The World of Psychology

The Biology of Behavior

Book authors:

E.H. Ettinger

Chapter 3

The Biology of

Behavior

Slide authors:

Larry D. Thomas

Landon O. Thomas

This multimedia product and its contents are protected under copyright law.

The following are prohibited by law:

•Any public performance or display, including transmission of any image over a network;

•Preparation of any derivative work, including the extraction, in whole or in part, of any images;

•Any rental, lease, or lending of the program

Copyright 2007 Horizon Textbook Publishing

Neurons and the

Neurotransmitters



Neuron

– A specialized cell that conducts impulses through the nervous system and contains three major partsa cell body, dendrites, and an axon

– Afferent neurons relay messages from the sense organs and receptors —eyes, ears, nose, mouth, and skin —to the brain or spinal cord

– Efferent neurons convey signals from the central nervous system to the glands and the muscles, enabling the body to move

– Interneurons carry information between neurons in the brain and between neurons in the spinal cord

Copyright © 2007 Horizon Textbook Publishing All Rights Reserved

Neurons and the




Anatomy of a Neuron

– Cell body

 The part of the neuron that contains the nucleus and carries out the neuron’s metabolic functions

– Dendrites

 The branchlike extensions of a neuron that receive signals from other neurons

– Axon

 The slender, tail-like extension of the neuron that transmits signals to the dendrites or cell body of the other neurons or to muscles or glands

– Synapse

 The junction where the axon of a sending neuron communicates with a receiving neuron across the synaptic cleft


Neurons and the




Anatomy of a Neuron

– Glia Cells

 Cells that help to make the brain more efficient by holding neurons together, removing waste products such as dead neurons, making the myelin coating for the axons, and performing other manufacturing, nourishing, and cleanup tasks

– Mylin Sheath

 Insulating covers around some axons that increases neuron’s ability to conduct electrical impulses. Loss of mylin is Multiple Sclerosis

– Nodes of Ranvier

 Small gap or exposed portion of an axon between mylin covers.


Neurons and the



Neurons and the


 Sodium-Potassium Pump

– The penetration and removal of sodium (Na+) and potassium

(K+) through the cell membrane allows for the transmission of the action potential down the axon of the neuron without electrical energy loss.

 Permeability

– The capability of being penetrated or passed through

 Resting potential

– The membrane potential of a neuron at rest, about -55 millivolts

 Action potential

– The sudden reversal of the resting potential, which initiates the firing of a neuron

– Complete process takes about 1 millisecond (1/1,000) of a second


Cl & K +

Neurons and the


Na +

Na + & K +


Neurons and the




Action of


– Excitatory Postsynaptic Potentials

 EPSPs

 Influencing surrounding neurons to fire

– Inhibitory Postsynaptic Potentials

 IPSPs

 Influencing surrounding neurons not to fire


Neurons and the





– A chemical that is released into the synaptic cleft from the axon terminal of a sending neuron, crosses a synapse, and binds to appropriate receptor sites on the dendrites or cell body of a receiving neuron, influencing the cell either to fire or not to fire



Receptors

– Protein molecules on the dendrite or cell body of a neuron that will interact only with specific neurotransmitters


Neurons and the


 How synaptic vesicles can continually pour out neurotransmitters

– Cell body of the neuron is always working to manufacture more of the neurotransmitter substance

– Unused neurotransmitters in the synaptic cleft may be broken down into their component molecules and reclaimed by the axon terminal to be recycled and used again

– Reuptake

 The process by which neurotransmitter molecules are taken from the synaptic cleft back into the axon terminal for later use, thus terminating their excitatory or inhibitory effect on the receiving neuron

– Breakdown

 Neurotransmitter molecules that are not taken back up into the axon terminal are metabolized into waste products.


Neurons and the


 Neurotransmitters called monoamines

– Acetylcholine

 Excitatory neurotransmitter in the brain but may be excitatory or inhibitory in organs of PNS. Involved in learning, movement and memory.

– Norepinephrine

 Excitatory neurotransmitter of reticular system and involved in eating, emotional behavior, learning & memory

– Dopamine

 Inhibitory neurotransmitter involved in movement, emotional behavior, attention, learning, memory and reward.


Neurons and the


 Neurotransmitters called monoamines

– Serotonin

 Inhibitory neurotransmitter involved in emotional behavior

(depression), arousal and sleep

– Gamma-amino Butyric Acid (GABA)

 Inhibitory neurotransmitter regulating arousal and inhibiting general arousal of major neural systems

– Endorphins

 Inhibitory neurotransmitter involved as a natural analgesic for pain reduction and also involved in emotional behavior, eating & learning.

