Lecture Four- Biological Basis.pptx

PSY 369 Announcements The content from this lecture and the last will be the content tested on Weekly Quiz 1 In other words, the content from “Introduction to Learning & Memory” and “The Biological Basis of Learning & Memory” will be the topic of Weekly Quiz 1 Don’t forget to sub...

PSY 369 Announcements The content from this lecture and the last will be the content tested on Weekly Quiz 1 In other words, the content from “Introduction to Learning & Memory” and “The Biological Basis of Learning & Memory” will be the topic of Weekly Quiz 1 Don’t forget to submit today’s reflection at the end of class This week’s reflection recording has been posted The Syllabus Quiz is due next Sunday at 11:59 PM Syllabus has been updated with office hour info TA Information: Joao Lopes [email protected] Psychology BS & Biology Men’s Club Soccer Pre-Dental 2 dogs  Who am I? Personal Life: - I love playing video games, I currently play a lot of Fortnite, Dead by Daylight, and Disco Elysium - I love listening to the Smiths, Radiohead, Lamp, Clairo, Arctic Monkeys, etc. - My favorite film is ‘Good Will Hunting’ which has my favorite actor, Robin Williams - I love reading books, over the summer I read ‘In the Miso Soup’, ‘Clockwork Orange’, etc. - My current hyperfixation is Deadpool & Wolverine, and by proxy Hugh Jackman Academic Life: - I’m the web graphic head for the Humanology Project - I’m the President/Creator of Reel Rendezvous, a movie club - I work in a Psychology lab The Biological Basis of Learning & Memory Nervous System The nervous system is composed of two major cells: Neurons and Glial Cells There are approximately 100 Billion Neurons in the human brain May be more than 100 Trillion Synapses (the gap where two neurons meet) in the human brain Glial Cells Are found throughout nervous system and provide support for neurons Outnumber neurons 10 to 1 Supply nourishment to neurons, remove waste products from neurons, and insulation around many axons Essentially, they are servicing the neurons and keeping them functioning! Neurons Neurons are individual cells in the nervous system that receive, integrate, and transmit information Basic Parts of the Neuron 1. Soma 2. Nucleus 3. Dendrites 4. Axon 5. Terminal Buttons 6. Synapse (or Synaptic Cleft) Soma and Nucleus Also referred to as the cell body (Soma is the Greek word for Body) Contains the Nucleus of the neuron as wellSoma as the organelles of the cell Dendrites The part of a neuron that receive information from other neurons Dendrites Axon Is a long, thin fiber that transmits signal from the soma to other neurons, muscles, or glands Most (but not all) axons are covered in Myelin Sheath (a fatty insulating material that speeds up transmissions) Axon Terminal Buttons Are small knobs that secrete neurotransmitters, which enters the synapse between two neurons, to send information to the dendrite of the neighboring neuron Terminal Buttons and Synapses Types of Neurons Principal Neurons – have highly organize set of dendrites and an axon that may connect with local cells or extend many millimeters to send signals to another brain region Interneurons – receive and send signals within a local region in the nervous system Motor neurons – have many branching dendrites and each neuron has a single axon that extends over a long distance to send signals to muscles Sensory neurons – have specialized dendrite endings to receive signals from sensory organs in the eyes, ears, nose, skin, and more How do Neurons Communicate? Neurons produce electrical energy to signal terminal buttons to release neurotransmitters into the synapse Resting Potential Inside and outside the neuron are electrically charged atoms This includes positively charged sodium (NA+) on the outside and positively charged potassium (K+) on the inside (along with large negatively charged proteins) The stable, negative charge when a cell is inactive is the Resting Potential Action Potential When activated channels (sort of like doors or gates) in the cell membrane (the wall of the cell) open This allows sodium (NA+)to flow into the neuron This causes the negatively-charged neuron to briefly turn positive, which allows a neuron’s electrical charge to travel down the axon Only takes a few thousandths of a second All or None Law Either an action potential occurs, or it does not. It can not halfway fire Why do you think that is? All or None Law Either an action potential occurs, or it does not. It can not halfway fire Why do you think that is? It can only be negatively charged (resting potential) or positively charged. There is no in between The strength of a stimulus is determined by the rate at which action potentials are fired  Chemical Signals The action potential causes vesicles (like packages of chemicals) to travel down the axon These fuse at the membrane of the neuron to release neurotransmitters into the synapse via the terminal buttons What is the synapse again?  Chemical Signals The action potential causes vesicles (like packages of chemicals) to travel down the axon These fuse at the membrane of the neuron to release neurotransmitters into the synapse via the terminal buttons What is the synapse again? The gap/junction between two neurons! Once there, some of the transmitter will bind to receptor sites on the dendrites that either excite or inhibit the next neuron The transmitter either binds, is brought back into the original neuron via reuptake, or is removed by enzymes in the synaptic cleft Synthesis and storage of Reuptake of neurotransmitters 1 neurotransmitter molecules in synaptic vesicles 5 sponged up by the presynaptic neuron Release of neurotransmitter 2 molecules into synaptic cleft Inactivation (by enzymes) or 4 removal (drifting away) of neurotransmitters Binding of neurotransmitters 3 at receptor sites on postsynaptic membrane Post Synaptic Potentials (PSP) Are either excitatory (EPSP) or inhibitory (IPSP) EPSP is a