Siento una soledad frio y terrible sin el calor de tu corazon,
La culpa fue mia, pero me duele sin tu amor
Quisiera haberte dicho esto el 2 de este mes, pero me dolia demasiado escribirlo
Perdi el amor de alguien increible y maravillosa, y honestamente no se que hacer sin ti.
Puedo decir todo esto ahora, porque ya te estas alejando de mi, y aunque lo lamento, yo se que es lo mejor.
Quiero ser mejor, porque algun dia, en algun futuro, yo espero encontrate y amarte otravez. Y cuando ese dia ocurre, espero que tu tambien quieras lo mismo.
Te amo con una furia y dolor y no puedo explicar.
Espero que estes contenta, amor, y aunque ya no lo crees por la manera que he estado actuando, te extrano, nada va cambiar eso.
Who would like to undulate in the darkness with me
Chemistry Valentine’s Cards by Nick Uhlig.
Snakes are so cute though!
Snakes and spiders evoke fear and disgust in many people. Even in developed countries lots of people are frightened of these animals although hardly anybody comes into contact with them. Until now, there has been debate about whether this aversion is innate or learnt. Scientists at the Max Planck Institute for Human Cognitive and Brain Sciences (MPI CBS) in Leipzig and the Uppsala University have recently discovered that it is hereditary: Babies as young as six months old feel stressed when seeing these creatures—long before they could have learnt this reaction.
Presumably, in Germany most people have never come across a poisonous spider or snake in the wild. Here in this country there are no spiders that pose a threat to humans. Likewise for snakes there are just two species that are indeed poisonous but they are so rare that you hardly ever encounter them. Nevertheless, there are few people that would not shiver at the thought of a spider crawling up their arm, however harmless it may be.
This fear can even develop into anxiety which limits a person’s daily life. Such people are always on edge and cannot enter a room before it is declared “spider free” or cannot venture out into nature for sheer fear that they may encounter a snake. In developed countries one to five per cent of the population are affected by a real phobia of these creatures.
Until now, it was not clear where this widespread aversion or anxiety stems from. While some scientists assume that we learn this fear from our surroundings when we are a child, others suppose that it is innate. The drawback of most previous studies on this topic was that they were conducted with adults or older children—making it hard to distinguish which behaviour was learnt and which was inborn. Such studies with children only tested whether they spot spiders and snakes faster than harmless animals or objects, not whether they show a direct physiological fear reaction.
Scientists at the Max Planck Institute for Human Cognitive and Brain Sciences (MPI CBS) in Leipzig and the Uppsala University, Sweden, recently made a crucial observation: Even in infants a stress reaction is evoked when they see a spider or a snake. And this already at the age of six months, when they are still very immobile and have had little opportunity to learn that these animals can be dangerous.
“When we showed pictures of a snake or a spider to the babies instead of a flower or a fish of the same size and colour, they reacted with significantly bigger pupils”, says Stefanie Hoehl, lead investigator of the underlying study and neuroscientist at MPI CBS and the University of Vienna. “In constant light conditions this change in size of the pupils is an important signal for the activation of the noradrenergic system in the brain, which is responsible for stress reactions. Accordingly, even the youngest babies seem to be stressed by these groups of animals.”
“We conclude that fear of snakes and spiders is of evolutionary origin. Similar to primates, mechanisms in our brains enable us to identify objects as ‘spider’ or 'snake’ and to react to them very fast. This obviously inherited stress reaction in turn predisposes us to learn these animals as dangerous or disgusting. When this accompanies further factors it can develop into a real fear or even phobia. "A strong panicky aversion exhibited by the parents or a genetic predisposition for a hyperactive amygdala, which is important for estimating hazards, can mean that increased attention towards these creatures becomes an anxiety disorder.”
Interestingly, it is known from other studies that babies do not associate pictures of rhinos, bears or other theoretically dangerous animals with fear. “We assume that the reason for this particular reaction upon seeing spiders and snakes is due to the coexistence of these potentially dangerous animals with humans and their ancestors for more than 40 to 60 million years—and therefore much longer than with today’s dangerous mammals. The reaction which is induced by animal groups feared from birth could have been embedded in the brain for an evolutionarily long time.
