Biological Foundations Flashcards
Synaesthesia
- Cross sensory experience could be related to creativity
- Tends to run in families
- Together sensation
- Theory that we start out this way + eventually lose this ability
Human Genome Project
map entire structure of human genetic material
•Identify precise order of molecule that make up each of the thousands of genes
•Consist of just 20,000 genes
•Human complexity due to subtleties in how those genes are expressed + regulated
Genes x Environment
–Impossible to separate genetic + environmental influences
•Interaction of nature + nurture responsible, always working together
(Caspi’s study examining violent criminal behaviour)
Epigenetics
- changes in gene expression that are due to non-genetic (‘epi-‘outer’) influences
- environmental type influence, not part of genetic makeup
Heredity
genetic transmission of characteristics from parents to offspring
Heritability
estimate of the genetic portion of the variation in some specific trait
-variability within pop, estimate of how much/% of the variation is determined by genetic influences
Twin Studies & Adoption Studies
•Help researchers study impact of genetic vs environmental influences
•Monozygotic vs. dizygotic twins
•How similar are twins with same genes, but raised apart
•Minnesota monozygotic: 2 men scary similar, in diff countries
•Shared environ: no one has same experiences, no one treated same
oless similar, family emphasize + encourage differences + uniqueness
Behaviour is Determined by Multiple Factors
•exceedingly complex
•Single-cause explanations may be accurate,
but incomplete
•Behaviour governed by complex network of interacting factors
–Heredity/Biology/Environment/Culture
•break down nature vs. nurture into components
The Nervous System
•body’s electrochemical communication circuitry •Central nervous system (CNS) •Peripheral nervous system (PNS) –Somatic nervous system –Autonomic nervous system •Sympathetic nervous system •Parasympathetic nervous system
Neurons
- Are the basic unit of the nervous system
- Operate through electrical impulses
- Communicate with other neurons through chemical signals
- Excitable
- Gets multiple info from thousands of diff neurons
Three types of neurons
- Sensory neurons (afferent neurons): pick up sensation for outside world
- Motor neurons (efferent neurons): brain to muscle
- Interneurons: communicate betw sensory + motor
When do neurons fire?
- Excitatory signals: increase likelihood neuron will fire, less polarized
- Inhibitory signals: decrease likelihood neuron will fire, hyperpolarizing
- affect the polarization
- Neurons fire (generate action potential) if excitatory input reaches certain threshold
All-or-noneprinciple
- neuron fires with same potency each time (fires/doesnt)
- how frequently neuron fires can vary
Action potential
neural impulse passes along axon + causes release of chemicals from terminal buttons
•Na + K goes through specific channels, need to be open
•Starts polarized, rapid depolarization along axon
•Repolarized
Common Neurotransmitters
- Acetylcholine: motor control at junction of nerves + muscles
- Epinephrine: adrenaline
- Norepinephrine: general alertness
- Serotonin: emotional regulation
- Dopamine: feel good, feel rewarded
- GABA: major inhibitory transmitter
- Glutamate: major excitatory
Neurotransmitters
•chemical substances that carry signals from one neuron to another
•stored in vesicles inside terminal buttons
•Action potentials cause vesicles to fuse to presynaptic membrane + release contents into synapse
-received by postsynaptic receptors on the postsynaptic membrane
•Receptors pick up specific neurotransmitters
Antagonists
Beta-blockers, botox (botulinum toxin) Inhibit neurotransmitters’ actions by –Blocking release of neurotransmitters –Destroying neurotransmitters in synapse –Mimicking a neurotransmitter + blocking binding
Agonists
Enhance neurotransmitters’ actions by
–Increasing the release
–Blocking the re-uptake, stays in synapse
–Mimicking a neurotransmitter + activating a postsynaptic receptor
•Cocaine, methamphetamine
The Brain: From the Bottom Up
- Cortical Structures: Complex Mental Activity
- Subcortical Structures: Emotion & Basic Drives
- Cerebellum: Movement
- Brain Stem: Survival
- What matters is ratio of brain weight
- Brain is interacting systems
Brainstem
•Controls life sustaining functions of the autonomic nervous system (breathing, digestion, heart rate)
–Medulla oblongata
–Pons
-Midbrain
•Reticular formation: alertness, sleep, neurons that project up to cerebral cortex
The Cerebellum
•Essential for coordinated movement and balance
Subcortical Structures: The Hypothalamus
- Tiny yet powerful: master regulatory structure
- Connects nervous to endocrine system
- Vital to: Fighting, Fleeing, Feeding, Fucking
Subcortical Structures: The Thalamus
- Gateway to the brain
- Gatekeeper of higher cognitive functioning
- Relay station: Handles all incoming sensory information except smell
Subcortical Structures: The Hippocampus
- Important for the storage of new memories
- grows larger with increased use
