Jeremy has Parkinson’s disease, a progressive neurodegenerative disease that affects motor skills. In addition to motor symptoms, Jeremy has noticed changes in his mood, and he feels the need to smoke more cigarettes than he used to. It is likely that Jeremy’s is producing less than it needs to. motor cortex; acetylcholine motor cortex; dopamine substantia nigra; acetylcholine substantia nigra; dopamine

Parkinson's disease is a chronic and progressive disorder of the nervous system, characterized by cardinal signs of stiffness, akinesia, bradykinesia, tremor and postural instability. It has an idiopathic etiology, but it is believed that its emergence comes from environmental and genetic factors, and may interact and contribute to the neurodegenerative development of Parkinson's disease. Parkinson's disease is a condition of the central nervous system, which is chronic and progressively expressed. It results from the death of dopamine-producing neurons in substantia nigra. As the disease progresses, the motor cortex begins to produce less dopamine. The result of this is the worsening of the symptoms of the disease.

Based on this, regarding Jeremy's case, we can conclude that it is likely that Jeremy's motor cortex is producing less dopamine than necessary, so he is experiencing worsening symptoms of Parkinson's disease.