Basics of Neuroscience
The Structures of the Brain
The human brain weighs about three pounds or about 2% of the body’s weight. It contains 1.1 trillion cells, including 100 billion neurons. Neurons on the average have 5000 connections called synapse from other neurons (Linden, 2007). The brain uses 20-25% of the body’s oxygen and glucose even though it is only 2% of the body’s weight (Lammert, 2008). The brain is always working and performing its functions and uses the same amount of energy when the body is asleep or when awake and the brain is hard at work thinking (Raichle & Gusnard, 2002).
The human brain interacts with the other systems in the body, which interacts with people and the world around it. The brain is shaped by the mind. In reality the mind is a creation of the brain, the body, the natural world and the human culture and the mind itself (Thompson and Varela, 2001). So it is a simplification to say that the Brain is the primary influence on or the basis of the human mind.
The human body has three brains in one:
1. Aggressive Brain: which lies in the primitive portion of the brain
2. Emotional Brain: which entails the Limbic system
3. Analytical Brain: which involves these components of the brain:
The brain reaches its maximum number of synaptic connections and its greatest metabolic activity around the age of 3 or 4.
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Primary Components of the Human Brain
For the most advanced overview of the Brain and all of its structures got to THE BRAIN a section of www.traumaticbraininjuryatoz.org at http://www.traumaticbraininjuryatoz.org/The-Brain.aspx
1. The Cerebral Cortex
a. The motor cortex – mediates motor activity
b. The premotor cortex - plans complex motor activity
c. Prefrontal Cortex (PFC) – It makes meaning of sensory input. It sets goals, makes plans, directs actions, and shapes emotions. It processes information, maintains conscious attention, and forms behavioral responses. It guides and sometimes inhibits the limbic system. It conducts executive reasoning and is critical for sequencing behavior. It handles working memory – which is the temporary holding and manipulating of information necessary to do daily tasks such as cooking a meal by following recipes or for sending an email through the internet. It has two components
i. The orbitofrontal cortex (OFC) - it controls working memory and consolidating of long term memory. It compares information with other data coming to it from other information centers of the brain
ii. The anterior cingulate gyrus (ACG) – It connects directly to the structures of the limbic system. it filters and amplifies information from lower regions to and from the prefrontal cortex
2. Anterior (frontal) Cingulate Cortex (ACC) – it steadies attention and monitors plans. It helps to integrate thinking and feeling (Yamasaki, LaBar, and McCarthy, 2002). A cingulate is a curved bundle of nerve fibers
3. Insula – it senses the internal state of the body, including those “gut feelings” which people experience. It helps a person to become empathic. It is located inside the temporal lobes on each side of the brain
4. Thalamus – it is the major relay station for sensory information. It relays sensory information from the outside world directly to the amygdala to identify the importance of the stimuli. It relays information from and to the cortex and between most parts of the brain. It is involved in the regulation of the brain waves.
5. Brain Stem – sends neuromodulators such as serotonin and dopamine to the rest of the brain
6. Corpus Callosum – is a nerve bundle which passes information between the two brain hemispheres. It is vital for integrated thoughts, feeling and action.
7. The Pons – (bridge) is the connection between the lower brain and the mid-brain. It affects physical arousal, including blood pressure and is responsible for the heightened physical arousal in anxiety. Nuclei within the pons are important in rapid eye movement (REM) sleep.
8. Cerebellum - it regulates body movement and is responsible for body and limb position, relating to balance, posture, walking etc. It integrates information. It is assumed that the Cerebellum plays an important role in dreaming, memory, and other functions.
Limbic System – it is the part of the brain which is central to emotion and motivation and memory. The Limbic System includes cortical as well as subcortical structures. It consists of the structures that ring the upper part of the brainstem. These separate parts of the system play separate and important roles, but they function together to regulate emotion and memory. They create context for sensory information. It includes
1. Basal Ganglia – it is involved with rewards, stimulation seeking and movement. “Ganglia” are masses of tissues
2. Cingulate gyrus – allows shifting of attention, cognitive flexibility, adaptability, and helps the mind move from idea to idea. It gives the mind the ability to see options, and helps the individual go with the flow through cooperation with other.
