Characterization: lack of background activity.
When perturbed with electrical stimulus the system quickly returns to rest without osciallation. This seems to indicate that the "open loop" state can be identified with a strong point attractor (very negative Liapunov constant). resting chaos -- waking rest
Characterization: low-amplitude chaotic activity.
When perturbed with electrical stimulus the system falls into exponentially decaying oscillations appearing as a spiral inside the well of its potential (phase) portrait.
Characterization: Extremely high amplitude spike activity.
Under several seconds of intense electrical stimulation an epileptic seizure is released. It is intiated after the failure of excitatory input transmission as shown by the decreasing responses at left to the last 5 pulses of the stimulus train. The seizure spike train then progressively emerges from a relatively quiet post-stimulus state. [1] The "oscillatory burst" has been saved for last as it embodies the most interesting character -- complexity.
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oscillatory burst -- inhalation Characterization: limit cycle attractor. The limit cycles formed by the oscillatory burst can be classified by their spatial parttern of amplitude modulation. These patterns have been found to correspond to specific stimulus odors. Thus, the scent of a mango and the scent of a banana will form recognizably different attractors. These attractors are latent during exhalation, but crystallize as a mosaic of basins during inhalation. |
Below, the basins of attraction are realized as wells seated in the
large, central peak of the
potential (phase) portrait
and associated section of
bifurcation diagram.
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| The exhalation process acts as a sort of reset button, causing all attractors throughout the olfactory bulb to vanish. |
