Neuro

What is the human visual light range?

400-700nm

What is the innermost layer of the eye that contains 100 million photoreceptors?

Retina

What component of the eye contains a muscular component that shapes the lens?

Ciliary body

What are the stages in the path of light in the eye?

Cornea, anterior chamber, pupil, lens, vitreous humor, fovea

What term describes some type of refractive error?

Ametropia

What is normal vision where the image falls on the retina called?

Emmetropia

What condition is characterized by nearsightedness?

Myopia

What condition is defined as farsightedness where the image falls beyond the retina?

Hyperopia

What is astigmatism?

Distorted/blurred vision because of defective curvature in the lens or cornea

What effect reduces the size of the hole through which light passes to prevent unfocused light?

Pinhole effect

Where is visual acuity the highest in the eye?

Fovea

What is a 'blind spot' in the visual field called?

Scotoma

What is defined as the visual space each eye sees?

Visual field

What phenomenon is caused by the overlap of the left and right visual fields?

Binocular depth perception

What are the two types of photoreceptors found in the outer nuclear layer of the retina?

Rods and cones

What kind of cells are found in the outer plexiform layer?

Bipolar cells and horizontal cells

Which cells in the inner nuclear layer have their cell bodies and function as interneurons?

Amacrine cells

What are the end cells in the inner plexiform layer that send axons as the optic tract?

Retinal ganglion cells

What is the process of converting photons into electrical signals called?

Phototransduction

What change happens during hyperpolarization caused by light activation?

Change in the rate of neurotransmitter release onto postsynaptic neurons

What photopigment do rods express?

Rhodopsin

What do cones express in terms of photopigments?

Opsins (short, medium, long wavelength)

What photopigment do intrinsically photosensitive ganglion cells express?

Melanopsin

What happens in phototransduction during light conditions?

Transducin is activated leading to the closure of Sodium and Calcium channels.

What occurs in phototransduction during dark conditions?

Opening of calcium channels leads to neurotransmitter release.

Which photoreceptor has a greater density throughout the retina with the exception of the fovea?

Rods

How many contacts does each cone receive from a bipolar neuron?

Only one contact

Are rods more or less sensitive than cones?

More sensitive, activated by as little as a single photon.

How many photons are required to activate cones?

More than 100 photons.

Which photoreceptor operates well at low illumination levels and has low spatial resolution?

Rods

What type of vision is characterized by light sensitivity operating well at low illumination levels?

Scotopic vision

Which photoreceptor is highly sensitive to bright light but not to low light?

Cones

What type of vision is highly sensitive to bright light?

Photopic vision

What phenomenon describes how an object can appear to be a different color when its surroundings vary?

Color contrast

What is color constancy?

An object appears to be the same color when its surroundings are similar.

What kind of ganglion cell fires action potentials when illuminated in the receptive field?

ON-center ganglion cell

What happens to OFF-center ganglion cells when light is decreased in their receptive field?

They decrease firing action potentials.

What is the role of horizontal cells regarding neurotransmission?

They use GABA.

What kind of neurotransmitters do amacrine cells use?

GABA, glycine, acetylcholine, dopamine, and glutamate.

What are the brain regions that process image-forming information called?

Retino-recipient brain regions.

What is the function of retino-no-recipient brain regions?

They process non-image forming information.

What is the pathway that projects to layer 4 of the primary visual cortex?

Retino-geniculo-cortical pathway.

What are the possible visual field deficits caused by damage to the retino-geniculo-cortical pathway?

Anopsias and hemianopsia.

What organization characterizes the primary visual cortex?

Cellular and columnar organization with 6 layers.

What layers in the primary visual cortex contain pyramidal neurons that release glutamate?

Layers 2, 3, 5, and 6.

What specialization does layer 4 of the primary visual cortex have?

Contains spiny stellate cells and appears as stripes (striate).

What is preferred orientation in the context of cortical neurons?

The orientation of a stimulus to which a cortical neuron maximally responds.

What areas are devoted to visual processing of information from the primary visual cortex?

Extra striate visual areas.

What stream of processing recognizes an object or scene and where does it start?

The ventral stream, starting at the primary visual cortex.