Problems inside the Cingulate Gyrus: Worrying: holds onto hurts from the past; Stuck on thoughts (obsessions); Stuck on behaviors/compulsions; Oppositional behavior, argumentativeness, uncooperativeness. Automatic tendency to say no; Addictive behaviors (alcohol, drug abuse, eating disorder, pain); Cognitive inflexibility-OCD disorders; Eating disorders; Road rage Cognitive control
3. Hippocampus – it forms new memories and it detects threats. It has a critical role in memory storage and retrieval. It is part of the behavioral inhibitory system to facilitate withdrawal in the face of anxiety-provoking stimuli. It stores short-term details of events without interpretation or emotional tone. It accumulates the facts and just the facts leaving the emotional response to other structures of the limbic system. The hippocampus consists of the fornix and mamillary bodies. It provides for episodic and recall memory handles long term memory-through transduction of memory and reuse of memory
4. Amygdala - it functions as the “alarm bell” for the brain that responds to emotionally charged or negative stimuli (Rasia-Filho, Londero & Archaval, 2000). It is responsible for recognizing changes in the environment and assigning positive or negative emotional values to the stimuli. It communicates with the other structures of the limbic system to alert the brain to danger and communicate immediate need for response to external changes or events. It is the brain’s early warning system. The Amygdala is the center for emotion and fear: it handles the emotions; fear, and anxiety, fear of survival, The Amygdala is controlled by the prefrontal cortex of the brain.
5. Hypothalamus - it regulates primal drives such as hunger and sex. It makes oxytocin. It activates the pituitary glands. It is the relay station for the internal regulatory system. It monitors information about the functioning of the body’s organs, including the blood for oxygen and glucose levels., monitoring all information from the autonomic nervous system and commanding the body through the nerves and the pituitary gland.
6. Pituitary gland – it makes endorphins and triggers hormones. It stores and releases oxytocin. It directs activity in the endocrine system which produces secretions of the body. It is important to the function of the stress response system because it alerts the adrenal cortex to release glucocorticoids – especially adrenalin and cortisol – in response to a “stress alert.”
The Lobes of the Brain
1. Frontal lobe
2. Parietal lobe
3. Temporal lobe
4. Occipital lobe
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Areas of Brain Involved in Cognitive Functioning
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Cognitive Function
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Brain Areas Involved
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Arousal & Attention
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Frontal Cortex; Limbic System & Brain Stem
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Motor & Somatosensory
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Frontal & Parietal Cortex; Thalamus;
Striatum & Cerebellum
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Executive Functions
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Frontal Cortex
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Language Functions
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Dominant Cerebral Hemisphere Cortex
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Visuospatial Functions
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Nondominant Cerebral Hemisphere Cortex
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Intellectual Reasoning
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Diffusely Represented in Cortex
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Learning & Memory
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Cortex & Limbic System
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Brain Hemispheres
Left Hemisphere of Brain organizes information, understands sequences and comprehends time in conjunction with activities or events, putting events in sequential order and placing them in time. This side of the brain is where verbal work and making meaning of experience occurs. In this hemisphere the brain forms symbols (language and math) for experience. It creates explanations for experience. This side of the brain works on inhibiting the activity of right hemisphere which deals with emotions. It moderates the emotional information which goes into the right side of the brain. The left side of the brain mediates memory and the nonverbal, emotional responsiveness of the right-side brain functions.
Right Hemisphere of Brain is responsible for recognizing faces, reading emotions, assessing the emotional significance of an event in conjunction with the data from the senses which it interprets. It is specialized for nonverbal recognition and emotional memory which are vital for quick and accurate response to the world in which the human lives. The right hemisphere has a strong role in creativity and nonverbal problem solving. It helps create novel responses to both practical and emotional situations. The right side of the brain comprehends spatial relationships and is alert for and creates the cadence and rhythm in speech, movement, music, etc. It regulates the nervous system and hormonal response coming in from the senses.
