Unit 2: Biological Bases of Behavior Flashcards
Why are psychologists concerned with human biology?
Everything physiological is simultaneously biological
Who is Franz Gall? What did he study?
German physician who studied phrenology - the study of bumps on the skill to reveal brain size and subsequent mental abilities and character traits
Neurons
a nerve cell: basic building block of the nervous system - act as an information system in the body (we have billions)
Dendrites
A neurons often bushy, branching extensions that receive and integrate messages, conducting impulses toward the cell body
Axons
The neuron extension that passes messages through its branches to other neurons or to muscles/glands
Myelin sheath
A fatty tissue layer segmentally encasing the axons of some neurons; enables vastly greater transmission speed
- insulates and speeds their impulses, increasing neural efficiency
- when it deteriorates we can develop multiple sclerosis: communication to muscles slows, with eventual loss of muscle control
Cell body
the part of a neuron that contains the nucleus; the cell’s life support center
Terminal branches of the axon
forms junctions with other cells
Glial cells
cells in the nervous system that support, nourish, and protect neurons; they also play a role in learning, thinking, and memory
Action potential
(exchange of ions)
- Resting potential: when the axon’s surface is selectively permeable, maintaining a positive charge outside the axon, and a negative charge inside it
- Depolarization: the axon opens it’s gates and positively charged sodium ions flood through the now-open channels to produce a loss of the inside/outside charge difference; this initiates the opening of the nest set of axon channels to open (like dominos)
- Refractory period: neurons need short breaks; subsequent action potentials cannot occur until the axon returns to its resting state
All-or-none response
- a neuron’s reaction of either firing with a full-strength response or not firing at all
like a toilet flush, it needs a certain threshold to trigger
Excitatory vs. inhibitory signals
excitatory signals are like pushing a neuron’s gas pedal, and inhibitory signals are like pushing it’s break
Synapse
the junction between the axon top of the sending neuron and the dendrite or cell body of the receiving neuron - the tiny gap at the junction is called the synaptic gap
Reuptake
- the reabsorption of a neurotransmitter by the sending neuron
- they do this to remove excess neurotransmitters for reuse, and to prevent the job from continuing
Neurotransmitters
chemical messengers that cross the synaptic gap between neurons. when released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether that neuron will generate a neural impulse
Neurotransmitters and their functions/malfunctions
ACh (Acetylcholine)
- enables muscle action, learning, and memory
- with Alzheimer’s disease, ACh-producing neurons deteriorate
Dopamine
- influences movement, learning, attention, and emotion
- oversupply linked to schizophrenia, undersupply linked to tremors and decreased mobility in Parkinsons disease
Serotonin
- affects mood, hunger, sleep, and arousal
- undersupply linked to depression
Norepinephrine
- helps control alertness and arousal
- undersupply can depress mood
GABA
- a major inhibitory neurotransmitter
- undersupply liked to seizures, tremors, and insomnia
Glutamate
- a major excitatory neurotransmitter, involved in memory
- oversupply can over-stimulate brain, producing migraines or seizures
Endorphins
- influence the perception of pain or pleasure
- oversupply with opiate drugs can suppress the body’s natural endorphin supply
Agonists vs antagonists
Agonists - a molecule that increases a neurotransmitter’s action
Antagonist - a molecule that inhibits or blocks a neurotransmitter’s action
Nerves
bundled axons that form neural cables connecting the central nervous system with muscles, glands and sense organs
Types of neurons
Sensory/afferent neurons - neurons that carry incoming information from the body’s tissues and sensory receptors to the brain and spinal cord
Interneurons - neurons within the brain and spinal cord; they communicate internally and process information between the sensory inputs and motor outputs
Motor/efferent neurons - neurons that carry outgoing information from the brain and spinal cord to the muscles and glands
Peripheral Nervous System
sensory and motor neurons that connect the CNS to the body; a combination of the somatic nervous system and the autonomic nervous system
somatic - the division of the peripheral nervous system that controls the body’s skeletal muscles
autonomic - the part of the peripheral nervous system that controls the glands and the muscles of the internal organs
Divisions of the PNS
Sympathetic nervous system - arouses and expends energy (fight or flight)
Parasympathetic nervous system - conserving energy/calming(rest and digest)
^ these work together to maintain homeostasis
** you hear a weird sound in the night and your sympathetic nervous system kicks in, but when you realize it’s just your dog, your parasympathetic calms you down
Central Nervous System
two-way information highway: connects the peripheral nervous system and the brain
Simple reflex
a simple, automatic response to a sensory stimulus - no time for a middle step to/from the brain before the action takes place
** when you touch something hot, your hand jerks away before your brain registers you are in pain
Endocrine system
chemical communication system; glands that secrete hormones into the bloodstream
Hormones
chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissue
Hormones vs. neurotransmitters
- chemically identical
- hormones are slow acting, neurotransmitters are fast
- hormones are long-lasting, neurotransmitters are short-lived
- hormones are produced in glands, neurotransmitters come from the brain
Adrenal glands
