ap psych c4--biological bases of behavior

basic overview—genetic predisposition

• genetic predisposition is the increased chance of developing a specific trait or condition because of our genetic code

• twins are heavily studied because of their genetic code similarities

• some people have extra chromosomes

what are neurons?

• neurons are individual nerve cells that make up our entire nervous system (pg 23)

how does a neuron fire (buckle up)

• neurons transmit messages through neural transmission

• in resting stages (resting potential), neurons have slightly negative ions inside and positive outside which is regulated through selectively permeable material

• one neuron releases neurotransmitters into the synapse (gap between neurons). once the other neuron has received enough and reaches a threshold, the charge in the second neuron rapidly changes (action potential)

• neurons either fire completely or not at all (all or nothing principle)

• firing is called depolarization because the cell fires due to the resting potential of the cell (its negative charge) which “depolarizes it” when the charge changes

excitatory neurons vs. inhibitory neurons

• some neurotransmitters are excitatory (excite the next cell into firing) while others are inhibitory

what are some important neurotransmitters?

• dopamine for movement, too much causes schizophrenia

• serotonin helps with mood

• norepinephrine is for alertness

• glutamate for memory

• GABA for an inhibitory

• endorphins control pain

• substance P helps you feel pain

• acetylcholine for movement

what do sensory neurons do?

sensory neurons take info from senses to brain

what to interneurons do?

interneurons take messages to other places in the brain or to motor neurons

what do motor neurons do?

take info from brain to other parts of the body

central nervous system

• our central nervous system has our spinal chord, which has a bunch of nerves and is inside the spine, and brain

• NOTE: some reflexes to do not follow the “i pass things down through the spinal chord” idea. some are called reflex arcs and our spine immediately processes information before the brain realizes it

peripheral nervous system (somatic, autonomic, sympathetic, parasympathetic)

anything not encased in bone

endocrine system

• endocrine system helps secrete hormones that affect many processes in our bodies

some important hormones/body parts found in the endocrine system

• adrenaline for fight or flight, produced by adrenal glands

• ovaries and testes for sex hormones

• leptin to regulate weight and eating

• ghrelin to increase eating

• melatonin for sleep

• oxytocin for good feelings like trust

lesioning

• taking off a part of the brain which is done if patients maybe have a tumor or another problem, we can see the before and after

electroencephalogram/EEG

• detects brain waves, shows consciousness and sleep patterns

computerized axial tomography (CAT scans)

to get a picture of the structure of a brain

magnetic resonance imaging

• CAT but more detailed, without radiation like a CAT scan

positron emission tomography (PET)

looks at what parts of the brain are active during certain tasks, which is coded for by different colors

functional MRIs

• if PET and CAT scans had a baby

we can study the brain by looking at how people are…

before/after accidents

hindbrain—pons, medula, cerebellum (pg 29 for pic)

• hindbrain is anything on top of the spinal chord

• medulla is what controls blood pressure, heart rate, and breathing

• pons connects the hindbrain with the midbrain and forebrain and is used for facial expressions

• cerebellum is for muscle movements

midbrain—reticular formation

• midbrain helps your simple movements with sensory information (so your muscles in your eyes move to keep them focused on a book when you turn your head)

  • integrates sensory information and muscle movements

  • reticular formation is cells in the midbrain that keep us attentive and awake, otherwise we would be in a coma

forebrain—thalamus, hypothalamus, amygdala/hippocampus

• forebrain is thought and reason

  • thalamus is on top of the brain stem (which connects brain and spinal chord) and gets sensory signals and sends them to other places

  • hypothalamus is for body temp, hunger, thirst, etc.

  • amygdala/hippocampus: amygdala is for emotion, hippocampus is for memories

forebrain—cerebral cortex and its two hemispheres

• cerebral cortex is the wrinkly layer on top. it has a bunch of neurons connected together. the reason it is wrinkly is because if it wasn’t it would have to be much more spread out

  • left hemisphere: sensory messages/ motor functions for right half of the body, right hemisphere is the opposite (this is contralateral hemispheric organization)

forebrain—hemispheric specialization and corpus callosum

• hemispheric specialization: how function is specialized in each hemisphere

• split brain patients have their corpus callosum, a nerve that connects the two, cut, and thus they behave differently

what are the four areas of the cerebral cortex?

• 4 different lobes which are called frontal, parietal, temporal, and occipital. see pg 32

what are association areas, and how are they different from most parts of the brain?

• association areas in the cerebral cortex do not receive sensory info or control muscles

frontal lobes—prefrontal cortex, broca’s area

• prefrontal cortex to direct thinking processes, acts as the central executive of the brain to help pursue goals, predict consequences, etc.

• broca’s area is in the frontal lobe in the left hemisphere and controls the muscles that help you talk, one of two areas for language processing

parietal lobes

• somatosensory cortex/sensory cortex is right behind the motor cortex in the frontal lobe

• phantom limb syndrome comes from this cortex

occipital lobes

process what our eyes see

temporal lobes

process sound

wernicke’s area is for linguistric processing, writing, and spoken speech

can we reform our brain? how?

• our brains can have plasticity attributes so if a part of our brain is damaged we might be able to reform it