Basics of Neuroscience

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Basics of Neuroscience

• James J. Messina, Ph.D.

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Structures of the Brain

• Facts about human brain
• weighs about 3 pounds or about 2 of the bodys
  weight
• Contains 1.1 trillion cells, including 100
  billion neurons
• Neurons on the average have 5000 connections
  called synapse from other neurons (Linden, 2007)
• Brain uses 20-25 of the bodys oxygen and
  glucose even though it is only 2 of the bodys
  weight (Lammert, 2008).
• Brain is always working and performing its
  functions
• Brain uses the same amount of energy
• when the body is asleep or when awake it is hard
  at work thinking (Raichle Gusnard, 2002).

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The Brain and the Mind

• The 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.

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The Three Human Brains

• Aggressive Brain which lies in the primitive
  portion of the brain
• Emotional Brain which entails the Limbic system
• 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 Human Brain (Part 1)

• The Cerebral Cortex (Described in next slides)
• Anterior (frontal) Cingulate Cortex (ACC)
  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
• Insula 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
• Thalamus 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

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Primary Components of Human Brain (Part 2)

• Brain Stem Sends neuromodulators such as
  serotonin and dopamine to the rest of the brain
• Corpus Callosum Nerve bundle which passes
  information between the two brain hemispheres -
  vital for integrated thoughts, feeling and action
• The Pons (bridge) Connection between the lower
  brain and the mid-brain. It affects physical
  arousal, including blood pressure and responsible
  for heightened physical arousal in anxiety.
  Nuclei within the pons are important in rapid eye
  movement (REM) sleep.
• Cerebellum - Regulates body movement and
  responsible for body and limb position, relating
  to balance, posture, walking etc. Integrates
  information. It is assumed that the Cerebellum
  plays an important role in dreaming, memory, and
  other functions.

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The Cerebral Cortex

• The motor cortex mediates motor activity
• The premotor cortex - plans complex motor
  activity
• Prefrontal Cortex (PFC) Makes meaning of
  sensory input.
• The orbitofrontal cortex (OFC) - Controls working
  memory
• The anterior cingulate gyrus (ACG) Connects
  directly limbic system

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Prefrontal Cortex (PFC)

• Makes meaning of sensory input
• Sets goals, makes plans, directs actions, and
  shapes emotions
• Processes information, maintains conscious
  attention, and forms behavioral responses
• Guides and sometimes inhibits the limbic system
• Conducts executive reasoning and is critical for
  sequencing behavior
• Handles working memory

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Prefrontal Cortexs Components

• 1. The orbitofrontal cortex (OFC)
• Controls working memory
• Consolidates long term memory
• Compares information with other data coming to it
  from other information centers of the brain
• 2. The anterior cingulate gyrus (ACG)
• Connects directly to the structures of the limbic
  system
• Filters and amplifies information from lower
  regions to and from the prefrontal cortex

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Limbic System

• Limbic System
• central to emotion and motivation and memory
• includes cortical as well as subcortical
  structures
• consists of the structures that ring the upper
  part of the brainstem
• Basal Ganglia Involved with rewards,
  stimulation seeking and movement. Ganglia are
  masses of tissues
• Cingulate gyrus allows shifting of attention,
  cognitive flexibility, adaptability, and helps
  the mind move from idea to idea
• Hippocampus Forms new memories and idetects
  threats.
• Amygdala - Functions as the alarm bell for the
  brain that responds to emotionally charged or
  negative stimuli (Rasia-Filho, Londero
  Archaval, 2000)
• Hypothalamus - Regulates primal drives such as
  hunger and sex activates the pituitary glands
• Pituitary gland it makes endorphins and
  triggers hormones.

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The Limbic System
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The Lobes of the Brain
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Areas of Brain Involved in Cognitive Functioning
Cognitive Function Brain Area Involved
Arousal Attention Frontal Cortex Limbic System Brain Stem
Motor Somatosensory Frontal Parietal Cortex Thalamus Striatum Cerebellum
Executive Functions Frontal Cortex
Language Functions Dominant Cerebral Hemisphere Cortex
Visuospatial Functions Nondominant Cerebral Hemisphere Cortex
Intellectual Reasoning Diffusely Represented in Cortex
Learning Memory Cortex Limbic System
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Left Hemisphere of Brain

• Organizes information, understands sequences
  comprehends time in conjunction with activities
  or events, putting events in sequential order
  placing them in time
• where verbal work making meaning of experience
  occurs
• Forms symbols (language and math) for experience
• Creates explanations for experience
• Inhibits activity of right hemisphere which deals
  with emotions
• Moderates emotional information which goes into
  right side of brain
• Mediates memory, nonverbal, emotional
  responsiveness of right-side brain functions

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Right Hemisphere of Brain

• Responsible for recognizing faces, reading
  emotions, assessing emotional significance of
  event in conjunction with data from senses which
  it interprets
• Specialized for nonverbal recognition emotional
  memory - vital for quick accurate response to
  world in which human lives
• Strong role in creativity nonverbal problem
  solving
• Creates novel responses to both practical
  emotional situations
• Comprehends spatial relationships
• Alert for creates cadence rhythm in speech,
  movement, music
• Regulates nervous system hormonal response
  coming in from senses.

