1. Behavioral components of prey capture in the frog1 2 3 4
2,3
none of the behavioral components are a necessary prerequisite for the others to occur: they are independent “FAPs”
If these are FAPs in the true sense the lets find what controls its:
Step 1 Find cell/s that recognize prey

2. Laboratory analysis of innate orientation behavior of toad to varying stimuli
Toad in glass jar above turntable
Turntable used to pass targets in front of toad
Results:
Toad optimally responds to “worm-like” stimuli
Worm must move along long axis but can move in any direction
Orientation responses to worm are consistent FAPs “they are invariant.”

3. Sensory transduction: the eye

4. Sensory transduction: the retina
Rods and cones
(toads rods only)
Bipolar cells
Amacrine cells
Horizontal cells
Ganglion cell
Optic nerve (blind spot)

5. Sensory transduction: the retina

6. Synaptic interactions of bipolar, horizontal and amacrine cells produce center surround fields in ganglion cells
Results from intracellular recordings

7. Vertebrate ganglion cells in general can be classified into two types
On-center/off-surround
Off-center/on-surround
Additionally, some are sensitive to movement in their field

8. The retina is a matrix of overlapping center/surround fields of ganglion cells

9. The search for the cell/s that recognize prey features
Neurophysiological method:
Animal placed on stage
Electrodes placed in specific neuropil
Stimulated visually while recording from cells
Results 1:
Retinal ganglion cells can be typed based on response type based on size of receptive field:
R2 4 degrees
R3 8 degrees
R4 16 degrees
-no ganglion cell matched behavior

10. Visual pathway in the toad
Optic nerve crosses at the optic chiasm and projects contralaterally to:
Optic tectum
Pre-tectum of the thalamus
Retinotopic organization is maintained in both these regions

11. Example of Retinotopy from the Macaque visual system
A flickering stimulus
Retinotopic representation in layer 4C of V1
Tootell et al (1988a).

12. Retinotopic organization is maintained in both these regions
Cross sectional reference
Thalamus

13. The search for the cell that recognizes prey
Results 2: Thalamic pretectal TH3 cell responses to test stimuli
Small receptive fields
Responsive to moving stimuli
Collectively (as a population) map visual field
Do not correlate to behavior- are not prey detectors

14. The search for the cell that recognizes prey
The T5 cell integration of worm features:
Size
Shape
Movement
2 types defined by different response profiles
T5(2) cells in particular produced invariant responses across changes in a number of parameters:
Contrast
Velocity
Distance
So long as the worm-like stimulus moved along its long-axis

15. The T5(2) response: Putting it all together

16. Antatomical and physiological organization of TH3, T5(1) and T5(2) cells+ -
Output
Output options:
T5(1) HIGH/ TH3 LOW = T5 (2) HIGH
T5(1) HIGH/TH3 HIGH = T5(2) CANCELED
T5(1) LOW/TH3 LOW = T5(2) NO INPUT/CANCELED
T5(1) LOW/TH3 HIGH = T5(2) INHIBITED

17. So what do you predict would happen behaviorally and in terms of T5(2) cells if you cut the output from TH3 to T5(2)?
T5(1)
TH3
T5(2) + -
Output
TH3 lesion
Pre leison