– Glutamate

 Major excitatory neurotransmitter in brain involved in learning.


Central Nervous System





Two parts of a nervous system

– Central Nervous System (CNS)

 The brain and the spinal cord

– Peripheral Nervous System (PNS)

 Connects the central nervous system to all other parts of the body





Spinal cord

– An extension of the brain,reaching form the base of the brain through the neck and spinal column, that transmits messages between the brain and the peripheral nervous system

– Protected by bone and spinal fluid

– Spinal nerves are 31 matched pairs with one on the right side of the spinal cord and it’s counter part on the left side of the spinal cord

– Basic reflexes (such as the quick withdrawal of the hand from a hot surface) is controlled by the spinal cord.


Spinal Cord Reflex





Brainstem

– The structure that begins at the point where the spinal cord enlarges as it enters the brain

– Medulla

 The part of the brainstem that controls heartbeat, blood pressure, breathing, coughing, sneezing and swallowing

– Cerebellum

 Coordinates and regulates motor movements and muscle control necessary for posture

– Pons

 Brainstem structure just above the medulla does finetuning of motor messages, programming species-typical behaviors, processing sensory information and controlling respiration





Brainstem (continued)

– Reticular Formation or Reticular Activating

System (RAS)

 Neural circuits extending from lower brain to thalamus that play a critical role in arousal and alertness.

 Research suggest that Attention-Deficit Hyperactivity

Disorder (ADHD) results from insufficient arousal of the noradrenergic system.

– Stimulant medications as amphetamines and Ritalin facilitate norepinephrine and increase alertness helping ADHD individuals to stay more alert and thus pay attention.



 Limbic System

– Amygdala

 Expression of anger, rage, fear and aggressive behavior (intense uncomfortable emotions)

– Hippocampus

 Plays an important role in memory

– Septum

 Plays an important role in the experiencing of pleasure (intense comfortable emotions)

– Hypothalamus

 Helps maintain the bodies homeostasis (sleep, hunger, thirst, body temperature, & sex drive), controls the pituitary gland which in turn controls the endocrine (hormone) system, and emotional expression

– Thalamus

 Relay station for routing sensory information to the cerebral cortex and regulating sleep cycles (circadian rhythm)







Basal Ganglia

– Initiation of motor movement and emotion

– Includes:

 Caudate Nucleus

– Control and initiation of motor movement

– Huntington’s Disease

 Putamen

– Control and initiation of motor movement

– Huntington’s Disease

 Substantia Nigra

– The midbrain structure that controls unconscious motor movements

– Parkinson’s Disease

– Ecstasy Users Beware


Cerebrum



Cerebrum

– Largest structure of the human brain comprised of billions of neurons

– Consisting of the two cerebral hemispheres

– Connected by the Corpus Callosum

– Covered by the Cerebral Cortex

– Gray in color because neurons are not covered with myelin on the surface.

– Inner core is white because neurons are not myelinated and occur in three types:

 Commissural fibers - pass from one hemisphere to another

 Projection fibers – convey impulses to and from cortex

 Association fibers – connects various parts within a hemisphere


Cerebrum


Cerebrum

Frontal Lobe Parietal Lobe

Temporal

Lobe


Occipital

Lobe

Cerebrum

Motor Cortex Somatosensory

Cortex

Audition


Visual

Somatosensory Man


Cerebrum

 Sensory Cortex

– Involved in receiving sensory messages

– Primarily Parietal Lobes

 Motor Cortex

– Involved in transmitting messages to muscles for intentional movement of body

– Primarily Frontal Lobes

 Association Cortex

– Largest portion of brain (75%)

– Integrating sensory and motor messages

– Higher functions such as thinking, interpreting & remembering


Cerebrum



Corpus callosum

– The thick band of nerve fibers that connects the two cerebral hemispheres and make possible the transfer of information and the synchronization of activity between them


Cerebrum



Frontal lobes

– The lobes that control voluntary body movements, speech production, and such functions as thinking, motivation, planning for the future, impulse control, and emotional responses

 Motor cortex

 Broca’s area

 Frontal association areas


Cerebrum



Motor Cortex

– The strip of tissue at the rear of the frontal lobes that controls voluntary body movement

– Discovered by Fritsch and Hitzig

– Wilder Penfield

 Applied electrical stimulation to the motor cortex of conscious human patients undergoing neurosurgery

