This information is followed by integrative processes in the association cortices. Here the primary input is mixed with previously stored information. The cortex, however, does not work alone. The thalamus below it is gaiting everything coming into the cortex. If the thalamus is injured or damaged, information to the cortex can be incomplete or inaccurate.
Several steps take place before the thalamus processes the sensory information.
Input to the thalamus depends upon the condition of the receptors which gather sensations from the external and internal environment. To gain some idea on how the environment influences the cortex, we can turn briefly to our own long term studies here at Berkeley to indicate how we can measure morphological changes in the cerebral cortex as a consequence of stimulating or deprived environments. Learning must take place before wisdom. We have been able to demonstrate cerebral cortical changes in response to the environment at any age. With greater exposure to new input, more regions of the cortex respond.