It is understood that the left side of the brain controls the right side of the body and the right side of the brain controls the left side of the body. The above diagram demonstrates that the left eye's image is translated on the right side of the brain and the right eye's image is translated on the left side of the brain. The image which a person perceives comes after a process in the brain in which the left and right side images are translated or decoded by the left and right side of the brain and then made sense for the observer. Any sight, thought, sound, smell, touch, or taste a person has is simply a series of biochemical electrical impulses which are sent out by the senses to the brain. This is a physiological process by which all of the senses and thinking are impacted on.
If a human has faulty perceptions it can impact the way the human thinks, feels and acts. As a result the faulty perceptions which come from obscuring the translation of the faulty perception can impair problem solving, decision making, and conflict resolution. The human brain take time to sort out what senses are sending it.
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The Evolving Brain
Inside the brain one can find what has been termed as the reptilian, paleomammalian, and the neomammalian levels of development of the brain. The figures of the Midbrain & Hindbrain will help you understand the components of the evolving brain.
Cortical tissues of the brain that are relatively recent, complex, conceptualizing, slow and motivationally diffuse sit atop subcortical and brain stem structures that are ancient, simplistic, concrete, fast, and motivationally intense. The subcortical region lies in the center of the brain, beneath the cortex and on top of the brain stem. The Brain stem is also called the “reptilian brain” from which the rest of the brain has evolved.
The modern cortex of the brain has great influence over the rest of the brain. It has been shaped by evolutionary pressures to develop ever improving abilities to parent, bond, communicate, cooperate and love (Dimbar & Shultz, 2007).
The cortex is divided into two “hemispheres” connected by the corpus callosum. In the evolution of the brain the left hemisphere came to focus on sequential and linguistic processing and the right hemisphere focused on the holistic and visual-spatial processing. These two hemispheres did work closely together and it is often hard to differentiate their different functions as the brain operates in a human. Many of the neural structures in the evolving brain were duplicated so that there is one in each hemisphere. The usual way of talking about components of the brain is to refer to the structure as a single entity e.g. cerebellum
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Summary of Evolution of the Brain Structures
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Name
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Where Located
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Functions
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Structures of Brain Involved
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Reptilian;
“Archaic Brain”
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Inner portion of brain - Midbrain
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Responds to: Hunger; Temperature Control; Fight or Flight Fear Response; Defending Territory & Keeping Safe
Caudate Nucleus is involved in physiology of Obsessive-Compulsive Disorder behaviors
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Thalamus,
Caudate Nucleus,
Putamen
Globus Pallidus
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Paleomammalian;
Subconscious Brain;
“Old Brain”
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Central Brain
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Handles: Mood, Memory & Hormone Production Control
Anterior Cingulate: Mood & Impulse Control
Hippocampus: Memory
Amygdala: Fear, Fight or Flight & Anger
Hypothalamus: Endocrine System
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The Limbic System:
Anterior Cingulate
Hippocampus
Amygdala
Hypothalamus
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Neomammalian;
Conscious Brain;
“New Brain”
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The Outer Cerebral Cortex of Brain
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Handles: Higher Cognition, abstract thought, usage of tools, formation & comprehension of language & social behavior
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Cerebral Cortex: Frontal Lobes; Parietal Lobes; Temporal Lobes; Occipital Lobes & Corpus Callosum
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Brain Pathway:
A brain pathway is the powerline which connects two brain regions. Brain pathways are made up of interconnected neurons along which signals are transmitted from one brain region to another.
Neurons: The brain has over 100 billion neurons. Neurons on the average have 5000 connections called synapse from other neurons (Linden, 2007). Bio-chemical electrical impulses create a cascade of effects based on the messages sent to various organ receptors of the body. The neurons process information by receiving, integrating and transmitting information.
