Final answer:
Alcohol affects concentration, reaction time, and motor skills but does not directly affect synaptic capacity in its immediate impact on the brain.
Step-by-step explanation:
Once in the brain, alcohol affects several critical skills such as concentration, reaction time, and behavioral control leading to impaired motor control, coordination, and decision-making. However, alcohol does not directly affect synaptic capacity as part of its short-term influence on brain activity. Instead, its immediate effects are most prominent in areas such as blood flow, auditory response, and the aforementioned concentration. The alcohol-related impairment of these skills can manifest in various ways, including the performance on a Field Sobriety Test (FST), which assesses coordination and balance, tasks heavily influenced by ethanol's impact on the cerebellum.