Table 1.

Basal Glutamate Measurements in the Putamen of Awake NHPs

Animal	Deptha	First Recording (µM)	Follow – up Recordingb (µM)
NHP 1 (11 y.o.)	1	25.4	15.1
	2	34.2	12.6
NHP 2 (19 y.o.)	1	6.9	4.9
	2	10.6	5.3
NHP 3 (21 y.o.)	1	9.8	7.7
	2	11.5	5.6

^aMeasurements were not significantly different across depths (p=0.38).

^bFollow–up recordings (4 months later) were significantly lower compared to the first recordings(p=0.047).