cingulum bundle- part of the brain that when stimulated, produces smile and laughter

• This specific brain region is located at the crossroads of neural networks in the brain involved in regulating moods and emotions

Neurons: nerve cells

• basic building blocks of the nervous system

• inform your brain then carry messages from the brain that command your muscles to act accordingly

• single celled

  • consisting of a soma, an axon, and dendrites

  • Soma: cell body

    • contains nucleus of the cell, which stores DNA, and carries out the cell’s metabolic functions

• neurogenesis: The process by which new neurons are formed.

	part	description	functions
	Soma	Cell body containing the nucleus	Performs metabolic, or life-sustaining, functions of the cell
	Axon	Long cable projecting from the soma	Carries neural impulses to the terminal buttons
	Terminal buttons	Swellings at ends of axons	Release chemicals, called neurotransmitters, that carry neural messages to adjacent neurons
	Dendrites	Fibers that project from the soma	Receive messages from neighboring neurons

Brain: the mass of nerve tissue encased in the skull that controls virtually everything we are and what we do

terminal button: Swellings at the tips of an axon from which neurotransmitters are dispatched into the synapse.

• where chemicals called neurotransmitters are stored and released

  • neurotransmitters: Chemical messengers that transport nerve impulses from one nerve cell to another.

    • These chemicals are synthesized in the soma and ferry outgoing messages to neighboring neurons at the synapse

      • synapse: The small fluid-filled gap between neurons through which neurotransmitters carry neural impulses.

      • Neural impulses or messages cannot jump even this tiniest of gaps. They must be transferred by neurotransmitters

• Dendrites: branching structures that project from the soma

  • they have receptor sites that receive neurotransmitters released by neighboring neurons

    • how neurons communicate with each other

the nervous system, has three types of neurons:

1. sensory neurons: transmit information about the outside world to the spinal cord and brain (nervous system)

   • also called afferent neurons

2. motor neurons: convey messages from the brain and spinal cord to the muscles that control the movements of your body

   • also called efferent neurons

     • convey messages to you glands, causing them to release hormones

       • glands: body organs or structures that produce secretions called hormones

       • hormones: secretions from endocrine glands that help regulate bodily processes

3. interneurons: nerve cells within the central nervous system that process information

   • most common type of neurons

   • connect neurons to neurons

     • in the spinal cord, they connect sensory neurons to motor neurons

     • in the brain, they form collections of interconnected nerve cells that process information from sensory organs and control higher mental functions, such as planning and thinking

neuron is NOT THE SAME as a nerve

nerve: a bundle of axons from different neurons that transmit nerve impulses

• ex> optic nerve transmits messages from the eyes to the brain contains more than a million axons

glial cells: small but numerous cells in the nervous system that support neurons and that form the myelin sheath found on many axons

• remove waste products

• provide insulation between neurons

• assist neurons in communicating with one another

• form the myelin sheath

  • myelin sheath: a fatty layer of cells that acts as a protective shield on axons of certain neurons and helps speed transmission of nerve cells

nodes of Ranvier: gaps in the myelin sheath that create non-insulated areas along the axon

• The neural impulse appears to jump from node to node as it speeds down the axon

multiple sclerosis (MS): chronic and crippling disease of the central nervous system where the body’s own immune system attacks and destroys the myelin sheath

• 1/1,000 adults, about 1 million Americans between the ages of 20-50 yrs

• loss of myelin impairs the transmission of nerve impulses

• leading to problems with balance, fatigue, and progressing in severe cases to inability to speak, walk, or even breathe

• possibly due to genetics

Both inside and outside the neuron are electrically charged atoms and molecules called ions

ions: electrically charged chemical particles that either have a positive(+) or negative(-) charge

• movements of ions across the cell wall, or cell membrane, cause electrochemical changes in the cell that generate an electrical signal to travel down the cell’s axon in the form of a neural impulse.

• The movement of ions through the cell membrane is controlled by a series of gates, or tiny doors, that open to allow ions to enter the cell and close to shut them out.

• The most important ions in this process are two types of positively charged ions, sodium ions and potassium ions.

  • When a neuron is at rest, the gates that control the passage of sodium ions are closed

  • When the cell is stimulated, usually by neurotransmitters released from adjoining neurons, sodium gates at the base of the axon open.

