Final answer:
The most characteristic feature of cognitive disorders is the deficit in memory. Such disorders entail disruption in cognitive functions and can be distinguished from emotional disorders like depression. They often involve neurological changes affecting memory, learning, and motor tasks execution.
Step-by-step explanation:
The most characteristic feature of cognitive disorders is D. Deficit in memory. Cognitive disorders often entail a disruption in cognitive functions, such as memory, attention, and learning abilities. Examples of these disruptions include disruptive memory loss, confusion about time or place, and difficulty with complex tasks. Unlike depression, which is more emotionally oriented with symptoms such as a feeling of dread or persistent sadness, cognitive disorders focus on impairments in mental processes. Conditions like Parkinson's disease can cause cognitive deficits alongside motor symptoms such as rigid muscles and balance problems due to neurodegeneration. Furthermore, learning disabilities are generally classified as neurological disorders that can affect cognitive functions like memory and learning new motor tasks.
An example of a cognitive disorder is Alzheimer's disease, where there is significant memory loss, confusion, and personality changes. Similarly, deficits in dopaminergic transmission in the prefrontal cortex have been linked with cognitive deficits, highlighting the neurobiological underpinnings of these disorders.