1. Xiao-Jie Cao, Shalini Shatadal, and Donata Oertel
Voltage-sensitive Conductances of Bushy Cells of the Mammalian Ventral Cochlear Nucleus
Conductance – ability of material to pass ions
Xiao-Jie Cao, Shalini Shatadal, and Donata Oertel

2. Anatomy: Characteristic of Bushy Cells
Class Notes
Paper

3. Physiology: Characteristic of bushy cells
In vivo
In vitro
Two groups?

4. Methods – Slice preparation
Exact location
Controlled environment
Drugs
Patch Clamp Simultaneous stimulation & recording
Caudal VCN

5. Goal
Using the slice preparation technique, can the authors provide further evidence that there are two groups of bushy cells?
In vitro patch clamp experiments
Current clamp
# APs
Voltage clamp
Voltage sensitivity of conductances

6. Results – Depolarizing Current Steps

7. Results – Hyperpolarizing Current Steps

8. Current clamp to Voltage clamp!

9. Results – Low voltage K+ conductance
Voltage Clamp
Current defined by blocker

10. Results – High voltage K+ conductance and mixed conductance
High-voltage activated K+ conductance
Blocked by 10 mM TEA
Hyperpolarization activated conductances
Blocked by 50 M ZD7288

11. Two separate groups?
Faster Depolarizations

12. Major Findings Low threshold K+ conductance Multi AP BCs
Conductance variance for ‘two groups’

13. Conclusions Possibility of two different BC groups
BCs encode fine timing
Low threshold K+ conductance
Presence may play a role in BCs ability to encode fine timing
Two groups may = two different timing functions

14. Considerations Did they accomplish the following goal:
[evidence that there are two groups of bushy cells]
Why two BC groups important?
Histological staining show three groups
Differ in size and projection patterns
Mouse vs. gerbil
Lack of low frequency hearing & MSO
In vitro vs. in vivo
Direct comparisons possible?
Slice preparation
Advantages and Disadvantages
Approx. range (Hz)
Species
rat
200-76,000 
mouse
1,000-91,000 
gerbil
100-60,000 

16. Bushy Cells! Encode fine timing Project to SOC
Two projections = two cell types?
MSO  receives projections from small BCs
LSO  receives projections from large BCs

17. Figure 2

18. Figure 7

19. Figure 8

20. Figure 9

21. Figure 10