Response to the first 'review' of 'Functional specialization in the visual cortex?'


It is obvious that in the case of criticisms 1 and 3, the reviewer read only the titles, and ignored the body of these completely. For criticism 1, he simply reiterate the assumptions of Howard et al, with additional bizarre comment. For criticism 3, he simply discusses another potential criticism of Howard et al, which has nothing to do with my criticism.

In the case of criticism 2, the reviewer try to refute it with a broken logic and irrelevant examples, and then branch to an irrelevant discussion.

In short, the reviewer did not answer any of the criticisms I raised.

1) The authors ignore the higher level nature of the stimuli, i.e their conceptual emotional significance

[1] "It is unlikely that MT/MST would be much affected by emotional significance...."
The reviewer just reiterate the assumption of Howard et al. This assumption is not supported by any evidence or a logical argument.

[2] "and it is not clear what "conceptual" significance means ....."
This sentence is really bizarre. One of the stimuli of Howard et al is an uninterpretable pattern, one looks like distant lights in the dark, and one is a moving person. Apparently the reviewer does not see "conceptual" difference between a person and an uninterpretable pattern.

This sentence also shows that the reviewer did not read the body of the criticism. If the reviewer have read this, he would have found several examples of "conceptual" significance in the first sentence.

2) The authors assume that high differential activity is equivalent to functional significance.

[3] "On the one hand, this argument is not really valid."
The reviewer tries to refute my criticism by bringing few examples. That is broken logic. My argument is that high activity and functional significance are not equivalent, but that does not mean they are contradictory. Thus even if the argument is true, we would still expect to find few cases when activity and functional significance co-localize. Thus bringing few examples of co-localization does not refute the argument. In Howard et al, the underlying assumption is that high activity and functional significance are equivalent, and to prove that the reviewer has to show that these two co-localize consistently in almost all cases.

In addition, both of the examples that the reviewer brings are not relevant, as discussed next.

[4] "In the extreme case, switching from auditory to a visual stimulus will cause overall activation to switch from auditory cortex to visual cortex."
This example is not relevant. The first important point is the localization of audio and visual signals is at a resolution of much more coarse grain (several cm) than the resolution of the results of Howard et al. I explicitly state that the criticism is about the assumption of equivalence at the resolution that Howard et al present their data (second sentence of the second paragraph of criticism 2). The reviewer simply ignores this.

The second point is that this case is not only extreme, but also special, because the localization is a result of input entering the cortex in different locations. It is thus not possible to generalize from it to other cases.

[5] "For example, if cells in a region of the cortex respond only to color stimuli, ...."
This example is not relevant, from the same two reasons that the previous example is not relevant. The resolution of the color sensitive regions is again at the range of cm. Even though the reviewer regard color as just a "submodality", color is a very special "submodality". It is one of the two major variables that humans identify in the visual input ( the other is intensity), it is 'recognized' already at the level of the receptors, and part of the path from the eye to cortex seems to specialize in high color sensitivity.

[6] "The criticism in its most general form could be applied to all previous and future studies of brain imaging."
Agreed. Because the criticism can be applied to all studies, it is important to discuss it seriously, rather than dismiss it with an irrelevant discussion, which is what the reviewer is going to do next.

[7] "What the criticism really means is that a negative result using brain might not mean very much."
Wrong. The argument is equally relevant to the positive and negative case, and I explicitly suggested what could be the reasons for obtaining false positives. The reviewer does not give any reason why the argument is not applicable to the positive result case, and simply evade the point by branching into an irrelevant discussion of the negative result case.

[8] "Zeki, fortunately, has a positive result."
But the reviewer does not discuss this case at all.

The authors regard localization as specialization.

[9] "An area activated while subjects view biological motion, for example, might be equally activated when subjects view a motion stimulus that was not tested. this is similar to the negative result argument above."
This is another potential criticism of Howard et al, and has nothing to do with my criticism. Obviously, the reviewer has not read the body of the third criticism, as there is no relation between his comments and what I wrote.