Table 1.

Immunohistochemical marker distribution in rat zona incerta.

Marker	ZID	ZIV	Caudal ZI
Calbindin	Negative	Negative	Positive cells ++
Calretinin	Positive cells ++	Negative	Positive cells +
NADPH-d	Positive cells +++	Negative	Positive cells +
Parvalbumin	Medial part positive +++	Positive cells and neuropil ++++	Negative or weak neuropil +
SMI-32	Positive cells and fibres ++	Positive cells and fibres ++	Negative
Tyrosine hydroxylase	Negative	Negative	Negative
Acetylcholinesterase	Light neuropil staining ++	Light neuropil staining ++	Medium intensity patch – caudal pole +++

The intensity of immunohistochemical staining was categorised as weak (+), light (++), medium (+++) or strong (++++). Where it was obvious, we recorded whether the staining was present in neuronal cell bodies, fibres, or the neuropil.