chapter 8

State of consciousness

levels of alertness

Conscious experiences

experiences that a person is conscious of

Electroencephalogram (EEG)

electrical potential difference between points on the surface of the scalp

Amplitude (measured in µV)

degree of synchronous firing of neurons that generate synaptic activity

Frequency (Hz)

level of alertness

What do you use EEG for?

anesthesia, neurological diseases, coma, brain death, epilepsy

Oscillation

repetitive variation

Alpha Rhythm (8-12Hz)

most prominent EEG wave pattern of a conscious

Beta Rhythm (>12Hz)

smaller-amplitudes & higher frequency of oscillations

Sleep

causes changes in EEG pattern; patterns change beta to alpha; consists of lower frequencies

NREM (non-rapid eye movement)

initial stage of sleep, 30-45 min progression

3 stages of NREM

N1, light sleep and theta waves over alpha pattern; N2, sleep spindles & k complexes interrupt theta rhythm; N3, deep sleep causes delta waves to slowly dominate alpha

REM (rapid eye movement)

“dreaming” state, occurs 50-90 mins after sleep, episodes last 10 mins; paradoxical sleep

importance of sleep

necessary for nervous system; homeostatic requirement

Selective attention

focusing; avoiding distraction of irrelevant stimuli

Habituation

progressively decreasing behavior response to repetitive stimulus

Temporary sets

set of neurons that temporarily function together for conscious experience

Motivation

processes responsible for direct quality of behavior

how is motivation influenced?

rewards & punishment

Reticular activating system

involved in motivation, rewards & punishments, DOPAMINE IS NT

Mesolimbic dopamine pathway

goes through limbic system; releases dopamine and is involved in reward

Mesocortical dopamine pathways

midbrain to frontal lobe; signals positive emotions with rewarding events

Dopamine

NT that mediates reward systems and motivation

Amphetamine

abused drug that increases presynaptic release of dopamine

Chlorpromazine

antipsychotic drug that blocks dopamine receptors & lowers activity in catecholamine pathways (negative reinforcement)

Emotions

relationship b/n individual & environment

3 aspects of emotions

anatomical sites, emotional behavior, inner emotions

anatomical sites for emotions

amygdala, cerebral cortex, limbic system

Altered states of Consciousness

unusual sensations occurring with hypnosis, drugs, or psychiatric illnesses

Mood

long-lasting inner emotion that influences perception of world

Mood disorders

conditions that involve the loss of control over a person’s moods

Depressive Disorder (Depression)

decreased neuronal activity & metabolism in anterior portion of limbic system & nearby prefrontal cortex

Tricyclic antidepressant drugs

interfere w/serotonin and/or norepinephrine reuptake by presynaptic endings

Monoamine oxidase (MAO) Inhibitors

interfere w/enzyme responsible for breaking down serotonin & norepinephrine

Serotonin-specific reuptake inhibitors (SSRIs)

selectively inhibit serotonin reuptake by presynaptic terminals

Electroconvulsive Therapy (ECT)

applied pulses of elect. currents that activate a large amt of neurons to induce convulsion

ECT fx

alters NT fx by changing sensitivity of targeted serotonin and adrenergic postsynaptic receptors

Repetitive Transcranial Magnetic Stimulation (rTMS)

electromagnets stimulate brain which disorders or sometimes silences neural activity in targeted brain region

Bipolar Disorder

swings b/n mania and depression

Mania

abnormally & persistently elevated mood

Lithium

normalizes both manic & depressing moods w/o sedation; used to treat patients w/bipolar disorder

Psychoactive Substances/Recreational Drugs

directly or indirectly alters NT receptor interactions in biogenic amine pathways; usually elevates mood

Tolerance

increasing doses of substance to achieve effects that initially occurred in response to a smaller dose

Substance Abuse Disorders

psychoactive substances that are misused in a way that results in a diagnosis; acts on mesolimbic & mesocortical DA pathways

Learning

acquisition and storage of information as a consequence of an experience

Memory

relatively permanent storage form of learned info

Declarative (explicit) Memory

retention and recall of conscious experiences

declarative memory sx

hippocampus, amygdala, limbic system

Procedural Memory

how to do things;

procedural memory sx

sensorimotor cortex, basal nuclei, cerebellum

Short-term (working) memory

registers and retains incoming information for short time

consolidation

process for short-term memory to become long-term; requries ongoing graded/action potentials

Long-term memory

stored information for days to years and can be recalled anytime

Amnesia

any loss of memory

Retrograde Amnesia

short-term memory is interrupted and recent memories are abolished

Anterograde Amnesia

loss of consolidation after the injury; damage to limbic system and related sx

Long-term potentiation (LTP)

heavily-used synapses undergo long-lasting increase in effectiveness

Plasticity

increased # of heavily-used synapses or receptors

Left hemisphere

produces and comprehends language

Aphasia

impaired language disorder from physical damage to brain

Aprosodia

impaired ability to convey & interpret emotional and tonal aspects of speech

Broca’s Area

region of frontal lobe required for articulation of speech

Wernicke’s area

temporal region responsible for comprehension

Expressive aphasias

impaired ability to physically form speech but still able to comprehend

Epilepsy

abnormally synchronized discharges of cerebral neurons

Coma

extreme decrease in mental fx due to sx, fx, or metabolic impairment of the brain

Brain Death

non-functioning brain beyond repair

Attention-Deficit/Hyperactivity Disorder (AD/HD)

difficulty in maintaining selective attention and/or impulsiveness and hyperactivity; dysfunction in basal nuclei & prefrontal cortex

Methylphenidate (ritalin)

prescribed to increase synaptic conc. of dopamine & norepinephrine; typically prescribed to ppl w/ADHD

Schizophrenia

information is not properly regulated in brain; mesocortical DA pathways are overactive; hallucinations & god-complexes occur

what drugs treat depression?

tricyclic antidepressents, monoamine (MAO) inhibitors, serotonin specific reuptake inhibitors (SSRIs)