Zinc: it's not just for your prostate anymore (from Pete Land's lab.)

Flattened section through layer IV of adult rat cortex stained histochemically for synaptic zinc (black reaction product) - a marker for a unique class of glutamateric terminals. Note that dysgranular and agranular regions of cortex contain a high density of zinc-containing terminals, whereas such inputs are relatively weak in areas that receive input from primary sensory thalamic nuclei. A = primary auditory cortex; V = primary visual cortex; a-e = rows of barrels in primary somatosensory cortex associated with large vibrissae; f = barrel-like structures associated with forepaw; t = trunk representation. Reference: Somatosen. Motor Res. 16(2), pp. 129-140, 1999.