For modern risks such as knives, syringes or sockets, presumably the same is true. From an evolutionary perspective they have only existed for a short time, and there has been no time to establish reaction mechanisms in the brain from birth. "Parents know just how difficult it is to teach their children about everyday risks such as not poking their fingers into a socket”, Hoehl adds with a smile.
Your grandmother bequeaths a statue of an angel to you in her will. You find it creepy, but not having the heart to sell it, you store it in the basement. The next morning, to your horror, the basement door is wide open, and there is a note lying where you left the statue. Picking it up, you barely make out the scrawled words. “Find me before I find you.”
Net Neutrality
You have the power to heal others. You are a villain.
A single “dictator neuron” can take charge of complex behaviors
How does the architecture of our brain and neurons allow each of us to make individual behavioral choices? Scientists have long used the metaphor of government to explain how they think nervous systems are organized for decision-making. Are we at root a democracy, like the U.K. citizenry voting for Brexit? A dictatorship, like the North Korean leader ordering a missile launch? A set of factions competing for control, like those within the Turkish military? Or something else?
In 1890, psychologist William James argued that in each of us “[t]here is… one central or pontifical [nerve cell] to which our consciousness is attached.” But in 1941, physiologist and Nobel laureate Sir Charles Sherrington argued against the idea of a single pontifical cell in charge, suggesting rather that the nervous system is “a million-fold democracy whose each unit is a cell.”
So who was right?
For ethical reasons, we’re rarely justified in monitoring single cells in healthy people’s brains. But it is feasible to reveal the brain’s cellular mechanisms in many nonhuman animals. As I recount in my book “Governing Behavior,” experiments have revealed a range of decision-making architectures in nervous systems – from dictatorship, to oligarchy, to democracy.
A Neural Dictatorship
For some behaviors, a single nerve cell does act as a dictator, triggering an entire set of movements via the electrical signals it uses to send messages. (We neurobiologists call those signals action potentials, or spikes.) Take the example of touching a crayfish on its tail; a single spike in the lateral giant neuron elicits a fast tail-flip that vaults the animal upward, out of potential danger. These movements begin within about one hundredth of a second of the touch.
Similarly, a single spike in the giant Mauthner neuron in the brain of a fish elicits an escape movement that quickly turns the fish away from a threat so it can swim to safety. (This is the only confirmed “command neuron” in a vertebrate.)
Each of these dictator neurons is unusually large – especially its axon, the long, narrow part of the cell that transmits spikes over long distances. Each dictator neuron sits at the top of a hierarchy, integrating signals from many sensory neurons, and conveying its orders to a large set of subservient neurons that themselves cause muscle contractions.
Such cellular dictatorships are common for escape movements, especially in invertebrates. They also control other kinds of movements that are basically identical each time they occur, including cricket chirping.
Small Team Approach
But these dictator cells aren’t the whole story. Crayfish can trigger a tail-flip another way too – via another small set of neurons that effectively act as an oligarchy.
These “non-giant” escapes are very similar to those triggered by giant neurons, but begin slightly later and allow more flexibility in the details. Thus, when a crayfish is aware it is in danger and has more time to respond, it typically uses an oligarchy instead of its dictator.
Similarly, even if a fish’s Mauthner neuron is killed, the animal can still escape from dangerous situations. It can quickly make similar escape movements using a small set of other neurons, though these actions begin slightly later.
This redundancy makes sense: it would be very risky to trust escape from a predator to a single neuron, with no backup – injury or malfunction of that neuron would then be life-threatening. So evolution has provided multiple ways to initiate escape.
Neuronal oligarchies may also mediate our own high-level perceptions, such as when we recognize a human face.
Majority Wins
For many other behaviors, however, nervous systems make decisions through something like Sherrington’s “million-fold democracy.”
For example, when a monkey reaches out its arm, many neurons in its brain’s motor cortex generate spikes. Every neuron spikes for movements in many directions; but each has one particular direction that makes it spike the most.
