Comprehensive Neuroscience and Vision: Receptive Fields, Spectral Sensitivity, and Visual Disorders

Modularity

The concept that cognitive processes can be divided into distinct modules or units that operate independently.

Wernicke's area

A region in the brain located in the left temporal lobe, associated with language comprehension.

Absorption spectrum

A graph showing the wavelengths of light absorbed by a substance, indicating which wavelengths are absorbed and which are transmitted.

Accommodation

The process by which the eye adjusts its focus for objects at different distances by changing the shape of the lens.

Amacrine cells

Interneurons in the retina that play a role in visual processing by connecting ganglion cells and bipolar cells.

Center-surround receptive field

A type of receptive field in which the center responds differently to stimuli than the surrounding area, enhancing contrast.

Chevreul illusion

An optical illusion where adjacent colors appear to be different due to the influence of surrounding colors.

Cone spectral sensitivity

The sensitivity of cone photoreceptors in the retina to different wavelengths of light.

Cones

Photoreceptor cells in the retina responsible for color vision and function best in bright light.

Convergence

The process by which multiple neurons synapse onto a single neuron, increasing the sensitivity of the neuron to stimuli.

Cornea

The transparent front part of the eye that covers the iris and pupil, helping to focus light onto the retina.

Dark adaptation

The process by which the eyes become more sensitive to low light levels after being in darkness.

Dark adaptation curve

A graph that depicts the increase in visual sensitivity over time as the eyes adjust to darkness.

Dark-adapted sensitivity

The level of sensitivity of the visual system in low light conditions after a period of darkness.

Detached retina

A condition where the retina separates from the underlying tissue, potentially leading to vision loss.

Edge enhancement

A visual effect that increases the contrast at the edges of objects, making them more distinguishable.

Excitatory area

The part of a receptive field that, when stimulated, increases the firing rate of the associated neuron.

Excitatory-center, inhibitory-surround receptive field

A type of receptive field where the center stimulates the neuron while the surrounding area inhibits it.

Eyes

Organs of vision that detect light and convert it into electrochemical signals for the brain.

Farsightedness

A vision condition (hyperopia) where distant objects are seen more clearly than close ones due to the eye's shape.

Fovea

The small central pit in the retina where visual acuity is highest due to a high concentration of cones.

Ganglion cells

Neurons in the retina that receive input from photoreceptors and transmit visual information to the brain.

Horizontal cells

Retinal neurons that connect photoreceptors to bipolar cells, playing a role in lateral inhibition.

Hyperopia

A vision condition where distant objects are seen clearly, but close objects appear blurry due to the eye's shape.

Inhibitory area

The part of a receptive field that, when stimulated, decreases the firing rate of the associated neuron.

Inhibitory-center, excitatory-surround receptive field

A type of receptive field where the center inhibits the neuron while the surrounding area stimulates it.

Isomerization

The process by which a molecule changes its structure, often referring to the change in visual pigments when exposed to light.

Lateral inhibition

A process in the retina where activated photoreceptors inhibit their neighbors, enhancing contrast and edge detection.

Lens

The transparent structure in the eye that helps focus light onto the retina.

Light-adapted sensitivity

The level of sensitivity of the visual system in bright light conditions after a period of adaptation.

Mach bands

An optical illusion that enhances the perception of edges by creating the appearance of bands of light and dark.

Macular degeneration

A medical condition that results in the deterioration of the central portion of the retina, leading to vision loss.

Monochromatic light

Light that consists of a single wavelength or color.

Myopia

A vision condition (nearsightedness) where close objects are seen clearly, but distant objects appear blurry.

Nearsightedness

A vision condition (myopia) where close objects are seen clearly, but distant objects appear blurry.

Neural circuits

Networks of interconnected neurons that process and transmit information in the nervous system.

Neural convergence

The phenomenon where multiple neurons synapse onto a single neuron, allowing for integration of information.

Ommatidia

The individual optical units that make up the compound eyes of insects, each functioning like a small camera.

Optic nerve

The nerve that transmits visual information from the retina to the brain.

Outer segments

The part of photoreceptor cells (rods and cones) that contains the light-sensitive photopigments.

Peripheral retina

The outer regions of the retina that are more sensitive to motion and dim light but less sensitive to color.

Photoreceptors

Specialized cells in the retina (rods and cones) that detect light and convert it into electrical signals.

Preferential looking technique

A research method used to study visual perception in infants by measuring their gaze towards different stimuli.

Presbyopia

An age-related condition where the eye's lens loses elasticity, making it difficult to focus on close objects.

Pupil

The opening in the center of the iris that regulates the amount of light entering the eye.

Purkinje shift

The shift in color perception that occurs in low light conditions, where blue and green colors appear brighter than red.

Receptive field

The specific region of sensory space in which a stimulus will modify the firing of a neuron.

Refractive errors

Vision problems caused by the eye's inability to focus light correctly, leading to blurred vision.

Refractive myopia

A type of myopia caused by the eye's shape or the curvature of the cornea, leading to light focusing in front of the retina.

Retina

The light-sensitive layer at the back of the eye that contains photoreceptors and converts light into neural signals.

Retinitis pigmentosa

A genetic disorder that leads to the degeneration of photoreceptors in the retina, causing vision loss.

Rod monochromats

Individuals who have only rod photoreceptors and no functioning cones, resulting in complete color blindness.

Rod-cone break

The point during dark adaptation when the sensitivity of rods surpasses that of cones.

Rod spectral sensitivity curve

A graph that shows the sensitivity of rod photoreceptors to different wavelengths of light.

Rods

Photoreceptor cells in the retina that are sensitive to low light levels and are responsible for night vision.

Spectral sensitivity

The sensitivity of photoreceptors to different wavelengths of light.

Spectral sensitivity curve

A graph that represents the sensitivity of a photoreceptor type to various wavelengths of light.

Transduction

The process by which sensory stimuli are converted into electrical signals in the nervous system.

Visible light

The portion of the electromagnetic spectrum that is visible to the human eye, typically ranging from 380 to 750 nanometers.

Visual acuity

The clarity or sharpness of vision, often measured by the ability to discern letters or numbers at a standardized distance.

Visual evoked potential

An electrical potential recorded from the scalp in response to visual stimuli, used to assess visual pathway function.

Visual pigment bleaching

The process by which visual pigments change structure upon exposure to light, leading to a decrease in sensitivity.

Visual pigment regeneration

The process by which visual pigments are restored to their original state after bleaching, allowing for continued vision.

Visual pigments

Light-sensitive molecules in photoreceptors that undergo a chemical change when exposed to light, initiating the visual process.

Wavelength

The distance between successive peaks of a wave, often used to describe the color of light.