As a cognitive neuroscientist with a focus on the neural underpinnings of cognition, I can provide a comprehensive answer to your question regarding the part of the brain that controls reasoning.
The frontal lobes, particularly the prefrontal cortex, are the primary areas associated with reasoning. This region of the brain is located at the front of the cerebrum, which is the largest part of the brain and is composed of right and left hemispheres. The cerebrum is responsible for higher cognitive functions, which include interpreting sensory information from touch, vision, and hearing, as well as speech, reasoning, emotions, learning, and fine control of movement.
Reasoning involves the ability to make judgments, solve problems, and draw logical conclusions based on available information. The prefrontal cortex plays a crucial role in these processes by integrating information from various sources and using it to guide behavior and decision-making. It is involved in several aspects of reasoning, including:

1. Working Memory: The prefrontal cortex is essential for maintaining and manipulating information in the short term.

2. Executive Functions: These are high-level cognitive processes that include planning, organizing, abstract thinking, and problem-solving.

3. Inhibition: The ability to suppress irrelevant or inappropriate responses is a key component of reasoning and is facilitated by the prefrontal cortex.

4. Cognitive Flexibility: The capacity to switch between thinking about different concepts or to think about multiple concepts simultaneously is supported by this region.

5. Judgment and Decision Making: The prefrontal cortex is critical for evaluating options and making choices based on complex cognitive processes.
The cerebellum, which is located under the cerebrum, is traditionally associated with motor control and coordination but has also been implicated in some cognitive functions, including aspects of attention and cognitive sequencing, which can indirectly influence reasoning.
It's important to note that reasoning is a complex cognitive function that likely involves a network of brain regions rather than being solely dependent on one area. Other areas of the brain, such as the parietal lobes, which are involved in processing sensory information, and the temporal lobes, which are involved in memory and language processing, also contribute to the reasoning process.
In conclusion, while the prefrontal cortex is the primary region for reasoning, it works in concert with other parts of the brain to enable the complex cognitive processes that underlie reasoning. The intricate interplay between these regions allows for the sophisticated level of reasoning that is a hallmark of human cognition.

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Cerebrum: is the largest part of the brain and is composed of right and left hemispheres. It performs higher functions like interpreting touch, vision and hearing, as well as speech, reasoning, emotions, learning, and fine control of movement. Cerebellum: is located under the cerebrum.read more >>