- how we remember arrangements of ppl + objects in space
- Taxi drivers: by learning all these spatial info, creates larger body of brain cells in hippo
Subcortical Structures: The Thalamus
•Tatiana and Krista Hogan: Conjoined twins who share a bridge between the thalamus
-share a thalamus, they can sense things that the other one senses
Subcortical Structures: The Basal Ganglia
•System of subcortical nuclei: –Caudate nucleus –Putamen –Globus pallidus –Nucleus accumbens: important in experiencing reward, activates dopamine neurons in area
Subcortical Structures: The Amygdala
•Essential to our ability to associate things with emotional responses
–front of the hippocampus
•Intensifies memory’s function during times of emotional arousal
The Cerebral Cortex
- outer layer of the brain
- four lobes
- corpus callosum: (massive bridge of axons) connects the hemispheres and allows information to flow between them
Temporal lobes
- Hearing
- specialized visual areas for recognizing details
- Primary auditory cortex
Parietal lobes
- Touch
- Primary somatosensory cortex
Frontal lobes
- Planning + movement
- Primary motor cortex + premotor cortex
- Prefrontal cortex
Occipital lobes
- Vision
- Primary visual cortex
Prefrontal Cortex
- 30% of the human brain
- Important for attention, working memory, decision making, social behaviour, personality
- Damage to the prefrontal cortex: Phineas Gage - rod through prefrontal cortex, personality completely changed
The Somatosensory + Motor “Homunculus”
- Connected parts of the body tend to be represented beside each other
- More sensitive regions tend to have more cortical area devoted to them (lips, fingers)
- Phantom limb: takes brain longer time to rearrange itself than getting arm chopped off
Plasticity
- Fire together, wire together: establish strong connection, synaptic connection strengthens
- Neurogenesis: process of growing new neurons
Plasticity
•brain able to be changed, reorganized, as result of experience, drugs/injury
–Rats raised in enriched vs impoverished environments
•Enrichment can lead to more neurons, bigger neurons/increasing connections (synapses)
Spinal Cord
•Connects brain to PNS
•reflex arc: sensory info sent to spinal cord via sensory neuron, synapses to interneuron, synapses to motor neuron controlling muscles
-allowing to move hand without waiting for instructions from the brain
Beyond the Brain:
The Peripheral Nervous System
•Transmits info to CNS + responds to messages to perform behaviours/make bodily adjustments
•Divided into two primary components:
–Somatic nervous system (SNS)
–Autonomic nervous system (ANS)
Somatic nervous system:
–Concerned with external environment
–Controls functions under conscious, voluntary control
–Consists motor neurons responsible for sending signals from the brain to the muscles
•CNS-Muscles/skin/joints
Somatic nervous system:
–sensory neurons send signals to the brain
•Muscle/skin/joints-CNS
Autonomic nervous system:
–Concerned with internal environment
•Glands/internal organs-CNS (somatosensory neurons)
• CNS-glands/internal organs (motor neurons)
Autonomic nervous system:
–2 types of signals travel from CNS to glands/internal organs:
•Sympathetic division
•Parasympathetic division
Sympathetic Division of the ANS
- Prepares the body for action (“fight or flight”)
- Heartbeat, pupils (get as much info), breathing rate, inhibits digestive system that don’t need to be active, more blood to legs + arms
- Don’t wanna get a boner if getting chased by bear=inhibits sexual
Parasympathetic Division of the ANS
- Returns body to normal state
* Opposing functions of the sympathetic system, but work in a complementary (not antagonistic) fashion
ANS
- Chronic activation of either system can lead to health problems
- High blood pressure, heart and kidney failure (sympathetic)
- Low blood pressure, depression, withdrawal (parasympathetic)
Hormones
-chemical substances released into the blood stream by endocrine glands until they reach the targeted tissues
–Communication slower (bloodstream)
–Effects can be long lasting + widespread
•Can affect many targeted areas
Communication: More than Nerves
- endocrine system works with the NS to regulate psychological activity
- uses hormones
Major Endocrine Glands: Pituitary gland
Master gland: Governs release of hormones from endocrine glands
•Neural activation=hypothalamus secrete releasing factor - pituitary gland release hormone specific to factor
-hormone travels through bloodstream to target sites throughout the body
Neuron Structure
- Dendrite: branch like, receiving end of chemical signals
- Cell body: info integrates it, decides what to do
- Axon: range in size, how signal propagates itself, generates action
- Terminal buttons: release chem signals into synapse, don’t ever touch dendrites
- Myelin sheath: allows rapid transportation, jumps from node to node of ranvier
- Synapse: gap, where chem signals dropped into
Basal Ganglia
•Producing and planning movement
–Cortex-basal ganglia-motor centres of brain stem
–projects back to cortex’s motor planning area
•regulating movement
•working with motor areas to plan various movements
