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1 | 1 | # Synapses |
2 | 2 |
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3 | | -The synapse is a key building block for connecting/wiring together the various |
4 | | -component cells that one would use for characterizing a biomimetic neural system. |
5 | | -These particular objects are meant to perform, per simulated time step, a |
6 | | -specific type of transformation -- such as a linear transform or a |
7 | | -convolution -- utilizing their underlying synaptic parameters. |
8 | | -Most times, a synaptic cable will be represented by a set of matrices (or filters) |
9 | | -that are used to conduct a projection of an input signal (a value presented to a |
10 | | -pre-synaptic/input compartment) resulting in an output signal (a value that |
11 | | -appears within one of its post-synaptic compartments). Notably, a synapse component is |
12 | | -typically associated with a local plasticity rule, e.g., a Hebbian-type |
13 | | -update, that either is triggered online, i.e., at some or all simulation time |
14 | | -steps, or by integrating a differential equation, e.g., via eligibility traces. |
| 3 | +The synapse is a key building block for connecting/wiring together the various component cells that one would use for characterizing a biomimetic neural system. These particular objects are meant to perform, per simulated time step, a specific type of transformation -- such as a linear transform or a convolution -- utilizing their underlying synaptic parameters. Most times, a synaptic cable will be represented by a set of matrices (or filters) that are used to conduct a projection of an input signal (a value presented to a pre-synaptic/input compartment) resulting in an output signal (a value that appears within one of its post-synaptic compartments). There are three general groupings of synaptic components in ngc-learn: 1) non-plastic static synapses (only perform fixed transformations of input signals); 2) non-plastic dynamic synapses (perform time-varying, input-dependent transformations on input signals); and 3) plastic synapses that carry out long-term evolution. |
| 4 | +Notably, plastic synapse components are typically associated with a local plasticity rule, e.g., a Hebbian-type update, that either is triggered online, i.e., at some or all simulation time steps, or by integrating a differential equation, e.g., via eligibility traces. |
15 | 5 |
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16 | 6 | ## Non-Plastic Synapse Types |
17 | 7 |
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@@ -74,6 +64,20 @@ This (chemical) synapse performs a linear transform of its input signals. Note t |
74 | 64 | :noindex: |
75 | 65 | ``` |
76 | 66 |
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| 67 | +### Double-Exponential Synapse |
| 68 | + |
| 69 | +This (chemical) synapse performs a linear transform of its input signals. Note that this synapse is "dynamic" in the sense that its efficacies are a function of their pre-synaptic inputs; there is no inherent form of long-term plasticity in this base implementation. Synaptic strength values can be viewed as being filtered/smoothened through a doubleexpoential / difference of two exponentials kernel. |
| 70 | + |
| 71 | +```{eval-rst} |
| 72 | +.. autoclass:: ngclearn.components.DoubleExpSynapse |
| 73 | + :noindex: |
| 74 | +
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| 75 | + .. automethod:: advance_state |
| 76 | + :noindex: |
| 77 | + .. automethod:: reset |
| 78 | + :noindex: |
| 79 | +``` |
| 80 | + |
77 | 81 | ### Alpha Synapse |
78 | 82 |
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79 | 83 | This (chemical) synapse performs a linear transform of its input signals. Note that this synapse is "dynamic" in the sense that its efficacies are a function of their pre-synaptic inputs; there is no inherent form of long-term plasticity in this base implementation. Synaptic strength values can be viewed as being filtered/smoothened through a kernel that models more realistic rise and fall times of synaptic conductance.. |
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