Interconnectivity¶

class arbor.connection¶

Describes a connection between two cells, defined by source and destination end points (that is pre-synaptic and post-synaptic respectively), a connection weight and a delay time.

The dest does not include the gid of a cell, this is because a arbor.connection is bound to the destination cell which means that the gid is implicitly known.

connection(source, destination, weight, delay)¶: Construct a connection between the source and the dest with a weight and delay.

source¶: The source end point of the connection (type: arbor.cell_global_label, which can be initialized with a (gid, label) or a (gid, (label, policy)) tuple. If the policy is not indicated, the default arbor.selection_policy.univalent is used).

dest¶: The destination end point of the connection (type: arbor.cell_local_label representing the label of the destination on the cell, which can be initialized with just a label, in which case the default arbor.selection_policy.univalent is used, or a (label, policy) tuple). The gid of the cell is implicitly known.

weight¶: The weight delivered to the target synapse. The weight is dimensionless, and its interpretation is specific to the type of the synapse target. For example, the expsyn synapse interprets it as a conductance with units μS (micro-Siemens).

delay¶: The delay time of the connection [ms]. Must be positive.

An example of a connection reads as follows:

import arbor

def connections_on(gid):
   # construct a connection from the "detector" source label on cell 2
   # to the "syn" target label on cell gid with weight 0.01 and delay of 10 ms.
   src  = arbor.cell_global_label(2, "detector")
   dest = arbor.cell_local_label("syn") # gid of the destination is is determined by the argument to `connections_on`
   w    = 0.01
   d    = 10
   return [arbor.connection(src, dest, w, d)]

class arbor.gap_junction_connection¶

Describes a gap junction between two gap junction sites.

The local site does not include the gid of a cell, this is because a arbor.gap_junction_connection is bound to the destination cell which means that the gid is implicitly known.

Note

A bidirectional gap-junction between two cells c0 and c1 requires two gap_junction_connection objects to be constructed: one where c0 is the local site, and c1 is the peer site; and another where c1 is the local site, and c0 is the peer site. If ggap is equal in both connections, a symmetric gap-junction is formed, other wise the gap-junction is asymmetric.

peer¶: The gap junction site: the remote half of the gap junction connection (type: arbor.cell_global_label, which can be initialized with a (gid, label) or a (gid, label, policy) tuple. If the policy is not indicated, the default arbor.selection_policy.univalent is used).

local¶: The gap junction site: the local half of the gap junction connection (type: arbor.cell_local_label representing the label of the destination on the cell, which can be initialized with just a label, in which case the default arbor.selection_policy.univalent is used, or a (label, policy) tuple). The gid of the cell is implicitly known.

ggap¶: The gap junction conductance [μS].

class arbor.spike_detector¶

A spike detector, generates a spike when voltage crosses a threshold. Can be used as source endpoint for an arbor.connection.

threshold¶: Voltage threshold of spike detector [mV]