Experimental setup for biased competition and attentional modulation of surround suppression.
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Experimental setup for biased competition and attentional modulation of surround suppression.
- Author
- Frederik Beuth
Data: This is a model prediction, so no data is available
Setup:
- Combine the biased competition setup, containing a preferred and an anti-preferred stimulus inside the classical receptive field (cRF), with an anti-preferred stimulus in the surround
- Three stimuli: preferred inside cRF, anti-preferred inside cRF, anti-preferred in the surround. A real setup should contain an additional stimulus for attend-away, which we do not simulate
- Use spatial attention as it is more common in biased competition. However, feature-based attention would be complicated as two stimuli are similar
- Attention has the same size as the stimulus
- Stimuli inside cRF are chosen small to place two of them within the cRF, and to ensure that both stimuli fall only in a single V4 receptive field.
- Surround stimulus is large to increase its influence.
- Contrast of all stimuli is maximal (1.0)
Significant results (p. 957, left column):
- Attend away: Surround suppression decreases the response of neurons in the classical receptive field (cRF) with similar features, thus the neurons encoding the anti-preferred stimulus. This leads to a decreased feature-based suppression to neurons encoding the preferred stimulus, increasing the response of them. Thus it favors the competition between the stimuli inside the cRF for the other stimulus.
- Attend preferred stimulus inside the cRF: Similar effect as in classical biased competition. The response of preferred encoding neurons is amplified, which cancels out the feature-based suppression from the anti-preferred encoding neurons.
- Attend anti-preferred stimulus inside the cRF: Similar effect as in classical biased competition. The response of the anti-preferred encoding neurons is amplified, which diminishes feature-based as well as surround suppression at these neurons. Thus, anti-preferred encoding neurons are strongly active, suppressing the preferred encoding neurons.
- Attend anti-preferred stimulus in the surround: The neurons in the surround are amplified, increasing suppression to the anti-preferred encoding neurons. This diminished response eliminates the feature-based suppression to the preferred encoding neurons almost completely. So, the response of these neurons for this configuration is almost identical to the response of the preferred stimulus being presented alone.
Calibration of the fit:
- 1) Use standard values for all parameters
- 2) Increase size of surround stimulus to show a significant surround suppression effect