Neural Coding and Synaptic Transmission: Participation Exercises for Introductory Psychology

We present two simulations of neural transmission for use in an Introductory Psychology class. These simulations illustrate the complex coding properties of a single neuron, especially how excitatory and inhibitory postsynaptic potentials accumulate to produce an action potential. A follow-up exercise, using the framework of the simple children's game Musical Chairs, illustrates synaptic transmission, including the effects of psychoactive drugs at the synapse.

We report herein two addiri~nal exercises &at involve mdents 'in asvies o~simulationsofnewronal pmesses. 'The first exetcisa illusnates how kifatory and inhibitory postsynaptic: potentials arnmuht+ to ptoduce Bhiicoiqn potential. The w a n d &eh, a&llow-up t& the fm, illtlirwrg ohemical rans&ion at the synape. Newal C6dlng Exercise system and permbations at t h~ mutonal level need nor affect the outp~t tkm a higher ordet w e m . We i n d u c e the exercise soon afcer neural fimcfioning has been presented in a repiar ckss =ion.
We use the exercise in discussion seaions El0 to 25 students), aithough it d also be performed indssses of 30 to 45. Some students' a t l i to view the proceedings may be reshirred in classes larget than +5. The minimum time t w qrrired is 8 to 1 0 min. The only m a t d s needed am seven index car&; slx cards have che LetterE in one color &, b d the seventh cad has an 1 I a anpasting color. We have b m d that the following sequence of fawr caws is optimal.
The B a s e SimIafion ihdiffafian Only) ~. ~nesNdent:acts as the receiuing.neurom andis stationed at h.bkkboaxd facirq the cim, Sixother%~dents, &rk ably in the hunt tow of the c k , teplesent six input pMhs. sm&ti@ a* refwed to & inpw.) The '&~+auct~r g i m ea& + E index card, thus .a inpun in die basic S h~l a d~~a r e , e~& a t b~~ Baeh d the it@& is :hxmucted to hold uphis.orher,dfor 3 s, wirh a 5 a interval beorreen card Aashe~ '(i..~., ea& uial lase.8 s; the 'hcructrn shonid aaggq the smting times for each of che hpue by abut 1 to 2 3. The ~i v I n g l l~r o n f i f e s w h e n e +~~t i y threec&&are vbible at the same t i m e that isi the neuron reathe afuinp threshold whenever :.&tee cards are s k a u l~w l~ presented. To. represent firing, the receiving neuon rums around and writes ' T fire" on the btackbod. This turntap axmy fram the inputs &tors a refPaCtOry period, duting which time the neuron m t repond to @puts. The fe-ceivingix&&& tid&@ hoieafard t&isin,the,pmtes~:of pingup or down, and die inputsare insmtatd to &&their cad pmentatio~ qrisp. Afte~ 1 or 2 min, the 'im~ctor ends the simulation, and the ala& aunts the number of times the r&eiving nemgu h d .
Students simulate how the neuron accumulates and decodes inputs to produce an nction potential. This exercise Exitution and Inhibition demmtwtes q.atial and temporal summation olgradedex. cifacotg and inhibirory . h he+v!hg den&=. hf%ences a o a g dnrgs tharblock reuptake, w cupyreceptox si,res, and:mimiC the n e m . m @ t t + a n be illusuatad easily.
Phw four chaw in the frorir ot the c k , to r e p~~~, t otigin sites of the re'tea~ing :axom'amd an aqua1 n m k i of chaw facinp.&em to q&smt the :meprof sites on the r&Iiving d@,&w, k~ &e basic shnulacior*. s m d b reprer~~