  • A greater concentration of positively charged sodium ions remains outside the cell, causing the cell to have a slightly negative charge, called a resting potential

  • The sudden reversal of electrical charge is called an action potential, or neural impulse

    • resting potential: the electrical potential across the cell membrane of a neuron in its resting state

      • holds potential energy that can be used to generate a neural impulse in response to stimulation

        • like a charged battery sitting on a shelf

    • action potential: an excitation travelling along an axon at a constant strength regardless of distance

      • begins at the juncture between the soma and axon called the axon hillock

      • Once an action potential reaches the end of an axon, it causes the release of neurotransmitters from the terminal buttons that carry the neural message to the next neuron

        • All-or-none law states an axon cannot vary the strength or velocity of its action potentials.

          • a neuron will fire completely (generate an action potential) if sufficient stimulation is available, or it will not fire; there is no halfway pointy of its
            

for about one thousandth of a second after firing, a neuron busies itself preparing to fire again and goes through a process called a refractory period

• sodium gates along the cell membrane close preventing sodium +ions going into the cell

• the cell pumps out mostly potassium +ions, at the same time, the neuron’s -resting potential is restored

• then in a slower process, the cell restores the electrochemical balance by pumping out sodium ions & drawing in potassium ions, making it possible for another action potential to occur

  • like a gun being reloaded, it cannot fire

reuptake: process by which neurotransmitters are reabsorbed by the transmitting neuron.

• Through reuptake, neurotransmitters not taken up by the receiving cell are reabsorbed by their vesicles to be used again

enzymes: organic substances that produce certain chemical changes in other organic substances through a catalytic action.

• enzymes in the synapse break down neurotransmitters, which are then eliminated from the body in the urine

neuromodulators: chemicals released in the nervous system that influence the sensitivity of the receiving neuron to neurotransmitters

• terminal buttons release neuromodulators, chemicals that either increase or decrease the sensitivity of the receiving neuron to neurotransmitters.

Normal psychological functioning depends on the smooth transmission of messages among neurons in the brain. - everything you do depends on neurotransmitters

• When the body produces too little or too much of a neurotransmitter, problems may occur.

  • Excesses or deficits of particular neurotransmitters in the brain are associated with many disorders

    • ex> irregularities in neurotransmitter functioning are linked to eating disorders, depression, and schizophrenia

antagonists: drugs that block the actions of neurotransmitters by occupying the receptor sites in which the neurotransmitters dock.

• prevent transmission of the messages the neurotransmitters carry

• ex> neurotransmitter dopamine

  • dopamine: a neurotransmitter involved in controlling muscle contractions, processes of learning and memory, feelings of pleasure or well-being, and social bonding , and caring for others

    • irregularities in how the brain uses dopamine may help explain the development of schizophrenia

      • schizophrenia: A severe and chronic psychological disorder characterized by disturbances in thinking, perception, emotions, and behavior.

        • people with schizophrenia may experience hallucinations and delusions

        • hallucinations: perceptions experienced in the absence of corresponding external stimuli.

        • delusion: fixed but patently false beliefs, such as believing that one is being hounded by demons.

          • Antipsychotic drugs, which are antagonists that block receptor sites for dopamine, help control hallucinations and delusional thinking

Parkinson’s disease: a progressive brain disease involving destruction of dopamine-producing brain cells and characterized by muscle tremors, shakiness, rigidity, and difficulty walking and controlling fine body movements.

• leads to a progressive loss of motor functioning or physical movements

  • We don’t know what causes dopamine-producing cells to die off, but scientists believe that mutations of particular genes are involved

agonists: drugs that either increase the availability or effectiveness of neurotransmitters or mimic their actions.

• ex> stimulant ,caffeine, increase the availability of a neurotransmitter called glutamate

  • amphetamines and cocaine, are agonists that increase the availability of the neurotransmitter dopamine in the brain by blocking its reuptake by the transmitting neuron

    • stimulant: a drug that activates the central nervous system, such as amphetamines and cocaine

      • increase energy, alertness, & activity

      • block protein the presynaptic neuron uses to reabsorb dopamine or serotonin molecules

    • amphetamines: a class of synthetically derived stimulant drugs, such as methamphetamine or “speed”

      • Glutamate is an excitatory neurotransmitter that keeps the central nervous system aroused and humming

• antidepressants work as agonists to increase the availability of the neurotransmitters norepinephrine and serotonin in the brain

  • antidepressants: drugs that combat depression by affecting the levels or activity of neurotransmitters.

