PYSCH 101 1st Edition Lecture 4Outline of Last Lecture I. MemoryII. ThemesIII. Memory systemsIV. Short-term memoryV. Long-term memoryVI. RetrievalVII. ForgettingVIII. Where memory resides IX. Memory distortions and dysfunctionsX. Working memoryXI. How we rememberOutline of Current Lecture I. NeuronsII. NeurotransmittersIII. Action PotentialIV. Neuron communicationV. ThresholdVI. SynapseVII. Lock and key mechanismVIII. ReuptakeIX. Nervous systemX. Cerebral hemispheresXI. Tour of the brainCurrent LectureThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.I. The Neuron and NeurotransmittersA. Components of neurons1. Dendrite—receives information, takes it to cell body2. Axon—long fiber that transmits signals from cell body to other neurons, muscles, glands3. Myelin sheath—insulation on many axons that speeds up electrical transmission 4. Terminal buttons—end of axon, release chemicals called neurotransmitters5. Synapse—space between neuronsB. Neurotransmitters1. Neurotransmitters cross the synapse; increase or decrease likelihood of neuron firing2. Important neurotransmitters: Acetylcholine (Ach), dopamine, serotonin, and endorphins3. released from the sending neuron travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing the likelihood of an action potentialC. Action Potential1. A neural impulse, a brief electrical charge that travels down an axon.2. Generated by the movement of positively charged atoms in and out of the axon’s membrane3. All‐or‐None Response: The action potentials strength or speed never change. The neuron either fires or it doesn’t. 4. Question: If the intensity of an action potential remains the same throughout the length of the axon, how might a mild sensation of pain and serious sensation of pain differ?D. Neuron: communication1. Excitatory messages- a chemical secretion that makes it more likely that a receiving neuron will fire (action potential will travel down its axon)2. Inhibitory messages- a chemical secretion that makes it less likely a receiving neuron will fireE. Threshold1. Each neuron receives excitatory and inhibitory signals from many neurons via neurotransmitters2. When the excitatory signals exceed a minimum intensity (threshold), the neuron fires an action potentialF. Synapse1. Also called synaptic gap2. A tiny junction or space between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuronG. Lock and Key mechanism1. Neurotransmitters bind to the receptors of the receiving neuron in a key-lock mechanismH. Reuptake1. Neurotransmitters in the synapse are reabsorbed into the sending neurons2. This process applies the brakes on neurotransmitter actionII. Organization of the nervous system, and measuring activityA. Methods to study the brain (case studies, EEG, fMRI, PET, CT) B. Central nervous system—brain and spinal cordC. Peripheral nervous system1. Somatic division—neurons under voluntary control, attached to skeletal muscles2. Autonomic division—controls glands, organs, blood vessels automaticallya. Sympatheticb. ParasympatheticD. Electroencephalogram (EEG)- an amplifies recording of the electrical waves sweeping across the brain’s surface, measured by electrodes placed on the scalpE. Positron emission tomography (PET scan)- visual display of the brain activity that detects a radioactive form of glucose while the brain performs a given task, lighter colors reflect more activityF. Magnetic resonance imaging (MRI)- uses magnetic fields and radio waves to produce computer generated imagesG. Functional magnetic resonance imaging (fMRI)- uses radio waves and magnetic fields to make a “movie” of changes in brain activity H. Computerized axial tomography (CAT/CT)- uses x-raysIII. Nervous SystemA. All the body’s nerve cells; he body’s electrochemical communication systemB. Central nervous system (CNS)- the brain and spinal cordC. Peripheral nervous system (PNS)- the sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body1. Somatic nervous system- the division of the PNS that controls the body’s skeletal muscles2. Autonomic nervous system- division of the PNS that controls the glands and other musclesa. Sympathetic nervous system- division of ANS that arouses the body, mobilizing its energy in stressful situations (fight of flight) “arouses”b. Parasympathetic nervous system- division of the ANS that calms the body, conserving energy (rest and digest)Two Cerebral Hemispheres A. Contralateral arrangement and the corpus callosum B. Contralateral Transmission: information generally crosses from one side of the body to the opposite side of the brain C. Split-Brain research 1. Broca thought language functions mostly on left side (what did the right side do?)2. Epileptics whose corpus callosums had been cut—some strange behaviors!3. Left visual field for each eye goes to right hemisphere, and vice versa4. Some interesting experiments on split-brain patients5. Our conclusions about lateralization (hemispheric specialization)D. Hemispheric Specialization1. Left: language, logical thought, math, does the speaking, processes sequentially2. Right: spatial, visual tasks (e.g. recognizing faces or patterns), emotional expression, can’t speak, processes globally or holistically3. These two hemispheres work together not against each otherIV. Tour of the BrainSome key parts of the brain:A. Brain Stem (includes medulla, thalamus, reticular formation)1. Medulla- base of the brainstem that controls heartbeat and breathing2. Thalamus- the brain’s sensory switchboard on top of the brainstem, directs messages to the sensory areas in the cortex and transmits replies to the cerebellum and medulla3. Reticular formation- a nerve network in the brainstem that plays an important role in controlling arousal4. Cerebellum- the “little brain” attached to the rear of the brainstem, it helps coordinatevoluntary movements and balanceB. Limbic System- system of neural structures between the brainstem and cerebrum, associated with emotions such as fear, aggression and drives for food and sex, includes amygdala and hypothalamus (emotions and motivations)1. Amygdala- consists of two lima bean-sized neural clusters linked to the emotions of fear and anger2. Hypothalamus-