a pair of endocrine glands that sit just above the kidneys and secrete hormones (epinephrine and norepinephrine) that help arouse the body in times of stress
Pituitary gland
The endocrine system’s most influential gland. under the influence of the hypothalamus, the pituitary gland regulates growth and controls other endocrine glands
Lesion
tissue destruction; a brain lesion is a naturally or experimentally caused destruction of brain tissue
Electroencephalogram (EEG)
an amplified recording of the waves of electrical activity sweeping across the brain’s surface, measured by electrodes placed on the scalp
Magnetoencephalogram (MEG)
a brain imaging technique that measures magnetic fields from the brains natural electrical activity
Computed tomography
a series of X-ray photographs taken from different angles and combined by computer into a composite representation of a slice of the brain’s structure
PET scan
a visual display of brain activity that detects where a radioactive form of glucose goes while the brain is performing a task
MRI
a technique that uses magnetic fields and radio waves to produce computer-generated images of soft tissue - show brain anatomy
f-MRI
a technique for revealing blood flow and, therefore, brain activity by comparing successive MRI scans (shows function as well as anatomy)
Brainstem
(brain’s oldest and innermost part; automatic survival functions)
- Medulla: base of the brainstem, controls heartbeat and breathing
- Thalamus: the brain’s sensory control center, located on the top of the brainstem. it directs messages to sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla
- Reticular formation: a nerve network that travels through the brainstem into the thalamus and plays an important role in controlling arousal
Cerebellum
the “little brain” at the rear of the brainstem; functions include processing sensory input, coordinating movement output and balance, and enabling nonverbal learning and memory
Limbic system
(sits between the oldest part of the brain and the newest - associated with emotions and drives)
- Hippocampus: a neural center helps process for storage explicit (conscious) memories of facts and events
- Amygdala: two small neural clusters linked to emotion
- Hypothalamus: a neural structure lying below the thalamus, directs several maintenance activities (eating, drinking, body temp), helps govern the endocrine system via the pituitary glass, and is linked to emotion and reward
Cerebral cortex
(interconnected neural cells covering the cerebral hemisphere; ultimate control and information processing center)
Frontal lobes: the portion of the cerebral cortex lying just behind the forehead involved in speaking/muscle movements/planning/judgment
Parietal lobes: the portion of the cerebral cortex lying at the top of the head and toward the rear that receives sensory input for touch and body position
Occipital lobes: the portion of the cerebral cortex lying at the back of the head; includes areas that receive information from the visual fields
Temporal lobes: the portion of the cerebral cortex lying roughly above the ears; including auditory areas, each receiving information primarily from the opposite ear
Motor cortex
An area at the rear of the frontal lobes that controls voluntary movement.
- when parts of the cortex are stimulated, it moves different body parts. stimulating regions in the left/right hemisphere produce movements on the opposite side of the body
- body areas requiring precise control, such as fingers and mouth, occupy the greatest amount of cortical space
Somatosensory cortex
An area at the front of the parietal lobe that registers and processes body touch and movement sensations
- specializes in receiving information from the skin senses, such as touch and temperature from the movement of body parts
- the more sensitive the body region, the larger the somatosensory cortex area devoted to it
Association areas
(areas of the cortex involved in higher mental functions rather than primary motor or sensory functions)
-Frontal lobes (prefrontal cortex): enables judgement, planning, and processing of new memories
- Parietal lobe: enable mathematical and spatial reasoning
- Right temporal lobe: facial recognition
- Broca’s area: the ability to speak
- Wernicke’s area: understanding of speaking
Plasticity - how does it work?
The brain’s ability to change, especially during childhood, by reorganizing after damage or by building new pathways based on experience (may cause expansion or shift functions)
Neurogenesis
the formation of new neurons
Corpus callosum
the large band of neural fibres connecting the two brain hemispheres and carrying messages between them
Split brain
a condition resulting surgery that isolates the brain’s two hemispheres by cutting the fibres (mainly those of the corpus callosum) connecting them
Vogel and Bogen//Sperry and Gazzaniga
Vogel and Bogen:
- theorized the epileptic seizures were caused by an amplification of abnormal brain activity bouncing back and forth between cerebral hemispheres
- found that people with split-brain are hardly affected, there is just no information sharing from one hemisphere to the other
Sperry and Gazzaniga:
- they recognized that they could intentionally send information to a person’s left or right hemisphere because communication had been cut
- with a split brain, both hemispheres can comprehend and follow an instruction to copy simultaniously
Left vs. Right hemisphere
Left: language and logic
Right: creativity and spatial perception/processing
Consciousness
our subjective awareness of ourselves and our environment
Cognitive neuroscience
the interdisciplinary study of the brain activity linked with cognition (including perception, thinking, memory, and language)
Dual processing
the principle that information is often simultaneously processed on separate conscious and unconscious tracks
** when we look at a bird we are conscious of our cognitive processing (“It’s a bluebird”) but not our sub-processing of the bird’s color, form, movement, etc.
