The Hindmarsh-Rose model is a three-dimensional dynamical system for neuronal spiking and bursting (Hindmarsh and Rose 1984). In a parameterized form, its ordinary differential equations are
|
(1)
| |||
|
(2)
| |||
|
(3)
|
where
represents membrane voltage,
is a recovery variable,
is a slow adaptation variable, primes denote derivatives
with respect to time
, and
is the applied current. The parameter
sets the time scale of the adaptation. For small
, the fast subsystem is obtained by holding
fixed in the first two equations.
At an equilibrium point, and
. Substitution leaves the
cubic equation
|
(4)
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For ,
,
,
,
,
, and
, numerical
solution from the initial state
gives regular bursts after a transient.
A burst is a group of rapid spikes separated from the next group by a much longer
quiet interval. Linaro et al. (2012) used bifurcations
of the fast subsystem and of the full model to analyze how changing parameters can
add a spike to each burst.