The key difference between X and Y ganglion cell receptive fields is that X ganglion cell receptive fields show a simple centre-surround organization whereas Y ganglion cell receptive fields show a more complex organization with three concentric regions.
The retina is a thin layer of tissues located at the back of the eyeball. It converts light into neural signals. In order to do that, there are three layers of neurons in the retina. Ganglion cells are the neurons present in the third layer of neuron tissue. Ganglion cells receive inputs from bipolar cells or amacrine cells and send information to the brain visual centres. There are three classes of retinal ganglion cells: W-ganglion, X-ganglion and Y-ganglion cells. Each ganglion cell has a receptive field. They are fixed in space and immobile. Receptive fields are graded according to the sensitivity. Receptive fields are larger but do not extend beyond 1 mm in diameter.
CONTENTS
1. Overview and Key Difference
2. What are X Ganglion Cell Receptive Fields
3. What are Y Ganglion Cell Receptive Fields
4. Similarities Between X and Y Ganglion Cell Receptive Fields
5. Side by Side Comparison – X vs Y Ganglion Cell Receptive Fields in Tabular Form
6. Summary
What are X Ganglion Cell Receptive Fields?
X Ganglion cells are a class of retinal ganglion cells. These cells are numerous in the retina, and they are called brisk sustained cells. They have rather narrow receptive fields. Morphologically, the cells are beta cells. X ganglion cell receptive fields show a simple centre-surround organization. Moreover, X ganglion cells show a linear response, unlike Y ganglion cells.
Figure 01: Ganglion Cell Receptive Fields
What are Y Ganglion Cell Receptive Fields?
Y Ganglion cells are another class of retinal ganglion cells. In comparison to X ganglion cells, Y ganglion cells are distinguished due to their larger axon diameters and quicker conduction times. Y ganglion cells are also called ‘brisk transient’ cells. Moreover, They are morphologically alpha cells. Y ganglion cells are rather sparsely distributed and have wide receptive fields. Furthermore, Y ganglion cell receptive fields show a more complex organization with three concentric regions: a central region of centre-type response, a region of mixed centre-type and surround-type responses, and a region of surround-type response. Y ganglion cells show non-linearity in the response.
What are the Similarities Between X and Y Ganglion Cell Receptive Fields?
- X and Y ganglion cell receptive fields are portions of sensory spaces that can elicit neuronal responses when stimulated.
- They are found in the retina.
- They are composed of input from all of the photoreceptors (from many rods and cones).
- Moreover, they are arranged into a central disk.
- This ganglion cell receptive filed would enclose all the synapsing network of photoreceptors, bipolar, horizontal and amacrine cells that converge to them.
What is the Difference Between X and Y Ganglion Cell Receptive Fields?
The key difference between X and Y ganglion cell receptive fields is that X ganglion cell receptive fields show a simple centre-surround organization while Y ganglion cell receptive fields show a more complex organization with three concentric regions. Moreover, X ganglion cell receptive fields are narrower and Y ganglion cell receptive fields are wide.
The below infographic tabulates side by side the differences between X and Y ganglion cell receptive fields.
Summary – X vs Y Ganglion Cell Receptive Fields
X Ganglion cell receptive fields are rather narrow receptive fields which show a simple centre-surround organization. In contrast, Y Ganglion cell receptive fields are wider and show a more complex organization with three concentric regions. Thus, this is the key difference between X and Y ganglion cell receptive fields. Moreover, X ganglion cells show linearity in the response, while Y ganglion cells show non-linearity in the response.
Reference:
1. “Ganglion Cell Physiology by Ralph Nelson.” Webvision, Available here.
2. “Receptive Field.” Wikipedia, Wikimedia Foundation, 23 Nov. 2020, Available here.
Image Courtesy:
1. “Receptive field” By original uploaded to en by user:delldot, modified by Xoneca – Own work (Public Domain) via Commons Wikimedia