What stream analyzes motion and spatial relationships and where does it start?

The dorsal stream, also starting at the primary visual cortex.

What controls pupillary dilation?

The autonomic nervous system and cranial nerve III (oculomotor).

What action occurs in ciliary muscles during the near response?

They thicken and round up the lens for near vision.

What is required for optimal acuity during near response viewing?

Accommodation, convergence, and constriction.

What are conjugate eye movements?

Coordinated movements by both eyes maintained by extra ocular eye muscles.

What are the two types of eye movements for redirecting gaze?

Smooth pursuit and saccadic eye movements.

What describes smooth pursuit?

Both eyes shift their positions to track a moving object in a smooth manner.

What are saccadic eye movements characterized by?

Rapid, sudden changes in eye position to redirect focus.

What is saccadic suppression?

The inability to detect a visual percept during a saccadic eye movement.

What type of receptors are olfactory cells classified as?

Chemoreceptors.

What is the term for the area of sensory input that alters the firing rate of a neuron?

Receptive field.

What does haptic touch refer to?

Exploration and perception of somatosensory stimuli using active touching and proprioception.

Which eye controls the right visual field?

The right eye.

What are the areas on the skin where a shingles rash typically appears called?

Dermatomes.

Where do lateral axons from the retina decussate?

They don’t; they remain ipsilateral.

What is the part of the outer ear that includes a small cartilaginous bump?

Tragus.

What tube is essential for maintaining air pressure in the middle ear?

Eustachian/auditory tube.

What fluid fills the cochlear duct and membranous labyrinth?

Endolymph.

What is perilymph and where is it found?

Potassium poor fluid that bathes the basal ends of hair cells.

What is anosmia?

The inability to smell/distinguish odors

MAY be permanent, if new ORNs do not regenerate, can also be corrupted with age

Where is melatonin produced?

Pineal gland.

What are the five established tastes detectable by gustatory cells?

Bitter, sweet, umami, sour, salty.

What is the white matter tract connecting septal nuclei and hypothalamus with the hippocampus?

Fornix.

What area damage results in the inability to verbally respond?

Broca’s area/motor speech area.

Which neurotransmitter do nicotinic receptors respond to?

Acetylcholine.

Which cranial nerves are tested during the pharyngeal gag reflex?

Glossopharyngeal (IX) and vagus (X).

Which cranial nerve is associated with some shoulder and neck muscles?

Spinal accessory (XI).

How many mixed cranial nerve pairs exist in humans?

Four: trigeminal, facial, glossopharyngeal, vagus.

Bell’s palsy is associated with which cranial nerve?

Facial (VII).

What germ layer is the notochord derived from?

Mesoderm.

How does brain volume change after the age of five in humans?

It changes.

Which primary brain vesicles give rise to the cerebral cortex?

Telencephalon.

What is the term for the failure of iris formation called?

Aniridia.

In which nervous system is axon regrowth more likely to occur?

Peripheral nervous system.

Where do neural crest cells arise from in the neural tube?

Dorsal aspect.

From which secondary brain vesicle does the hypothalamus arise?

Diencephalon.

What directly prevents repair after peripheral nerve damage when pharmacologically blocked?

Schwann cells/neurolemmocytes.

What part of the eye is trouble reading associated with?

Fovea.

Which quadrant of the retina corresponds to an object in the inferior, nasal quadrant of visual field?

Superior, temporal quadrant.

Which taste are animals most sensitive to?

Bitter.

What is chemesthesis related to?

Detection of potentially harmful chemicals like the burning sensation from capsaicin.

What is Parkinson’s disease caused by?

Progressive degeneration of dopaminergic-producing neurons in the substantia nigra.

What neurotransmitter is most associated with the raphe nuclei in the brainstem?

Serotonin.

What is referred pain?

Pain perceived as coming from a site other than its origin.

Sound is

a pressure wave composed of different frequencies and compression of air molecules

pure tone is

a sine wave

pitch

frequency

loudness/intensity

amplitude

Pure tones are ___ found in nature

rarely

complex waveforms can be deconstructed using

fourier analysis

power spectrum

presents frequencies