Biological PsychologyNerve CellsSlide 3Slide 4Slide 5Electrical ActivitySlide 7Action PotentialsNeurotransmittersSlide 10Slide 11Slide 12Neural PlasticitySlide 14Slide 15Biological Biological PsychologyPsychologyNerve CellsNerve Cells•Cells are the brain’s most basic unit of communication•Neurons–Nerve cells intricately designed to communicate with each other•Soma–The cell body that is the central region of the neuronNerve CellsNerve Cells•Dendrites–Portion of the neuron that receives signals–These distinguish neurons from other cells•Axons–Portion of neuron that sends signals–Very thin near the cell, creating a trigger zone–Contain axon terminals at the end of the axonNerve CellsNerve Cells•Axon terminals contain synaptic vesicles–Spherical sac containing neurotransmitters–Manufactured in cell body and travels down the axon•Neurotransmitters–Chemical messenger specialized for communication from neuron to neuron–Synaptic vesicles burst at axon terminal and release neurotransmitters into the synapseNerve CellsNerve Cells•Neurotransmitters enter the synapse–Space between two connecting neurons through which messages are transmitted chemically–Contains the synaptic cleft•Neurotransmitters are then picked up by the dendrites of nearby neuronsElectrical ActivityElectrical Activity•Neurons respond to neurotransmitters by generating electrical activity•Electrodes–A conductor through which electricity enters or leaves an object•Resting Potential–When there are no neurotransmitters acting on the neuron–More negative particles inside than outside the neuronElectrical ActivityElectrical Activity•When the electrical charge in the neuron reaches a high enough level relative to the outside, called the threshold, an action potential occurs.•Action Potential–Electrical impulse that travels down the axon triggering the release of neurotransmitters–“All or none” lawAction PotentialsAction Potentials•Neurons fire at rates of 100 to 1,000 times per second•Each action potential is followed by an absolute refractory period–Brief interval during which another action potential cannot occur–This period limits the maximal firing rateNeurotransmittersNeurotransmitters•Neurotransmitters bind with receptor sites along the dendrites of a neighboring neuron•Reuptake–Process by which the synaptic vesicle reabsorbs the neurotransmitter•Some neurotransmitters excite the nervous system, increasing its activity, whereas others inhibit the nervous system, decreasing its activityNeurotransmittersNeurotransmitters•Glutamate and GABA are the most common neurotransmitters in the CNS•Glutamate–Rapidly excites neurons–Enhances learning and memory–High doses can be toxic•GABA–Inhibits neurons–Most antianxiety drugs bind to GABA receptorsNeurotransmittersNeurotransmitters•Monoamines consist of dopamine, serotonin, and norepinephrine–Dopamine: plays critical role in rewarding experiences that occur, whether it be through sex, a good meal, or a gambling jackpot–Serotonin: plays an important role in mood, sleep, and learning–Norepinephrine: has a stimulating effect, fosters alertness, and plays a role in long-term memoryNeurotransmittersNeurotransmitters•Drugs that interact with neurotransmitter systems are called psychoactive, meaning they affect mood, behavior, or arousal•Agonists: drugs that increase receptor site activity–Opiates–Tranquilizers–Anti-depressants•Antagonists: drugs that decrease receptor site activityNeural PlasticityNeural Plasticity•Plasticity–Ability of the nervous system to change•Our brain is most capable of changing during early development•Our brains do not fully mature until late adolescence or early adulthoodNeural PlasticityNeural Plasticity•Four primary ways the network of neurons in the brain change over the course of development:1. Growth of dendrites and axons2. Synaptogenesis, the formation of new synapses3. Pruning, death of certain neurons and retraction of axons to remove connections that are not useful4. Myelination, the insulation of axons with a myelin sheathNeural PlasticityNeural Plasticity•Our brains change as we learn–Neural and structural plasticity•Neural plasticity and injury•Stem cells–Have the potential to become a wide variety of specialized cells–Gene therapy–Controversy surrounding stem cell research•Neurogenesis–Creation of new neurons in the adult