Neurons have specific components:
1. Cell body – sends out the dendrites
2. Axon – when a neuron fires an electrochemical wave ripples down from its axon which is the fiber which extends toward other neurons it is sending signals to
3. Dendrites-are spikes from the neuron which receive neurotransmitters from other neurons
4. Myelin – fatty substance that insulates the axons
5. Terminal Buton - which faces the synapse
Synapses: Synapses are the junction of two neurons. There are approximately 1000 synapses per neuron or 100 trillion synapses in the brain. At its receiving synapse a neuron gets signals usually as a burst of chemicals called neurotransmitters from other neurons. Signals tell the neuron either to fire or not. Whether to fire or not depends on the combination of signals it receives. When a neuron fires it send signals to other neurons through its transmitting synapse telling those neurons whether to fire or not. A typical neuron fires 5-50 times a second. Each neural signal is a bit of information. The body’s nervous system moves information around the body just like the heart moves blood through the body.
Glial Cells: provide the structural support of the neurons in the brain, supply nutrients, remove waste, repair damage and provide insulation
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Components of a neuron synapse
1. Terminal Buton: end of a neuron which contains the neurotransmitters and this region of the neuron is referred to as presynaptic
2. Receptors: are on the end of the receiving neuron which is call postsynaptic and it through which the neurotransmitters are transmitted
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Neurochemicals
There are major chemical inside the brain that affect neural activity. These chemicals have different functions.
Neurotransmitters: All of the neurotransmitters affect functions throughout the body.
The Brain is made up of billions of brain cells called Neurons. The Neurons transmit information by means of electrical conduction within nerve cells and between nerve cells. The message once carried through body cell (Axon) crosses space called the Synapse to the new receiving cell.
The tip of neuron axon-tiny sacs contain neurotransmitter chemicals which are automatically released by sending nerve cell. Neurotransmitter chemicals excite receiving cell causing cell to fire to send message through its own body-Axon to next receiving cell. Once message received neurotransmitter is deactivated and taken up from synapse and stored in sacs so as not to cause repeated firing of the receiving cell.
Primary Neurotransmitters associated with emotional balance, sleep patterns and anxiety and mood. These are the brain’s major workhorse neurotransmitters.
1. Glutomate: excites the receiving neurons. Over half of all brain synapses release glutamate
2. GABA -Gamma amino-butryic acid: inhibits receiving neurons. 40-40% of all brain synapses release GABA.
Since GABA is inhibitory and glutamate is excitatory, both transmitters work together to control many processes, including the brain’s overall level of excitation. Many of the drugs of abuse affect either glutamate or GABA or both to exert tranquillizing or stimulating effects on the brain.
Neuromodulators
1. Serotonin: regulates states of consciousness, mood and anxiety, it also regulates sleep and digestion and affects appetite, sleep and sexual behavior. Most antidepressants aim at increasing it effect
2. Dopamine: influences emotional behavior and cognition, regulates motor activity and regulates endocrine activity. It is also involved in rewards and attention. It promotes the “approach” behaviors for individuals who face stressors
3. Norepinephrine: Its function is to alert and arouse. It regulates alertness, anxiety and tension and is secreted by adrenal glands in response to stress or arousal
4. Acetylcholine: promotes wakefulness and learning
Neuropeptides – are built from peptides which is a kind of organic molecule
1. Opiods – buffer stress, provide soothing and reduce pain, and produce pleasure - these include the endorphines
2. Oxytocin – promote nurturing behaviors toward children and bonding in couples. It is associated with blissful closeness and love. Women typically have more oxytocin than men.
