1. The Inhibition of the
Startle Reflex
(ABI Summer Internship 2015)
Logan Meurer

2. Purpose of Research
Many clinical conditions affect how individuals
respond to being startled. Such as…
• PTSD
• Generalized Anxiety Disorder
• Acute Stress Reaction
• Jumping Frenchman (rare)

3. Aims of Research
Overall Goal: To better understand the brain circuitry
underlying the inhibition of the startle reflex
1. To determine if the PMT (pontomesencephalic
tegmental nucleus) projects directly to the caudal
pontine nucleus (PnC) and, if so, is the projection
cholinergic.

4. Aims of Research (cont.)
2. To determine if the inferior colliculus projects directly to
the PnC and, if so, are the pontine cells also contacted by
cholinergic PMT cells.
3. To determine if the superior colliculus cells that project to
the caudal pontine (this is a known projection) are
contacted by inferior colliculus cells that project to the
superior colliculus.

5. Proposed Circuitry

6. Steps and Procedures
1. Surgery
2. Perfusion
3. Slicing and Mounting
4. Microscopy

7. 1. Surgery

8. Section of Tissue
PPT
(PMT)
PnC
(Injection Site)
IC

9. 2. Perfusion

10. 3. Slicing and Mounting

11. 4. Microscopy

12. 4. Microscopy (cont.)

13. Proposed Circuitry

14. New Proposal

15. Unexpected Results