Receptive field

Question 1

Receptive Field (RF) of an individual sensory neuron

Answer 1

= region of the sensory space in which a stimulus will modify the firing of that neuron, that can be either a hair on the cochlea, a piece of skin, retina, or other part

Question 2

Auditory system

Answer 2

RF modeled as spectro-temporal patterns that cause the firing rate of the neuron to modulate with the auditory stimulus

Question 3

Spectro-temporal RFs can be understood as

Answer 3

transfer function that maps an acoustic stimulus input to a firing rate response output

Question 4

Somatosensory System

Answer 4

receptive fields are regions of the skin or of internal organs.

Some types of mechanoreceptors have large receptive fields, while others have smaller ones

Question 5

Tactile-sense-related cortical neurons

Answer 5

large RFs and can discriminate details due to patterns of excitation and inhibition which leads to spatial resolution

Question 6

Visual system Receptive Field

Answer 6

receptive field = Center + surround

RF = region of the retina, where the action of light alters the firing of the neuron

Question 7

Hubel and Wiesel

Answer 7

RF of a cell at one level of the visual system are formed from input by cells at a lower level

Small RFs can be combined to form a larger one

Question 8

Retina ganglion cells

Answer 8

RF increases with intensifying light (in the largest field, light must be more intense at the periphery)

Question 9

Stimulating a center of an on-center cell’s RF produces ..

Answer 9

..depolarization (= increased firing) of the cell

Question 10

stimulation of the periphery produces..

Answer 10

..hyperpolarization (decreased firing)

Question 11

If th center of a off-center cell gets stimulated it leads to

Answer 11

inhibiton

Question 12

Lateral geniculate nucleus (LGN)

Answer 12

RF similar as in the ganglion cells with an antagonistic center surround system

Question 13

Visual Cortex

Answer 13

larger RFs and more complex stimulus requirements

Question 14

Hubel und Wiese classificate visual cortex into:

Answer 14

1. simple cells: elongated
   e.g., with an excitatory central oval and an inhibitory surrounding;
   images need to have a particular orientation to excite cell
2. complex cells: a correctly oriented bar of light need to move into a particular direction to excite the cell
3. hypercomplex cells: bar might also need to be of a particular length

Question 15

Extrastriate visual areas

Answer 15

cells can have large RFs requiring complex images to excited cell, e.g., faces in the FFA

Question 16

RFs are also used as a term in artificial neural networks

• Convolutional neural networks

Answer 16

designed to mimic the way in which animal brains are understood to function; it’s a 3-dimensional structure, primarily used in computer vision

o Each input neuron represents one pixel from the original image
o First layer = input layer
o Next layer receives input from some of the input neurons, but not all: receptive field like layout in which each neuron receives connections only from a subset of neurons in the previous layer

o Advantage: recognizing visual patterns

Question 17

Large receptive fields of somatosensory system allow the cell to..

Answer 17

detect changes over a wider area, but lead to a less precise perception

Question 18

Receptors with large receptive fields usually have a “hot spot”
Where is it and what does it do?

Answer 18

an area within the receptive field (usually in the center, directly over the receptor) where stimulation produces the most intense response.