3. Vasopressin – supports pair bonding and in men it may promote aggressiveness towards sexual rivals
Other Neurochemicals
1. Cortisol – released by the adrenal glands during stress response. It stimulates the amygdala and inhibits the hippocampus
2. Estrogen – the brains of both men and women contain estrogen receptors which affects the libido, mood and memory
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Summary of Major Neurotransmitters
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Name of Neurotransmitter
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Related to:
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Related to which Diseases:
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Medications that fill in
for it
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Acetycholine
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1. Memory Function
2. Autonomic nervous system regulation
3. Signal transmission from nerves to muscles
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Alzheimer’s
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Nicotine
Atropine
Curare
Botulinum toxin Aricept
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Norepinephrine (noradrenaline)
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1. Motivation
2. Energy level
3. Socializing
4. appetite
5. basal metabolic rate
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Autonomic nervous system disorders (hypertension)
Depressive Disorders
Anxiety Disorders
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Ephedrine
Yohimbine
Amphetamines
Merida
Effexor
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Dopamine
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1. Motor neuron control
2. Concentration
3. Food seeking or Sexual Desire
4. Socializing
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Parkinson’s
Schizophrenia
ADHD
Addictions
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L-dopa
Amphetamines
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Serotonin
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1. Mood
2. Food intake regulation (vomiting)
3. Limbic system functioning
4. Pain
5. Sleep
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Depressive Disorders
Anxiety Disorders
Appetite Disorders
Migraines
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Prozac
Paxil
Imitrex
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Gamma-aminobutyric acid (GABA)
(Inhibitory Neurotransmitter)
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Affects:
1. Emotional Balance
2. Sleep Patterns
3. Anxiety
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Anxiety Disorders
Restlessness
Sleeplessness
Insomnia
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Benzodiazepines
Barbiturates
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Glutamate (Excitatory Neurotransmitter)
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Associated with potentiation of other neurotransmitters
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Psychoses
Epilepsy
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Lamitrigine (Lamictal)
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b-Endorphin
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Affects perception of pain
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Addictions
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Morphine
Heroine
Codeine
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The Nervous System
The nervous system is responsible for sensing and reacting to the environment and for coordinating the bodily functions of its organ components. The Central Nervous System (CNS) includes the brain and the spinal cord as well as the Peripheral Nervous System (PNS) and the Autonomic Nervous System (ANS).
The Peripheral Nervous System
The PNS affects the heart and the muscles and directs communications between the skin and the brain. The skin is vital for receiving data about the external environment and the safety of the body. Changes in pressure, temperature, and other environmental factors cause both conscious and automatic adjustments to the environment. Norepinephrine activates the PNS which then activates the heart, muscles, and extremities. As norepinephrine increases so does heart rate and blood pressure and anxious symptoms such as sweating, flushing and trembling.
The Autonomic Nervous System
The ANS enervates and controls the action of all internal organs. It consists of three parts:
1. Sympathethic nervous system (SNS) which is responsible for arousal of the brain and body. It is important in creating the physical responses of arousal under stress and trauma
2. Parasympathetic nervous system (PSNS) which inhibits arousal. It restores balance to internal organs and stress response systems.
3. The diffuse enteric nervous system which controls digestion and peristaltic action
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Training of Brain to Improve Brain Health and Performance
1. Lumosity: http://www.lumosity.com/ is a website on which you can journey to improve your brain's functioning by doing online exercises on a daily basis. The goal of using the website would be to improve memory, attention and creativity.
2. Fit Brains: http://www.fitbrains.com/ offers online training tools to help individuals enhance their memory, concentrate more deeply and build an overall stronger brain. They do this through games that are accessed through the site, and information about improving your brain’s health through mental stimulation, nutrition, physical activity, socialization, and spirituality. The site reviews ways that individuals can implement these changes and ways to train your brain to improve its fitness.
3. The American Association of Retired People - http://www.aarp.org/health/brain-health/?intcmp=HP-LN-sec5-pos1 offers lots of information for the growing number of aging individuals. The section under Health: Brain Health & Longevity offer numerous resources in the form of articles, games, quizzes and even apps to help those maintain and even improve their brain fitness and health. The site offers nutrition information as well as tips to help keep the mind “fit forever.” Articles and videos on living with Alzheimer’s and other conditions for those affected and their caregivers are also available. The site provides individuals with lots of knowledge and activities to help promote and improve overall brain health.