 Mapped the primary motor cortex in humans

– Plasticity is maintained throughout life

 The capacity of the brain to adapt to changes such as brain damage


Cerebrum



Broca’s area

– The area in the frontal lobe, usually in the left hemisphere, that controls the production of speech sounds

– Paul Broca

 Among the first scientists to demonstrate the existence of localized functions in the cerebral cortex and concluded that the site of damage was the part of the brain responsible for speech production

– Broca’s aphasia

 An impairment in the physical ability to produce speech sounds, or in extreme cases an inability to speak at all


Cerebrum



Bronca’s area (continued)

– Aphasia

 A loss or impairment of the ability to understand or communicate through the written or spoken word, which results from damage to the brain



Frontal Association Areas

– Consists of association areas involved in thinking, motivation, planning for the future, impulse control, and emotional responses


Cerebrum



Parietal lobes

 The lobes that contain the somatosensory cortex and other areas that are responsible for body awareness and spatial orientation

 Somatosensory cortex

– The strip of tissue at the front of the parietal lobe where touch, pressure, temperature, and pain register in the cerebral cortex


Cerebrum



Occipital lobes

– The lobes that contain the primary visual cortex and association areas involved in the interpretation of visual information

– Primary visual cortex

 The area at the rear of the occipital lobes where vision registers in the cerebral cortex

 Each eye is connected the the primary visual cortex in both right and left occipital lobes


Cerebrum



Temporal lobes

– The lobes that contain the primary auditory cortex,

Wernicke’s area, and association areas for interpreting auditory information

– Primary auditory cortex

 The part of the temporal lobes where hearing registers in the cerebral cortex


Cerebrum



Wernicke’s area

– The language area in the temporal lobe involved in comprehension of the spoken work and in formulation of coherent speech and written language

– Wernicke’s aphasia

 Aphasia that results from damage to Wernicke’s area and in which the person’s spoken language is fluent, but the content is either vague or incomprehensible to the listener

– Another kind of aphasia is auditory aphasia

 Word deafness


Cerebrum



Temporal association areas

– House memories and are involved in the interpretation of auditory stimuli

– There is a special association area where familiar melodies are stored


Cerebral Hemispheres

 Lateralization

– The specialization of one of the cerebral hemispheres to handle a particular function

 Left hemisphere

– The hemisphere that controls the right side of the body, coordinates complex movements, and in 95% of right-handers and 62% of left-handers, controls most functions of speech and written language

 Right hemisphere

– The hemisphere that controls the left side of the body and that, in most people, is specialized for visual-spatial perception and for interpreting nonverbal behavior







Right hemisphere’s role in emotion

– The right hemisphere is involved in our expression of emotion through tone of voice and facial expressions

– Controls the left side of the face and usually conveys stronger emotion than the right side of the face

– Lawrence Miller

 Describes the facial expressions and the voice inflection of people with right hemisphere damage as “often strangely blank – almost robotic”





Right hemisphere’s roles





Left hemisphere’s roles





Split brain

– Split-brain operation

 An operation in which the corpus callosum is cut, separating the cerebral hemispheres and usually lessening the severity and frequency of grand mal seizures





Split brain (continued)

– Joseph Bogen and Philip Vogel

 Found that patients with severe epilepsy could be helped by surgery that severed their corpus callosum rendering communication between the two hemispheres impossible

– Roger Sperry and Michael Gazzaniga and Jerre

Levy

 Their research with split-brain patients has expanded knowledge of the unique capabilities of the individual hemispheres

– Roger Sperry

 Found that when the brain was surgically separated, each hemisphere continued to have individual and private experiences, sensations, thoughts, and perceptions





Roger Sperry 1981 Nobel Prize research

– The right hemisphere knows and remembers what it sees just as well as the left, but unlike the left hemisphere, the right cannot name what it has seen


How the Brain is Studied



Hans Berger

– Invented the electroencephalograph, a machine that amplifies a million times the electrical activity occurring in the brain



Electroencephalogram

– A record of brain-wave activity made by the electroencephalograph





Beta wave

– The brain wave associated with mental or physical activity



Alpha wave

– The brain wave associated with deep relaxation



Delta wave

– The brain wave associated with slow-wave (deep) sleep





Microelectrode

– An electrical wire

– So small that it can be inserted near or into a single neuron without damaging it

– Can be used to monitor the electrical activity of a single neuron or to stimulate activity within it

– Used to discover the exact functions of single cells within the primary visual cortex and the primary auditory cortex





CAT scan (computerized axial tomography)

– A brain-scanning technique involving a rotating Xray scanner and a high-speed computer analysis that produces slice-by-slice, cross-sectional images of the structure of the brain



