Lifeboat Foundation

By Kevin Kang

A recent article in ScienceDaily reviews a new approach in Synthetic Biology that allows cells to respond to a series of input stimuli and simultaneously remember the order of these stimuli over many generations. As noted by the senior investigator, Timothy Lu from MIT, combining computation with memory creates complex cellular circuits that can perform logic functions and store memories of events by encoding them in their DNA (1,2). In their current work, Dr. Lu and his colleagues created cells that can remember and respond to three different inputs, including chemical signals in a particular order, and in the future may be able to incorporate even more inputs (1,2,3). The cellular machines thus created are referred to as biological “state machines” because they exist in different states depending on the identity and order of inputs that they receive. The state machines rely on enzymes called recombinases. When activated by a specific input, recombinases either delete or invert a particular segment of DNA depending on the orientation of two DNA target sequences known as recognition sites. The segment of DNA between these sites may have recognition sites for other recombinases that respond to different inputs. Flipping or deleting these sites permanently changes what will happen if a second or third recombinase is later activated. Therefore, a cell’s history is determined by sequencing its DNA. In a version of this system with just two inputs, there are five possible states for this circuit: states corresponding to no input, input A alone, input B alone, A followed by B, and B followed by A. Dr. Lu’s team in MIT has designed and built circuits that record up to three inputs, in which sixteen states are possible (1,2).

Besides creating circuits that record events in a cell’s life and then transmit these memories to future generations, the researchers from MIT also placed genes into the array of recombinase binding sites along with genetic regulatory elements. In these circuits, when recombinases rearrange the DNA, the circuits record the information as well as control which genes get turned on and off. Lu’s lab tested this work in bacteria by color coding the identity and order of input stimuli, so input A followed by B would would lead to bacteria fluorescing red and green, but input B followed by A would lead to red and blue fluorescence. Hence, these techniques can be used not only to record the states that the cells experience over time, but also to deploy in state-dependent gene expression programs (1,2).

Continue reading “Novel Approach to Biological Circuit Design Allows Scientists to Track Cell Lineages” »

New insights on the Thalamo-Cortical Nuero Netowrk of Acute Ischaemic Stroke victims.

The neocortex and thalamus provide a core substrate for perception, cognition, and action, and are interconnected through different direct and indirect pathways that maintain specific dynamics associated with functional states including wakefulness and sleep. It has been shown that a lack of excitation, or enhanced subcortical inhibition, can disrupt this system and drive thalamic nuclei into an attractor state of low-frequency bursting and further entrainment of thalamo-cortical circuits, also called thalamo-cortical dysrhythmia (TCD). The question remains however whether similar TCD-like phenomena can arise with a cortical origin. For instance, in stroke, a cortical lesion could disrupt thalamo-cortical interactions through an attenuation of the excitatory drive onto the thalamus, creating an imbalance between excitation and inhibition that can lead to a state of TCD. Here we tested this hypothesis by comparing the resting-state EEG recordings of acute ischaemic stroke patients (N = 21) with those of healthy, age-matched control-subjects (N = 17). We observed that these patients displayed the hallmarks of TCD: a characteristic downward shift of dominant α-peaks in the EEG power spectra, together with increased power over the lower frequencies (δ and θ-range). Contrary to general observations in TCD, the patients also displayed a broad reduction in β-band activity. In order to explain the genesis of this stroke-induced TCD, we developed a biologically constrained model of a general thalamo-cortical module, allowing us to identify the specific cellular and network mechanisms involved. Our model showed that a lesion in the cortical component leads to sustained cell membrane hyperpolarization in the corresponding thalamic relay neurons, that in turn leads to the de-inactivation of voltage-gated T-type Ca²⁺ -channels, switching neurons from tonic spiking to a pathological bursting regime. This thalamic bursting synchronises activity on a population level through divergent intrathalamic circuits, and entrains thalamo-cortical pathways by means of propagating low-frequency oscillations beyond the restricted region of the lesion. Hence, pathological stroke-induced thalamo-cortical dynamics can be the source of diaschisis, and account for the dissociation between lesion location and non-specific symptoms of stroke such as neuropathic pain and hemispatial neglect.

The thalamus is involved in the relay and processing of most sensory information, and provides an interface between subcortical structures and the neocortex. However, disruptions in the subcortical communication with the thalamus are known to lead to thalamo-cortical dysrhythmia (TCD), which is linked to symptoms in a range of illnesses including Parkinson’s disease, neurogenic pain syndrome and tinnitus. Thus far, TCD has solely been interpreted in terms of changes within subcortical pathways, but here we investigate how cortical disturbances (i.e., ischaemic stroke) may affect thalamic function in a similar manner. We do so by analysing the electroencephalogram (EEG) of stroke patients with a cortical lesion, and show that their EEG power spectra display the characteristic features of TCD.

Continue reading “The Impact of Cortical Lesions on Thalamo-Cortical Network Dynamics after Acute Ischaemic Stroke: A Combined Experimental and Theoretical Study” »

Video games. The last i heard AI had been up to playing and Mastering Atari 2600 games, and that was a few years ago. Figured it was only a matter of time til they started playing around with current gen stuff.

