Neurobiological Bases of Behavior and Psychology

• Koleshiyo ng Lungsod ng Dasmarinas presents Neurobiological Bases of Behavior and Psychology Department

Learning Outcomes

• Students should be able to familiarize themselves with the structure and function of the nervous system in humans
• Students should be able to identify the structure and function of the endocrine system
• Students should be able to explain the interaction between biological factors and experience
• Students should be able to list down methods and issues related to biological advances

Techniques to Learn About the Brain and Neural Function

• With technology advancements, scientists use various techniques to study the brain and neural function
• Three fundamental ways to study brain functions include lesion, stimulation, and recording

Greek Philosophers and Physicians

• Hippocrates (460-377 B.C.) stated that emotions, thought, and mental health originate from the brain
• Plato (427-347 B.C.) agreed with Hippocrates
• Galen (circa 130-200 A.D.) believed that fluids in the brain's ventricles are responsible for sensations, reasoning, judgment, memory, and movement

Franz Gall and Johann Spurzheim

• Franz Gall (1758-1828) and Johann Spurzheim (1776-1832) incorrectly linked bumps and depressions on the skull's surface to personality traits and moral character
• The study was known as phrenology
• Later researchers explored localization of functions in the brain with more systematic research

Studying Patients with Brain Damage

• Studying patients with brain damage linked a loss of structure with loss of function
• Phineas Gage, a level-headed railroad foreman (1848), became volatile after an explosion that destroyed major parts of his prefrontal lobes
• Paul Broca (1824-1880) performed an autopsy on Leborgne (aka Tan), who lost speech capacity without paralysis or loss of verbal comprehension
• Gunshot wounds, tumors, strokes, Alzheimer's, and Korsakoff's syndrome enabled further brain mapping

Examination of Neural Tissue

• Examination of neural tissue led to understanding the neuron as the basic unit of structure and function of the nervous system
• Santiago Ramon y Cajal (1852-1934) perfected a silver staining technique developed by Camillo Golgi (1843-1926) to examine single neurons
• Cajal described the structure of a neuron and noted that each cell was distinct from the next

Direct Electrical Stimulation of the Brain

• Direct electrical stimulation of the brain provides another way to test the functions of certain brain areas
• Wilder Penfield (1952) used an electrode to localize the origin of seizures in patients
• Stimulation of different cortical areas caused movement for different body parts, enabling mapping of the motor cortex
• Walter Hess (1955) inserted electrodes more deeply into nonhuman animal brains under anesthesia and related start/stop functions with specific brain structures

EEG (Electroencephalogram)

• EEG is an amplified tracing of brain activity produced when electrodes on the scalp transmit brain wave signals to an electroencephalograph
• EEGs have been used to study the brain during states of arousal (sleeping, dreaming), detect abnormalities (deafness, visual disorders, epilepsy), or study cognition

Imaging Techniques

• Imaging techniques in widespread use provide images of brain anatomy
• CAT Scan (Computerized Axial Tomography) creates a computerized image of X-rays passed through the brain, showing two-dimensional "slices" that can be arranged to show the extent of a lesion
• MRI (Magnetic Resonance Imaging) is a method that uses a magnetic field and computer-generated radio waves to create detailed images of the organs and tissues in your body
• fMRI (Functional Magnetic Resonance Imaging) capitalizes on the ability of MRI scanners to detect the change in oxygen that occurs in an area of heightened neuronal activity
• PET scans (Positron Emission Tomography) helps reveal the metabolic or biochemical function using a radioactive drug (tracer) to show both normal and abnormal metabolic activity

The Neuron

• The neuron is the basic cell of the nervous system
• There are many types of neurons, each performing different functions but structured similarly

Three Major Structures

• Three major cell structures enable them to communicate with other cells, including the cell body, dendrites, and axon

The Cell Body (Soma)

• The cell body contains the nucleus and much of the machinery for cell processes
• The nucleus contains genetic material (chromosomes) necessary for cell development, protein synthesis, maintenance, and survival

Dendrites

• This branched, tree-like structure is attached to the soma of a neuron, which receives information from the terminal buttons of other neurons
• Extending outward from the soma are dendrites, which are receiving/input branches of the neuron

Axon

• The axon is a long, slender tube covered by a myelin sheath
• The axon carries information from the cell body to its terminal button
• The axon branches and ends in tips called presynaptic terminals (terminal buttons, boutons, or telodendria)
• Neurotransmitters are stored in structures of the presynaptic terminal known as vesicles

Neurotransmitters

• Many neurotransmitters have similar chemical structures and hypothesized functions
• Acetylcholine (ACh) causes contraction of skeletal muscles, regulates heart muscles, promotes arousal, and transmits messages between the brain and spinal cord
• Glutamate and aspartate stimulate receptors associated with learning, memory, sensory, and motor functions
• Glutamate is the most abundant excitatory neurotransmitter in the brain
• GABA (gamma-aminobutyric acid) inhibits the firing of neurons, is the most abundant inhibitory neurotransmitter, and is associated with calming effects
• Dopamine (DA) is primarily involved in processing smooth and coordinated motor movements, attention, learning, and reinforcing effects of abused drugs
• Norepinephrine (NE) is found in neurons in the autonomic nervous system (ANS) and governs sympathetic arousal by activating the heart and blood vessels, thus giving rise to the “fight or flight” syndrome
• Serotonin (SE or 5-HT) plays a role in the regulation of mood, control of eating, sleep, arousal, pain, and dreaming

