AP Psychology Unit 2

Glial Cells (Aka neuroglia)

Help support neurons (structure, nutrition, etc.) ex. Schwann Cells

Neurons

The basic building block of the nervous system

Dendrites - receive incoming messages

Cell Body (Soma) - Contains the Nucleus

Nucleus - Makes the decision to fire or not fire

Myelin Sheath - Fatty tissue that insulates axon, speeding up transmission of the passage

Node of Ranvier - Space between the sheath

Schwann Cells - Non-neural cells in the CNS that form myelin sheath

Axon - Longest part of the neuron which the electrical message travels the length of

Axon Terminal Buds - The end point of a neuron that releases neurotransmitters into the synapse, hence sending the message on to the next neuron

Resting Potential

When a neuron is NOT firing and has a negative charge with mostly potassium ions inside and mostly sodium ions outside. A neuron in homeostasis

Polarization

At resting potential, when sodium is on the outside, potassium on the inside of a neuron

Action Potential

“nerve impulse” - causes the neuron to fire - the electrical pulse or message that travels the length of an axon.

All-or-nothing principle

When the nucleus decides to fire, it fires down the axon completely (all the way) or not at all. - At the same intensity

• Intensity - Strength/power of message

Depolarization

When message begins, Sodium (+Na) ions come in & depolarize (neutralize) section of axon

• When “opposites” are no longer away from each other

Refractory Period

Potassium (+K) ions are pushed out and neuron “pauses to reload.” During this time a neuron is unable to fire

Threshold

The minimum level of stimulation required to trigger a neural response or produce a detectable sensation

• Axon Terminal

• Dendrites

Neurotransmitters - chemical substance that crosses the synapse to carry on the message to the next neuron

Synapse - open space between two neurons at which neurotransmitters cross

Receptor sites - specific points on dendrites of neurons that receive specific types of neurotransmitters

Reuptake - Reabsorption of neurotransmitters by firing neurons

Neurotransmitter - Acetylcholine

Learning. Enables muscle action (spinal cord & skeletal muscles), learning attention, & Memory. Deterioration leads to Alzheimer.

Neurotransmitter - Glutamine

Memory. Major excitatory (helps neurons fire) involved in memory. Oversupply can overstimulate the brain leading to migraines and seizures.

Neutransmitter - Dopamine

Reward / pleasure. Influences movement, learning, attention, and emotion (similar to cocaine). Oversupply = schizophrenia. Undersupply = tremors and Parkinson's. Completing a tasks gets Dopamine.

Neurotransmitter - Serotonin

Mood. Affects hunger, mood arousal, and sleep (similar to LSD & Ecstasy). Undersupply = depression. Antidepressant drugs increase levels.

Neurotransmitter - Norepinephrine

Concentration. Also associated with sympathetic nervous system. Increases alertness, blood pressure, and heart rate. Release glucose to support fight or flight.

Neurotransmitter - GABA (gamma-aminobutyric acid)

Calming. Major inhibitory (slows neurons firing) “Get A Break Adjustment.” Undersupply linked to seizures, tremors, insomnia, & anxiety.

Neurotransmitter - Endorphins

Pain or pleasure. Linked to europhia, pain control, and pleasure. Associated with OCD & “Runners High.” Opioids can suppress natural supply.

Neurotransmitter - Substance P

Pain & immunity. Found in the brain and spinal cord and is associated with inflammatory processes and pain. Oversupply can lead to chronic pain.

Excitatory Neurotransmitters

Increase the likelihood that a neuron will fire an action potential. They essentially stimulate the next neuron.

• Glutamate: Learning and Memory

• Acetylcholine (in some contexts): excitatory in the muscles 

  • Also plays a role in learning and memory

• Norepinephrine (sometimes considered excitatory in CNS): Increases arousal, alertness, and attention.

Inhibitory Neurotransmitters

Decrease the likelihood that a neuron will fire an action potential. They essentially calm or slow down neural activity.

• GABA: reduce anxiety and stress

• Serotonin: Regulates mood, appetite, and sleep.

Agonist

MIMIC neurotransmitter activity.

• Fitting in the receptor site like a master key

• It works just like the original key but it is not exactly the same

Example:

• Morphine (opiate derivative) mimics endorphins

  
  

Antagonist

BLOCK neurotransmitter activity

• Fitting in the receptor site like a fake key, preventing the neurotransmitters from getting to its receptor site and doing its job

Example

• Botox (form of botulism) blocks Acetylcholine.