Blindsight
a condition in which a person can respond to a visual stimulus without consciously experiencing it
** someone who cannot consciously see cannot verbalize the width of a book in front of them, but can grab it with the right finger-thumb distance
Parallel processing
processing many aspects of a problem simultaneously; generally used to process well-learned information or solve easy problems
Sequential processing
processing one aspect of a problem at one time; generally used to process new information or to solve difficult problems
Chromosomes
threadlike structures made of DNA molecules that contain the genes
DNA
a complex molecule containing the genetic information that makes up the chromosomes
Genes
the biochemical units of heredity that make up the chromosomes; segments of DNA capable of synthesizing proteins
Genome
the complete instructions for making an organism, consisting of all the genetic material in that organism’s chromosomes
Behavior genetics
the study of the relative power and limits of genetic and environmental influences on behavior
Heredity
the genetic transfer of characteristics from parents to offspring
Environment
every nongenetic influence, from prenatal nutrition to the people and things around us
Identical twins
(monozygotic twins)
develop from a single fertilized egg that splits in two, creating two genetically identical organisms
Fraternal twins
(dizygotic twins)
develop from two separate fertilized eggs. they are genetically no different than ordinary brothers and sisters, but they have shared prenatal environments
Separated twins research
- Bouchard located and studied 74 pairs of identical twins raised apart; they continued to find similarities not only of tastes and physical attributes but also of personality, abilities, attitudes, interests, and even fears
Heritability
The proportion of variation among individuals in a group that we can attribute to genes. the heritability of a trait may very, depending on the range of populations and environments studied
Molecular behavior genetics
Molecular genetics: the subfield of biology that studies the molecular structure and function of genes
Molecular behavior genetics: the study of how the structure and function of genes interact with our environment to influence behavior
Sleep
- the body’s natural loss of consciousness - as distinct from unconsciousness resulting from a coma, general anesthesia, or hibernation
- even when deeply asleep, the body has not entirely stopped functioning
Circadian rhythm
our biological clock; regular body rhythms that occur on a 24h-cycle (our bodies roughly synchronize to the day and night)
- most teens and young adults are evening-energized, with performance increasing throughout the day, and most older adults are morning-loving, with performance declining as the day goes on
Sleep stages
NREM-1
- 1-5 minutes
- body hasn’t fully relaxed; brain and body activity present but starting to slow with periods of brief movement
NREM-2
- 10-25 minutes (half the time we spend asleep)
- drop in temperature, relaxed muscles, slowing of breathing and heart rate, brain activity slows, but short bursts of activity help resist being woken up by external stimuli
NREM-3
- 20-40 minutes, stages get shorter as the night progresses
- delta waves (large, slow brain waves)
- restorative: bodily recovery, growth, bolstering of immune system
REM
- entered around 90 minutes: stages get longer as the night progresses
- brain activity picks up, with paralysis of all muscles other than eyes and respiratory
- essential to cognitive functions, e.g. memory, learning, creativity
- vivid dreams
Sleep spindles
bursts of rapid, rhythmic brain wave activity
Sleep paralysis
- Occurs during REM
- Your brain is active, but your brainstem blocks its messages, rendering you essentially paralyzed; the immobility may linger as you awaken, producing sleep paralysis
Suprachiasmatic nucleus
A pair of cell clusters in the hypothalamus that controls circadian rhythm. in response to light, the SCN causes the pineal gland to adjust melatonin production, thus modifying our feelings of sleepiness
Why do we sleep?
- protects (safer for our ancestors to be sleeping)
- helps us recuperate (restores immune system/repairs brain tissue)
- helps restore and rebuild our fading memories of the day’s experiences
- feeds creative thinking
- sleep supports growth (pituitary gland releases HGH when we sleep)
Insomnia
recurring problems staying asleep
Narcolepsy
A sleep disorder characterized by uncontrollable sleep attacks. The sufferer may lapse directly into REM sleep, often at inopportune times
Sleep apnea
a sleep disorder characterized by temporary cessations of breathing during sleep and repeated momentary awakening
Night terrors
high arousal and an appearance of being terrified; unlike nightmares, they occur during NREM-3 sleep, within two/three hours of falling asleep and are seldom remembered
Manifest vs. Latent content
Freud proposed that dreams provide a psychic safety valve that discourages otherwise unacceptable feelings
Manifest: the apparent, remembered storyline of a dream
Latent: the unconscious drives and wishes/underlying meaning (often erotic) that would be threatening if exposed in another context
Why do we dream?
- To satisfy our own wishes (Freud)
- Information processing
- Physiological function
- Activation synthesis (REM triggers neural activity, triggering memories)
REM rebound
the tendency of REM sleep to increase following REM sleep deprivation
Depressants
drugs (alcohol, barbiturates, opiates) that reduce neural activity and slow body functions
Stimulants
drugs (caffeine, nicotine, cocaine, amphetamines, methamphetamines, Ecstacy) that excite neural activity and speed up bodily functions
Hallucinogens
psychedelic drugs (LSD) that distort perceptions and evoke sensory images in the absence of sensory input
