Injections of tracers

The brain slices illustrate the injection sites of rat "89183" and rat "89161" with CTb retrograde tracer. Study these images and answer the questions below.

Rat 89183 injection site

Stained with CTb/ENK

Rat 89161 injection site

Stained with CTb

Questions

Question 1: What is the name of the brain area in which these injections took place?

Question 2: Which rat got a lateral injection and which rat got a medial injection?

Question 3: In rat 89183 and 89161 you can see a rather circular fibre bundle structure around the site of injection. What is the name of this structure?

Question 4: In rat 89161 you can see that something happened to the structure mentioned in question 3, compared to rat 89183. What happened here?

Question 5: Does the phenomenon mentioned in question 4 influence the areas stained in the brain?