Bipolar cells and many ganglion cells possess concentric receptive fields organized with an on-center/off-surround or off-center/on-surround arrangement. Horizontal cells facilitate this center-surround antagonism by mediating the interaction. Photoreceptor, bipolar, and horizontal cells exhibit responses to stimulation through modulation of their membrane potential and release of neurotransmitters.

Routine neurological examinations typically do not encompass olfaction assessment. Nevertheless, smell can be evaluated by instructing the patient to inhale and identify an odorant. One nostril should be examined at a time while the other nostril is blocked. It is advisable to avoid strong odorants, such as ammonia, as they may also activate trigeminal nerve fibers. The loss of smell sensation, known as anosmia, can occur following a basal skull fracture or damage to one or both olfactory bulbs or tracts caused by a tumor, such as an olfactory groove meningioma. Concussions can also lead to anosmia due to the sudden movement of the brain within the skull, resulting in shearing of the small unmyelinated olfactory nerve fibers. During unciante seizures, which are epileptic seizures originating in the medial temporal lobe, an aura characterized by an unpleasant odor, often resembling the smell of burning rubber, may be experienced.

Gustatory receptors have a narrow range compared to the extensive repertoire of olfactory receptors. Additionally, due to its close connections with limbic and hypothalamic structures, the olfactory system provides input to subconscious mechanisms associated with emotions, memory, and sexual behavior. Ganglion cells respond to stimuli by generating action potentials.

The axons of ganglion cells in the temporal retina project ipsilaterally to the brain, whereas those in the nasal retina cross in the optic chiasm. As the lens flips the image falling on the retina, each side of the visual field is projected to the opposite side of the brain for both eyes. In the lateral geniculate nucleus (LGN) of the thalamus, the input from each eye terminates in separate layers, and the M ganglion cells (sensitive to movement) and P ganglion cells (sensitive to detail and color) also project to distinct layers.

The LGN sends projections to the primary visual (striate) cortex through the visual radiation, primarily terminating in layer 4, which exhibits an orderly retinotopic map. Within this map, information from each eye is mapped to alternating adjacent points, forming ocular dominance columns that extend vertically in the cortex. Neurons in the striate cortex outside of layer 4 display optimal response to stimuli such as bars or edges oriented in specific ways. Cells that prefer a particular stimulus orientation are grouped within orientation columns.

The extrastriate visual areas serve various functions. Inferotemporal cortex regions are predominantly influenced by P cells and contribute to form detection, color vision, and face discrimination. M cells exert influence on areas of the middle temporal and parietal cortex, which are involved in motion detection and the control of eye movements.

A pure tone is characterized by its amplitude, frequency, and phase. Natural sounds consist of combinations of pure tones. Sound pressure is measured in decibels (dB), relative to a reference level.

Airborne sound waves are conveyed to the tympanic membrane by the pinna and auditory canal. The vibrations of the tympanic membrane are transmitted to the oval window of the fluid-filled inner ear by the three small bones (ossicles) within the middle ear. Hearing sensitivity is highest at approximately 3000 Hz due to the dimensions of the auditory canal and the mechanics of the ossicles.

The cochlea in the inner ear consists of three main compartments: the scala vestibuli, the scala tympani, and the intervening scala media (cochlear duct). The basilar membrane separates the cochlear duct from one side, and it is on this membrane that the organ of Corti, the sound transduction mechanism, is situated.
Bipolar cells and many ganglion cells have concentric receptive fields with an on-center/off-surround or off-center/on-surround organization. Horizontal cells mediate this center-surround antagonism. Photoreceptor, bipolar, and horizontal cells respond to stimulation by modulating their membrane potential and their release of neurotransmitters,
Olfactionisnotgenerallyexaminedinaroutineneurologicalexamination.However,smellcanbetestedbyhavingthepatientinhaleandidentifyanodorant.Onenostrilshouldbeexaminedatatimewhiletheothernostrilisoccluded.Strongodorants,suchasammonia,shouldbeavoidedbecausetheyalsoactivatetrigeminalnervefibers.Smellsensationcanbelost(anosmia) afterabasalskullfractureorafterdamagetooneorbotholfactorybulbsortractsbyatumor(suchasanolfactory groove meningioma).Concussionscancauseanosmiabecausethesuddenmovementofthebraininsidetheskullcanshearthesmallunmyelinatedolfactorynervefibers.Anauraofadisagreeableodor,oftenthesmellofburningrubber,occursduringuncinate seizures, whichareepilepticseizuresthatoriginateinthemedialtemporallobe.
narrow range of gustatory receptors with the wide repertoire of olfactory receptors. In addition, via its intimate connections with limbic and, by extension, hypothalamic structures, it provides input to subconscious mechanisms related to emotions, memory, and sexual behavior.
but ganglion cells respond by generating action potentials.
5.
The axons of ganglion cells in the temporal retina project to the brain ipsilaterally; those in the nasal retina cross in the optic chiasm. Because the lens inverts the image that falls on the retina, each side of the visual field is projected to the contralateral side of the brain for both eyes. In the lateral geniculate nucleus (LGN) of the thalamus, the input from each eye terminates in separate layers, and the M ganglion cells (sensitive to movement) and P ganglion cells (sensitive to detail and color) project to separate layers as well.
6.
The LGN projects to primary visual (striate) cortex via the visual radiation and terminates largely in layer 4, where there is an orderly retinotopic map. Within the map, information from each eye maps to alternating adjacent points to create ocular dominance columns that extend vertically in the cortex. Striate cortical neurons outside of layer 4 respond best to bar or edge stimuli oriented in a particular way. Cells that “prefer” a particular stimulus orientation are grouped in orientation columns.
7.
The extrastriate visual areas have different functions. Some in the inferotemporal cortex are influenced chiefly by P cells, and they function in form detection, color vision, and face discrimination. M cells influence regions of the middle temporal and parietal cortex, which function in motion detection and the control of eye movements.
8.
A pure tone is characterized in terms of its amplitude, frequency, and phase. Natural sounds are combinations of pure tones. Sound pressure is measured in decibels (dB), in relation to a reference level.
9.
The pinna and auditory canal convey airborne sound waves to the tympanic membrane. The three small bones (ossicles) of the middle ear transmit the vibrations of the tympanic membrane to the oval window of the fluid-filled inner ear. Hearing is most sensitive at about 3000 Hz because of the dimensions of the auditory canal and the mechanics of the ossicles.
10.
The cochlea of the inner ear has three main compartments: the scala vestibuli, the scala tympani, and the intervening scala media (cochlear duct). The cochlear duct is bounded on one side by the basilar membrane, on which lies the organ of Corti, the sound transduction mechanism.
11.