BUT will signpost a counterpoint / development point
Central Nervous System + Synaptic Transmission
● Neurons are information messengers that have dendrites that receive
messages from other neurons to trigger action potential; myelin sheath
insulates electrical signals, increasing rate of transmission; axon passes
electrical impulses across both ends; axon terminal where nerve impulses
become chemical messages to pass to another dendrite.
● In synaptic transmission: electrical impulse travels along presynaptic neuron,
reaches synaptic vesicles to release neurotransmitters, which diffuse across
synaptic gap to attach to receptors on postsynaptic neuron.
● Neurotransmitters are chemical messengers, enabling communication between
neurons. Excitatory neurons (dopamine, +ve) increase likelihood of firing
another action potential; inhibitory neurons decrease likelihood (serotonin, -
ve).
Drugs Affecting Synapses (Biological Explanation of Drug Addiction)
● All recreational drugs increase dopamine produced in reward pathway
(mesolimbic pathway: VTA + NA), leading to euphoria (intense pleasure).
Downregulation of natural production causes dysphoria (intense
dissatisfaction). Repeated use to compensate causes further downregulation,
leading to withdrawal symptoms. Tolerance means larger doses needed for the
same effect.
● Cocaine = amphetamine, similar structure to dopamine; enters axon terminal of
presynaptic neuron via transporter proteins; blocks reuptake of dopamine by
binding to transporter proteins, causing surplus in synapse = euphoria.
● Nicotine mimics neurotransmitter acetylcholine; binds to acetylcholine
receptor in reward pathway; excites neuron causing dopamine release =
euphoria.
● Heroin = opiate; binds to opioid receptors; triggers endorphins; muffles pain
perception; boosts pleasure; inhibits GABA, causing indirect excess of
dopamine production.
Evolutionary Explanation of Aggression
, ● Aggression is feelings of anger resulting in hostile behavior. It is an important
survival trait, giving males survival benefits to protect and provide from
predators; thus, passed down and inherited. Females chose big, strong,
aggressive males due to traits with survival benefits, giving offspring good
genes and creating competition for masculine aggression.
● Females are less aggressive to avoid risking a baby during pregnancy and
breastfeeding. They are verbally aggressive and emotional instead, denigrating
other females to attract mates (Buss, 1999).
● Male and female jealousy occurs when a partner reproduces elsewhere,
passing down rival genes at the expense of their own, allowing evolution to
find this trait attractive.
● Buss (1988) described male retention via direct guarding (checking
partner/messages) or negative inducement (physical/verbal abuse against
infidelity).
● Too much physical aggression leads to being rejected or attacked.
● Social aggression = antisocial behavior aimed at damaging reputation, used by
physically weak members. Also a survival trait; more valuable due to less risk
of being attacked.
Brain Cortical Lobes + Limbic System
● Cerebral cortex (outer layer, distinguishes humans from animals; responsible
for higher-order functions) divided into 4 lobes with different functions:
● FPOT (go left around back to left): Frontal → Parietal → Occipital →
Temporal
● Frontal lobe: front of brain, 40% of cerebral cortex, contains prefrontal cortex
(PFC) for self-control, decision making, dealing with aggression. Contains
motor cortex for contralateral functioning, Broca’s area for speech production.
● Parietal lobe behind it, contains somatosensory cortex, processes sensory
information from skin, e.g., touch, works contralaterally.
● Occipital lobe: posterior region responsible for perception and processing of
visual information (color); contains primary and secondary visual cortex.
Primary receives visual info from retina; secondary receives from primary.
● Temporal lobe sits behind ears, contains auditory cortex for sound information
from opposite ear (contralateral), contains Wernicke’s area associated with
understanding language.
● Limbic system: brain areas associated with aggression and controlling fight-
or-flight response to danger: midbrain, amygdala, hypothalamus, PFC.