Serotonin- serves to regulate mood states, feeling full after meals, and sleep

• works as a kind of behavioral seat belt to curb impulsive behaviors, including impulsive aggression

endorphins: natural chemicals released in the brain that have pain-killing and pleasure-inducing effects.

• Norepinephrine does double duty as a neurotransmitter and a hormone

Norepinephrine (noradrenaline) is a chemical cousin of the hormone epinephrine (adrenaline).

nucleus accumbens: this group of interconnected brain cells is involved in feelings of pleasure. It is sometimes called the "reward center" of the brain.

Hallucinogenic Drugs

• induce sensory distortions

  • LSD: stimulates serotonin type 2 receptors at inappropriate times

    • may cause psychotic reactions, accidents, panic attacks, flashbacks

  • MDMA/ ecstasy: stimulates neurons that release dopamine

    • high doses stimulate neurons that release serotonin/ cause hallucinations

    • low doses increase arousal

marijuana: softens pain but less powerful than opiates

• THC (tetrahydrocannabinol) : impairs attention and memory

  • medically used to reduce nausea, suppress tremors, reduce pressure in the eyes, decrease cell loss after a stroke

  • attaches to receptors that are abundant in the brain especially those located on the presynaptic neuron

• nervous system: the network of nerve cells and support cells for communicating and processing information from within and outside the body

  • divided into two parts

    • central nervous system: the brain and spinal cord

      • spinal cord: the column of nerves that transmits information between the brain and the peripheral nervous system.

        • literally an extension of the brain

      • spine: the protective bony column that houses the spinal cord.

    • peripheral nervous system: connects the central nervous system to other parts of the body

      • divided into two parts

        • somatic nervous system: transmits information between the central nervous system and the sensory organs and muscles; also controls voluntary movements.

        • autonomic nervous system (ANS): automatically regulates involuntary bodily processes, such as breathing, heart rate, and digestion.

          • sympathetic nervous system: the branch of the autonomic nervous system that speeds up bodily processes and releases stored energy needed to meet increased physical demands.

          • parasympathetic nervous system: the branch of the autonomic nervous system that regulates or slows down bodily processes, such as digestion, that replenish stores of energy.

  • reflex : an automatic, unlearned reaction to a stimulus

  • spinal reflex : a reflex controlled at the level of the spinal cord that bypasses the brain

three major divisions of the brain:

1. hindbrain

   • medulla: structure in the hindbrain involved in regulating basic life functions, such as heartbeat and respiration

     • lies closest to spinal cord and forms the core of the brainstem

       • brainstem: “stalk” in the lower part of the brain that connects the spinal cord to higher regions of the brain.

   • pons: structure in the hindbrain involved in regulating states of wakefulness and sleep.

     • lies directly above the medulla

     • contains nerve fibers that conduct information from the spinal cord and lower parts of the brain through the midbrain to the forebrain

   • cerebellum: structure in the hindbrain involved in controlling coordination and balance

     • located behind the pons

     • behaviors that require aim. timing, voluntary eye movement, learned response, emotional expression

2. midbrain

   • lies above hindbrain, contains pathways that connect the hindbrain with the forebrain

   • parts of midbrain makeup brainstem

   • perform important roles including control of automatic movements of the eye muscles, which allows you to keep your eyes focused on an object as your head changes position in relation to the object. Parts of the midbrain make up the brainstem.

   • reticular formation: a web-like formation of neurons involved in regulating states of attention, alertness, and arousal that rises from the hindbrain and passes through the midbrain to the thalamus in the forebrain

3. forebrain

   • largest part of the brain

   • cerebrum: largest mass of the forebrain, consisting of two cerebral hemispheres.

   • cerebral hemispheres: the left and right halves of the forebrain that control sensations and movement on opposite sides of the body which are joined by the corpus callosum

     • the left specializes in language

     • right is key to understanding spatial relationships and interpreting emotional expressions

     • both constantly exchange information

     • corpus callosum: the thick bundle of nerve fibers that connects the two cerebral hemispheres

       • if damaged, the two cannot share information

   • thalamus: structure in the forebrain that serves as a relay station for sensory information and that plays a key role in regulating states of wakefulness and sleep.

