1. GOOD FRIENDS
Psychologists have long known that having a set of cherished companions is crucian to mental well-being. In addition, a recent study by Australian investigators concluded that our friends even help to prolong our lives. The scientists analyzed data from a decade-long survey called the Australian longitudinal study of aging, which was initiated in 1992. it concentrated on the social environment, general health, life style and as of death of 1,477 persons older then 70 years. Study participants wear asked how much personal and telephone contact they had with friends, children, relatives and acquaintances.
Researchers were surprised to learn that friendship increased life expectancy to a far greater extent than, say, frequent contact with children and other relatives. This benefit held true even after these friends had moved away to another city and was independent of factors such as socioeconomic status, heath and way of life.
What exactly underlies this effect on longevity? Apparently, the scientists posit, it is not mearly the mutual buoying of spirits that occurs among associates. What is more important is that the support given and received by friends is voluntary and pleasurable and not just the result of a sense of duty or convention. In contrast to our own families, we are able to choose our friends.
According to the Australian scientists, the ability to have relationships with people to whom one is important has a positive effect on physical and mental heath. Stress and the tendency toward depression are reduced, and behaviors that are damaging to health, such as smoking and drinking, occur less frequently. The investigators speculate that in times of calamity in particular, our support networks can raise our moods and filings of self-worth and offer helpful strategies for dealing with difficult personal challenges.
2. THE HUMAN BRAIN
The brain is the complex organ in the human body. It produces our every thought, action, memory, feeling and experience of the world. This jelly-like mash of tissue weighing around 1.4 kilograms contains a staggering one hundred billion nerve cells, or neurons. Each neuron can make contact with tens of thousands of others, via tiny structures called synapses. Our brains form of million new connections for every second of our lights. The pattern and strength of the connections is constantly changing and no two brains are alike. It is in these changing connecting that memories are stored, habits learned and personalities shaped, buy reinforcing certain patterns of brain activity, and losing others.
While people often speak of their ‘grey matter’, the brain also contains whit matter. The grey matter is the cell bodies of the neurons, while the white matter is the branching network of thread-like tendrils-called dendrites and axons-that spread out from the cell bodies to connect to other neurons. The brain also has another, more numerous type of cell, called glial cells. These outnumber neurons ten times over. Once thought to be support cells, they are now known to amplify neural signals and to be as important as neurons in mental calculations. There are many different types of neural, only one of which is unique to humans and the other great apes, the so-called spindle cells.
Brain structure is formed partially by genes, but largely by experience. Only relatively recently it was discovered that new brain cells are being born through out our lives-a process called neurogenesis. The brain has bursts of growth and then periods of consolidation, when excess connections are pruned. The most notable bursts are in the first to or three years of life, during puberty, and also final burst in young adulthood. How a brain ages also depends on genes and lifestyle too. Exercising the brain and giving it the right diet can be just as important as it is for the rest of the body.
The neurons in our brains communicate in a variety of ways. Signals pass between them by the release and capture of neurotransmitter and neuromodulator chemicals. Some neurochemicals work in the synapse, passing specific messages from release sites to collection sites, called receptors. Others also spread their influence more widely, like a radio signal, making whole brain regions more or less sensitive.