Researchers hypothesized that each neuron contributes to all reaches to some degree, but spikes the most for reaches it’s contributing to most. To figure it out, they monitored many neurons and did some math.
Researchers measured the rate of spikes in several neurons when a monkey reached toward several targets. Then, for a single target, they represented each neuron by a vector – its angle indicates the neuron’s preferred reaching direction (when it spikes most) and the length indicates its relative rate of spiking for this particular target. They mathematically summed their effects (a weighted vector average) and could reliably predict the movement outcome of all the messages the neurons were sending.
This is like a neuronal election in which some neurons vote more often than others. An example is shown in the figure. The pale violet lines represent the movement votes of individual neurons. The orange line (the “population vector”) indicates their summed direction. The yellow line indicates the actual movement direction, which is quite similar to the population vector’s prediction. The researchers called this population coding.
For some animals and behaviors, it is possible to test the nervous system’s version of democracy by perturbing the election. For example, monkeys (and people) make movements called “saccades” to quickly shift the eyes from one fixation point to another. Saccades are triggered by neurons in a part of the brain called the superior colliculus. Like in the monkey reach example above, these neurons each spike for a wide variety of saccades but spike most for one direction and distance. If one part of the superior colliculus is anesthetized – disenfranchising a particular set of voters – all saccades are shifted away from the direction and distance that the now silent voters had preferred. The election has now been rigged.
A single-cell manipulation demonstrated that leeches also hold elections. Leeches bend their bodies away from a touch to their skin. The movement is due to the collective effects of a small number of neurons, some of which voted for the resulting outcome and some of which voted otherwise (but were outvoted).
If the leech is touched on the top, it tends to bend away from this touch. If a neuron that normally responds to touches on the bottom is electrically stimulated instead, the leech tends to bend in approximately the opposite direction (the middle panel of the figure). If this touch and this electrical stimulus occur simultaneously, the leech actually bends in an intermediate direction (the right panel of the figure).
This outcome is not optimal for either individual stimulus but is nonetheless the election result, a kind of compromise between two extremes. It’s like when a political party comes together at a convention to put together a platform. Taking into account what various wings of the party want can lead to a compromise somewhere in the middle.
Numerous other examples of neuronal democracies have been demonstrated. Democracies determine what we see, hear, feel and smell, from crickets and fruit flies to humans. For example, we perceive colors through the proportional voting of three kinds of photoreceptors that each respond best to a different wavelength of light, as physicist and physician Thomas Young proposed in 1802. One of the advantages of neuronal democracies is that variability in a single neuron’s spiking is averaged out in the voting, so perceptions and movements are actually more precise than if they depended on one or a few neurons. Also, if some neurons are damaged, many others remain to take up the slack.
Unlike countries, however, nervous systems can implement multiple forms of government simultaneously. A neuronal dictatorship can coexist with an oligarchy or democracy. The dictator, acting fastest, may trigger the onset of a behavior while other neurons fine-tune the ensuing movements. There does not need to be a single form of government as long as the behavioral consequences increase the probability of survival and reproduction.
Image Credit: Getty Images/iStockphoto (MARS)
Source: The Conversation (by Dr. Ari Berkowitz)
girl crush
Please read this if you want to make a sick boy happy. Lorenzo Snippe is a 9-year-old boy from the Netherlands who is very sick. In 2016 he was diagnosed with leukemia and in 2017 with x-ald. On the third (3) of February is his tenth (10) birthday, and it will probably be his last. Because he can’t get any visitors due to being so sick, his parents have asked people in this news article to send him a happy birthday postcard as soon as possible.
If you’re able to, please send him a postcard wishing him a happy birthday and tell him where you’re from! If you can’t, please reblog this post to make sure it will reach as many people as possible! His address is:
Prinses Wilhelminastraat 22
7753 TM Dalerpeel
The Netherlands
He really loves animals, so it would be great if you could send a postcard with an animal on it or something like that!
Don’t send him or his family rude things and don’t use his address for other things than described in this post!