Rats Can Be Depressed, Too!!

How are humans and rats the same?

Well, rats can be depressed, too. There are signs that pet rats are depressed, such as losing their playfulness, no longer eating, having anxiety, and attacking each other (Black, 2021). This study about their depression indicates that their brain function is similar to humans. Like humans, rats also have the BDNF gene, which is responsible for making a protein that plays a role in growth and maturation. When BDNF was reduced in mice(same as rats physiologically), they began showing depressive behaviors and were unable to make proper nests (Kojima, 2020). A 1987 research study found that the posterior parietal cortex of primates is analogous to the posterior parietal cortex of rats. In the experiment:

The anatomical connections of Krieg's area 7 in the rat were examined by placing the retrograde tracer, True blue, into the frontal or posterior cortex, and the behaviour of rats with this cortex removed was studied on a variety of tasks. Lesions produced deficits on tasks of tactile discrimination, and walking a narrow beam, two tasks requiring animals to navigate accurately to a point in space, and a task requiring the association of two spatially discontiguous cues (Kolb & Walkey, 1987).

The rats were unable to do regular tasks, such as walking when the posterior parietal cortex was damaged. The post parietal cortex is responsible for action planning and control in primates and is proven to be the same as rats. Another similarity human and rats have is similar DMN functions. In humans, DMN is a set of brain regions responsible for internal mental-state processes such as imaging, memory retrieval, etc. Through a 1991 research study, DMN can be inactivated by suppressing the dorsal anterior cingulate cortex and this resulted in the awake rats to change their “usual” behaviors (Tu et al., 1991). The rats have become disconnected with their behaviors as well as brain network function, indicating that DMN is responsible for their behavior.