The main thinking part of the brain is

The brain is the main coordinating center of the body, and the forebrain is specifically identified as the main thinking part of the brain [3]. The forebrain consists of the cerebrum, which is the largest part of the brain and serves as the center for higher cognitive functions, including reasoning, problem-solving, judgment, and thinking. While the midbrain and hindbrain are responsible for involuntary actions like blood pressure, salivation, and motor coordination (posture and balance), the forebrain receives sensory information from across the body and integrates it to decide on voluntary actions [3]. The cerebral cortex, located in the forebrain, is the site where most actual information processing and complex neural interactions occur, enabling humans to be 'thinking beings' [2]. Consequently, the forebrain is the primary region for conscious thought and intelligence.

Sources

1. [2] Science , class X (NCERT 2025 ed.) > Chapter 6: Control and Coordination > 6.1.2 Human Brain > p. 103
2. [3] Science , class X (NCERT 2025 ed.) > Chapter 6: Control and Coordination > 6.1.1 What happens in Reflex Actions? > p. 102
3. [1] Science , class X (NCERT 2025 ed.) > Chapter 6: Control and Coordination > 6.1.2 Human Brain > p. 104