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Nutritional Care of the Brain
There are some basic rules of eating to follow to keep the brain healthy
1. Eat a well-balanced diet on a daily basis – lots of proteins and lots of vegetable including a variety of brightly colored fruits and vegetable (5 servings a day) for flavonoids and carotenoids (both of which fight off free radicals which help to deteriorate the health of the brain) from natural sources.
2. Reduce the amount of sugar intake on a daily basis-avoid refined sugars
3. Eat at least 2 servings of fish a week
4. Limit fat consumption to 30% of caloric intake
5. Avoid foods which the body is allergic to
6. Take supplements to help the brain
Take a good multivitamin/multimineral supplement
Take Omega-3 Fatty Acid – found in fish oil – 500 milligrams a day because it contains both DHA and EPA acids which are very beneficial to the brain given that DHA is the predominant structural fatty acid in the central nervous system
Take Vitamin E as Gamma –Tocopherol – this is the main antioxidant in the cellular membranes within the brain
7. Take supplements to support the neurotransmitters:
Serotonin supplements: Iron, Vitamin B-6 and 5-Hydroxytryptophan and Tryptophan
Norepinephrine and Dopamine supplements: Iron and Vitamin B-6
Acetycholine supplement: egg yolks, beef, liver, or dairy fats or use phosphatidylserine, acetyl-l-carnitine or huperzine-A
NOTE: to get information on the purity and quality of any supplement go to: www.Consumerlab.com
Lifestyle Habits to Keep the Brain Healthy
1. Physical Activity and Exercise – 3 times weekly for 45 minutes including some aerobics
Improves the cognitive functions and sustains cerebral blood flow
Encourages angiogenesis which is the development of new blood vessels
Increases neurogenesis and neuronal growth in the hippocampus
2. Engaging in intellectually stimulating activities throughout life
As people age it buffers against longitudinally-measured cognitive decline. Humans need high levels of cognitive activity throughout their adult life to optimize their cognitive functioning later on as they age.
For an online assistance in finding engaging cognitive activities go to Brain Workshop which give exmpls of Neurobic – brain gymnastics at: http://brainworkshop.sourceforge.net/
3. Strategies for Optimizing Brain Function over the Life Span
1. High intake of foods and supplements which provide brain nutrients
2. Physical activity and exercise over one’s entire lifetime
3. Engaging in intellectual and cognitive activities over one’s entire lifespan
4. Moderate caloric intake with low saturated fat intake
5. Monitor and maintain normal blood pressure over one’s entire lifespan
6. Insure that cholesterol levels are maintained within the normal range
7. Avoid chronic stress
8. Maintain a daily intake of caffine.
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REFERENCES
Dunbar, R. & Shultz, S. (2007) Evolution in the social brain. Science, 317, 1344-1347.
Hanson, R. & Mendius, R. (2009) Buddha’s Brain-The Practical Neuroscience of Happiness, Love and Wisdom. Oakland, CA: New Harbinger Publications.
Lammert, E. (2008). Brain wnts for blood vessels. Science, 322(5905), 1195-1192.
Linden, D.J. (2007). The Accidental Mind: How Brain Evolution Has Give Us Love, Memory, Dreams, and God. Cambridge, MA: The Belknap Press of Harvard University Press.
Rachel, M.E. & Gusnard, D. (2002). Appraising the brain’s energy budget. Proceedings of the National Academy of Sciences, 99(16), 676-682.
Rasia-Filho, A., Londero, R. & Archaval, M. (2000). Functional activities of the amygdala: An overview. Journal of Psychiatry and Neuroscience. 25, 14-23.
Siegel, D. J. (2010) Mindsight-The New Science of Personal Transformation. New York: Random House
Thompson, E. & Varela, F.J. (2001). Radical embodiment: Neural dynamics and consciousness. Trends in Cognitive Sciences, 5, 418-425.
Wehrenberg, M. & Prinz, S.M. (2007). The Anxious Brain. New York: Norton & Company.
Yamasaki, H, LaBar, K. & McCarthy, G. (2002). Fearful expressions gain preferential access to awareness during continuous flash suppression. Emotions 7, 882-226.
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