• Prevents muscles in the face from moving by blocking the neurotransmitter, which ultimately stops wrinkles

Reuptake Inhibitor

A type of agonist that blocks the reuptake process to increase a neurotransmitter

Example

• Selective serotonin reuptake inhibitors (SSRI) like fluoxetine (Prozac), setraline (Zoloft) and citalopram (Celexa), which are widely used to treat depression and other conditions by increasing seretonin levels in the brain

Two parts fo the nervous system

• Peripheral: Sensory and motor neurons that connect the CNS to the rest of the body

  • Includes Autonomic and Somatic

• Central (CNS): Contains the spine and brain. In the center of the body

Autonomic vs Somatic

• Autonomic: Controls involuntary functions or items that happen automatically within our body - berathing, heartbeat, digestion, etc.

  • *includes sympathetic and parasympathetic

• Somatic: Control voluntary (soma = body) movements and communications to and from the sense organs

  • You control these items, they don’t “just happen”

Sympathetic Nerves

Physically arouses the body, preparing it to act/react in stressful situations, expending energy. Initiates “fight or flight.”

• Dilate pupils

• Inhibit Salvation

• Increase heartbeat

• relax airways

• inhibit activity of stomach

• inhibit galbladder

• inhibit activity of intestines

• secrete (produce) epinephrine & norepinephrine

• relax bladder

Parasympathetic Nerves

Calms the body, conserving its energy and helping keep a constant internal state (returns the body to homeostasis). Initiates “rest and digest”.

• Constrict Pupils

• Stimulate saliva

• Slow heartbeat

• Constrict airways

• Stimulate activity of stomach

• Stimulate galbladder

• Stimulate activity of intestines

• Contract bladder

Brain vs Spinal Cord

• Brain: The neural center of the body; the body’s control center

• Spinal Cord: Super Highway of nerves - the body’s means of transmitting messages to and from the brain

Reflex Arcs

The neural pathway for a rapid, automatic response to a stimulus bypassing the brain and acting through the spinal cord

Ex. Withdrawal reflex: When you touch a hot stove

Interneurons vs Sensory Neurons vs Motor Neurons

• Interneurons: The only neurons in the CNS, acting as messengers between sensory and motor neurons

• Sensory (afferent) neurons: Carries incoming mesages/information from the sense receptors to the CNS

• Motor (efferent) neurons: Carries outgoing information from the CNS to the peripheral nervous system and muscles.

Endocrine system

Communicates with the brain using chemical messages called hormones

• Hormones are released into and circulate through the bloodstream - recieved only at a specific site

• Under “normal” circumstances works in parallel with the parasympathetic NS to sustain our basic processes. (HOMEOSTASIS)

• In a crisis, the sympathetic nervous system actitvates, and the endocrine system (adrenal gland) releases adrenaline/epinephrine

The Pituitary Gland

• The “Master Gland

  • Directed by the hypothalamus

  • It releases several important hormones and controls the function of many other endocrine system glands.

Adrenaline

Secreted by the adrenal glands; responsible for arousal and the "fight or flight" response. Plays a role in emotional memory formation. Same chemical as Epinephrine.

Leptin

Involved in turning off hunger (keeps you LEAN). Produced by fat cells it sends signals to your hypothalamus.

Ghrelin

Involved in turning on hunger (tummy goes grrrr) comes from the stomach and activates the pituitary gland

Melatonin

Secreted by the pineal gland; signals the relaxation and lower body temperature that help with a restful sleep.

Oxytocin

Produced by the hypothalamus and secreted by the pituitary gland. When it affects the brain, it acts as a neurotransmitter. Plays a role in mother-child attachment; believed to play a role in social bonding and is the “Us vs them” hormone (social trust / bonding).

Hormones vs Neurotransmitters

	Hormones	Neurotransmitters
Speed	Minutes or longer	Milliseconds
Length	Hours, days, or weeks	Short-term
Method	Travel through the blood	Neuron-to-neuron signaling

Cerebral Cortex

• Outer portion of brain, higher order thought processes, perception, and voluntary movement (& 4 lobes)

• 💀 If damaged: Varied effects including memory, personality, decision making, motor control.

Corpus Callosum

• Bundle of nerve fibers that connect hemispheres, enabling communication

• 💀 If damaged: “Split-Brain

Hippocampus

• Processes conscious memories (explicit memories)

• Converts short-term to long-term memory

• Involced in processing and retrieving declarative (facts and events) memory

• Spacial Relationship memories

• 💀 If damaged: Inability to remember, getting lost, difficulty following directions.

Thalamus

• Brain’s relay center for all but smell

• Directs messages to sensory receptors

• Transmits replies to cerebellum & medulla

• 💀 If damaged: sensory issues (blind, aphasia), numbness, coma.

Hypothalamus

• Directions maintenance activities (eating, drinking, body temp)

• Helps govern endocrine system

• Fight or Flight

• Linked to emotion & reward/pleasure.

