Brainwave Coherence - Intro, Free meditation technique, Evolution

It was only with the advent of real science that the West began to catch up. With instruments of observation evolving rapidly, the West could delve into the physical properties of the minutest entity. As technology took over, new sciences were developed -- specializations within specializations within specializations -- as the physical world from the smallest to the almost invisible became open to us. Using electron microscopes and MRI scans, it became possible to examine the minutest details of the cells within the brain and to monitor global brain activity in real time. Through reducing the spectrum of consciousness to a set of brightly coloured brain scans, Western science began to explain the activity and processes of consciousness. It was able to identify and define (to some extent) the activities of various parts of the brain and explain how brain cells react individually and collectively to various stimuli. It could see thinking in process and trace the neural connections that created each thought. Wonderful stuff, indeed.

None of this, however, explained how different states of consciousness could be experienced. Whilst all these innovative revelations showed how the brain functioned during the traditionally accepted three states of consciousness -- waking, dreaming and deep sleep -- it said nothing about other states. That such states existed became clear as the Western world became familiar with Eastern philosophy and spiritual practices.

MIND OVER MATTER;
MATTER OVER MIND

Before we consider the subject of the neurology of higher states of consciousness and the effects they have on the brain, perhaps it would be well for us to familiarise ourselves with that lump of grey matter. Although what follows might sound like a lecture on bio-neurology, without it the illuminating and worthwhile information still to come would have little point. Although we try to include only boring copy of the very highest standards, sometimes the need for information forces us to do otherwise. Please read on and try not to doze off.

However, before we consider the parts of the brain in detail, it is important to appreciate that it is a single organ that functions as a whole. Although certain parts of the brain may be associated with certain functions, they do not carry out these functions in isolation. Every function of the brain is a co-operative effort to which neurons in a number of areas contribute.

Our illustration is of the right side of the brain with the main external areas coloured for easy identification. Although the brain is in two parts, the left and right hemipheres, both of which have different co-operative and individual functions, the external areas of the brain are the same whichever side is viewed.

In broad terms the neocortex, the six layer thick outer area that covers the both the cerebral hemispheres, is responsible for higher brain functions such as sensory-perception, learning and memory. These functions are concentrated within the frontal lobes and are defined as ‘executive functions.’ They include self-control, planning, reasoning and abstract thought.

The temporal lobes, situated on each side of the brain just above the ears, deal with auditory perception, some visual perception and the categorization of objects.

The occipital lobes are responsible for vision.

The brain monitors the environment and the body’s reaction to it and regulates the body’s actions and reactions. It continuously receives sensory information and rapidly analyses this data. It then responds accordingly, controlling the appropriate bodily systems and functions. The brain stem, through the medulla oblongata, controls breathing, heart rate and other autonomic processes that are independent of conscious brain functioning. Maintaining a state of homeostasis (where all the systems are functioning and balanced) within the body is controlled by the hypocampus with some help from the cingulate gyrus (part of the anterior cingulate) and the pituitary gland, which secretes the hormones that maintain homeostasis. The hypothalamus is also implicated in homeostasis, regulating such systems as blood sugar, temperature and hunger. Interestingly, the hypocampus is also associated with long-term memory -- a demonstration of the brain’s ability to multi-task. The cerebellum is responsible for the body’s balance, posture, and the coordination of movement.

The hypocampus is part of the temporal lobe. It deals with auditory perception, semantics and language processing.

The parietal lobe gives us a sense of ourself in time and space and is implicated in time/space perception, touch perception and hand/eye skills.

The pons is a bridging structure that connects the brain stem to the two hemispheres.

Deep within the brain is the limbic system, consisting of the anterior cingulate, the fornix, the hypothalamus, the thalamus, the hypocampus and the amygdala. This seems to support such functions as emotions and behaviour. The earliest part of the brain to develop, the basic limbic system is common to all mammals, though not all its functions are shared. In humans, as well as controlling emotions and behaviour the limbic system is responsible for the most basic instincts, including the fight or flight response. The prime mover in this response are the amygdala (there are two of them,) which are responsible for generating suspicion and fear.

The corpus callosum is a nerve bundle connecting the two cerebral hemispheres that acts as a relay station for impulses from the autonomic nervous system.

