1. Synapses, Chemical messaging NBE-E5700 Introduction to Cognitive Neuroscience Ilia Kempi

2. Where are we?

3. Transmission agents Ions Concentration directly affects electrical potential Present in high volumes outside glial cells Neurotransmitters Modulate the inflow of ions into neural cells

4. Channels and receptors AMPA receptor example Activated with glutamate Acts as an ion channel Permeability to calcium ion depending on GluR2

5. Types of ion channels Directly gated channels ligand – gated (LGIC) Indirectly gated channels second messenger mechanism e.g. Metabotropic receptors Voltage gated channels Pumps

6. Depolarization process

7. Depolarization process [.......]

8. Depolarization process [□....]

9. Depolarization process [□□..]

10. Depolarization process [□□□]

11. Action potential

12. Action potential propagation

14. Analogy Axon propagation dynamics is very similar to squeezing a small amount of dough through a cake dressing bag Mother nature gave this process an improvement

15. Myelin sheath Schwann cell warps around axon Regenerative function Inhibits local depolarization

16. Speed improvement

17. Synaptic action

18. Synaptic action [......]

19. Synaptic action [□....]

20. Synaptic action [□□..]

21. Synaptic action [□□□]

22. Complete model A A D D Astrocyte controls local neuron communication with neurotransmitters Glutamate, ATP and GABA Drugs may affect neural communication by mimicking neurotransmitters or by other indirect methods

23. Conclusions Neurotransmitters launch depolarization process Action potential is generated in the cell Axon propagates the potential to synapses Synapses release neurotransmitters

24. Additional material Chemical Synapse animation (McGrawHill Education) Chemical Synapse animation (McGrawHill Education) Action at the synapse (Pearson Higher Education)

25. References Page 2 Iiro P. Jääskeläinen, Introduction to Cognitive Neuroscience Page 3 Middle School Chemistry, American Chemical Society Page 4 Wikipedia: Glutamate receptor Page 11 StackExchange: Biology #31404

26. References Page 13 Rice University, CNX /cs_Pb-GW@5 Page 15 Modesto Junior college, Elementary Anatomy and Psychology: nervous system Page 16 Johnson County community college, Schwann Cell and Action potential Page 22 Braintalks blog, 2012. Astrocytes: Keeping your brain healthy Wikipedia: Astrocyte, Morphine