Functional Retina

Which retinal cells are horizontal

Horizontal, amacrine

Which retinal cells are vertical

Rods, cones, bipolar cells, ganglion cells

Spontaneous activity

Cells spontaneously generate action potentials in the absence of a spot of light

Whether a stimulus in the receptive field will either increase or decrease the firing rate of the neuron depends on _______


A small light located within the center of a receptive field causes an ____ in the frequency of action potentials


A small light positioned in the surround of a receptive field causes a _____ in the frequency of action potentials


If a larger spot of light fills the entire center of a receptive field, action potentials will fire at a _____ rate


A ganglion cell response to a stimulus that fills the entire receptive field about the same as if ____

There were no stimulus

Spatially antagonistic ganglion cells do not respond well to ____ illumination


_____ are a strong stimulus for ganglion cells

Sine-wave gratings

As the diameter of the spot ______, the cell's firing rate increases until the entire receptive filed center is covered with light and the response is at its maximum


Firing will decreases as the diameter of the light exceeds that of the center of a receptive field because it falls on the inhibitory surround, which is _____ to the excitatory center


When is the frequency of action potentials zero?


What types of cells generate action potentials

Amacrine, ganglion

Cells which do not generate action potentials generate _____

Graded potentials

A spot and annulus elicit responses of ______ from the bipolar and ganglion cells because the spot falls on the receptive field center whereas the annulus falls on its antagonistic surround

Opposite signs

Photoreceptors respond to light with a ______ response

Slow hyperpolarizing

Rods detect dim light and respond to relatively _____ changes


Cones detect bright light and respond to ______ light fluctuations


______ are the first synaptic level in the retina

Horizontal cells

______ receive input from many cones

Horizontal cells

Horizontal cells have a _____ receptor field and therefore respond to light over a large area


Horizontal cells modulate the photoreceptor signal under _______, which allows the signaling to become less sensitive in bright light and more sensitive in dim light

Different lighting conditions

______ shape the receptive field of bipolar cells

Horizontal cells

H1 horizontal cells receive excitatory input from which type of cones

L and M cones

H2 horizontal cells receive excitatory input rom which type of cones

L, M, S cones

Which type of cone provides a particularly strong input to H2 horizontal cells

S cones

Bipolar cells receive input from a handful of cones and therefore have a ______ receptor filed

Medium size

______ add an opponent signal which gives bipolar cells its center and surround organization

Horizontal cells

Two types of amacrine cells

Small field, wide field

Small field cells spread vertically across _____ in the IPL

Several strata

Small field cells collect signal from about _____ rod-connected bipolar cells as bipolar cells


Small field amacrine cells link ______ and _____

Rod-connected bipolar cells, ganglion cells

Wide field cells stretch horizontal across the IPL but typically confine to _____

One strata

What type of cells sharpen the boundary between center and surround even further than H cells do

Amacrine cells

How many bipolar and ganglion cells do wide field cells interact with


OFF center ganglion cells are _____ when a spot of light falls in the periphery of their receptive field


Ganglion cells in the fovea are connected to _____ in a one-to-one ratio

Bipolar cells

How is a point-to-point image relayed from fovea to brain

Info travels from single cone to single ganglion cell to single bipolar cell

The message that goes to the brain delivered from ganglion cells carry both _____ and ____ information of the finest resolution

Spatial, spectral

What would happen if there were no retinal layers and information went from photoreceptors directly to the brain?

Coarse-grained, blurry image