Final answer:
The frontal lobes, located behind the forehead, are associated with executive functions. Deficits in these cognitive functions are linked to issues in the prefrontal cortex, affecting judgment, reasoning, and impulse control.
Step-by-step explanation:
Marked deficits in frontal lobe cognitive functions, such as planning and organization, are associated with damage or dysfunction in the prefrontal cortex. This area of the brain is involved with various executive functions, including judgment, reasoning, and impulse control. The frontal lobes are located at the front of the brain behind the forehead and are responsible for high-level cognitive activities such as attention, planning, problem-solving, language, and personality. Damage to these areas, as observed in the case of Phineas Gage, can result in significant changes to personality, mood, and behavior, and can affect a person's ability to regulate emotions and perform complex tasks.