Attention: Due to an upgrade beginning on Friday, the 22nd August 2025, any new collabs, groups and any changes to teams will not be kept beyond the weekend. User creation will also be disabled during this time. The actual upgrade will take place on Wednesday, 27th August. On that day, any service requiring a Keycloak login will be unavailable for the duration of the upgrade. Thank you for your understanding as we complete this important work.

For the duration of the maintenance period, Collaboration and Group creation features will be temporarily disabled and will return HTTP 503 Service Unavailable errors until further notice.


Last modified by adavison on 2022/10/04 13:55
From version 11.4
edited by adavison
on 2021/09/30 14:18
Change comment: There is no comment for this version
To version 11.3
edited by adavison
on 2021/09/30 14:01
Change comment: There is no comment for this version

Summary

Details

Page properties
Content
... ... @@ -219,11 +219,8 @@
219 219   v_reset=RandomDistribution('normal', {'mu': -65.0, 'sigma': 1.0}), (%%)
220 220  (% style="color:#000000" %) t_refrac=1, tau_m=10, cm=1, i_offset=0.1)(%%)
221 221  (% style="color:#000000" %)population1 = sim.Population(100, cell_type, label="Population 1")(%%)
222 -(% style="color:#e74c3c" %)population2 = sim.Population(100, cell_type, label="Population 2")
223 -population2.set(i_offset=0)(%%)
224 -(% style="color:#000000" %)population1.record("v")(%%)
225 -(% style="color:#e74c3c" %)population2.record("v")(%%)
226 -(% style="color:#000000" %)sim.run(100.0)(%%)
222 +(% style="color:#000000" %)population1.record("v")
223 +sim.run(100.0)(%%)
227 227  (% style="color:#000000" %)data_v = population1.get_data().segments[0].filter(name='v')[0]
228 228  Figure(
229 229   Panel(
... ... @@ -237,84 +237,7 @@
237 237  \\**Run script in terminal, show figure**
238 238  )))
239 239  
240 -Now we want to create synaptic connections between the neurons in Population 1 and those in Population 2. There are lots of different ways these could be connected.
241 241  
242 -(% class="box successmessage" %)
243 -(((
244 -**Slide** showing all-to-all connections
245 -)))
246 -
247 -We could connect all neurons in Population 1 to all those in Population 2.
248 -
249 -(% class="box successmessage" %)
250 -(((
251 -**Slide** showing random connections
252 -)))
253 -
254 -We could connect the populations randomly, in several different ways.
255 -
256 -(% class="box successmessage" %)
257 -(((
258 -**Slide** showing distance-dependent connections
259 -)))
260 -
261 -(% class="wikigeneratedid" %)
262 -We could connect the populations randomly, but with a probability of connection that depends on the distance between the neurons.
263 -
264 -(% class="box successmessage" %)
265 -(((
266 -**Slide** showing explicit lists of connections
267 -)))
268 -
269 -(% class="wikigeneratedid" %)
270 -Or we could connect the neurons in a very specific manner, based on an explicit list of connections.
271 -
272 -(% class="wikigeneratedid" %)
273 -Just as PyNN provides a variety of neuron models, so it comes with a range of connection algorithms built in. You can also add your own connection methods.
274 -
275 -(% class="box successmessage" %)
276 -(((
277 -**Slide** showing addition of second population, and of connections between them, labelled as a Projection.
278 -)))
279 -
280 -(% class="wikigeneratedid" %)
281 -In PyNN, we call a group of connections between two populations a _Projection_. To create a Projection, we need to specify the presynaptic population, the postsynaptic population, the connection algorithm, and the synapse model. Here we're using the simplest synapse model available in PyNN, for which the synaptic weight is constant over time, there is no plasticity.
282 -
283 -(% class="box infomessage" %)
284 -(((
285 -**Screencast** - current state of editor
286 -\\(% style="color:#000000" %)"""Simple network model using PyNN"""
287 -\\import pyNN.nest as sim(%%)
288 -(% style="color:#000000" %)from pyNN.utility.plotting import Figure, Panel(%%)
289 -(% style="color:#000000" %)from pyNN.random import RandomDistribution(%%)
290 -(% style="color:#000000" %)sim.setup(timestep=0.1)(%%)
291 -(% style="color:#000000" %)cell_type  = sim.IF_curr_exp(
292 - (% style="color:#e74c3c" %) (% style="color:#000000" %)v_rest=RandomDistribution('normal', {'mu': -65.0, 'sigma': 1.0}),
293 - v_thresh=RandomDistribution('normal', {'mu': -55.0, 'sigma': 1.0}),
294 - v_reset=RandomDistribution('normal', {'mu': -65.0, 'sigma': 1.0}), (%%)
295 -(% style="color:#000000" %) t_refrac=1, tau_m=10, cm=1, i_offset=0.1)(%%)
296 -(% style="color:#000000" %)population1 = sim.Population(100, cell_type, label="Population 1")(%%)
297 -(% style="color:#000000" %)population2 = sim.Population(100, cell_type, label="Population 2")
298 -population2.set(i_offset=0)
299 -population1.record("v")
300 -population2.record("v")(%%)
301 -(% style="color:#e74c3c" %)connection_algorithm = sim.FixedProbabilityConnector(p=0.5)
302 -synapse_type = sim.StaticSynapse(weight=0.5, delay=0.5)
303 -connections = sim.Projection(population1, population2, connection_algorithm, synapse_type)(%%)
304 -(% style="color:#000000" %)sim.run(100.0)(%%)
305 -(% style="color:#000000" %)data_v = population1.get_data().segments[0].filter(name='v')[0]
306 -Figure(
307 - Panel(
308 - data_v[:, 0:5],
309 - xticks=True, xlabel="Time (ms)",
310 - yticks=True, ylabel="Membrane potential (mV)"
311 - ),
312 - title="Response of first five neurons with heterogeneous parameters",
313 - annotations="Simulated with NEST"
314 -).show()(%%)
315 -\\**Run script in terminal, show figure**
316 -)))
317 -
318 318  (% class="wikigeneratedid" id="HSummary28Inthistutorial2CyouhavelearnedtodoX202629" %)
319 319  (% class="small" %)**Summary (In this tutorial, you have learned to do X…)**
320 320