positive voltage shift that increases the likelihood the next neuron will fire an action potential IPSP is a negative voltage shift that decreases the likelihood the next neuron will fire an action potential Amino Acids Neurotransmitters GABA Produces inhibitory effects on neurons Think for a moment, how does an Inhibitory action affect the communication of neurons. Amino Acids Neurotransmitters GABA Produces inhibitory effects on neurons Think for a moment, how does an Inhibitory action affect the communication of neurons. It slows them down! Involved with Anxiety related disorders Glutamate Produces excitatory effects on neurons Think for a moment, how does an Excitatory action affect the communication of neurons. Amino Acids Neurotransmitters GABA Produces inhibitory effects on neurons Think for a moment, how does an Inhibitory action affect the communication of neurons. It slows them down! Involved with Anxiety related disorders Glutamate Produces excitatory effects on neurons Think for a moment, how does an Excitatory action affect the communication of neurons. It speed them up! Involved with Learning and Memory Artificial Neurotransmission Agonists are chemicals that mimic the action of a neurotransmitter Examples: Nicotine is an Acetylcholine Agonist and benzodiazepines (xanax or valium) are GABA Agonists Antagonists are chemicals that oppose the action of a neurotransmitter Example: Narcan is an Opioid Connections Between Neurons Greater network connectivity is associate with greater learning power Learning can increase the number and intensity of neural connections These new connections are part of the neural basis of new memories Cognitive aging - some individuals lose connections between neurons and have learning and memory problems as they age Hebb (1949) “When an axon of cell A is near enough to excite a cell B and repeatedly or persistently takes part in firing it, some growth process or metabolic change takes place in one or both cells such that A‍'​s efficiency, as one of the cells firing B, is increased.” Cell Assembly - interconnected neurons representing a perception or concept, which could be strengthened by experience “Neurons that fire together wire together” Hebb (1949) - Continued Long Term Potentiation (LTP) - a cellular mechanism for strengthening connections between neurons, thus increasing the EPSP and probability of an action potential. LTP promotes the formation of a cell assembly “Neurons that fire together, wire together” “Associative LTP” supports new associations between stimuli and responses Long Term Potentiation (LTP) LTP requires two synaptic events: 1. A pre-synaptic signal 2. In increase in the potential of the post synaptic cell The initial activation produces action potentials in the post-synaptic cell and an increase in that cell’s potential…for several hours Subsequent activations produce simultaneous pre- synaptic signals Long Term Depression (LTD) Long Term Depression – mechanism of depotentiation, a decrease in synaptic efficiency The opposite of LTP If synaptic efficiency could only be increased, they would all become saturated, and no learning could occur  Where does LTP and LTD Occur? LTP and LTD happen in the hippocampus, amygdala, striatum and elsewhere in cerebral cortex According to evolution, hippocampus was the first cortical area to develop in mammals, part of the forebrain If the forebrain and hypothalamus are damaged, patients can’t properly regulate eating, drinking and sleeping Limbic System Is a loosely connected network of structures located roughly along the border between the cerebral cortex and deeper subcortical areas These structures play a large role in both the learning process and memory Consists of the hypothalamus, the hippocampus, amygdala, olfactory bulb, and the cingulate gyrus Limbic System (Continued) Hippocampus deals with consolidation of memory Amygdala deals with emotions, fear, and aggression Olfactory Bulb deals with processing sense of smell Study Tip: Remember Bulbs are a type of flower and people buy flowers for their smell! Cingulate Gyrus deals with emotions and behaviors The Case of H.M. The Four Lobes of the Cerebrum 1. The Occipital Lobe 2. The Parietal Lobe 3. The Temporal Lobe 4. The Frontal Lobe Lobes 1. The Occipital Lobe is where visual signal are sent, and their processing begins Study Tip: Remember occipital sounds like ocular which is related to seeing! Lobes 1. The Occipital Lobe is where visual signal are sent, and their processing begins Study Tip: Remember occipital sounds like ocular which is related to seeing! 2. The Parietal Lobe is where the sensation of touch is processed (primary somatosensory cortex and primary motor cortex), as well as where some visual processing occurs Lobes 1. The Occipital Lobe is where visual signal are sent, and their processing begins Study Tip: Remember occipital sounds like ocular which is related to seeing! 2. The Parietal Lobe is where the sensation of touch is processed (primary somatosensory cortex and primary motor cortex), as well as where some visual processing occurs 3. The Temporal Lobe is responsible for hearing processing, including speech comprehension and language Study Tip: Remember Temporal sounds like Tempo which is related to hearing! Lobes 1. The Occipital Lobe is where visual signal are sent, and their processing begins Study Tip: Remember occipital sounds like ocular which is related to seeing! 2. The Parietal Lobe is where the sensation of touch is processed (primary somatosensory cortex and primary motor cortex), as well as where some visual processing occurs 3. The Temporal Lobe is responsible for hearing processing, including speech comprehension and language Study Tip: Remember Temporal sounds like Tempo which is related to hearing! 4. The Frontal Lobe controls movement of muscles, and contains the Pre-Frontal Cortex which is involved in decision making abilities, planning for the future, and working memory