• Homeostasis

• 💀 If damaged: Weight change, fatigue, insomnia, thirst, dehydration, high or low blood pressure, frequent urination, infertility

Amygdala

• Plays a role in emotion, (fear, anger, aggression, anxiety)

• 💀 If damaged: high emotional responses, no emotional responses

Cerebellum

• Processes sensory input, coordinates movement output and balance

• Enables nonverbal learning and implicit memory. (long-term memory that involves unconscious recall of skills, tasks, and knowledge without conscious effort)

• Known as the “little brain”

Pons

• Connects upper and lower brain

• Sleeping

• waking

• dreaming

• Bladder Control

• 💀 If damaged: Coma, sleep issues

Medulla

• Controls autonomic functions heartbeat and breathing, blood pressure, reflexes.

• 💀 If damaged: respiratory failure, paralysis, or loss of sensation.

Reticular formation

• Controls arousal, alertness, attention, regulating sleep cycle

• 💀 If damaged: Coma, difficulty staying awake or paying attention.

Ventricles

Fluid filled with cavities in the brain which serve as reservoirs of cerebrospinal fluid

Left to right

1. Corpus Callosum

2. Thalamus

3. Hypothalamus

4. Pituitary Gland

5. Spinal Cord

6. Cerebral Cortex

7. Cerebellum

8. Pons

9. Medulla

10. Reticular Activating System (RAS) *Back of brain stem (activiating system)

Left to Right

1. Hypothalamic Nuclei

2. Amygdala

3. Hippocampus

4. Cingulate Gyrus

5. Corpus Callosum

6. Thamalus

Cingulate Gyrus

Involved in processing emotions, regulating behavior, as well as autonomic motor function

The Lymbic System’s functions include…

controlling emotion, behavior, motivation, learning & memory

Hindbrain

Lizard Brain -brainstem, cerebellum, and hypothalamus

Midbrain

Mammal Brain - limbic system and hippocampus

Forebrain

Human Brain - cerebral cortex

Brain Lesions

• Portions of the brain are cut / removed.

• Changes as a result of the lesions (what is different?).

• Shows Structure.

EEG (electroencephalogram)

• Electrodes placed on the scalp.

• Measures electrical activity of neurons in the brain.

• Often used to study sleep, seizures, and brain activity over time.

• Shows Function; brain activity – not specific

PET scan (Positron emission tomography)

• Brain activity detected by a radioactive form of glucose.

• Active regions “light up” as they consume more energy.

• Used to observe metabolic processes in the body and brain.

• Shows function; “hot spots” where brain areas are active as a person does various activities

Magnetic resonance imaging (MRI)

• Magnetic fields and radio waves to create images of brain structure

• Provides detailed pictures of soft tissues, including the structure of the brain

Functional magnetic resonance imaging (fMRI)

• Comparing successive MRI scans by looking at blood flow.

• Shows which areas are active during specific tasks.

• Reveals brain functioning as well as structure

Computed tomography Scan (CT / CAT)

• X-Rays taken from multiple angles and combined into a composite.

• Reveals brain structure, including brain damage

Cerebral Cortex & Cerebrum

• As mass of deeply folded tisue that accounts for 80% of the brain’s total mass

• It is responsible for most of the sophisticated information processing in the brain

• It makes up Four major sections of lobes

Frontal Lobe

• Involved with personality, decision-making, and movement.

• Found at the front of the head.

• Planning, speech, sounds, emotions, temperment.

• Frontal lobe sensors your amygdila

• Includes Motor Cortex (voluntary movements) and Borca’s Area (speech, production, left hemisphere

Parietal Lobe

• Processes body’s senses (touch, temperature, pain).

• Found on top of the head and includes the somasensory cortex (body position, spacial reasoning)

Temporal Lobe

• Language, Hearing, Facial recognition.

• Found near the temples of the head. Long term memories, speech, and understanding.

• Auditory Cortex (hearing).

• Wernicke’s Area (language comprehension, left hemisphere)

Occipital Lobe

Vision. Found at the back of the head, allows us to interpret visual data like location, space, motion, and colors recieived from our retinas. Visual Cortex (visual info)

Association areas

Over ½ of cerebral cortex is uncommitted to sensory or muscular acivity… these “areas” are involved in higher mental functioning

• Wernike’s area

• Broca’s area

Wernicke’s area

• Area in left temporal lobe that is involved in language, comprehension, and expression

• Wernicke’s Aphasia = Damage where person speaks fluently but nonsensically and has trouble understanding language

Broca’s area

• Area in the left frontal lobe that directs muscle movement involved in speech

• Broca’s Aphasia = Damage here, person struggles to produce speech (slow, halting, but meaning intact)

Left to Right then down

Frontal Lobe, Motor Cortex, Somasensory Cortex, Pariental Lobe, Occipital Lobe, Temporal Lobe

Psychoactive Drugs

A chemical substance that alters perceptions and mood (affects consciousness)

• Blood-brain barrier - protective filter that blocks out substances from entering the brain, but psychoactive drugs can cross it to alter neurotransmitters activity and change behavior

Additiction

• Tolerance:

• Dependence:

• Withdrawal:

• Tolerance: Continued use of psychoactive drug produces tolerance . With repeated exposure to a drugm the drug effect lessens. Thus it takes bigger doses to get the desired effect.