The Organizations of the Brain

• There are a number of ways to conceptualize the structure of the brain
• One approach involves dividing the brain into three main regions based on location including the hindbrain, the midbrain, and the forebrain

Hindbrain

• The hindbrain includes structures located in the hind ('posterior') part of the brain, closest to the spinal cord

Midbrain

• The midbrain is located in the middle of the brain

Forebrain

• The forebrain includes structures located in the front ('anterior') part of the brain

Conceptualizing the Human Brain

• Paul MacLean proposed that we think of the human brain as three concentric layers
• The central core regulates primitive behaviors
• The limbic system controls emotions
• The cerebrum regulates higher intellectual processes

Parts of the Brain and General Functions (HindBrain)

• The first slight enlargement of the spinal cord as it enters the skull is the medulla, which controls breathing and reflexes related to posture
• Pons are located above the medulla and are important for attentiveness as well as timing of sleep
• Reticular formation extends from the lower brainstem to the thalamus in the forebrain, and is a network involved with arousal
• The cerebellum primary function is the coordination of movement

Parts of the Brain and General Functions (MidBrain)

• The midbrain includes the superior and inferior colliculus which relays sensory information to the brain and allows for movement control, including eye movement
• The substantia nigra is a crucial part of the dopamine pathway, which is often referred to as the reward pathway

Parts of the Brain and General Functions (ForeBrain)

• The thalamus functions as a sensory relay station
• The thalamus directs incoming information from the senses such as vision and hearing to the cerebrum
• Centers in the hypothalamus regulate eating, drinking, and sexual behavior
• The hypothalamus is critical for maintaining homeostasis through control of the autonomic nervous system

Forebrain Glands

• Pituitary gland is the most important part of the endocrine system via the pituitary gland
• The influence of the pituitary gland is controlled by the hypothalamus
• The limbic system imposes control over some instinctive behaviors regulated by the central core

Cerebrum

• The cerebrum initiates and coordinates movement and regulates temperature
• Other areas of the cerebrum enable speech, judgment, thinking and reasoning, problem- solving, emotions and learning

The Structure and Features of the Nervous System

• The nervous system is primary internal communication system, a specialized network of cells
• Basic features include the central nervous system and the peripheral nervous system

Basic Features of the Nervous System

• The central nervous system is the body's master control unit
• The peripheral nervous system is the body's link to the outside world

Central Nervous System Parts

• The spinal cord is a column of nerves between the brain and peripheral nervous system
• The brainstem connects the brain to the spinal cord
• The brain is divided into three major parts including the hindbrain, midbrain, and forebrain

Central Nervous System (Peripheral)

• The autonomic nervous system regulates involuntary bodily processes, including heart rate, respiration, digestion, and pupil contraction The autonomic nervous system operates automatically without conscious direction
• The somatic nervous system carries sensory information from sensory organs to the CNS and relays motor commands to muscles to control voluntary movements
• The sympathetic nervous system prepares the body for action and stress, referred to as "fight or flight"
• The parasympathetic nervous system calms the body and helps it conserve energy

Overview of CNS

• The brain and spinal cord are the control panel for bodies and is responsible for cognition, movement, sense, and emotion
• The brain is protected by the skull and the spinal cord travels from the back of the brain, down the center of the spine

More CNS

• The central nervous system is the processing center of the nervous system, It receives information and sends information to the peripheral nervous system
• The brain controls everything inside and outside the human body
• The spinal cord connects everything inside and outside of the body

Peripheral Nervous System

• PNS is outside the brain and spinal cord
• The PNS primary function is to connect the brain and spinal cord to the rest of the body and the external environment
• The peripheral nervous system transmits information to and from the CNS

Somatic Nervous System

• The PNS is made up of 31 spinal nerves which radiate outward
• The somatic nervous system (SNS) connects the central nervous system to the senses and is composed of sensory and motor nerves
• Sensory nerve pathways carry information to the CNS and motor nerve pathways send instructions to muscles

Autonomic Nervous System

• The autonomic nervous system (ANS) regulates involuntary actions, such as bodily arousal, body temperature, and homeostasis
• The sympathetic nervous system helps us deal/defend against emergencies, with results like increased heart rate and reduced digestion
• The parasympathetic nervous system calms the individual once the emergency has passed and conserves energy

The Endocrine System

• Hormones are secreted from structures (glands) in the body which pass through the bloodstream
• The network of glands is called the endocrine system

The Pituitary Gland

• The pituitary gland is the master gland and controls the release of hormones from many of the glands described above
• The pituitary is divided into the anterior and posterior

Anterior Pituitary

• ACTH stimulates the release of corticosteroids during flight-flight response
• Prolactin stimulates the production of milk from mammary glands (breasts)
• Growth Hormone induces cell growth and multiplication

Posterior Pituitary

• Vasopressin regulates water balance
• Oxytocin promotes uterine contractions during childbirth

Glands, Hormones, and their Functions

• Thyroid glands secrete thyroxine that regulate metabolic rate and protein synthesis
• Adrenal medulla secrets adrenaline and noradrenaline that induces a fight or flight response
• Adrenal cortex produces corticosteroids that release of glucose and fats for energy and suppresses the immune system
• Testes produce testosterone that enables male sexual characteristics and increase muscle mass
• Ovaries produce oestrogen that enables female sexual characteristics, menstruation, and pregnancy
• Pineal produces melatonin that regulates the sleep-wake cycle