Extended Data Fig. 5: Measurement of the neurotransmitter release during fear conditioning and extinction training, and chronic stability of the NeuroString for neurotransmitter sensing.
From: A tissue-like neurotransmitter sensor for the brain and gut
a–d, Dopamine release in the NAc measured during various phases of a fear extinction task (NeuroStrings were implanted at least two weeks before the behaviour assay started). a, Trial structure for the fear extinction training. b, Percentage of freezing to the CS during the early extinction phase (E-Ext, 1–8 trials) and the late extinction phase (L-Ext, 9–15 trials) (n = 5 mice). The CS evoking lower freezing levels during the late phase indicated successful extinction learning. P-value 0.0005. c, Quantification of dopamine responses to the CS during habituation (before Cond.), the fear conditioning (an electric shock after the tone) and fear extinction phase (n = 5 mice). P-values: 0.0018 (shock), 0.003 (E-Ext), 0.0706 (L-Ext). d, Exemplar time-aligned dopamine signals from a mouse during each phase. e, Chronic measurement of dopamine in the NAc evoked by optogenetic stimulation of dopamine neurons in the VTA of DAT-Cre mice expressing ChR2 (error bars are obtained from measurements from n = 6 biologically independent mice). P-values: 0.9011 (week 4), 0.9926 (week 8), 0.6946 (week 12), 0.4462 (week 16). f, g, Representative measurements from a NeuroString electrode in a mouse across 16 weeks in the form of background-subtracted cyclic voltammogram (f) and the corresponding electrochemical impedance (g). P-values are calculated by paired two-tailed Student’s t-test: NS, P > 0.05; *P ≤ 0.05; **P ≤ 0.01; ***P ≤ 0.001.
