Final answer:
The basal ganglia are the forebrain structures that control posture, muscle tone, and smooth movement. They are a part of the extrapyramidal system, working in coordination with other parts of the brain to regulate movement and autonomic functions.
Step-by-step explanation:
The set of forebrain structures controlling posture, muscle tone, and smooth movement is known as the basal ganglia. These interconnected brain areas are essential for movement control and posture. In addition, the basal ganglia play a role in regulating motivation. Damage to this area can lead to motor impairments, such as those seen in Parkinson's disease, characterized by symptoms like a shuffling gait. The extrapyramidal system is also important in this context as it includes projections from the brain stem and higher centers that influence movement, mostly to maintain balance and posture, as well as to maintain muscle tone.
The basal ganglia work in conjunction with other systems, such as the reticulospinal tract and motor cortices, to control voluntary muscle movement and regulate autonomic functions. Ascending and descending neural pathways integrate and coordinate these functions through different parts of the brain, including the hypothalamus and the brain stem. This coordination allows us to perform complex motor tasks and maintain necessary body functions.