Lecture on Synapses, Learning, and Memory with Roberto Milano

Introduction

• Speaker: Bill Mobley and guest Roberto Milano, Professor at UCSD in Neurosciences and Neurobiology
• Topic: Learning and memory in the brain, focusing on the role of synapses

Roberto Milano's Background

• Research Focus: Synapses—sites of communication between nerve cells
• Relevance to Alzheimer's: Synapses are among the first sites affected
• Key Hypothesis: Learning involves the modification and long-term maintenance of synapses

Synapses and Brain Communication

• Structure: Tiny structures (~1/1000th the width of a hair), approximately 300 billion in the brain
• Function: Site for neurotransmitter release and receptor activation, leading to electrical signals in receiving cells
• Variables: Amount of neurotransmitter, number of receptors, receptor sensitivity

Learning and Memory

• Key Concept: Synaptic modification is central to memory
• Long-Term Potentiation (LTP): Strengthening of synapses; identified in the 1970s through experiments with high-frequency stimulation
• Long-Term Depression (LTD): Weakening of synapses through low-frequency stimulation
• Importance: Both LTP and LTD regulate how nerve cells communicate and could form the building blocks of memory

Experimental Findings

• Rat Experiment: Associative memory formed using optogenetics
  • Replace auditory tone with light-sensitive proteins to activate nerve cells
  • Pairing light activation with a foot shock created a memory; rats freeze when re-exposed to light
• LTP and LTD in Memory Formation: Experiment shows creation and erasure of memory by inducing LTP and LTD at synapses in the fear center of the brain

Connection to Disease

• Alzheimer's Disease: Research shows beta-amyloid plaque weakens synapses similarly to LTD
• Implications: Understanding synaptic weakening by beta-amyloid can lead to new therapies to prevent or restore memory loss

Conclusion

• Call to Action: Research like Milano's informs disease understanding and treatment development for conditions like Alzheimer's
• Future Work: Further testing on memory formation and removal using beta-amyloid in animal models

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• Note: Remember the importance of synaptic health in learning and memory, and the potential for targeted therapeutic approaches in neurodegenerative diseases.