chapter 6: states of consciousness Flashcards
a type of surgery that cuts the connections (corpus callosum) between the two hemispheres of the brain
split-brain
what is the purpose of the split-brain surgery
to reduce frequency and severity of seizures associated with epilepsy, though it leads to the inability of sharing information across the cortex
the idea that the two hemispheres have different functions
hemispheric specialization
“sense of self” the subjective experiences of the internal and external world
conscious content
the different levels of arousal and attention
state of consciousness
the process of selecting information from the internal and external environments to prioritize for processing (usually involuntary and automatic)
attention
occurs when bottom-up information from the external environment requires a response
passive attention
when attention is directed by goals and top-down processing
active attention
occurs when you attend to one source of information while ignoring other stimuli
selective attention
refers to the bottom-up qualities of a scene that influence how we direct attention (stimuli captures our attention by their physical properties)
stimulus salience
examples of low-level features
colour of an object or loudness of a sound
occurs when our attention is diverted because of the salience of a stimulus
attentional capture
processing that allows one to be engaged in a conversation while ignoring other stimuli in the background (selective attention)
cocktail party effect
a selective attention task where each ear listens to different inputs, individuals would be asked to attend to only one sound, then later asked about information in the unattended input (proves that brain still processes unattended information)
dichotic listening
measure of arousal level of the sympathetic nervous system and responds when you hear something startling or emotionally engaging (measure changes in sweat glands that indicate emotional state)
galvanic skin response (GSR)
occurs when we simultaneously attend to two or more tasks at the same time
divided attention / multitasking
refers to fast and effortless processing that can be accomplished without conscious thought
automaticity
occurs when we are engaged in one task and completely miss other information
inattentional blindness
a change attention task used to study intentional change detection and inattentional blindness
flicker task
an attention task that requires participants to actively search for a change made to the stimulus
intentional change detection
sensory stimulus that is processed but does not reach the threshold for conscious perception
subliminal stimulus
processing of information we are aware of, but not necessarily aware that it is influencing our behaviour
subconscious processing
processing of information we cannot consciously detect, even if we were looking for it
subliminal processing
messages that are presented too quickly for the visual system to perceive
subvisual messages
auditory messages played at a low volume or in a way that the brain cannot be consciously aware of the content
subaudible messages
damage to the right parietal lobe causes..
lost of awareness of visual stimuli on the left
dorsal stream
“where stream” dorsal visual system travels to the inferior parietal lobe to identify the location of visual stimuli
symptoms of ADHD
impulsivity, poor planning, hyperactivity, and inability to sustain attention on a single task. characterized by difficulties that interfere with task-oriented behaviours in general
possible cause of ADHD
genetic influences, symptoms are similar to those produced by damage to the prefrontal cortex
medication for ADHD
ritalin and adderall seem to improve concentration and reduce hyperactivity
therapies that help individuals learn strategies to manage ADHD symptoms or attention problem. designed to train parents and teachers to reward desired behaviour and ignore undesirable actions
cognitive-behavioural therapies
a rare hereditary disease affecting the thalamus, which causes individuals to die from lack of sleep (accompanied by weight loss and inability to maintain homeostasis) (death usually occurs within 12-18 months)
fatal familial insomnia
a device that measures electrical activity across the surface of the brain
electroencephalograms (EEG)
a device used to measure eye movements
electrooculograms
a device used to measure the muscle tension in the jaw
electromyograms
measure in hertz (Hz),
frequency
the height of the wave
amplitudes
measure of how consistent or erratic the waves appear
regularity of the wave
brain wave when we are awake, irregular, mostly low amplitude, frequency of 13-30Hz, desynchronized and erratic
beta waves
reflects the fact that many neural circuits in the brain are actively processing information
desynchrony
brain waves when we are awake but relaxed, more regular and predictable, frequency of 8-12Hz, occurs when a person is quietly resting and not thinking much
alpha activity
