The receptive field size of neurons in primary visual cortex depends
strongly on the stimulus contrast
. The size can be more than two times larger when measured with low contrast stimuli than when measured with high contrast stimuli.
Why do we get larger and more specific receptive fields in the visual cortex?
Receptive fields of cells in the visual cortex are larger and have
more-complex stimulus requirements than retinal ganglion cells
or lateral geniculate nucleus cells. … Images for these receptive fields need to have a particular orientation in order to excite the cell.
What does it mean that a neuron has a large receptive field?
In the somatosensory system, receptive fields are regions of the skin or of internal organs. … Some types of mechanoreceptors have large receptive fields, while others have smaller ones. Large receptive fields
allow the cell to detect changes over a wider area, but lead to a less-precise perception
.
What is receptive field size?
“…the receptive field size for the layer. This is
the size (in pixels) of the local image region that affects a particular element in a feature map
.” which makes sense with the traditional definition of a receptive field. Its usually thought as the number of pixels that affect a particular node in the feature map.
Which neurons generally have the smallest receptive fields?
Nevertheless,
photoreceptors
typically have the smallest receptive fields of any of the retinal neurons (Figure 7).
How do you calculate receptive fields?
The classic method to determine the location and extent of the receptive field is
to present discrete stimuli at different locations in the sensory periphery
, such as on the retina or the skin.
How do we measure a receptive field?
Functional magnetic resonance imaging (fMRI)
was used to estimate the average receptive field sizes of neurons in each of several striate and extrastriate visual areas of the human cerebral cortex.
What is a receptive field skin?
The receptive field of a somatic sensory neuron is
the region of the skin within which a tactile stimulus evokes a sensory response in the cell or its axon
(Boxes A and B). … The importance of receptive field size is easy to envision.
Where are the receptive fields for V1 neurons?
In many neurons this arrangement is accompanied by selectivity for binocular depth, or disparity (Cumming and DeAngelis, 2001). Each V1 neuron has two receptive fields,
one per each eye
.
Which of the following is involved in pain pathways in the spinal cord?
Pain Pathways In the Central Nervous System.
Primary afferent nociceptors
transmit impulses into the spinal cord (or if they arise from the head, into the medulla oblongata of the brain stem).
What affects receptive field size?
The receptive field size of a unit can be increased in a number of ways. One option is to
stack more layers to make the network deeper
, which increases the receptive field size linearly by theory, as each extra layer increases the receptive field size by the kernel size.
What are visual receptive fields?
Definition. The term receptive field refers to
the region of visual space where changes in luminance influence the activity of a single neuron
. Also known as the classical receptive field (CRF).
What is effective receptive field?
As a natural consequence, one can define the relative importance of each input pixel as the effective receptive field (ERF) of the feature. In other words, ERF defines the effective receptive field of
a central output unit as the region that contains any input pixel with a non-negligible impact on that unit
.
Do photoreceptors have receptive fields?
The deepest layer of neurons processes the light first. These neurons are the photoreceptors, the only cells in the retina that can convert light into nerve impulses. … This area in space where
the presence of an appropriate stimulus
will modify the activity of this neuron is called the receptive field of this neuron.
What is the relationship between the two point threshold and the receptive field?
The model predicts that the two-point threshold
is higher in the long axis of receptive fields
. In the human it is higher in the long axis of the arm, which might mean that the receptive fields are elongated in this axis too.
What is the receptive field of a ganglion cell?
The classical receptive field of a ganglion cell is defined as
the area of the retina where stimulation with a small spot of light produces a change in ganglion cell firing rate
.
