1. In Visual and Auditory System Development
Critical Periods
In Visual and Auditory System Development
Nicholls et al, “From Neuron to Brain” Chapter 25
Purves, “Neuroscience” Chapter 24

2. Visual System - How do you measure perception?
Nicholls, From Neuron to Brain. Chapter 25

3. Perception  Developed Animal
Purves, Neuroscience Chapter 24

4. Visual Changes after Deprivation
Purves, Neuroscience Chapter 24

5. Vision in deprived eye Occular dominance columns
Right Eye
Left Eye
Left Eye
Right Eye
(Closed)
Occular dominance columns
How are these experiments done?
Nicholls, From Neuron to Brain. Chapter 25

6. Binocular Deprivation from Birth
Nicholls, From Neuron to Brain. Chapter 25

7. Orientation Preferences
Nicholls, From Neuron to Brain. Chapter 25

8. Orientation Preferences
Closed eye ’out competed’ by the open eye
Nicholls, From Neuron to Brain. Chapter 25

9. What is the Mechanism? How does this pruning occur? Neurotrophins
Neuronal Activity
TTX

10. Spontaneous Activity
How could you test whether RGCs have spontaneous activity in-utero, and what that activity is?
Maffei L, Galli-Resta L. PNAS 1990

11. Waves of activity
Electrode Array
-Mediated by starburst amacrine cells, and maybe electrical coupling
-It is still not know how this firing causes overlap to be removed in the LGN
Nicholls, From Neuron to Brain. Chapter 25

12. Auditory System
Nicholls, From Neuron to Brain. Chapter 25

13. Auditory System 0° (Normal) 20° (Deviated) Visual Input
(Retina and Forebrain) 0°
(Normal) 50
100
150
20°
(Deviated)

14. Auditory System Raised in Cages Raised in Aviary
J Neurosci May 15;18(10):

15. Song Development in Birds10 20 30 40 50 60 70 80 90
100
110
120
Sensory Acquisition
Sensory motor learning
Crystallized song
 Days 
Birds can reproduce songs and refine them.
Listening to songs
of ‘tutors’ 10-20x
Current Opinion in Neurobiology 9, 1 , Feb 1999 ( )

16. Language Critical Period
Since we are all from an ‘enriched environment’ we have no excuse. Our critical period is extended just like the owls.
Purves, Neuroscience Chapter 24

17. Feral Children