This is the oldest structure in the brain that can be traced back to about million years. Reptiles and amphibians have a cerebrum that works very similar to the R- Complex, which is the signature evolution has left within our brain from the time mammals were evolving from reptiles and amphibians. Any damage to it would result in inability to control our voluntary muscle movements.
Schematic diagram of the Brains of Reptile, Bird and Mammal. Cerebellum and Medula Oblongata are parts of the hindbrain7 As reptiles evolved into mammals, the brain necessarily increased in size and complexity as new structures evolved to control and coordinate the increased complexities and activities of mammalian life.
The mammalian brain is similar to the limbic system that lies within the neo-cortex, in the centre of the brain surrounding parts of the reptilian brain and is prominent among animals that live in social groups like the apes. These social groups with their complex dynamics of behavior would need a sophisticated limbic system to distinguish between potential enemies, allies and rivals.
The limbic brain which emerged in the first mammals about one hundred and fifty million years ago is capable of storing memories of behaviours that produced pleasant and unpleasant experiences, and is thus responsible for emotions in human beings.
It is the seat of our value judgments which influences our behavior, often unconsciously. In the paleo-cortex and limbic system, the brain has indeed preserved the memories of our evolution from reptiles and mammals, as shown in the picture alongside of the Triune Brain. These three parts of the brain do not operate independently, but have numerous neural interconnections through which they interact. The neural pathways from the limbic system to the cortex are especially well developed. We share the limbic system with other mammals though not fully with the reptiles.
The main structures of the limbic brain shown in the picture alongside are the hippocampus, the amygdala, and the hypothalamus. Within each hemisphere of brain is located a thalamus that relays the incoming sensory signals to appropriate areas of the brain for processing. Below it lies the hypothalamus, which controls hunger, thirst, the circadian rhythm, anger, pleasure and emotions. The largest structure of the limbic system is the hippocampus which plays a large role in processing our short term memories into long term memory.
The amygdala controls our fear and aggression, and is also involved in emotion and memory. Electrical stimulation of the amygdala in animals causes extreme fear or frenzy.
It is believed that altruistic behavior originated in the limbic system. Mammals and birds are the only living beings that harbor and display affection towards their young offspring and care for them. The relatively larger capacity for information processing among the mammalian brains owes its roots to this distinction.
The olfactory cortex related to smell is among the oldest parts of the limbic system, and played the most vital part in evolutionary progression of mammals, in identifying food, predators, also preys , mates and in sexual behaviour. Finally, we have the third layer of the brain in the cerebral cortex, the outermost layer of the brain with its two large cerebral hemispheres, which is responsible for the development of human language, abstract thought, imagination and consciousness.
Most of our cognitive abilities spring from here. The neo-cortex, the latest evolutionary structure within the cerebral cortex, governs our higher cognitive behavior and our immense learning abilities. It makes up about 80 percent of the total brain-mass and is most developed among the humans. As it evolved gradually, it became progressively more and more wrinkled, the wrinkling allowing the cortex to develop much larger surface area, and hence more neurons to accommodate within the small space available inside the skull.
At birth, the cortex forms a smooth covering over the structures of the brain, but as it increases in size and complexity over a period after birth, it becomes more and more wrinkled, finally teaching a total surface area of about square centimetres in a fully grown adult.
The increase in wrinkling of the cortex is known as corticalisation and is the real measure of human intelligence. This increase in the folds of the cortex has been a major evolutionary factor that enabled a better coordination and organization of the complex behaviours in higher primates and humans. It is responsible for our humanness, even though the higher primates and some cetaceans like dolphins and whales also have well-developed neocortex. A larger cortex obviously houses a larger number of neurons, but more than the number what actually matters is the number of connections between these neurons that determines the responses to a given stimulus, on in the extensive neural network within the brain.
Major elements of this network are the axons, dendrites and synapses. Unlock Your Hidden Brain Power is a comprehensive guide to science-based mental and emotional. A new edition of the bestselling classic — published with a special introduction to mark its 10th anniversary This pioneering account sets out to understand the structure of the human brain — the place where mind meets matter.
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All of us make choices all the time, and we may think we're making those choices freely. But psychologist Eric Johnson says there's an architecture behind the way choices are presented to us, and this invisible architecture can influence decisions both large and small.
With the new year close at hand, we revisit our conversation with psychologist Wendy Wood, who shares what researchers have found about how to build good habits — and break bad ones. Justin is sitting on the side of the freeway, hoping someone will help him fix his busted wheel. Bababa, dadada, ahgaga. Got that? Babies are speaking to us all the time, but most of us have no clue what they're saying.
To us non-babies, it all sounds like charming, mysterious gobbledegook. To researchers, though, babbling conveys important information about a baby's readiness to learn. This week, we'll revisit a favorite episode exploring the language and behavior of the newest members of the human family. Why do we prefer to speak rather than listen? Our unconscious motives drive more than just our private behavior; they also infect our venerated social institutions such as Art, School, Charity, Medicine, Politics, and Religion.
In fact, these institutions are in many ways designed to accommodate our hidden motives, to serve covert agendas alongside their "official" ones. The existence of big hidden motives can upend the usual political debates, leading one to question the legitimacy of these social institutions, and of standard policies designed to favor or discourage them.
You won't see yourself - or the world - the same after confronting the elephant in the brain. Daniel Amen equips you with powerful weapons to battle the inner dragons that are breathing fire on your brain, driving unhealthy behaviors, and robbing you of joy and contentment. Your brain is always listening and responding to these hidden influences and unless you recognize and deal with them, they can steal your happiness, spoil your relationships, and sabotage your health.
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