6 - Increasing input vs increasing output

Question 1

What does Attention increase within the tuning curve of a V4 neuron?

Answer 1

The amplitude and the asymptote. There was no change in width or preferred orientation.

Question 2

What does the slope of attended responses in a function of unattended responses represent?

Answer 2

This is the constant factor by which the unattended response needs to be multiplied with in order to get the attended response.

Question 3

Explain the statement: attention is a dimension of the stimulus.

Answer 3

Attention is comparable with feature-feature interaction. A neuron which prefers a higher spatial frequency over a lower spatial frequency gives the same multiplicative scaling in the neuron’s tuning curve as attention does.

Question 4

What does the response/output gain model predict?

Answer 4

It predicts that with attention, neural activity is higher in high firing rate (higher amplitude). As the neuron usually fires more with strong contrast the firing rate should be higher for the high contrast vs the low contrast targets.

Question 5

What does the contrast/input gain model predict?

Answer 5

The effects of attention on firing rates are greatest at low contrast and smallest at high contrast.

Question 6

What is the method of mcAdams?

Answer 6

single unit measurement in monkeys. trained in delayed match-to-sample task. had to attend to either gaussian (outside RF, unattended) or gabor (inside RF, attended). always presented simultaneously. attention effect could be due to spatial attention or feature directed attention. DID NOT CHANGE THE CONTRAST!

Question 7

What is the method of Reynolds?

Answer 7

two stimuli presented simultaneously, one within and one outside RF. Monkey attend and pull lever when detected target rotation. CHANGED THE CONTRAST!