braintools.input.ramp

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braintools.input.ramp#

braintools.input.ramp(c_start, c_end, duration, t_start=None, t_end=None)#

Generate a linearly ramped input current.

Creates a current that changes linearly from a starting value to an ending value over a specified time window. The ramp can be increasing or decreasing, and can be confined to a portion of the total duration.

Parameters:

  • c_start (Array | ndarray | bool | number | bool | int | float | complex | Quantity) – The starting current amplitude. Supports current units.

  • c_end (Array | ndarray | bool | number | bool | int | float | complex | Quantity) – The ending current amplitude. Must have same units as c_start.

  • duration (Array | ndarray | bool | number | bool | int | float | complex | Quantity) – The total duration of the signal.

  • t_start (Array | ndarray | bool | number | bool | int | float | complex | Quantity | None) – Time point when the ramp begins. Before this, current is 0. Default is 0.

  • t_end (Array | ndarray | bool | number | bool | int | float | complex | Quantity | None) – Time point when the ramp ends. After this, current remains at c_end. Default is duration.

Returns:

current – The ramped current array with shape (n_timesteps,).

Return type:

ndarray or Quantity

Raises:

UnitMismatchError – If c_start and c_end have different units.

Examples

>>> import brainunit as u
>>> import brainstate
>>> brainstate.environ.set(dt=0.1 * u.ms)

Simple linear ramp from 0 to 10 pA over 100 ms

>>> current = ramp(
...     c_start=0 * u.pA,
...     c_end=10 * u.pA,
...     duration=100 * u.ms
... )

Decreasing ramp (10 to 0 pA)

>>> current = ramp(
...     c_start=10 * u.pA,
...     c_end=0 * u.pA,
...     duration=100 * u.ms
... )

Ramp with delay and early stop

>>> current = ramp(
...     c_start=0 * u.nA,
...     c_end=5 * u.nA,
...     duration=200 * u.ms,
...     t_start=50 * u.ms,   # Start ramping at 50 ms
...     t_end=150 * u.ms      # Stop ramping at 150 ms
... )

Negative to positive ramp

>>> current = ramp(
...     c_start=-5 * u.pA,
...     c_end=5 * u.pA,
...     duration=100 * u.ms
... )

Slow ramp for adaptation studies

>>> current = ramp(
...     c_start=0 * u.pA,
...     c_end=20 * u.pA,
...     duration=1000 * u.ms,
...     t_start=100 * u.ms,
...     t_end=900 * u.ms
... )

Ramp for I-V curve measurements

>>> current = ramp(
...     c_start=-100 * u.pA,
...     c_end=100 * u.pA,
...     duration=500 * u.ms
... )

Sawtooth wave component

>>> current = ramp(
...     c_start=0 * u.pA,
...     c_end=10 * u.pA,
...     duration=10 * u.ms,
...     t_start=1 * u.ms,
...     t_end=9 * u.ms
... )

Notes

  • The ramp is perfectly linear between t_start and t_end

  • Before t_start, the current is 0 (not c_start)

  • After t_end, the current remains at the value it reached

  • Unit consistency is enforced between c_start and c_end

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