     • first sorts through sensory information, sending information about vision to one area, information about hearing to another, and so on. From these relay stations in the thalamus, the information is then transmitted to the appropriate parts of the cerebral cortex for processing

     • also receives input from the basal ganglia

       • basal ganglia: an assemblage of neurons lying in the forebrain that is important in controlling movement and coordination.

   • hypothalamus: small, pea-sized structure in the forebrain that helps regulate many vital bodily functions, including body temperature and reproduction, hunger, thirst, daily sleep cycles, as well as emotional states, aggression, and responses to stress.

   • limbic system: formation of structures in the forebrain that includes the hippocampus, amygdala, and parts of the thalamus and hypothalamus

     • amygdala: A set of almond-shaped structures in the limbic system believed to play an important role in aggression, rage, and fear.

   • cerebral cortex: outer covering of the forebrain; The wrinkled, outer layer of gray matter that covers the cerebral hemispheres; controls higher mental functions, such as thought and language.

     • frontal lobes: the parts of the cerebral cortex, located at the front of the cerebral hemispheres, that are considered the “executive center” of the brain because of their role in higher mental functions such as access memories, self-awareness, mulling things over, and decision making

       • prefrontal cortex (PFC): the area of the frontal lobe that lies in front of the motor cortex and that is involved in higher mental functions, including thinking, planning, impulse control, and weighing the consequences of behavior.

       • motor cortex: A region of the frontal lobes involved in regulating body movement.

         • mirror neurons: neurons located in the motor cortex that fire both when an action is performed and when the same action is merely observed.

           • may be involved in some forms of social behavior, such as empathy

       • Broca’s area: an area of the left frontal lobe involved in speech

     • occipital lobes: the parts of the cerebral cortex, located at the back of both cerebral hemispheres, that process visual information.

     • parietal lobes: the parts of the cerebral cortex, located on the side of each cerebral hemisphere, that process bodily sensations.

       • At the front of the parietal lobes lies a strip of nerve cells called the somatosensory cortex,

       • somatosensory cortex: processes sensory information received from receptors in the skin, giving rise to our experience of touch, pressure, temperature, and pain

     • temporal lobes: located at the sides of the head, is main area for hearing and some vision

       • lie beneath and behind the frontal lobes, directly above the ears

       • Wernicke’s area: an area of the left temporal lobe involved in processing written and spoken language

   • hippocampus: structure in the limbic system involved in memory formation

The Endocrine System

endocrine system: the body’s system of glands that release their secretions, called hormones, directly into the bloodstream.

• helps maintain homeostasis

  • homeostasis: tendency of systems to maintain a steady, internally balanced state

pancreas: endocrine gland located near the stomach that produces the hormone insulin

• Insulin stimulates cells throughout the body to draw more glucose from the blood, which decreases the level of glucose in the body.

  • As this level declines to its set point, the pancreas reduces the amount of insulin it secretes = homeostasis

• insulin opens glucose receptors on cells, allowing sugar to pass from the bloodstream into the cells where it is used as fuel

pituitary gland: an endocrine gland in the brain that produces various hormones involved in growth, regulation of the menstrual cycle, and childbirth.

• referred to as the “master gland”

• pituitary gland & hypothalamus are the two most important glands

pineal gland: a small endocrine gland in the brain that produces the hormone ­melatonin, which is involved in regulating sleep–wake cycles.

adrenal glands: a pair of endocrine glands located just above the kidneys that produce various stress-related hormones.

gonads: the sex glands that produce germ cells

• ovaries: The female gonads, which secrete the female sex hormones estrogen and progesterone and produce mature egg cells.

• testes: the male gonads, which produce sperm and secrete the male sex hormone testosterone.

  • germ cells: sperm and egg cells from which new life develops.

thyroid gland: an endocrine gland in the neck that secretes the hormone thyroxin, which is involved in regulating metabolic functions and physical growth.

• Excess thyroid hormones are associated with states of anxiety and irritability

• Deficiencies of thyroid hormones can lead to sluggishness ,weight gain , and can retard intellectual development in children.

premenstrual syndrome (PMS) : a cluster of physical and psychological symptoms occurring in the few days preceding the menstrual flow.