MRI (magnetic resonance imagery)

– A diagnostic scanning technique that produces highresolution images of the structures of the brain





PET scan (positron-emission tomography)

– A diagnostic scanning technique that produces highresolution images of the structures of the brain



Functional MRI (fMRI)

– A brain-imaging technique that reveals both brain structure and brain activity





SQUID (superconducting quantum interference device)

– Images brain activity by measuring magnetic changes produced by the electric current neurons discharge when they fire



MEG (magnetoencephalography)

– Measures magnetic changes produced by the electrical activity from firing neurons and can also image neural activity within the brain as rapidly as it occurs, much faster than PET or fMRI


Brain Across the Lifespan



Synaptogenesis

– Process where synapses develop as a result of growth of both dendrites and axons

– Pruning

 The process through which the developing brain eliminates unnecessary or redundant synapses



Myelination

– The development of myelin sheaths around axons, begins prior to birth but continues well into adulthood





Hemispheric specialization

– Language processing occurs primarily in the left hemisphere

– Spatial perception is not lateralized to right side but not until around the age of 8



Plasticity

– The ability of the brain to reorganized, to reshape itself in response to input from both internal and external sources, and to compensate for damage





Stroke

– The most common cause of damage to adult brains, arising when blockage of an artery cuts off the blood supply to a particular area of the brain or when a blood vessel bursts

– A high percentage of stroke survivors suffer from depression

– Patients who receive TPA (a blood clot-dissolving drug) within 3 hours of the onset of a stroke are

30% more likely to have minimal or no disability


Peripheral Nervous System



Peripheral Nervous System (PNS)

– The nerves connecting the central nervous system to the rest of the body

– Contains two subdivisions

 Somatic Division

 Autonomic Division – contains two divisions

– Sympathetic Division (Activates)

– Parasympathetic Division (Inhibits)







Somatic Division

– Consists of all the sensory nerves, which transmit information from the sense receptors-eyes, ears, nose, tongue, and skin-to the central nervous system

– Consists of all the motor nerves, which relay messages from the central nervous system to all the skeletal muscles of the body





Autonomic Division

– Operates without any conscious control or awareness on your part

– Transmits messages between the central nervous system and the glands, the cardiac muscle, and the smooth muscles





Autonomic Division (continued)

– Divided into two parts

 Sympathetic nervous system

– Mobilizes the body’s resources during stress, emergencies, or heavy exertion, preparing the body for action

– Named the fight-or-flight response by Walter Cannon

 Parasympathetic nervous system

– Associated with relaxation and the conservation of energy.

The division that brings the heightened bodily responses back to normal following an emergency.




Endocrine System



Endocrine system

– A system of ductless glands in various parts of the body that manufacture and secrete hormones into the bloodstream or lymph fluids, thus affecting cells in other parts of the body

– Hormones

 A substance manufactured and released in one part of the body that affects other parts of the body

 Chemical messengers of the endocrine system







Pituitary gland

– The endocrine gland located in the brain and often called the “ master gland ”, which releases hormones that control other endocrine glands and also releases a growth hormone

– Releases the hormones that activate the other glands in the endocrine system

– Brain controls activity of the pituitary gland through the production of a group of chemicals known as the hypothalamic-releasing factors

– Hormones exert primary influence over a single organ or specific cells which are referred to as target organs .







Thyroid gland

– Produces the important hormone thyroxine, which regulates the rate at which food is metabolized



Pancreas

– Regulates the body’s blood sugar levels by releasing the hormones insulin and glucagon into the bloodstream



Adrenal glands

– A pair of endocrine glands that release hormones that prepare the body for emergencies and stressful situations and also release small amounts of the sex hormones





Gonads

– Sex glands –the ovaries in females and the testes in males

– Release the sex hormones that make reproduction possible and that are responsible for the secondary sex characteristics


Depressants & Behavior

 Sedatives

– Class includes tranquilizers, barbituates & non-barbituates

– Induce relaxation, calmness and sleep

 Opiates (Narcotics)

– Includes opium, morphine, codeine & heroine

– Widely used as pain killers

 Alcohol

– Dampens impulse control (less inhibited)

– Withdrawal (nausea, vomiting, fever, shakes [delirium tremens]

& bizzare hallucinations

– 0.10% blood alcohol level is 5 times more likely to have a car accident

– Loss of memory, Fetal Alcohol Syndrome


Stimulants & Behavior

 Caffeine

– Most widely used stimulant

– Chocolate, tea, coffee

– Heart and respiration rates and blood pressure increase

– Blocks adenosine receptors

 Adenosine is an inhibitory neurotransmitter that produces neural sedation and regulates the dilation of blood vessels (Julian, 2001)