brain waves that appear when we are deeply relaxed or falling asleep, present throughout the sleep cycle, 3.5-7.5Hz
theta waves
stage 1 sleep
very light stage of sleep, move from a state of relaxation to early sleep, firing rate across he cortex becomes more synchronized
what occurrences best identify the transition from stage 1 into stage 2 sleep
sleep spindles and K-complexes
brief bursts of activity that occur roughly two to five times per minute during non-REM stages of sleep (12-14Hz)
sleep spindles
a pattern of neural excitation followed by inhibition, occurs during stage 2 sleep around once a minute, often triggered by unexpected noises, if woken you wouldn’t have any sense that you had been asleep
K-complexes
brain waves when a person is deeply asleep, less than 4Hz, regular, high-amplitude waves, occurs during stages 3 and 4 (slow-wave sleep)
delta waves
15-20 minutes after stage 2, firing across the cortex becomes coordinated and transitions into delta activity
slow-wave sleep (SWS)
non-REM sleep
stages 1, 2, and SWS
45 minutes after the beginning of SWS, desynchronized beta waves appears on EEG, eyes moving side to side, brain becomes highly active (similar to when we are awake and alert), easier to wake up than SWS, vivid and narrative-based dreams occur, blood flow to the brain is reduced (prefrontal and visual association cortex still receives large proportion of oxygenated blood), increased time spent during intense brain development, consolidates memories and skills, gets longer throughout the night
rapid eye movement (REM)
becomes paralyzed during REM sleep
REM sleep antonia
a graphic depiction of a person’s progress through the stages of sleep over the course of a night
hypnogram
suggests there is a need for a certain amount of REM
rebound phenomenon
which stage of sleep is important for explicit memories
SWS
suggests the experience of dreaming really has no explicit or reliable meaning, but rather a consequence of the other process that occur across the cortex during sleep
activation-synthesis hypothesis
a hypothesis about dreaming that suggests it has biological significance (evolutionary purpose)
evolutionary hypothesis of dreams
what did Revonsuo suggest about the purpose of dreaming
he argues that we dream about things that are directly related to survival to enhance performance when encountering threatening events
refers to problems with the quality of sleep disorders
dyssomnias
refers to disturbances that occur during sleep
parasomnias
most commonly diagnosed sleep disorders, the inability to fall asleep or remain asleep
insomnia
causes of insomnia
stress, serious underlying medical condition, abuse of certain substances or underlying mental disorders (environmental factors)
refers to habits and behaviours that are conducive to sleeping well
sleep hygiene
most commonly diagnosed forms of primary insomnia, occurs when cues that indicates sleep causes anxiety surrounding the inability to fall asleep
conditioned insomnia
“child onset insomnia”, results from a neurophysiological abnormality in the CNS, begins in childhood and experienced through adulthood, more resistant to treatment
idiopathic insomnia
excessive sleepiness, most common causes is poor sleep quality during the night
hypersomnia
condition where the intake of oxygen is reduced as the person sleeps for a short periods of time, breathing becomes shallow or stops breathing completely, blood oxygen level decreases, causing the affected to wake up (occurs throughout the night)
sleep apnea
how does CPAP work
treatment for sleep apnea, it pushes pressurized air through the airway to improve sleep
“sleep attacks” rare genetic neurodegenerative disorder characterized by a sudden and extreme need to sleep, can last from a few seconds to few minutes, enters REM sleep
narcolepsy
most commonly associated with narcolepsy, the experience of muscle weakness or paralysis during the waking hours (initiated by emotionally engaging events like arguments, laughter, and sex)
cataplexy
vivid sensory hallucinations that occur right before falling asleep (sleep paralysis)
hypnagogic hallucinations 鬼壓床
vivid sensory hallucinations that occur just before waking up (sleep paralysis)
hypnopompic hallucinations
a neurodegenerative disorder where the affected acts out the contents of their dreams (unable to paralyze the body during sleep)
REM sleep behaviour disorder
treatment for REM sleep behaviour disorder
minor tranquilizers, anxiolytics (Clonazepam), or melatonin
referred to as nocturnal enuresis, can often be treated by the use of a small alarm that sounds at the first signs of moisture on the sheets
bedwetting
experiences of frantic, panicked screaming but often little or no memory of what caused the episode, disorder of slow-wave sleep
night terrors
“sleepwalking”, able to conduct behaviours while deeply asleep as if they were awake, could be dangerous, occurs during slow-wave sleep
somnambulism
internal clocks that prepare the body for daily, seasonal, and annual rhythms
biological clocks
