Cellulose is a structural component of the plant cell wall. It is a polysaccharide consisting of a long linear chain of multiple β - 1, 4 linked glucose units.
Cellulose is difficult for most animals to digest except herbivores because they lack the ability or enzyme to digest cellulose. This enzyme needed is the cellulase which cleave to its β - 1,4 glycosidic bond and hydrolysis it into its constituent molecules (glucose).
In a mammalian brain, there are four major lobes that are present and one of them is the frontal lobe.
The frontal lobe is mainly rich in dopaminergic neurons and thus, it is mainly concerned with functions such as memory, reward, motivation, planning, attention, etc.
The process of break down of tissues and cell death in the tissues is referred to as atrophy and since the frontal lobe is associated with the functions as mentioned above its atrophy would lead to a slow decline in these functions.
Since Mr. Klondlike behavior is changing his blunt comments are most likely a result of atrophy of the frontal lobe.