• Dependence: Upon stop taking a drug (after addiction) users may experience undersirable effects of withdrawal.

• Withdrawal: Absence of drub may lead to feelings of…

  • Physiologically: Physical Pain, Intense Cravings

  • Psychologically: Negative Emotions

Depressants

“downers” - drugs that reduce neural activity and low body functions

• Alcohol

• Barbiturates

• Opiates

Alcohol

• Depressant

• In low doses - relaxes the drinker by slowing down sympathetic nervous system (lowering inhibitions and judgement)

• In high doses - reactions slow, speech slurs, and skilled performance

• Also affects memory by - disrupting the processing of recent events into long-term memory, reduces self-awareness, and focuses one’s attention on immediate situation rather

Barbiturates

• Depressant

• Mimics the effects of alcohol - depresses CNS activity and in larger doses, can lead to impared memory and judgement (Nembutal, Seconal, Amytal)

• In large doses - unconsciousness, supressed breathing, coma, or even death

Opiates (Narcotics)

• Depressant

• Opium and derivatives (morphine, heroin) depress neural activity, temporarily lessening pain and anxiety. They are highly addictive

• Heroin - Causes short-lived feeling of blissful pleasure (3-5 hours), then craving for another, in larger doses, and physical withdrawal symptoms

  • Methadone used to combat this addiction

Stimulants

“Uppers: drugs that exite neural activity and speed up body function.

• Ex. Caffine, Nicotine, Cocane, Ecstasy, Amphetamines, Methamphentamines

Caffine

• Stimulant

• Effects: Increase heart and breathing rates, and other autonomic functions to provide energy. Increases attentiveness

• Improves modd by mimicking adenosine (a neurotransmitter). Physically addictive

Amphetamines

• Stimulant

• “speed” or “uppers”

• Effects: Suppress appetite and were onece prescribed as diet pills (No longer because its addicting)

• Increases concentration and reduces fatigue… can increase anxiety and irritability as well

Cocaine

• Stimulant

• Illegal - derived from coca trees. Derivatives (nonvacaine) are used today as anesthetics

• When inhaled/”snorted” - reaches brain in minutes - producing intense euphoria, mental alertness and self-confidence which lasts for several minutes (10-30 fir binge users)

• Blocks the reuptake of dopamine causing the brain to be flooded with dopamine

Hallucinogens (aka psychedelics)

(mind-manifesting) drugs that distort perceptions and evoke sensory images in the absense of sensory input

• Ex. LSD (Lysergic Acid Diethylamide), Marijuana

LSD (Lysergic Acid Diethylamide) “Acid”

• Hallicinogen

• one of the most powerful drugs - only takes one-millionth of an ounce to produce altering effects

• Trip lasts 6-14 hours - effects vary greatly (visual distortions and hallucinations)

• “Bad Trips” - Terrifying and users are in a state of panic, feek as they will go mad and never come out

• Flashbacks - have sudden without warning brief recurrences of trip weeks/months after use

Marijuana

• Hallucinogen

• Produces feeling of elation, promotes relaxation, relieves inhibitions

• THC - the ingredient that produces the high, remains in the body long after use (10% after 7 weeks)

• Effects - Impairs attention/coordination, slows reaction time, intenferes with concerntation, logical thinking, ability to form new memories and ability to hold in mind what is said

• Chronic use associated with - loss of motivation and general apathy also causes respiratory damage faster than cigarettes, smoking and heavy use/abuse affects the reproductive system

Role of expectations in drug use

Expectation (placebo effect) plays a rule because a persons beliefs about a drug’s effect can influence how strongly they actually experience those effects, sometimes even mimicking or amplifying the drugs impact.

Multiple Sclerosis

Autoimmune attack on the myelin sheath surrounding axons, slowing neural communication.

Myasthenia Gravis

Disruption of communication between neurons and muscles due to antibodies interfering with neurotransmitter receptors.

Alzheimer’s Disease

Degeneration of neurons and loss of acetylcholine, leading to impaired memory and cognitive function. Associated with acytlcholine