theories when they talk about matter or life related aspects, while they are thousands of year old in time.
One of the hymn illustrated here in adjoining picture-page is from 'Sukla-Yajur-veda', which says: "All the measures of time have been born from 'illustrious phenomena' (Sanskrit विद्युत, विद्युतः / electric, electricity, electrical). None can comprehend that above, across or in the middle."

Matter: Matter takes up space, has mass and composes most of the visible universe around you.

Energy: Energy takes multiple forms and is essentially the force that causes things to happen in the universe.
Energy can neither be created nor destroyed as per the first law of thermodynamics, which is actually a conservation of energy equation.

Matter and energy interchangeable: Albert Einstein theorized that matter and energy are interchangeable. Both matter and energy are variations of the same thing. Each can convert into the other. As per Einstein and the first law of thermodynamics, a fixed quantity of energy and matter exist in the universe.

pic credit:http://science.howstuffworks.com/

Annihilation: When two protons collide in the Large Hadron Collider, they may break apart into subatomic particles called quarks and a mitigating particle force called a gluon. Even when matter and antimatter annihilate each other, they produce energy, in the form of photons, which are quantum units of light.

Manufacturing matter: In the lab, creating matter entails a reaction called pair production, so called because it converts a photon into a pair of particles: one matter, one antimatter (the reverse of the matter-antimatter annihilation).

We can turn light into subatomic particles: Brookhaven National Lab, the European Organization for Nuclear Research (CERN) and Fermilab have all generated this reaction by firing a photon into a heavy atomic nucleus. The nucleus shares the energy and allows the photon to disintegrate into an electron and a positron, the antimatter opposite of an electron. The positron inevitably turns back into a photon when it collides with an electron.(credit:http://science.howstuffworks.com/environmental/earth/geophysics/can-we-manufacture-matter.htm) 
* blog post of the author

Quantum teleportation: from light into matter

Science fiction dream: Sci-fi enthusiasts have dreamt of being able to teleport from one location to another since Gene Roddenberry popularised the idea in Star Trek.

Beam me up, Scotty
pic:http://www.gizmag.com

Researchers advance 'Quantum Teleportation'

This image shows crystals used for storing entangled photons, which behave as though they are part of the same whole. Scientists used these crystals in their process of teleporting the state of a photon across more than 15 miles (25 kilometers) of optical fiber. 
Credit: Félix Bussières/University of Geneva
credit: http://www.jpl.nasa.gov/news/news.php?feature=4384

From light into matter: Physicists can't instantly transport matter, but they can instantly transport information through quantum teleportation. This works thanks to a bizarre quantum mechanics property called entanglement.

Teleporting over 25 kilometres: Researchers from the University of Geneva, NASA's Jet Propulsion Laboratory and the National Institute of Standards and Technology used a superfast laser to pump out photons. Every once in a while, two photons would become entangled. Once the researchers had an entangled pair, they sent one down the optical fiber and stored the other in a crystal at the end of the cable. Then, the researchers shot a third particle of light at the photon traveling down the cable. When the two collided, they obliterated each other.


Memory After Triangulation: Though both photons vanished, the quantum information from the collision appeared in the crystal that held the second entangled photon.

Physicists think quantum teleportation will lead to secure wireless communication — something that is extremely difficult but important in an increasingly digital world. Advances in quantum teleportation could also help make online banking more secure.

The research was published in Nature Photonics. (Quantum teleportation from a telecom-wavelength photon to a solid-state quantum memory)

Date:

September 21, 2014

Source:

Université de Genève

Summary:

Physicists have succeeded in teleporting the quantum state of a photon to a crystal over 25 kilometers of optical fiber. The experiment constitutes a first, and simply pulverizes the previous record of 6 kilometers achieved ten years ago by the same team. Passing from light into matter, using teleportation of a photon to a crystal, shows that, in quantum physics, it is not the composition of a particle which is important, but rather its state, since this can exist and persist outside such extreme differences as those which distinguish light from matter. (http://www.sciencedaily.com)  

International Year of Light 2015

Let there be light

The UN’s 68th general assembly proclaimed an official “International Year” that will focus on the science and applications of light, and seek to raise global awareness of how optics and photonics can have a positive impact in fields as diverse as energy, education, agriculture and health.(courtesy:http://optics.org/)

The Year was endorsed by UNESCO’s Executive Board in 2012 before being proclaimed by the United Nations General Assembly in December 2013.
The International Year will be marked by the commemoration of a series of important milestones in the history of the science of light dating back 1,000, 200, 150, 100 and 50 years:

• In 2015, it will be 1000 years since Ibn al-Haytham published his seminal work on optics, during a period of heightened creativity and innovation known as the Islamic Golden Age. (Read the article on The Miracle of Light);
• Leaping forward to 1815, the next milestone is Augustin-Jean Fresnel’s theory of light as a wave;
• Then comes James Clerk Maxwell’s description of the electromagnetic theory of light, in 1865;
• Albert Einstein joins the Hall of Fame for his general theory of relativity in 1916, which confirmed the centrality of light in both space and time;
• Last but not least, we shall pay tribute to Arno Penzias and Robert Woodrow Wilson for their 1965 discovery of Cosmic Microwave Background Radiation, an echo of the origin of the Universe which enables us to ‘map’ the Universe as it would have appeared shortly after the Big Bang 13.7 billion years ago, using sophisticated technologies.(courtesy:http://www.unesco.org)