daily body clocks that tell the body when to sleep and wake, clock reset every morning by cues associated with morning activity
circadian rhythms
“time giver” time cues that are reliable stimuli in the environment that provide information about the time of day
zeitebers
without time cues, humans would revert to a clock with how many hours
our free running cycle is closer to 25 instead of 24
occurs when you travel someplace far away and your internal clock doesn’t match the external cues you receive from the new environment
jet lag
research done on shift work suugests what
suggests that when people are forced to abruptly alter their sleep-wake cycles, it results in sleep and mood disturbances and interferes with their ability to function during working hours
“timekeeper” sends signals to several regions of the brain, including the pineal gland, in response to light signals located directly above the chiasm
suprachiasmatic nucleus (SCN)
pineal gland’s response to light/dark signals
secretes melatonin
broadly defined as substances that influence mood, thoughts, or behaviour
psychoactive drugs
the increased ability to tolerate a specific drug, larger dose of drug is required to achieve the desired effect
drug tolerance
physical or psychological need for the drug to maintain normal functioning
dependence
symptoms of distress, restlessness, and irritability associated with the reduction or absence of a specific drug (headaches, shaking, vomiting, changes in mood)
withdrawal
drugs that slow or depress the arousal of the CNS
depressants
alcohol
most commonly used and abused depressant in the world, low doses creates sensations of relaxation or drowsiness (impaired judgement, slowed reaction times on physical tasks, and uncoordinated motor movements). large doses leads to alcohol poisoning, extreme disorientation and irregular heartbeat and breathing
glutamate
one of the primary excitatory neurotransmitters, alcohol inhibits the effectiveness of glutamate, especially in the hippocampus (memories of the night heavy drinking are often disorganized)
GABA
implicated in relaxed states, inhibitory effects in the nervous system
Dopamine
implicated in reward states in the brain, many drugs reinforces their effects on the production of dopamine
baribiturates
a group of drugs that cause sedation and induce sleep, prescribed for anxiety disorders, addictive, prolonged use slows metabolisms
benzodiazepine
a groups of drugs primarily used for treating anxiety, known to be fast-acting and highly addictive
most frequently prescribes barbiturates and benzodiazepines (anxiolytics)
Xanax, Valium, and Clonazepam
drugs that increase the activity of the nervous system
stimulants
what are some common stimulants
caffeine, nicotine, cocaine, and amphetamines
caffeine
most widely used psychoactive drug in the world, low doses increases energy, creativity, and the ability to focus on work, blocks inhibitory neurotransmitter adenosine
adenosine
creates inhibitory effects in the brain
nicotine
highly addictive stimulant, associated with almost half a million deaths in the US, stimulates the release of acetylcholin, absorption into the body and effects on the brain occur rapidly after administration
acetylcholine
prominent excitatory neurotransmitter
cocaine and amphetamines
both enhance the effects of dopamine, combat the effects of hunger and fatigue and create a subjective sensation of grandeur or euphoria and a heightened sense of alertness.
how does cocaine work
they bind to and deactivate the proteins that aid in the reuptake of dopamine, prolonging its effects
how does amphetamines work
inhibits the reuptake of dopamine and stimulate the release of dopamine from the terminal buttons
long term uses of cocaine and amphetamines causes…
hallucinations, delusions of paranoia, and psychotic behaviour
psychedelic drugs / hallucinogens
directly influence the sensory systems and our interpretation of reality, cause distortions in our sense of time and space
an experience where senses seem to blend and merge together (could be cause by hallucinogens)
synesthesia
Lysergic acid diethylamide (LSD)
a synthetic drug that causes altered emotions and a sense of being in a waking dream, causes vivid sensory hallucinations, alternations in perceptions of time and space, and blurring of perceptions between the senses by acting as an agonist of serotonin in the thalamus (the relay centre)
a neurotransmitter that is often implicated in mood
serotonin
Mescaline
derived from the peyote cactus, commonly associated with use in the religious ceremonies in the Native American culture, similar to LSD, enhances colour perception, repeats patterns in the visual field, and often feel out of body (also numbness, tension, anxiety, and intense nausea)
Cannabis
most commonly used hallucinogen, increases appetite, feelings of euphoria, relaxation, and even paranoia,
THC
active ingredient in cannabis, found in brain regions such as cerebellum, hippocampus, basal ganglia, and cerebral cortex