Neural net driving in GTAV — View all crizcraig’s Rockstar Editor videos at http://socialclub.rockstargames.com/member/crizcraig

Hmmm.

Testimonials from prominent physics researchers from institutions such as Cambridge University, Princeton University, and the Max Planck Institute for Physics in Munich claim that quantum mechanics predicts some version of “life after death.”

They assert that a person may possess a body-soul duality that is an extension of the wave-particle duality of subatomic particles.

Continue reading “Consciousness Lives in Quantum State After Death Physicists Claim” »

Neurons that fire together really do wire together, says a new study in Science, suggesting that the three-pound computer in our heads may be more malleable than we think.

In the latest issue of Science, neuroscientists at Columbia University demonstrate that a set of neurons trained to fire in unison could be reactivated as much as a day later if just one neuron in the network was stimulated. Though further research is needed, their findings suggest that groups of activated neurons may form the basic building blocks of learning and memory, as originally hypothesized by psychologist Donald Hebb in the 1940s.

“I always thought the brain was mostly hard-wired,” said the study’s senior author, Dr. Rafael Yuste, a neuroscience professor at Columbia University. “But then I saw the results and said ‘Holy moly, this whole thing is plastic.’ We’re dealing with a plastic computer that’s constantly learning and changing.”

Continue reading “Researchers ‘reprogram’ network of brain cells in mice with thin beam of light” »

Researchers have used CRISPR—a revolutionary new genetic engineering technique—to convert cells isolated from mouse connective tissue directly into neuronal cells.

In 2006, Shinya Yamanaka, a professor at the Institute for Frontier Medical Sciences at Kyoto University at the time, discovered how to revert adult connective tissue cells, called fibroblasts, back into immature stem cells that could differentiate into any cell type. These so-called induced pluripotent stem cells won Yamanaka the Nobel Prize in medicine just six years later for their promise in research and medicine.

Since then, researchers have discovered other ways to convert cells between different types. This is mostly done by introducing many extra copies of “master switch” genes that produce proteins that turn on entire genetic networks responsible for producing a particular cell type.

Mirror neurons allow individuals to, in essence, feel what others are experiencing. These neurons fire when an individual experiences something and when they observe the same or similar act happen to another.

Synesthesia, a neurological trait with more than 80 forms and growing numbers of people who recognize it in themselves, is mostly associated with famous creatives who have possessed it–from Pharrell Williams to David Hockney and from Mary J. Blige to Marilyn Monroe.

Continue reading “Synesthesia: How Neurons Can Let You Physically Feel What Others Experience” »

I know so many people who will benefit from this.

During the 2014 FIFA World Cup opening ceremony, a young Brazilian man, paralyzed from the chest down, delivered the opening kickoff. He used a brain-machine interface, allowing him to control the movements of a lower-limb robotic exoskeleton.

This unprecedented scientific demonstration was the work of the Walk Again Project (WAP), a nonprofit, international research consortium that includes Alan Rudolph, vice president for research at Colorado State University, who is also an adjunct faculty member at Duke University’s Center for Neuroengineering.

Continue reading “Long-term brain-machine interface use could lead to recovery in paraplegic patients” »

Controlling the minds of others from a distance has long been a favourite science fiction theme – but recent advances in genetics and neuroscience suggest that we might soon have that power for real. Just over a decade ago, the bioengineer Karl Deisseroth and his colleagues at Stanford University published their paper on the optical control of the brain – now known as optogenetics – in which the firing pattern of neurons is controlled by light. To create the system, they retrofitted neurons in mouse brains with genes for a biomolecule called channelrhodopsin, found in algae. Channelrhodopsin uses energy from light to open pathways so that charged ions can flow into cells. The charged ions can alter the electrical activity of neurons, influencing the animal’s behaviour along the way.

Soon researchers were using implants to guide light to channelrhodopsin in specific neurons in the brains of those mice, eliciting behaviour on demand. At the University of California the team of Anatol Kreitzer worked with Deisseroth to disrupt movement, mimicking Parkinson’s disease and even restoring normal movement in a Parkinsonian mouse. Deisseroth and his colleague Luis de Lecea later demonstrated that it was possible to wake up mice by activating a group of neurons in the brain that control arousal and sleep.

But optogenetics has been challenging. Since light does not easily penetrate dense fatty brain tissue, researchers must implant a fibre-optic cable to bring light into the brain. This limitation led to the development of another, less intrusive technique known as DREADD (designer receptors exclusively activated by designer drugs). In this case, a receptor normally activated by the neurotransmitter acetylcholine is modified to respond to a designer drug not normally found in the body. When the designer drug is delivered, neurons can be manipulated and behaviour changed over a number of hours. The major drawback here: the slow course of drug administration compared with the rapid changes in brain activity that occur during most tasks.

Continue reading “Remote control of the brain is coming: how will we use it?” »