• symptoms may include anxiety, depression, irritability, weight gain from fluid retention, and abdominal discomfort

• three out of four, women experience PMS symptoms

aphasia: loss or impairment of the ability to understand or express language

Epilepsy: neurological disorder characterized by seizures that involve sudden, violent discharges of electrical activity in the brain.

split-brain patients: People with a corpus callosum that has been surgically severed; left and right brain seem to act separately

Measuring Brain Activity

EEG/ electroencephalograph: measures and amplifies tiny electrical changes on the scalp that reflect brain activity

MEG/ magnetoencephalography: records magnetic changes

PET/ position-emission tomography: records radioactivity of various brain areas emitted from injected chemicals

MRI/ magnetic resonance imaging: A technique that uses a magnetic field to create a computerized image of internal bodily structures.

fMRI/ functional magnetic resonance imaging: procedure that uses magnetic detector outside the head to compare the amounts of hemoglobin with and without oxygen in different areas of the brain

CT / computed tomography scan: A computer-enhanced imaging technique in which an X-ray beam is passed through the body at different angles to generate a three-dimensional image of bodily structures (also called a CAT scan, short for computed axial tomography).

lesioning: part of the brain is destroyed and the effects on behavior are observed

electrical recording: a method of investigating brain functioning, a process of recording the electrical changes that occur in a specific neuron or groups of neurons in the brain in relation to particular activities or behaviors.

electrical stimulation: a method of investigating brain functioning, a process of electrically stimulating particular parts of the brain to observe the effects on behavior.

neuromarketing: an emerging field of marketing that examines brain responses to advertisements and brand-related messages.

plasticity: change caused by experience such as trauma or surgical alteration

• another part of the brain may take over its functions to a certain extent

  • experiences alter brain connections

  • prolonged unusual experiences change the brain in profound ways

  • stem cells (undifferentiated cells) develop into new neurons in brain area such as hippocampus

  • continues throughout life

Social Neuroscience

• social neuroscience: the study of the biological bases of social behavior

  • corresponding area of the brain responds when trying to understand what others know and why they act the way they do

• oxytocin: a hormone released by women when nursing a baby and by both men and women during sexual activity

  • effects of oxytocin are not prosocial

  • can increase awareness of possible danger and heighten avoidance strangers

• Binding problem: the question of how separate brain areas combine to produce a unified perception of a single object

  • long-range integration problem

  • to create binding:

    • the brain must be able to identify the different aspects of the stimulus come from the same location

    • the different aspects must occur simultaneously

Gene Principles

• chromosomes: strands of hereditary materials resided in the cell nucleus

  • X chromosome: females have 2 per cell and males have 1

  • Y chromosome: males have 1 per cell and females have 0

    • sex-linked genes: genes located on the X or Y chromosome

    • sex-limited genes: genes that occur equally in both sexes but exerts its effects mainly or entirely in one or the other

• genes: inherited structures that control the chemical reactions that direct development; basic units of heredity that are passed along from parent to offspring.

  • dominant: genetic effect that appears even with only a single copy of the gene

  • recessive: genetic effect that appears only if the dominant gene is absent

• genotype: an organism’s genetic code

• phenotype: observable traits

  • depend on both our genes and our environment.

• polygenic traits: traits that are influenced by multiple genes interacting in complex ways

  • ex> psychological traits, such as shyness, intelligence, or a predisposition to schizophrenia or alcoholism

• epigenetics: newly emerging field that deals with changes in gene expression as a result of environmental influences without modification of the DNA sequence (study of how DNA interacts with the multitude of smaller molecules found within cells which can activate and deactivate genes)

  • histones wrap DNA of a chromosome into balls

    • histone: a protein that provides structural support for a chromosome

  • acetyl groups attach to a histone to increase the expression of genes

heritability: an estimate of the variance within a population that is due to heredity

• zygote: a fertilized egg cell

• monozygotic twins: identical twins; same fertilized egg with identical genes

• dizygotic twins: fraternal twins; two separate eggs and only share half their genes

  • nature vs nurture: The debate in psychology about the relative influences of genetics (nature) and environment (nurture) in determining behavior.

• twin studies: studies that examine the degree to which concordance rates between twin pairs for particular disorders or characteristics vary in relation to whether the twins are identical or fraternal.

  • concordance rates: in twin studies, the percentages of cases in which both members of twin pairs share the same trait or disorder.

• adoptee studies: studies that examine whether adoptees are more similar to their biological or adoptive parents with respect to their psychological traits or to the disorders they develop.

Family association studies: studies that examine the degree to which disorders or characteristics are shared among family members

• a major limitation of this kind of study includes that closer their blood relationship, the more likely people are to share common environments