 Nicotine

– Second most widely used stimulant

– Tobacco products

– Increases heart rate, blood pressure and stomach activity while constricting blood vessels

– Withdrawal causes craving for tobacco, increased appetite, stomach cramps, headaches, restlessness, irritability, insomnia, anxiety and depression

– Smoking causes higher incidents of miscarriages, still births, low birth-weight babies and babies who die from Sudden Infant Death

Syndrome (SIDS) [Zotti, 2003]


Stimulants & Behavior

 Amphetamines

– Benzedrine, Dexedrine, Methedrine, Methamphetamine (street drug),

– Dramatically increase alertness and activity and counteract fatigue and promote feelings of euphoria and well-being

– Likely works on norepinephrine and dopamine by increasing the amount released from the nerve terminal and blocking reuptake

 Cocaine

– Made from the leaves of coca shrub and was active ingredient in

Coca Cola until 1903

– Increases heart rate & respiration rates, constricts blood vessels and dilates the pupils

– High only last 20-30 minutes so reuse must occur quickly

– Perhaps most addictive drug we know

– Heart and lung damage are common as well as anemia, damage to the nasal tissue, immune system impairment and rare cases of sudden death.


Hallucinogens & Behavior

 LSD (Lysergic acid diethylamide)

– Derived from a fungus that grows on rye grass

– Profound distortions of sensations, feelings, time & thought

– Suppresses the activity of Serotonin thus dream activity becomes activated without restraint

 Psilocybin ( Mushrooms)

– Suppresses the activity of Serotonin

 Mescaline ( Peyote Cactus)

– Effects the way the brain responds to Norepinephrine & Acetylcholine

 Ecstasy ( MDMA)

– Body and visual distortions

– Depersonalization

– Releases large amounts of Serotonin and interferes with synthesis of Serotonin

– Hyperthermia, rapid heart rate, high blood pressure, muscle rigidity and convulsions

– Appears to irreversibly destroy serotonin-containing neurons

– Parkinson’s Disorder Syndrome


Hallucinogens & Behavior

 Marijuana

– Derived from hemp plant Cannibis Sativa

– THC (delta9-tetrahydrocannabinol)

– Hallucinogen at high levels but usually a stimulant and depressant effect

– Increased heart rate & enhanced appetite

– Small doses create euphoria and enhance some sensory experiences

– Impairs reaction time and ability to concentrate

– Some people become confused, agitated or extremely anxious

– Has proved effective in epilepsy and glaucoma and reduces nausea during chemotherapy treatment of cancer patients

 Anadamide

– Devine et al., 1992

 Brains natural THC

 Regulates mood, pain, movement and appetite


The World of Psychology

The Biology of Behavior

Chapter 3

The Biology of

Behavior

Neuron

Anatomy of a Neuron

Anatomy of a Neuron

Action of

Neurotransmitters

Neurotransmitters

Receptors

Two parts of a nervous system

Spinal cord

Brainstem

Brainstem (continued)

Basal Ganglia

Cerebrum

Frontal Lobe Parietal Lobe

Temporal

Lobe

Occipital

Lobe

Motor Cortex Somatosensory

Cortex

Audition

Visual

Corpus callosum

Frontal lobes

Motor Cortex

Broca’s area

Bronca’s area (continued)

Frontal Association Areas

Parietal lobes

Occipital lobes

Temporal lobes

Wernicke’s area

Temporal association areas

Right hemisphere’s role in emotion

Right hemisphere’s roles

Left hemisphere’s roles

Split brain

Split brain (continued)

Roger Sperry 1981 Nobel Prize research

Hans Berger

Electroencephalogram

Beta wave

Alpha wave

Delta wave

Microelectrode

CAT scan (computerized axial tomography)

MRI (magnetic resonance imagery)

PET scan (positron-emission tomography)

Functional MRI (fMRI)

SQUID (superconducting quantum interference device)

MEG (magnetoencephalography)

Synaptogenesis

Myelination

Hemispheric specialization

Plasticity

Stroke

Peripheral Nervous System (PNS)

Somatic Division

Autonomic Division

Autonomic Division (continued)

Endocrine system

Pituitary gland

Thyroid gland

Pancreas

Adrenal glands

Gonads

Related documents

Add this document to collection(s)

Add this document to saved

Suggest us how to improve StudyLib