Question: The negative symptomatology of schizophrenia seems to be caused by: 
 Options:  <1> The excessive activity of some dopaminergic neural circuits. <2> The excessive activity of the GABAergic neurons. <3> The existence of brain damage. <4> Have a gene for schizophrenia that causes negative symptoms. <5> Insufficient activity of the serotonergic neurons of the frontal lobe.
3