At the centre of the limbic system is the thalamus. There are actually two thalamus (thalami), one for each hemisphere of the brain. These constitute the central processing station for all sensory inputs. Every sensation, thought, mood and emotion passes through the thalamus on its way to other parts of the brain. An inactive thalamus results in coma and even slight damage can severely impair brain functioning. The thalamus is the central co-ordinating factor orchestrating the play of impulses that light up the brain as it engages in the processes, functions and activities that give us life and the capacity to live it.

BEATS THE HELL
OUT OF OLDRONS

Although there are a couple of areas of the brain that are more or less dedicated to one activity, almost everything that happens in the brain involves many neurological centres. Impulses are received from the central nervous system through the brain stem and go straight to the limbic system where, led by the thalamus, they are assessed, sorted and redirected to those areas of the brain implicated in any response. These electro-chemical signals create an excitation among groups of brain cells, neurons, which then communicate amongst themselves and with other groups to create a physiological or neurological response.

Chemical signalling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. Neurons are the core components of the nervous system, which includes the brain, spinal cord and peripheral ganglia, but also exist throughout the body. A number of specialized types of neuron exist: sensory neurons respond to touch, sound, light and numerous other stimuli affecting cells of the sensory organs that then send signals to the spinal cord and brain. Motor neurons receive signals from the brain and spinal cord, cause muscle contractions and affect glands. Interneurons connect neurons to other neurons within the same region of the brain or spinal cord.

As a cellular organ the brain is nothing but neurons. Estimates of the number of neurons in the human brain vary from about 100 billion to 100 trillion. A typical neuron possesses a cell body (known as the soma,) dendrites and an axon. Dendrites are filaments that arise from the cell body, often extending for hundreds of micrometres and branching multiple times. These give rise to a complex ‘dendritic tree.’ An axon is a special cellular filament that arises from the cell body at a site called the axon hillock and travels for a distance, which can be as far as one metre in humans and even more in other species. The cell body of a neuron frequently gives rise to multiple dendrites, but never to more than one axon growth point, although the axon may branch hundreds of times before it terminates. At the majority of synapses, signals are sent from the axon of one neuron to a dendrite of another. There are, however, many exceptions to these rules: neurons that lack dendrites, neurons that have no axon, synapses that connect an axon to another axon or a dendrite to another dendrite, etc.

It is widely held that neurons in the adult brain do not generally undergo cell division and, therefore, usually cannot be replaced after being lost. However, as we will see, this belief is incorrect -- dying and even dead brain cells can be revived and returned to something close to full functionality. In fact, dead neurons are replaced by new neurons. These are created by stem cells which contain the basic encoded protein instructions to create many kinds of cells. In addition, astrocytes, a star shaped cell that exists in the brain and spinal column, have been seen to transform into neurons. (Astrocytes are a form of sub-cell, known as glial cells. Glial cells provide support and nutrients to other cells.)

The key to brain activity lies in the axon. As these filaments grow, extend and branch, they form complex networks that connect with other neurons. Connecting through the soma or dendrites, the branches of the axon forms a system of ‘hard-wired’ connections with other cells that constitute a neural network. These create neural circuits that can function in the background while other activities are being undertaken. This is particularly evident in driving skills; most people drive without thinking about it. Driving is an autonomic function that is written into certain neural circuits within the brain.

A tiny section of a neural network

The connection between one neuron and another via the axon is known as a synapse and provides the conduit through which the cells can communicate. A typical synapse, then, is a contact between the axon of one neuron and a dendrite or soma of another. With the synapses in place, a neuron or group of neurons can communicate with cells in any part of the brain. The signals that pass along the synapses can be excitatory or inhibitory. If the level of excitation is sufficient in a neuron, the soma can send out a brief pulse that activates the axon to instantly send out filaments to create synapses with other neurons that might be required in the neurological event taking place. The axon spread like tendrils of a creeping plant creating elaborate networks of connections throughout the brain.

The signals that pass along the synapses are partly electrical and partly chemical. They are generated within the nucleus of the neuron at an almost sub-atomic level by lipid molecules with many types of protein structures embedded in them which are housed in a plasma membrane that surrounds the nucleus.

Although there is much more I could say about the functions and processes of cells in general and neurons in particular, the information above is enough (did I hear you say: ‘Yes, please’?) to set the stage for the breathtaking information about the brain that follows.