What does hierarchical processing in the brain refer to?

Hierarchical processing in the brain refers specifically to the manner in which information is processed across different levels of neural organization, typically from simpler to more complex representations. This concept illustrates how sensory information is first handled by lower-order areas of the brain, which are responsible for basic processing, such as detection of simple features like edges or colors. As this information is relayed to higher-order areas, neurons in these regions respond to increasingly sophisticated and abstract stimuli, such as recognizing faces or understanding language.

This progression showcases a fundamental principle in neuroscience, where higher cortical areas integrate and build upon the outputs of lower areas, resulting in more nuanced interpretations of sensory information. Thus, neural responses become more complex as one moves from the primary sensory areas to higher cognitive processing centers, illustrating the concept of hierarchical processing effectively.