Lecture 21 - Vision 3 - Ganglion Cells & Parallel Paths FIB

At the first synapse in the retina, neurons in the visual system become detectors of __________.

contrast.

Bipolar cells respond to luminance contrast through changes in their __________.

membrane potentials.

Ganglion cells respond to luminance contrast through changes in their __________.

spike rates.

A difference in the number of photons that fall upon center versus surround is called __________ contrast.

luminance.

The receptive field center of an ON-center ganglion cell will generate a burst of __________ when bright light is introduced.

action potentials.

Removal of bright light stimulus in the surround of an ON cell elicits a strong __________ response.

OFF.

Rods are exquisitely sensitive to light whereas __________ require more photons.

cones.

The outer segment of rods has __________ outer segments packed with photopigment-filled discs.

long.

The outer segments of cones have fewer discs and change in width; they start __________ and grow narrower as they go from the inner segment.

wide.

The stability of the covalent bond between opsin and __________ is much higher in rods than in cones.

11-cis-retinal.

A dark-adapted rod responds to a single photon with a hyperpolarization of __________ mV.

To signal the capture of a single photon, a dark-adapted __________ requires at least 50 photons.

cone.

A single dark-adapted cone requires at least __________ photons to produce a 1 mV change in its membrane potential.

Rods express a single GRK called __________, which is slow acting.

GRK-1.

Cones express both GRK-1 and __________, which works quickly and produces rapid responses.

GRK-7.

Humans can respond to light levels as low as __________ candela/meter².

10⁻⁶.

Under scotopic conditions, rods are at their __________ sensitivity.

maximal.

Cones are minimally responsive at light levels lower than __________ candela/m².

Both rods and cones undergo __________ adaptation.

light.

Light adaptation allows a photoreceptor to retain responsiveness to __________ stimuli while adapting to weaker ones.

stronger.

Rods can signal a difference in light response even when two stimuli differ by as little as __________ photons.

The human retina is described as having a __________ retina due to the density disparities between rods and cones.

duplex.

The area around the fovea is dense with __________, whereas the fovea contains a much higher density of cones.

rods.

Luminance contrast is primarily detected by __________ ganglion cells.

midget.

The opsin expressed by a rod is called __________.

rhodopsin.

Rod and cone opsins capture photons over unique ranges of __________.

wavelengths.

A convergence of inputs from several rods allows __________ bipolar cells to have large receptive fields.

rod.

S cones are designed to capture shorter wavelengths, whereas __________ cones capture longer wavelengths.

L and M.

Rods absorb light best at wavelengths around __________ nanometers.

Human vision primarily detects visible light in the wavelength range from __________ to 700 nanometers.

The three types of cones in Old World primates include S, M, and __________ cones.

L.

S cones are also referred to as __________ cones.

blue.

The peak probability for the absorption of S cones occurs at around __________ nm.

The __________ law of color vision states that any single cone responds the same way to a photon regardless of wavelength.

law of univariance.

Color confusion often arises in individuals with anomalous __________.

trichromacy.

In the outer segment of cones, the __________ is altered in structure to allow for different photopigment configurations.

opsin.

The most significant structural differences between M and L cone opsins is defined by __________ amino acids.

five.

Under bright light conditions, the __________ receptive fields of midget ganglion cells are ideal for fine spatial acuity.

small.

An increase in luminance generally results in a corresponding increase in the number of __________ captured by cones.

photons.

The cone types S, M, and L provide the foundation for color __________ in the human visual system.

vision.

The __________ hypothesis posits that the perception of color is determined by the relative activation of the three types of cones.

trichromatic.

Luminance is interpreted in the brain as the __________ of an image.

brightness.

The __________ of ganglion cells allows them to respond to both chromatic and luminance contrast.

circuitry.

The synaptic structure of __________ ganglion cells enables them to form both ON and OFF pathways.

AII amacrine.

The two signaling pathways from the photoreceptors to the ganglion cells are characterized by their __________ and inhibitory nature.

excitatory.

In the fovea, midget ganglion cells collect information from only __________ bipolar cells.

one.

Along the peripheral retina, the size and number of inputs for midget ganglion cells __________ as distance from the fovea increases.

increase.

The __________ is the smallest unit of spatial acuity provided by retinal ganglion cell receptive fields.

dendritic field.

The distal dendrites of parasol ganglion cells receive input from __________ bipolar cells.

diffuse.

The combination of inputs from L and M cones in parasol ganglion cells results in a __________ contrast.

luminance.

Rods transmit their signal to ganglion cells via specialized __________ cells that aggregate the responses of several rods.

bipolar.

