The sensation of spiciness is not actually a taste, but a pain reaction. Chemicals in the food (such as capsaicin) trigger stimulation of free nerve endings in the mouth, resulting in the sensation of spiciness in the same way that the fibers would detect pain.

Sweet, salty, and umami are all tastes that gustatory receptors in the taste buds can recognize independently.

EEG (electroencephalogram) involves the placement of electrodes on a person's scalp to detect brain waves, specifically when the subject is asleep. 

Rods (which detect black and white) and cones (which detect colors) are both located in the retina, which lines the back of the eye. After the rods and cones detect visual stimuli the information is relayed to the brain via the optic nerve, which exits the eye via the optic disc. There are no photoreceptors on the optic disc, resulting in our blind spot.

An echoic memory is a momentary, sensory memory of auditory stimuli that lasts for only a couple of seconds. This form of sensory memory may be forgotten or sent to our long-term memory for further encoding. 

The just-noticeable difference is the minimal change that can occur in a stimulus to just barely be detected by the observer. In this case, the stimulus is the brightness of light. 

As for the other answer choices, the absolute threshold is the minimal intensity at which a stimulus can just barely be detected. This concept is similar to the just-noticeable difference but has to do with detection of existence, rather than detection of change. Sensory adaptation refers to how an observer becomes less sensitive to a stimulus over time. Signal detection states that an observer's response to a stimulus depends on both their sensitivity and their decision criterion. Transduction is the process of physical signals being converted to neural signals. 

Neurons are specialized cells that transmit nerve signals. These cells make up the nervous system, and consist of an axon (sends nerve impulses to other neurons), dendrites (receive nerve impulses from other neurons), and soma ( the cell body of the neuron).

Glial cells are considered part of the nervous system as well, but do not represent the fundamental functional unit. Instead, glial cells supply support and nourishment to neurons.

Top-down processing uses larger context to assume smaller bits of missing information. Bottom-up processing is the opposite - using small bits of information to understand a bigger picture. Signal detection theory is the ability to choose between and identify stimuli. Perceptual constancy refers to the tendency in humans to see familiar things as having similar shapes, colors, and sizes, in spite of changes that may have occurred in that object.

Rods and cones are the light-sensitive receptor cells that are responsible for transducing light waves into neural impulses. 

Autokinetic illusion is when a single unmoving light in a dark room appears to move when stared at for several seconds. It is not a monocular depth clue.

Interposition refers to the monocular depth clue indicating an objects relative closeness by seeing whether that object is stacked on top of an object, or whether an object is stacked on it.

Relative size refers to objects farther away appearing smaller.

Shadow (or shading) refers to closer objects reflecting more light, and thus appearing less dark, than objects further away.

Absolute threshold refers to the minimum amount of a given stimulus (light, odor, sound, pressure, or taste) that can be detected at least 50% of the time.