Biological Bases for Behavior

Previous Misconceptions- mind was located in the heart, certain parts of the brain controlled certain functions (some were wrong)

What we have learned in the last century- brain is wired by experiences, nerve cells conduct electricity and “talk” to one another, specific brain systems serve specific functions

different parts of neuron- dendrite, axon, bell body, myelin sheath

the function of the myelin sheath is to speed impulses

Glial cells function is to support neurons, play role in memory, thinking, and learning

action potential is an electrical charge that travels down axon; the impulse fired by neuron; temporary inflow of positive ions form the neural impulse

neural impulses can travel from 2-200 mph

fluid outside axon’s membrane is mostly positively charged

fluid outside is neg. changed

axon’s surface is selectively permeable

when excitatory signals exceed the inhibitory signals an action potential is created.

refractory period is needed in neurons

stronger stimulus can trigger more neurons, but not faster or stronger for one neuron

neurons communicate to another with the synaptic cleft

neurotransmitters allow for communication between two axons. They do this through neurotransmitter molecules crossing the synaptic cleftg/gap and bind to receptor sites of the receiving neruon. Electical charged atoms flow into the receiving neruons readiness to fire

reuptake: a neurotransmitter reabsroption by sending neruon

Neurotransmitters are influential through the functions of each neurotransmitter capabilities

Drugs and chemicals affect the brain by exciting or inhibiting neruon’s firing ability

The cerebrum is the largest part of the brain and is responsible for higher cognitive functions such as thinking, memory, perception, and voluntary movement. It is divided into two hemispheres, the left and right, which are connected by a bundle of nerve fibers called the corpus callosum. The outer layer of the cerebrum is called the cerebral cortex and is highly folded to increase its surface area. This allows for more neurons and synaptic connections, enabling complex mental processes.

Cerebrum- newer brain, conaisl neural networks, 95% of brain’s weight

Cerebral Cortex has 20-23 billion nerves; motor functions,

Frontal lobe- involved in speaking, muscle movement, and making plans/judgments

Parietal lobe- receives sensory input for touch and body

Occipital lobe recieses info from visual fields

Temporal lobe- auditory areas; receives infro from opposite ear

Cerebral Cortext discovered by German Physicaians Bustav Fritsch and Edward Hitzig in 1870

The brain has no sensory receptors which allows surgeons to stimulate areas of brain

sesory functions allows from skin senses, touch, temperature, and movement of body parts

the more sensitive the body region, the larger the somatosensory cortex

Association Areas are areas that receive sensory input or direct muscular output found in all four lobes

Brain is constantly changing by life experiences

The brain is changing by building new pathways through plasticity

brain damage effects traced to the fact nevered brain and spinal cord neurons don’t usually regenerate and some brain functions seem preassigned to specific areas

each hemisphere of the brain serves different functions

accidents to the left hemisphere can cause strokes/turmors; reading, writing, speaking, arithmetic reasoning, and understanding imparments

functions of the left hemisphere allows you to make quick, literal interpretation of language, speaking, or math calculations

Functions of the right hemisphere means excel in making inferences, helping to modulate speech, and self-awareness

no one knows how the mind works because the brain’s synchronized actibyt produces awareness of the world around us

parallel processing enables the mind to take care of routine business

sequential processing is the best for solving new problems, which require focused attention to one thing at a time

perception, memory, thinking, language, and attitudes operate on two levels. the conscious (high road) is reflective, and the unconscious (low road) is intuitive

Behavior genetics study power and limits of genetic and environmental influences

the environment can “turn on” genes

expressed genes are active

twin and adoption studies are used to see the influences of heredity and environmental influences

identical twins are more alike in extraversion and neuroticism (emotional instability) than fraternal twins and have similar behavior as they grow old

lots of issues can occur when testing twins such as testing when its too late

people who grow up together do not resemble one another in personality

environment shared by a family’s children have virtually no discernible impact on personalities

parents influence attitudes, values, mannes, politictis, and faith of children, but not their personality

heritability is the difference amond people due to genes

we all have capacity to adapt

genes and experience interact with each other

The goal of molecular behavior genetics is to find genes that orchestrate complet traits

environment can trigger or block genetic expression

diet, drugs, and stress can affect the epigenetic molecules that regulate gene expression

Evolutionary Psychology focuses on understanding root of behavior and mental processes

evolutinoary success explains similarities such as emotions, drives, and reasoning.

Evolutionary Psychology answers why people may be scared of less dangerous threats than more dangerous threats or why something happens.

sexual motivation is not limited to specific couples

women tend to be choosier when selecting partners because there is more at stake (carrying child, family)

men pair widely, women pair wisely

focusing on social script as an alternative explanation can help with determining how people should act in social situations

we are a product of nature and nurture

psychoactive drugs work in brain's synapse

Types of Psychoactive Drugs include depressants, stimulants, and hallucinogens

depressants calm nerual activity and body functions

Examples of depressants are alcohol, barbiturates, and opiates

stimulants excite neural activity and speed up body functions

examples of stimulants equal caffeine, nicotine, cocaine, amphetamines, methamphetamine, ecstasy

examples of nicotine are in tobacco products and e-cigs

cocaine depletes the brain’s supply of dopamine, serotonin, and norepinephrine

Methamphetamine triggers dopamine leading to 8 hours of energy or euphoria

ecstasy releases dopamine but releases serotonin and blocks reuptake