Design two fMRI experiments to test whether the brain contains regions that are selectively involved in perceiving snakes. In each case, state i) the specific hypothesis you are testing, ii) the experimental conditions you will test (including what study participants will see and do in your experiment), iii) what exactly you will measure, and iv) what your hypothesis predicts you will see. You can describe stimuli with words, sketch them, or find them and paste them in (with appropriate explanations). Next, list the alternative accounts that might remain even if the data from this experiment are consistent with the predictions of your hypothesis. Then, describe a second experiment to test one or more of those alternative hypotheses. Finally, list two important questions about snake-specific regions in the brain that can never be tested with fMRI, and give a different method that could be used to test each.

Experiment 1:

Measure activations when viewing snakes. Show pictures of snakes. There should be diversity in the environment of the snakes. Different natural environments, zoos, cages, empty background. We also want different types of snakes. There can also be different types of images: such as black and white, drawings, etc.

Here we are testing if there are brain regions that respond specifically to snakes.

Experiment 2:

We want to test specificity. We will show things that are similar to snakes such as environments where snakes usually live, and other animals. We can even show lizards which are the closest things to snakes. Worms are also an interesting option. Of the regions identified in experiment 1, this experiment can narrow down to regions that only respond to snakes if it exists.

One gap of these fMRI experiments is causality. We don’t know if activations in the brain region are caused perception of snakes or cause it. This can be tested by stimulating the region while the subject sees various visual stimuli not containing snakes. We can ask the subject whether they are perceiving snakes when they are not there.

It is likely that a region selectively involved in perceiving snakes is too small for fMRI to pick up. More invasive techniques are required in these cases, such as single neuron recordings.