Neural connections carrying signals from the cortex (the brain region responsible for thought) down to the amygdala (a brain region crucial for emotions) are less well developed than connections carrying signals from the amygdala up to the cortex. Thus, the amygdala exerts a greater influence on the cortex than vice versa. The argument's conclusion follows logically if which one of the following is assumed? ['The degree of development of a set of neural connections is directly proportional to the influence transmitted across those connections.', 'The region of the brain that has the most influence on the cortex is the one that has the most highly developed neural connections to the cortex.', 'The influence that the amygdala exerts on the rest of the brain is dependent on the influence that the cortex exerts on the rest of the brain.', 'The amygdala is not itself controlled by one or more other regions of the brain.']