Presentation on theme: "Biological Psychology"— Presentation transcript:
1Biological Psychology branch of psychology concerned with the links between biology and behaviorsome biological psychologists call themselves behavioral neuroscientists, neuropsychologists, behavior geneticists, physiological psychologists, or biopsychologists
2Principles of Biological Psychology Everything psychological is simultaneously biological.The nervous system is complexity built from simplicity.The brain is both specialized and integrated.The nervous system is “plastic” especially at early ages of development.
3Neurons: The Messengers About 100 billion neurons (nerve cells) in the human brainNeurons have many of the same features as other cellsNucleusCytoplasmCell membraneWhat makes neurons unique is their shape and function
4Structure of Neurons Dendrites Cell Body (Soma) Axon Myelin Sheath Carry information to the cell body from other neuronsCell Body (Soma)Contains nucleusAxonCarries information to the next cellMyelin SheathInsulates the axon and speeds up the neural impulse
7The Synapse Synaptic space (synaptic cleft) Terminal button Tiny gap between neuronsTerminal buttonEnlarged area at the end of an axonThe synapseComposed of the terminal button of one neuron, the synaptic space, and the dendrites or cell body of the receiving neuron
8Transmission Between Neurons Synaptic vesiclesSacs in terminal button that release chemicals into synaptic spaceNeurotransmittersChemicals released by synaptic vesiclesReceptor sitesLocation on receptor neuron for specific neurotransmitter
11Types of Neurons Sensory neurons Motor neurons Interneurons Carry information from sensory systems to the brainAlso referred to as afferentMotor neuronsCarry information from the brain to muscles and glandsAlso referred to as efferentInterneuronsCarry information between other neurons
12Glial Cells Cells that insulate and support neurons Create the myelin sheathRemove waste productsProvide nourishmentPrevent harmful substances from entering the brain
13The Neural Impulse Resting Potential Neuron is not transmitting information – it is resting
14Neural Communication Resting Potential Nothing is happening. The gates are closed and the positive ions are on the outside with the negative ions on the inside of the cell.“Negative Ions inside the Neuron is Natural”Action Potential – (Neural Impulse)a neural impulse; a brief electrical charge that travels down an axongenerated by the movement of positively charged atoms in and out of channels in the axon’s membraneThis process is due to stimulation from either heat, chemicals, pressure or light
15Neural Communication Cell body end of axon Direction of neural impulse: toward axon terminalsStimulation causes the gates to open and the positiveions enter the cell. An electrical spark is produced by the processcall depolarization. The positive ions are then pumped out.This chain reactioncan occur up to 100 a second.
16The Neural Impulse Polarization Depolarization When the inside of the Neuron is negatively charged relative to the outside (resting potential)DepolarizationWhen the electrical charge of a cell moves toward zero
17The Neural Impulse Action Potential Sudden, massive change in charge in the neuronOccurs when depolarization reaches the threshold of excitationIons flow across cell membrane400 ft per second (Myelinated) to 3 ft per second
18Neural Communication Refractory Period Threshold The time it takes for the positive ions to be pumped out.Thresholdthe level of stimulation required to trigger a neural impulse
19The Neural Impulse Graded Potentials What starts this whole process? A shift in the electrical charge in a tiny area of a neuron.Many subthreshold depolarizations are added together to produce an action potential (a process known as summation)
20The Neural Impulse All-or-None Law A neuron either fires or it does notWhen it does fire, it will always produce an impulse of the same strengthIntensity of a stimulus is seen by the frequency of action potentials
21The Neural Impulse Absolute refractory period Period immediately after an action potential when another action potential cannot occur1/1000th of a SecondRelative refractory periodPeriod following absolute refractory period when a neuron will only respond to a stronger than normal impulse
22SynapseSynapse [SIN-aps] a junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. This tiny gap is called the synaptic gap or cleft.OBJECTIVE 4| Describe how nerve cells communicate. Synapse was coined by Lord Sherrington ( ) who inferred it through behavioral experiments. Cajal ( ) described the synapse based on his anatomical studies of the brain.
23NeurotransmittersNeurotransmitters (chemicals) released from the sending neuron travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing it to generate an action potential.
24ReuptakeNeurotransmitters in the synapse are reabsorbed into the sending neurons through the process of reuptake. This process applies the brakes on neurotransmitter action.
25Lock & Key MechanismNeurotransmitters bind to the receptors of the receiving neuron in a key-lock mechanism.OBJECTIVE 6| Explain how drugs and other chemicals affect neurotransmission, and describe the contrasting effects of agonists and antagonists.
28Some Well-Known Neurotransmitters Acetylcholine (ACh)Released at the neuromuscular junctionPlays an important role in arousal and attentionLoss of ACh producing cells is linked to Alzheimer’s DiseaseToo much = Spasms / Too Little = ParalysisDopamineAffects neurons associated with voluntary movement and pleasurePlays a role in learning, memory, and emotionsImplicated in Parkinson’s Disease and Schizophrenia
29Some Well-Known Neurotransmitters SerotoninFound throughout the brainAppears to sets an “emotional tone”Affects mood, hunger, sleep, and arousalLow serotonin levels are implicated in depressionSome antidepressant drugs raise seratoninEndorphinsReduce pain by inhibiting or “turning down” neurons that transmit pain information“runner’s high”
30Some Well-Known Neurotransmitters NorepinephrineHelps control alertness and arousalUndersupply can depress moodGABA (Gamma-aminobutyric acid)A major excitatory neurotransmitter; involved in memoryOversupply linked to seizures, tremors, and insomnia
31PsychopharmacologyMost psychoactive drugs (and toxins) work by blocking or enhancing synaptic transmissionBotulismBlocks release of ACh at the neuromuscular junction, causing paralysis“Botox” is botulism toxin used to prevent facial muscles from making wrinkles
32Psychopharmacology Curare (koo-ra-ray) Antipsychotic medications Can stun or kill prey quicklyBlocks ACh receptors causing paralysisAntipsychotic medicationsBlock dopamine receptorsReduces schizophrenic hallucinationsCaffeineIncreases the release of excitatory neurotransmitters by blocking the inhibitory neurotransmitter adenosine (a-den-oh-seen)
33Psychopharmacology Cocaine Prevents reabsorption of dopamine Leads to heightened arousal of entire nervous system
34Neural PlasticityThe brain can be changed, both structurally and chemically, by experienceRat studies show that an “enriched” environment leads to larger neurons with more connectionsHas also been shown in humansRecent research has uncovered evidence of neurogenesis, or the production of new brain cells, in human brains