On a scale from 1-100, how much does the brain play a role in our behavior? Biology of the Mind • Dr. Canavero (Italy) and Dr. Ren (China) are currently investigating how to conduct full head transplants on brain-dead bodies Neural and Hormonal Systems • Biological Psychologists: using advanced technologies to the study the link between biological (genetic, neural, hormonal) processes and psychological processes • Neuroplasticity: Brain is sculpted by genes, but also changed and shaped by experiences • Build new pathways as it adjusts to new experiences Neural Communication • Neurons: Nerve cells, the building blocks of our neural system • Cell body with branching fibers (dendrites) • Dendrites: receive and integrate information • Axon: Fiber which passes the message through its terminal branches • Dendrites listen, axon speaks • Myelin Sheath: layer of fatty tissue that insulates and speeds their impulses • Glial cells: glue cells that provide nutrients, insulating myelin, guide neural connections Neural Impulse • Neurons transmit messages when stimulated by our senses or by neighboring neurons • Action potential: Brief electrical charge that travels down its axon • Neurochemical process: Generate electricity from chemical events (similar to batteries) • Transmit from speeds ranging from 2 miles to 200 miles per hour • Selectively permeable Neuron Communication • Small gaps between every neuron called: synapses • Release of a chemical message through neurotransmitters Neurotransmitters influencing us • Neurotransmitters send out serotonin molecules • Reuptake is the process of the sending neuron reabsorbing these molecules Opiates • The brain indeed produces its own naturally occurring opiates Drugs altering neurotransmission • Agonist: increase a neurotransmitter’s action • Increase production or block reuptake • Antagonist: decrease a neurotransmitter’s action • Blocking production or release (e.g., Botulin (Botox) blocking ACh release) Neural and Hormonal Systems Two communication systems • Electrochemical information system: Nervous system • Central nervous system and Peripheral nervous system • Hormone chemical messengers: Endocrine system The Nervous System • Nervous system: Neurons communicating via neurotransmitters • A communication network that takes in information from the world and the body’s tissues to make decisions and sends back information and orders to the body’s tissues • Central nervous system: Body’s decision maker • Peripheral nervous system: Responsible for fathering information and transmitting CNS decisions to other body parts The Nervous System • Nerves: Electrical cables formed from bundles of axons, link the CNS with the body’s sensory receptors, muscles, and glands (e.g., optic nerve has a bundles a million axons into a single cable carrying messages from the eye to brain • Sensory neurons: Carry messages from the body’s tissues and sensory receptors inward to the brain and spinal cord (input) • Motor neurons: Carry instructions from the central nervous system outward to the body’s muscles and glands (output) Peripheral Nervous System • Somatic nervous system: Enables voluntary control of our skeletal muscles (e.g., friend taps your shoulder, your SNS triggers to your brain, triggers your head to turn) • Autonomic (self-regulating) nervous system: Controls our glands and our internal organ, involuntary • Influences glandular activity heartbeat, digestion Autonomic Nervous Systems • Sympathetic nervous system: Arouses and expends energy (alarm) • Accelerates your heartbeat, raise blood pressure, slow digestion, raise blood sugar, cool with perspiration • Parasympathetic nervous system: Conserves energy and calms you (calm) • Slows heartbeat • Both work together (like an accelerator and brake) to keep you at homeostasis (steady state) Central Nervous System • Brain and Spinal cord • Brain is made up of neural networks • Spinal cord: Two-way information highway connecting the peripheral nervous system and brain • Communication pathways governing the reflexes • Information travels to and from the brain by way of the spinal cord Endocrine System • Glands and fat tissue system • Hormones: Secrete chemical messages • Hormones act and influence the brain, sex, food, and aggression • Endocrine system operates similar to the Nervous system in which chemical messengers diffuse across synapses and excite or inhibit adjacent neurons • Adrenal glands: hormones increase heart rate, blood pressure, blood sugar, assist in moments of danger and emergency • Pituitary gland: Master gland • Responsible for physical development, sex hormones, stress hormones