The science of consciousness: May 2018

Thursday, May 31, 2018

Cognitive Manipulation by parasites

Parasite-host interactions have been perfected over millions of years of evolution and reached surprising and even unnerving preciosity. The diversity of parasites that can manipulate behavior ranges from viruses to insects and even worms. In some of the most fascinating manipulations, the parasite taps into the host brain's neuronal circuits to control the host's cognitive functions. To exert long-term behavioral manipulation of the host, the parasite must secrete compounds that can modify gene expression with long-lasting effects. This way, parasites hijack the decision-making ability behavior of their host. Mind-altering manipulation can occur in practically all animals. Nevertheless, the phenomenon is often studied in insects due to their simple nervous system and their ability for goal-directed behavior. For example, when presented with two very near concentrations of the same odor, it takes longer for fruit flies to decide, and mistakes can occur.

Suicide manipulation:

Fungus infection manipulates insect behavior. The fungus (Ophiocordyceps unilateralis) infects ants. The fungus feeds on the ant's innards. The fungi produce chemicals that alter their hosts' navigational sense; the infected ant is compelled to leave its nest and seek a plant in a humid area to climb to its top. The ant clamps its mandibles around a leaf or leaf stem, a behavior that has never been reported for uninfected ants. The fungus feeds on the ant's brain until it finally produces spores, killing the animal. The spores explode and spread from the top of the tree to infect other ants and start another cycle.

In another example of parasitic infection, the Lancet liver fluke takes over the ant's navigational skills by migrating to the ant's head and settling near one of the cerebral ganglia. Unlike normal behavior, the ant climbs to the tip of a grass blade to be eaten by a grazing animal. The mature Lancet expels its eggs via the digesting system, allowing ants to be infected.

Another example is a hairworm, which requires water for its reproduction. The hairworm infects crickets and other terrestrial insects and develops inside their bodies. The mature hairworm causes the insect to seek out water. When the insect falls into the water, the parasite emerges to start reproduction.

Offspring Care:

Although solitary insects are not known to provide care and safety to their offspring, one of the parasites' most fascinating behavioral manipulations is to coerce a host to care for the parasite's offspring. Developmental symbiosis occurs when individuals of one species cannot reach maturity without another's aid. For example, a wasp sting injects her eggs into a caterpillar. The wasp larvae mature by feeding on the host and emerge after two weeks. However, one or two larvae remain within the caterpillar. These siblings activate the caterpillar's muscles to violently move its upper body back and forth. The behavior protects the pupae by deterring predators.

The caterpillar's aggressive guarding behavior can also occur in other insects without parasites in the host's body. For example, a single wasp larva develops inside the body of a ladybug, and it spins a cocoon between its legs. The ladybug is alive, but its programming triggers twitching and convoluting body movements, which keep the wasp pupa safe from potential predators. It is thought that the parasite co-infests with a virus, which induces a severe neuropathy and antiviral immune response that correlates with the symptoms of motor twitches.

Another example is the butterfly Maculinea arion, whose larvae mimic the smell of those of a particular ant species, causing its members to carry them into their nests, caring for them as their own. The sophistication and effectiveness of parasite infection might have given the idea for the simulation hypothesis.

Infections in People

The fungal pathogen Candida auris can cause bloodstream infections that can be fatal in 60% of cases. Toxoplasma infection can be linked to mood disorders and mental health issues, including schizophrenia and behavioral changes, such as promoting risky behaviors.

Watch a fascinating video: in praise of parasites

https://youtu.be/eOCiIgYQaFo

Consumption of raw fruits and vegetables might be beneficial for mental health

The old saying, “You are what you eat,” might need a new updating: your mind is shaped by what you eat. A new study found that raw fruit and vegetable intake predicted reduced depressive symptoms and lead to higher positive mood, life satisfaction, and flourishing. The top 10 natural foods related to better mental health were carrots, bananas, apples, dark leafy greens like spinach, grapefruit, lettuce, citrus fruits, fresh berries, cucumber, and kiwifruit.

The study investigated the differential associations between intake of raw fruits and vegetables, compared to processed (cooked or canned) fruits and vegetables, and mental health in young adults. Fruits and vegetables contain a variety of micronutrients critical to physical and psychological function. Antioxidants such as vitamin C and carotenoids might protect the body against oxidative stress. Water-soluble vitamins (vitamin C and B vitamins), and certain minerals (calcium, magnesium, and zinc), are essential for optimal cognitive and emotional functioning. Cooking and processing fruits and vegetables diminish their nutrient levels, limiting the delivery of critical vitamins and other food sources needed for optimal emotional functioning.

A recent discovery that the food you eat influences your brain health gives dietary consideration even more importance and urgency. For example, calorie restriction significantly improves blood supply to the brain. In mice, the Ketogenic Diet (high levels of fat and low levels of carbohydrates) leads to positive results in patients with epilepsy, Parkinson’s disease, and autism. Detailed studies have shown that reduced blood glucose levels and lower body weight might have resulted from the gut's improved microbiome. The most exciting finding has been an amyloid-beta reduction, a known hallmark of Alzheimer’s disease, from the brain. Thus, a Paleo diet, caveman diet, or stone-age diet might protect from Alzheimer's disease.

Picture credit: Fruit market by Diderot

Read the whole article:

Intake of Raw Fruits and Vegetables Is Associated With Better Mental Health Than Intake of Processed Fruits and Vegetables

Find the book on Amazon.

Sunday, May 13, 2018

Adopt a growth mindset by striving toward flexibility

From the Stone Age to the industrial revolution life conditions for the overwhelming majority of people were miserable; they suffered from a seasonal shortage of food, adverse temperatures, threats, and lack of proper housing. Social history, the pomp, the conquest, and the culture rode on the backs of oppressed classes. Religion was the mental comfort and deep-seated hope that gave meaning to life amid the grueling drudgery.

Things cannot be more different at the beginning of the twenty-first century. In most parts of the world, food, clothing, and housing is a natural part of the human condition. In big, overstuffed, middle-class homes, out of season clothes are discarded like garbage. At the time when we achieved never experienced prosperity, we are faced with an epidemic of addictions, alienation, crime, and abuse. Trying to understand the root causes of this seismic social change we need to analyze several factors that had transformed society. Compared to the rigid, impassable class division of yesteryear, social mobility is open to anyone with the drive to succeed. The news is full of examples of tech billionaires and executives who started from modest beginnings. However, the comparison with the proverbial Johnsons can make every member of the society left behind at one time or another. The news, social media, and the internet can serve as a constant reminder of our failure in the rat race. To justify our perceived ineptness, we manufacture imaginary and impassable obstacles to success; theories of unfairness, conspiracies, such as far right or far left political oppression, government or alien manipulations and excess to ‘connections,’ as excuses for inaction.

Spending time on these emotionally demanding fantasies drains mental energies. It wastes not only precious time, but derails attention from personal well-being and career goals. The technological developments, financial complexities, and social changes demand meaningful decision making at every level. Maneuvering the stormy waters of change requires grooming our intellectual quotients. Occupation with gossip and unfounded fantasies leaves one stuck, while society is progressing at a breakneck pace. Being left behind by a progressing society creates increasing anxiety, which can easily culminate in depression, addictions and acts of desperation. We are the first generation to have the ability to analyze how our emotions influence our behavior. Certain aspects of our emotional inheritance can destroy the upcoming generation’s ability to succeed. The rigid mindset of the class system must be replaced by a strong belief in the ability of the self to initiate change.

Picture credit: Mother and child by Eva Deli