Amacrine cells signal to both __________ bipolar cells when conditions change within their receptive fields.

ON and OFF.

The AII amacrine cells are considered __________ cells because they transform excitatory signals into inhibitory outputs.

sign-reversing.

Rods primarily serve vision under __________ light conditions that require high sensitivity.

dim.

Parasol ganglion cells collectively integrate responses from __________ and M cones.

L.

The center-surround organization of midget ganglion cells enhances their ability to detect __________.

contrast.

The structure of __________ determines the range of wavelengths absorbed by a cone.

opsin.

Rods generate action potentials primarily in response to very __________ stimuli.

dim.

The relative absorption of light across the cone types reflects __________ of the visual system.

color differentiation.

The average human fovea contains approximately __________ cones per square millimeter.

150,000.

The visual input from rods and cones integrates at the level of __________ before reaching the brain.

ganglion cells.

Distinct opsins allow cones to respond to different ranges of __________ and thus different colors.

wavelengths.

The midget ganglion cell's receptive field signals can be classified as either __________ or chromatic.

luminance.

AII amacrine cells exhibit __________ properties that help in processing visual signals from rods.

sign-preserving.

In the human retina, their combined effects on visual signals allow for adaptation to varying levels of __________.

illumination.

The strategic arrangement of receptors is key to understanding human color __________.

vision.

Phototransduction pathways ensure accurate signaling from __________ to the optic nerve.

photoreceptors.

High levels of light exposure reduce the response rates of __________ cells in the retina.

bipolar.

The outer segment structure of rods allows them to aggregate more __________ than cones.

photopigments.

Rod bipolar cells have large receptive fields that span areas covered by at least __________ rods.

thirty.

The neurons that connect rod bipolar cells to ganglion cells are classified as __________ cells.

amacrine.

Genetic mutations affecting opsin genes result in different forms of __________ in humans.

color blindness.

Mismatch between the absorption spectrum of cone types can lead to __________ issues in color vision.

confusion.

Rod pathways process visual input mainly through __________ cells that adapt to changes in light conditions.

bipolar.

Increased spikes in AII amacrine cells correlate with __________ brightness in their receptive fields.

high.

Color vision disorders related to X chromosome mutations predominantly affect __________.

males.

The continuous synaptic interactions of cells in the retina are crucial for establishing __________ cues.

contrast.

Color differentiation relies heavily on the input from at least __________ cone types in the retina.

two.

The unique configuration of the human retina enables vision across a range of light levels from __________ to bright sunlight.

dim.

The interplay of multiple ganglion cell signals can significantly affect an individual's color __________.

perception.

Efficient signal transduction from photoreceptors ultimately supports the brain's processing of __________ information.

visual.

The distinct structural organization of ganglion cells is vital for spatial and __________ acuity in vision.

color.

Understanding the operations of retinal circuits aids in comprehending the fundamentals of color __________ in vision.

perception.

Light adaptation in rods functions to adjust the response dynamics to varying __________ levels during exposure.

illumination.

Research into the opsin gene mutations has unveiled complexities in human __________ vision.

color.

Photoreceptor responses in the retina synchronize under diverse __________ conditions to optimize sensory input.

lighting.

Functional analysis of ganglion cells underscores the relationship between retinal signals and __________ perception.

visual.

The interconnectedness of retinal layers and their respective cell types facilitates intricate processing of __________ cues.

visual.

The findings in retinal biology illuminate the significance of opsin structure in defining light __________ properties.

sensitivity.

Advances in genetic research have established links between opsin gene variations and __________ in color detection.

disorders.

The effective functioning of retinal cells is essential for the accurate transmission of __________ to the brain.

visual signals.

The formation of visual pathways exemplifies the integrated efforts of __________ cells and their networks.

neural.

The complexity of human vision arises not only from receptor diversity but also from the __________ between cell types within the retina.

interactions.

Fundamental principles of light absorption highlight the importance of __________ in healthy visual function.

photoreceptors.

Understanding the workings of retinal neurons enriches our appreciation of the intricacies of __________ interaction.

light.

Cognitive processing of colors is ultimately dependent on the three distinct types of __________ present in the retina.

cones.

Color perception variation across different individuals can be attributed to genetic differences affecting cone __________.

function.

Explaining color vision mechanics involves examining both structural and __________ components of the visual system.

chemical.

The research into color blindness exemplifies the need for a deeper understanding of __________ genetics related to opsin genes.

human.

The discovery of anomalies in color perception stems from variations inherent in the gene sequences of __________ opsins.

cone.