Biology of the Mind Part 1 PDF

 For most of human history, a person’s mind was considered to have an existence completely separate from the body ◦ Called “mind-body dualism”  Idea that psychological experience is completely tied to our physical being (materialism) is a relatively new one...

 For most of human history, a person’s mind was considered to have an existence completely separate from the body ◦ Called “mind-body dualism”  Idea that psychological experience is completely tied to our physical being (materialism) is a relatively new one 1   Biological and biochemical processes underlie all of human behavior and thought—  It is not simply that our biology controls what we do, however ◦ Environmental forces, our actions, and our choices also modify the brain so that every time we learn or remember, feel or act, physical and chemical changes are occurring in our brain Did you know? Rats raised in enriched environments vs boring environments develop more connections between neurons? (Rosenzweig & Bennet, 1972) Rats who are deprived of touch in infancy grow less and have fewer connections between neurons; they also have higher levels of stress hormones through life? (Schanburg, 2003) Premature infants who receive massage grow faster and show better cognitive development than premature infants who aren’t touched as much? (Field, 2010) 2 Nervous System It is the body’s speedy, electrochemical communication system which both directs and is influenced by behavior and thought. Nervous System: It is the body’s speedy, electrochemical communication system which both directs and is influenced by behavior and thought. Is the physical basis for our psychological experience 3 Nervous System: It is the body’s speedy, electrochemical communication system which both directs and is influenced by behavior and thought. Divided into two major subsystems: Central Nervous system (CNS) Brain and spinal cord Peripheral Nervous system (PNS) All other nerve cells 4 Somatic Nervous System: The division of the peripheral nervous system that controls the body’s skeletal muscles. Autonomic Nervous System: Part of the PNS that controls the glands and other muscles. Sympathetic Nervous System: Division of the ANS that arouses the body, mobilizing its energy in stressful situations. Parasympathetic Nervous System: Division of the ANS that calms the body, conserving its energy. Maintains homeostasis. 5   Neurons:  Functional Unit of Nervous System  are cells that communicate with one another and organize every aspect of our experience  Approximately 100,000,000,000 in the human brain  Maybe 10,000 X more connections between neurons than neurons themselves  They form complex networks  Relay information  Store information (all memories & data)  Move muscles & bones  Regulate all internal processes  Sense information from outside world (eyes, ears, nose, etc.)  Make and release neurotransmitters (dopamine, serotonin, etc.)  Work with Endocrine System (hormones) to get stuff done 12 6  Sensory Neurons carry incoming information from the sense receptors to the CNS. Motor Neurons carry outgoing information from the CNS to muscles and glands. Interneurons connect the two neurons. Interneuron Neuron Sensory Neuron (Unipolar) (Bipolar) Motor Neuron (Multipolar) * Glial cells – important helper cells Functions: – Help nourish neurons – Move neurons around – Clean up debris – Form myelin – Repair neurons – Attack intruders: such as viruses, and bacteria There are 10 X more glia than neurons, so your brain is mostly glia! 14 7  Neurons growing new networks. They actually reach out to connect with other neurons. Neurons that “fire” together “stay” together. 15  Like other cells of the body in many ways ◦ Have cell membrane ◦ Nucleus with organelles to maintain cell health and metabolism ◦ Same genetic material as other cells  Specialized structures allow for communications ◦ Axons ◦ Dendrites ◦ Terminal buttons ◦ Synaptic vessicles ◦ Receptors 8  * Fires an “action potential” a little electrical impulse, a charge, a spark! Nucleus Dendrites Terminal ends * And when it fires, all of it fires: this is called the “all or nothing” principle 17  Single fibers extending from neuron  Can be microscopic or more than 2 feet in length  Serves as transmitter for cell (carries nerve impulses toward other neurons)  Many are covered with myelin sheath (fatty substance) that insulates it from other neurons, makes nerve signals move faster 9  At end on axon fiber is area called terminal button  Inside terminal button are small sacks called synaptic vessicles  Inside synaptic vessicles are chemicals called neurotransmitters Neurons are single nerve cells Nerves consist of neural “cables” containing many axons. They are part of the peripheral nervous system and connect muscles, glands, and sense organs to the central nervous system. 10  Figure 4.1 A motor neuron Myers: Psychology Copyright © 2010 by Worth Publishers  Multiple, usually shorter fibers which receive signals from the axons of other neurons  Are cells “receivers” 11  Axons and Dendrites of adjacent cells never touch  Is a gap between them, across which chemicals called neurotransmitters, are released.  All communication between neurons is accomplished via neurotransmitters migrating across the synaptic gap and binding with receptor sites on the dendrites of adjacent neurons Figure 4.3 How neurons communicate Myers: Psychology, Copyright © 2010 by Worth Publishers 12  Blue= Axons Green=Dendrites Red=Synapses  Now that you know about how neurons communicate, I want introduce you to a modern theory about how the structure and function of our brains may makes us who we are.  Hopefully, will give you a sense of both wonder and excitement about the complexity of your minds and brains, and interest you in what we are going to learn about next, which is how neurons talk to each other  Is also a good example of how science works—from theory to testable hypothesis to experiment 13  http://www.ted.com/talks/sebastian_seung Thought Questions: To what degree do you find this hypothesis/argument compelling? Is there enough evidence to “prove it” What does Dr. Seung suggest would allow at least a partial test of the theory? 14 End of Section 1 15