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Role of Brain Hemispheres

• Left side of brain controls right side of body
  right side of brain controls left side of body
• Previous slide demonstrates left eye's image is
  translated on right side of brain right eye's
  image is translated on left side of brain
• Image which person perceives comes after a
  process in brain in which left right side
  images are translated or decoded by left right
  side of brain then made sense for 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 senses
  to brain
• This is physiological process by which all senses
  thinking are impacted

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Cause of Faulty Perceptions

• If human has faulty perceptions it can impact the
  way human thinks, feels and acts
• As a result of faulty perceptions which come from
  obscuring translation of faulty perception can
  impair problem solving, decision making
  conflict resolution
• Brain take time to sort out what senses are
  sending it

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The Evolving Brain

• Inside brain are three levels of development of
  brain
• Reptilian - Brain stem is reptilian brain from
  which rest of brain has evolved is simplistic,
  concrete, fast, and motivationally intense
• Paleomammalian Limbic System
• Neomammalian - Cortical tissues relatively
  recent, complex, conceptualizing, slow
  motivationally diffuse sit atop subcortical
  brain stem structures

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Summary of Evolution of Brain Structures
Name Where Located Functions Structures of Brain Involved
Reptilian  Archaic Brain Inner portion of brain - Midbrain 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 Thalamus, Caudate Nucleus, Putamen Globus Pallidus
Paleomammalian Subconscious Brain  Old Brain Central Brain Handles Mood, Memory Hormone Production Control Anterior Cingulate Mood Impulse Control Hippocampus Memory Amygdala Fear, Fight or Flight Anger Hypothalamus Endocrine System The Limbic System Anterior Cingulate Hippocampus Amygdala Hypothalamus
Neomammalian Conscious Brain  New Brain The Outer Cerebral Cortex of Brain Handles Higher Cognition, abstract thought, usage of tools, formation comprehension of language social behavior Cerebral Cortex Frontal Lobes Parietal Lobes Temporal Lobes Occipital Lobes Corpus Callosum
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Evolving Brain Impact

• Modern cortex of brain has great influence over
  rest of brain
• Its been shaped by evolutionary pressures to
  develop ever improving abilities to parent, bond,
  communicate, cooperate love (Dimbar Shultz,
  2007).
• Cortex is divided into two hemispheres
  connected by corpus callosum
• In evolution of brain left hemisphere came to
  focus on sequential and linguistic processing
  right hemisphere focused on holistic
  visual-spatial processing
• Two hemispheres work closely together it is
  often hard to differentiate their different
  functions as brain operates
• Many neural structures in evolving brain were
  duplicated so that there is one in each
  hemisphere
• Usual way of talking about components of brain is
  to refer to structure as a single entity e.g.
  cerebellum

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So How Does the Brain Work?

• Brain Pathway
• Power line which connects two brain regions
• Made up of interconnected neurons along which
  signals are transmitted from one brain region to
  another
• Neurons
• Brain has over 100 billion neurons
• Neurons on average have 5000 connections called
  synapse from other neurons (Linden, 2007)
• Bio-chemical electrical impulses create a cascade
  of effects based on messages sent to various
  organ receptors of body
• Neurons process information by receiving,
  integrating transmitting information.

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Components of Neurons

• Cell body sends out dendrites
• Axon when a neuron fires an electrochemical
  wave ripples down from its axon which is fiber
  which extends toward other neurons it is sending
  signals to
• Dendrites - are spikes from neuron which receive
  neurotransmitters from other neurons
• Myelin fatty substance that insulates axons
• Terminal Buton which faces synapse

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Components of Neuron Synapse

• 1. Terminal Buton
• End of a neuron which contains neurotransmitters
• Referred to as presynaptic
• 2. Receptors
• On end of receiving neuron referred as
  postsynaptic
• Through which neurotransmitters are transmitted

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Neurochemicals

• Major chemical inside brain that affect neural
  activity
• These chemicals have different functions.

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Neurotransmitters

• All neurotransmitters affect functions throughout
  body
• Brain is made up of billions of brain cells
  called Neurons
• Neurons transmit information by means of
  electrical conduction within nerve cells and
  between nerve cells
• Message once carried through body cell (Axon)
  crosses space called Synapse to new receiving
  cell
• 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 taken up from synapse and stored in
  sacs so as not to cause repeated firing of
  receiving cell.

