How Does the Brain Work?
In truth over the last decade a growing number of scientific studies have shown that those disorders – as diverse as they may seem – all share the same common neurological origin. They are not distinct disorders or diseases but are rather part of a spectrum of disorders.
A little bit of neurophysiology…
Our central nervous system (which includes our brain) is made of billions of cells called neurons. A neuron is made of a cell body and an axon. The body of the cell contains a nucleus and various other organelles produce the energy necessary for the neuron to function optimally. The surface of the cell body is covered with hair-like structures called dendrites. Dendrites act as a line of communication between the cell body of a neuron and the axon of another neuron. A single neuron can be connected to hundreds and even thousands of other neurons.
The axon is a long tube-like “pipeline” which extends from the cell body and ends up in a synapse. The synapse is the communication point between an axon and another neuron. This interface between two neurons is done through a small space, called the synaptic cleft or interneuronal space.
When a nerve impulse reaches the end of the axon of a neuron, it triggers biochemical reactions which lead to the release of small chemical substances into the interneuronal space. These substances, called neurotransmitters, cross the space and attach themselves to receptors on the second neuron’s surface. If those neurotransmitters are in a high enough quantity, they trigger a new impulse on the second neuron. Once their work is done, the neurotransmitters are released from the receptors and recaptured by the first neuron to be recycled. This phenomenon is called neurotransmitter reuptake.
A little bit of neuroanatomy…
Starting with the oldest structures, our central nervous system (CNS) is broken down into several elements:
The spinal cord is the communication highway between the brain and the rest of the body; it has many relay stations and is the seat of all reflex activities (such as automatically taking your hand off a burning element).
The brain stem contains the breath and heart control centres, the cranial nerves, as well as some areas that control the state of alertness of the individual.
On the back of the brainstem, we find the cerebellum. It is involved in the coordination and timing of movements. Recent studies have shown that it also plays an essential role in coordinating visceral functions, emotions and attention.
Above the brain stem, we find the diencephalon which is made up of the thalamus – the relay centre for all the sensory information (except the sense of smell) that is moving up to the cortex – and the hypothalamus – which is the control centre for hormones and glands.
Finally, we find the telencephalon which is made of two cerebral hemispheres and the basal ganglia.
The cerebral hemispheres are made of four lobes (frontal, parietal, temporal and occipital) and the limbic system, which is the seat of emotions.
The basal ganglia are a series of nuclei or centres involved in movement control.
In our exploration of the brain’s anatomy as it relates to learning and behavioural disorders such as ADHD, two areas are particularly interesting. They are:
- A part of the frontal lobe, called the prefrontal cortex, which is the seat of so-called executive functions (attention, planning, organization, impulse inhibition, self-control).
- A system of circuits connecting the prefrontal cortex, the basal ganglia and the cerebellum.
In order to better understand ADHD, we must also understand how the brain integrates all the information it receives from the senses
The brain: a question of timing, synchronization and wavelength.
Each second, our brain is bombarded with thousands of pieces of sensory information coming from numerous sources: sight (eye), hearing, olfaction (smell), taste, touch, organs and viscera, skin, muscles, and articulations; in short, from our internal and external environment.
The brain cannot make sense of all these pieces of information unless they are integrated into a meaningful experience. Only then can the brain react optimally to its environment. However, there is no single physical area in the brain where all these pieces of information can meet. To solve this problem, our brain integrates and synchronizes these pieces of information in a temporal manner.
This means that two pieces of information coming from the same sensory experience can only be integrated – and therefore become meaningful – only if they are synchronized in time (« happen together »). In contrast, two pieces of information coming from the same sensory experience which are not synchronized in time cannot be integrated by our brain.
Imagine that you are watching a French movie that has not been properly dubbed. Imagine for example that the image and the sound are not synchronized. Imagine how the lips of the characters are sometimes immobile while the voice still speaks or imagine how the lips keep on moving although the sentence is already finished. The coherence is lost and it becomes annoying, shocking, meaningless, or even ridiculous. After a while, you would stop watching that movie. Children and adults suffering from ADHD have the same problem. Except that for them, the desynchronization is ongoing and never stops. Moreover, the desynchronization does not only affect our senses (such as hearing and sight in our example) but all the thousands of pieces of sensory information that are coming in from our various senses.
In order for the various pieces of information to be synchronized in time, our brain must have a very precise timing mechanism. And this timing mechanism requires a basic rhythm; the same as a music student uses a metronome to acquire his/her tempo skills.
In our brain, the metronome is our cerebellum. It gives the timing mechanism upon which all the incoming information will be synchronized. Any malfunction of the cerebellum can therefore lead to a desynchronization of the information, a frequent problem in children suffering from ADHD.
In addition to good timing, the different parts of our brain must be on the same wavelength or frequency to communicate properly.
In order to illustrate this concept, let’s imagine that you are using a walkie-talkie with your child who is in the garden. If both devices are on the same frequency (« the same wave length »), you will be able to communicate without any problems. However, if they are on two different wavelengths, there will be some crackling sounds on the line and communication will be more difficult. If both frequencies are too different, it becomes impossible to communicate.
Our cerebral hemispheres and our cortex function at a 40-hertz frequency (40 times per second). This frequency is the basis for human consciousness. At this speed, timing must be very precise or any error can be devastating.
Our brain functions at its best when both hemispheres are coherent, which means when they oscillate at the 40 hertz frequency. When this situation happens, both hemispheres cannot only communicate together through traditional neurological relays, but also energetically.
This 40-Hertz frequency originates in the thalamus, the relay centre for all information going toward the brain (except the smell).
In order to better understand this concept, let’s imagine an experiment where the right side of someone’s body isn’t stimulated anymore. The left hemisphere – because the information from the right side of the body crosses to the left side of the brain – will not be stimulated any longer, and the 40-Hertz rhythm cannot be maintained. In consequence, we develop a lack of coherence, a desynchronization between the two hemispheres. In this situation, the brain cannot work at its best.
Research in neuroscience has shown that ADHD is a consequence of brain timing errors which give rise to a desynchronization of incoming information or a coherence problem in which two or more parts of our brain «are no longer on same wavelength anymore ».
Cerebral hemisphericity and neurological lesions
In functional neurology, we use the word “cerebral hemisphericity” when both hemispheres « are no longer on the same wavelength anymore » and when, in coherence, one side of the brain is “weaker” than the other one. A neurological lesion (reversible) is a term which describes a part of the brain that is not functioning at 100%. The malfunction that is causing the lesion can be due to a lack of stimulation or to a delay in the development of the brain.
The neurological lesion is one of the principal causes of desynchronization (loss of timing) of information and of the loss of coherence between parts of our brain. The loss of coherence is called « hemisphericity » if the affected parts are the hemisphere. We also sometimes call this problem a “functional disconnection syndrome”.
Numerous scientific studies carried out in the past ten years have shown that neurological lesions and brain hemisphericity are the underlying brain problem in ADHD.
We can therefore conclude that ADHD and other neuro-behavioural conditions are due to some hypo-functioning or delayed development of some circuits of the brain that link the prefrontal cortex to the basal ganglia and to the cerebellum.
Many studies also showed that these parts are smaller in size in children suffering ADHD, than in “normal” children when they are measured by magnetic resonance imaging (MRI).
A health care professional specially trained in functional neurology is therefore able to evaluate the deficient areas (neurological lesions) in a precise manner for each individual and to develop an individualized program aimed at naturally rehabilitating these parts. In the next article, we’ll look at the various causes or triggers of Brain Imbalance and Hemisphericity.