2. Biological bases of cognition and behavior Part 1

3. How your “wetware” works... zBiological (Physiological) Psychology (Neuroscience) zNeuron ya nerve cell ythe basic building block of the nervous system yCommunication Highway!!!

4. How we work... zNeurons z Neurons do the “talking” zThe human brain has about 100 billion neurons, interconnected at 100 trillion synapses. zHere’s what a trillion pennies looks like:

6. How it works... zNeurons come in 3 basic flavors… zSensory neurons (“afferent” neurons) senses to brain for processing zMotor neurons (“efferent” neurons) brain to muscles/glands for reaction zInterneurons connectors; only in brain and spinal cord zExample: Water temp in shower

7. The Neuron

8. Neural communication down the axon zDendrite ythe bushy, branching extensions of a neuron that receive messages and conduct impulses toward the cell body zAxon ythe extension of a neuron, ending in branching terminal fibers, through which messages are sent to other neurons or to muscles or glands

9. Neural communication down the axon zMyelin [MY-uh-lin] Sheath ya layer of segmented fatty cells encasing the fibers of many neurons ygreater transmission speed of neutral impulses (Duct Tape) yMade from glial cells zAt rest, the neuron is polarized (at “resting potential”) ySodium (Na+) and chloride (CL-) outside and potassium (K+) inside y“Sodium pump” – Ion pump, resets to resting potential

10. When does a Neuron “Talk” zDendrite acts as a NET and grabs the chemical messages, sending info to the cell body/nucleus zNucleus or the “Office Executive” assesses and decides whether to command

11. Neural communication: down the axon zAction Potential ya neural impulse; a brief electrical charge that travels down an axon ypositively charged ions in and out of channels in the axon’s semi-permeable membrane zThreshold ythe level of stimulation required to trigger a neural impulse yThe “All or None” law; coded by firing rate

12. Neural communication: down the axon Cell body end of axon Direction of neural impulse: toward axon terminals Rapid influx of positive charge triggering electrical message: “RELEASE THE MESSAGE!!”

13. Neural communication: down the axon zGraded Potentials ySmall changes that make a neuron more or less likely to fire (i.e., change the threshold) yDepolarization = more sensitive yHyperpolarization = less sensitive zNucleus yMessage comes in as either a excitatory (Fire) or inhibitory (Don’t Fire) neurotransmitters (chemicals)

14. Neural Communication at the synapse zSynapse [SIN-aps] yJunction/gap between the axon end bulb and the dendrite “net” ytiny gap at this junction is called the synaptic gap or cleft zNeurotransmitters ychemical messengers that traverse the synaptic gaps between neurons (leave the axon) ywhen released, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron (dendrite part) yThis produces a graded potential in the receiving neuron!

15. Neural Communication: at the synapse

16. Neurotransmitters Excitatory neurotransmitters: FIRE!!!!! Inhibitory neurotransmitters: Don’t FIRE!!! Modulatory neurotransmitters (“neuromodulators”)

17. A shopping list of neurotransmitters... zAcetylcholine yLearning & memory, but also triggers muscle contraction (botulism = Ach receptor blocker) zDopamine yInfluences movement, learning, and yattention. y May be linked to schizophrenia & Parkinson’s disease

18. A shopping list of neurotransmitters... zSerotonin yAffects mood, hunger, sleep, and arousal. yProzac/Zoloft raises serotonin levels. zNorepinephrine and epinephrine yAffects alertness and arousal; also anxiety

19. A shopping list of neurotransmitters... zGamma-aminobutyric acid (GABA) yInhibitory neurotransmitter. yMay be involved in eating and sleep disorders. zNote that the effects of neurotransmitters depend on the receptor zA given neurotransmitter can trigger different types of receptors with different results!

20. Neural Communication Dopamine pathways

21. Neural Communication Serotonin pathways

22. Fun with neuromodulators... zEndorphines y“morphine within” ynatural, opiate-like neurotransmitters y linked to pain control and to pleasure

23. Drugs and Neural Communication Neurotransmitter molecule Receiving cell membrane Receptor site on receiving neuron Agonist mimics neurotransmitter Antagonist blocks neurotransmitter Just write down what agonist and antagonists do

24. The Nervous System configured Central (brain and spinal cord) Nervous system Autonomic (controls self-regulated action of internal organs and glands) Skeletal (controls voluntary movements of skeletal muscles) Sympathetic (arousing) Parasympathetic (calming) Peripheral

25. The Nervous System The body’s speedy, electrochemical communication system yconsists of all the nerve cells of the peripheral and central nervous systems zCentral Nervous System (CNS) ythe brain and spinal cord zPeripheral Nervous System (PNS) ythe sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body

26. The Peripheral Nervous System – part A zAutonomic Nervous System ycontrols the glands and the muscles of the internal organs (such as the heart) zSympathetic Nervous System yarouses the body, mobilizing it in stressful situations zParasympathetic Nervous System ycalms the body, conserving its energy

27. The Peripheral Nervous System – part B zThe skeletal nervous system yLots of efferent neurons (Motor) yBut also afferent (sensory) for the kinesthetic sense http://findarticles.com/p/articles/mi_g2699/is_0001/ai_2699000193/

28. The peripheral nervous system

30. An example of neural communication: zReflex: a simple, automatic, inborn response to a sensory stimulus Skin receptors Muscle Sensory neuron (incoming information) Motor neuron (outgoing information) Brain Interneuron Spinal cord

31. How your brain is “wired” zNeural Networks yinterconnected neural cells ywith experience, networks can learn, as feedback strengthens or inhibits connections that produce certain results ycomputer simulations of neural networks show analogous learning InputsOutputs Neurons in the brain connect with one another to form networks The brain learns by modifying certain connections in response to feedback