PVALB and Menkes disease: As for the morphological substrate of these behavioral changes, we have previously shown that MD decreased numbers of NeuN-expressing neurons and parvalbumin-expressing interneurons in the prefrontal cortex (Aksić et al., 2014, 2021), as well as the decreased overall number of NeuN-expressing neurons in the amygdala and nucleus accumbens (Aleksić et al., 2016).