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Neurotransmitters (1)

• Primary Neurotransmitters associated with
  emotional balance, sleep patterns anxiety
• Glutomate excites receiving neurons
• GABA -Gamma amino-butryic acid inhibits
  receiving neurons

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Neurotransmitters (2)

• Neuromodulators
• Serotonin regulates states of consciousness,
  mood and anxiety, it also regulates sleep
  digestion affects appetite, sleep sexual
  behavior. Most antidepressants aim at increasing
  its effect
• Dopamine influences emotional behavior
  cognition, regulates motor activity regulates
  endocrine activity. It is also involved in
  rewards attention. It promotes approach
  behaviors for individuals who face stressors
• Norepinephrine Its function is to alert
  arouse. It regulates alertness, anxiety tension
  is secreted by adrenal glands in response to
  stress or arousal
• Acetylcholine promotes wakefulness learning

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Neurotransmitters (3)

• Neuropeptides are built from peptides which is
  a kind of organic molecule
• Opiods buffer stress, provide soothing reduce
  pain, produce pleasure - these include the
  endorphines
• Oxytocin promote nurturing behaviors toward
  children bonding in couples. Associated with
  blissful closeness love. Women typically have
  more oxytocin than men.
• Vasopressin supports pair bonding in men it
  may promote aggressiveness towards sexual rivals

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Other Neurochemicals

• Cortisol released by adrenal glands during
  stress response. It stimulates amygdala
  inhibits hippocampus
• Estrogen brains of both men women contain
  estrogen receptors which affects libido, mood
  memory

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Name of Neurotransmitter Related to Related to which Diseases Medications that fill in for it
Acetycholine 1. Memory Function 2. Autonomic nervous system regulation 3. Signal transmission from nerves to muscles Alzheimers Nicotine Atropine Curare Botulinum toxin Aricept
Norepinephrine (noradrenaline) 1. Motivation 2. Energy level 3. Socializing 4. appetite 5. basal metabolic rate Autonomic nervous system disorders (hypertension) Depressive Disorders Anxiety Disorders Ephedrine Yohimbine Amphetamines Merida Effexor
Dopamine 1. Motor neuron control 2. Concentration 3. Food seeking or Sexual Desire 4. Socializing Parkinsons Schizophrenia ADHD Addictions L-dopa Amphetamines
Serotonin 1. Mood 2. Food intake regulation (vomiting) 3. Limbic system functioning 4. Pain 5. Sleep Depressive Disorders Anxiety Disorders Appetite Disorders Migraines Prozac Paxil Imitrex
Gamma-aminobutyric acid(GABA) (Inhibitory Neurotransmitter) Affects 1. Emotional Balance 2. Sleep Patterns 3. Anxiety Anxiety Disorders Restlessness Sleeplessness Insomnia Benzodiazepines Barbiturates
Glutamate (Excitatory Neurotransmitter) Associated with potentiation of other neurotransmitters Psychoses Epilepsy Lamitrigine (Lamictal)
b-Endorphin Affects perception of pain Addictions Morphine Heroine Codeine
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The Nervous System

• Responsible for sensing reacting to environment
  coordinating bodily functions of its organ
  components
• Central Nervous System (CNS) includes the brain
  and the spinal cord
• Peripheral Nervous System (PNS)
• Autonomic Nervous System (ANS).

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Peripheral Nervous System

• Affects heart muscles directs communications
  between skin brain
• Skin is vital for receiving data about external
  environment safety of body
• Changes in pressure, temperature other
  environmental factors cause both conscious
  automatic adjustments to environment.
• Norepinephrine activates PNS which then activates
  heart, muscles extremities
• As norepinephrine increases so does heart rate
  blood pressure anxious symptoms such as
  sweating, flushing trembling

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Autonomic Nervous System

• The ANS enervates controls action of all
  internal organs. It consists of three parts
• Sympathetic nervous system (SNS) which is
  responsible for arousal of brain body. It is
  important in creating physical responses of
  arousal under stress trauma
• Parasympathetic nervous system (PSNS) which
  inhibits arousal. It restores balance to internal
  organs stress response systems
• Diffuse enteric nervous system which controls
  digestion peristaltic action

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Nutritional Care of Brain

• There are some basic rules of eating to follow to
  keep the brain healthy
• Eat a well balanced diet on a daily basis lots
  of proteins lots of vegetable
• Eat at least 2 servings of fish a week
• Limit fat consumption to 30 of caloric intake
• Reduce amount of sugar intake on a daily
  basis-avoid refined sugars
• Avoid foods which body is allergic to

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Take Supplements to Help brain

• Multivitamin/multimineral supplement
• 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 brain
  given that DHA is the predominant structural
  fatty acid in central nervous system
• Vitamin E as Gamma Tocopherol this is main
  antioxidant in cellular membranes within brain

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Supplements for 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

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Lifestyle Habits to Keep the Brain Healthy (1)

• 1. Physical Activity and Exercise 3 times
  weekly for 45 minutes including some aerobics
• Improves cognitive functions sustains cerebral
  blood flow
• Encourages angiogenesis which is development of
  new blood vessels
• Increases neurogenesis neuronal growth in
  hippocampus

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Lifestyle Habits to Keep the Brain Healthy (2)

• 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