Chapter 3 Biological Psychology Biological Psychology aka behavioral neuroscience The study of the relationship between the nervous system and Using biology to study the physiological genetic and developmental mechanisms of behavior in organisms behavior Neurons We have about 100 billion Each neuron can make 160 trillion connections Parts of the Neuron 1 Cell Body soma the center of neuron contains the nucleus It builds all new cell components 2 Dendrites branchlike extensions that receive information from other neurons information neurotransmitters 3 Axons tail that spreads out from the cell body and transmits 4 Axon terminal end of axons that contains synaptic vesicles filled with 5 Myelin sheath fatty insulated wrapper that wraps around axons and helps to speed communication Glial Cells Multifunctional non neuronal cells that produce myelin Involved in thought memory and the immune system 4 primary functions o hold neurons in place o supply nutrients oxygen to neurons o insulates one neuron from another o destroys pathogens and removes dead neurons Examples Astrocytes communicate closely with neurons increase the reliability of their transmission control blood flow in the brain and play a role in embryo development Oligodendrocyte promotes new connections among nerve cells and releases chemicals to aid in healing Produces the myelin sheath Neuronal Communication When there are no transmitters acting on the neuron the membrane is at resting potential there are more negative particles inside than outside the neuron During an action potential positive particles rapidly flow into the axon o Action Potentials electrical impulse that travels down the axon triggers release of neurotransmitters referred to as neuron firing 2 o Once threshold is reached an action potential fires at constant strength o Neuronal activity from other neurons changes the internal charge of a neuron cell becomes depolarized inside is more positive o After the neuron fires and the inside of the axon accumulates maximal levels of positive charges particles begin to flow back out of the axon and the neuron experiences an absolute refractory period which is when a neuron cannot fire and pumps positive particles out repolarization Connecting Neurons Synapse tiny space between connecting neurons through which messages are chemically transmitted o Presynaptic occurring on the transmitting end before the synapse o Postsynaptic on the receiving end after the synapse Synaptic Vesicles tiny spherical sac containing neurotransmitters 3 Neurotransmitters chemical messenger specialized in communicating between neurons Receptor Site location on postsynaptic neuron that uniquely recognizes the neurotransmitters only specialized to receive certain types of neurotransmitters o Reuptake neurotransmitters being absorbed back up into the axon terminal and recycled o Have different effects Excitatory make the postsynaptic cell more likely to fire Inhibitory less likely to fire o Drugs affect neurotransmitters these drugs are called psychoactive Agonists increase receptor activity Antagonists block receptor activity Reuptake inhibitors block the reuptake allowing more neurotransmitters to stay in the synapse Examples of Neurotransmitters o Glutamate main excitatory tells receiving neuron to fire participates in relay of sensory information and learning o GABA main inhibitory neurotransmitter stops neurons from firing o Dopamine involved in motor function and reward Neural Plasticity How and when the brain changes 4 primary methods of change o growth of dendrites and axons o synaptogenesis the formation of new synapses o pruning death of neurons retraction of axons which removes useless connections and promotes efficiency o myelination insulation of axons with a myelin sheath 4 The Nervous System The Central Nervous System controls mind and behavior in charge of the sensory information The Peripheral Nervous System consists all of the nerves that extend beyond the CNS The Brain 1 Forebrain cerebrum split into two cerebral hemispheres a Corpus Callosum large band of nerve fibers connecting the hemispheres b Cerebral Cortex outermost part of the cerebrum responsible for analyzing sensory information c There are 4 lobes 5 Frontal Lobe a Motor function language memory b Its executive function control and management of I II IV other cognitive functions Parietal Lobe a For touch and perception b Somatosensory III Occipital Lobe a Process visual information b Primary visual cortex Temporal Lobe a Hearing language storing memories b Primary auditory cortex d Limbic System Thalamus sensory relay station regulates sleep I II Hypothalamus behaviors related to basic survival aka fight flight feed fuck sex the four f s Amygdala excitement arousal fear III IV Hippocampus memory esp new special memory 2 Brainstem Hindbrain a Brainstem located between spinal cord cortex preforms some basic functions that keep us alive I Midbrain plays an important role in movement Pons triggers dreams II III Medulla regulates breathing heartbeat etc 6 b Hindbrain consists of cerebellum medulla pons I Cerebellum sense of balance coordinated movement and learning new motor skills The Peripheral Nervous System Two branches o Somatic controls coordinates voluntary movement o Autonomic involuntary actions of internal organs and regulates emotions Two divisions flight digest Sympathetic active during crisis situations fight or Parasympathetic active when not threatened rest Brain Mapping Methods 1 Electroencephalograph EEG a Records brain s electrical activity at surface of skull using electrodes b Non evasive c Cheap to preform d Good at detecting rapid changes e NOT good at knowing where activity is coming from 2 Positron Emission Tomography PET a Measures brain s consumption of radioactive molecules and activity in response b Shows function c Good for knowing where the activity is taking place d NOT good for knowing when it is taking place e Invasive not ideal 3 Functional Magnetic Resonance Imaging fMRI a Using strong magnetic fields measures which brain areas show increased blood flow and activity b Good for showing where activity is 7 c NOT good for showing precise time d Very expensive 4 Imaging Data a Brain scans show the results of subtractions b Subtractions the difference in activity between some neutral control condition and the condition of interest c Colors are arbitrary only to indicate the level of difference 8
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