Lecture 8 - Neural Convergence Flashcards
Rods and cones send signals
vertically through:
– bipolar cells
– ganglion cells
Signals are sent horizontally:
– between receptors by horizontal cells
– between bipolar and ganglion cells
by amacrine cells.
trade-off between rods and cones
rod system is intrinsically sensitive to light and because they converge more they active retinal ganglion cells more but they lose something in visual acuity
cone advantage
one to one wiring, then you’re able to discriminate finer detail
high visual acuity
cones need more ____ to respond than rods
more intense light
Rods have greater convergence which results in
summation of the inputs
of many rods onto ganglion
cells, increasing the
likelihood of response.
rods are more sensitive to light than cones
that means that cones need more light to react
convergence can be either
excitatory or inhibitory
lateral inhibition
not horizontal excitatory
more IPSPs than EPSPs
How do we know if this is
(approximately) how it works?
Experiments with eye of Horseshoe crab
Lateral eye is made up of tiny
structures called ommatidia, each
with its own lens and receptor.
– We can record from each ommatidia receptor separately.
– Light shown into a single receptor leads to rapid firing rate of receptor.
– Adding light into neighboring
receptors leads to reduced firing rate of initial nerve fiber.
means it’s very likely that lateral inhibition is coming from the neighbor
• receptor when activated will send inhibition to neighbor that has something to do with
the signal intensity
the stronger the intensity the stronger the ….
….inhibition sent
