A lesion of the uncus may result in which type of perceptual disturbance?

A lesion of the uncus is associated with olfactory processing since the uncus is a part of the temporal lobe that plays a critical role in the olfactory system. Damage to this area can disrupt normal olfactory function and lead to disturbances in smell perception, often resulting in olfactory hallucinations. These hallucinations can manifest as the perception of smells that are not present in the environment, which is a direct consequence of the brain's altered processing of olfactory sensations.

In contrast, the other types of hallucinations, such as visual, auditory, or tactile, are typically associated with lesions or dysfunctions in different areas of the brain that are specifically responsible for processing those sensory modalities. For example, visual hallucinations may arise from occipital lobe involvement, auditory hallucinations from temporal lobe structures separate from the uncus, and tactile hallucinations from parietal lobe dysfunction. Hence, olfactory hallucinations are the most relevant perceptual disturbance linked to a lesion in the uncus, confirming the correctness of the answer.