What’s new in NEST 3.6¶

This page contains a summary of important breaking and non-breaking changes from NEST 3.5 to NEST 3.6. In addition to the release notes on GitHub, this page also contains transition information that helps you to update your simulation scripts when you come from an older version of NEST.

If you transition from an earlier version, please see our extensive transition guide from NEST 2.x to 3.0 and the list of updates for previous releases in the 3.x series.

Astrocytes in NEST¶

Astrocytes, one of the main non-neuronal cell types in the brain, interact with neurons through versatile cellular mechanisms and modulate neuronal activity in a complex and not fully understood way. We developed new NEST models to bring astrocytes and neuron-astrocyte interactions to spiking neural networks into NEST. Our new models support reproducible and collaborative large-scale modeling of neuron-astrocyte circuits.

See examples using astrocyte models:

See model docs:

Model directory: astrocyte

New model: glif_psc_double_alpha¶

This model is based on the glif_psc model, but uses the sum of two alpha functions instead of a single alpha function as the post synaptic current input.

See example:

Current-based generalized leaky integrate and fire (GLIF) neuron with double alpha synaptic function

See model docs:

glif_psc_double_alpha – Current-based generalized leaky integrate-and-fire (GLIF) models with double alpha-function (from the Allen Institute)

New way to set the volume transmitter on STDP dopamine synapse¶

Previously, the volume transmitter for the STDP dopamine synapse was set by supplying it with the “naked” node ID of the volume transmitter using its property vt. As it was rather inconvenient to obtain this ID and the procedure was inconsistent with how nodes are usually passed around in NEST, this is now no longer possible. Instead, the volume transmitter is now set by supplying a NodeCollection to the property volume_transmitter of the synapse’s common properties:

Up to NEST 3.5

from NEST 3.6 onward

vt = nest.Create("volume_tranmitter")
nest.SetDefaults(
    "stdp_dopamine_synapse",
    {"vt": vol.get("global_id")}
)

vt = nest.Create("volume_tranmitter")
nest.SetDefaults(
    "stdp_dopamine_synapse",
     {"volume_transmitter": vt}
)

Changes to kernel attributes¶

The following kernel attributes were removed:

sort_connections_by_source : Use use_compressed_spikes instead; it automatically activates connection sorting
adaptive_spike_buffers — spike buffers are now always adaptive
max_buffer_size_spike_data — there is no upper limit since all spikes need to be transmitted in one round

New kernel attributes that control or report spike buffer resizing:

spike_buffer_grow_extra
spike_buffer_shrink_limit
spike_buffer_shrink_spare
spike_buffer_resize_log

For details, see our docs on the new attributes.

Changes in NEST Server¶

We improved the security in NEST Server. Now to use NEST Server, users can modify the security options. See section on setting these varialbles in our NEST Server guide.