Question

As we progress from bipolar cells to ganglion cells to later cells in the visual system, are receptor fields ordinarily larger, smaller, or the same size? Explain the concept of a receptive field in the visual system and provide an example of this concept for a ganglion cell within the retina.

Answer 1

As we progress from bipolar cells to ganglion cells to later cells in the visual system, They become larger because each cell's receptive field is made by inputs converging at an earlier level.

The receptive field is the part of visual field that either excites or inhibits a cell in the visual system of brain.

for a receptor, the receptor field is the point in space from which light strikes it

for other visual cells, receptive fields are derived from the visual field of cells that either excite or inhibit.

an example of this are

ganglion cells that converge to form the receptive field of the next level of cells.

The receptive field of an individual sensory  neuron is the particular region of the sensory space (e.g., the body surface, or the visual field) in which a stimulus will modify the firing of that neuron. This region can be a hair in the cochlea or a piece of skin, retina, tongue or other part of an animal's body. Additionally, it can be the space surrounding an animal, such as an area of auditory  space that is fixed in a reference system based on the ears but that moves with the animal as it moves (the space inside the ears), or in a fixed location in space that is largely independent of the animal's location ( place cells ). Receptive fields have been identified for neurons of the auditory system, the somatosensory  system, and the visual  system.

The term receptive field was first used by Sherrington(1906)  to describe the area of skin from which a scratch reflex could be elicited in a dog. According to Alonso and Chen (2008).it was  Hartline(1938) who applied the term to single neurons, in this case from the retina of a frog.

The concept of receptive fields can be extended further up the nervous system; if many sensory receptors all form synapses with a single cell further up, they collectively form the receptive field of that cell.

For example, the receptive field of a ganglion cell in the retina of the eye is composed of input from all of the photoreceptors which synapse with it, and a group of ganglion cells in turn forms the receptive field for a cell in the brain. This process is called convergence.