Locus Coeruleus Activation Patterns Differentially Modulate Odor Discrimination Learning and Odor Valence in Rats

LC (Locus ceruleus) UBERON:0002148 functionally connects to BLA (basal amygdaloid nucleus) UBERON:0002887 · Rat

Optogenetic stimulation of locus coeruleus neurons redistributed which odor-activated basolateral amygdala neurons expressed cFos: 10-Hz phasic light favoured accumbens-projecting cells while 25-Hz tonic light favoured central-amygdala-projecting cells, with total cFos counts unchanged. Light alone without odor did not change BLA cFos patterns, and intra-BLA α- and β-adrenoceptor antagonists abolished the conditioned odor preference and aversion driven by these LC patterns, indicating a noradrenergic modulatory action.

Fig. 7B–F; Fig. 6C,D; Supplementary Fig. S5

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VTA (Ventral tegmental area) UBERON:0002691 projects to ACB (Nucleus accumbens) UBERON:0001882 · Rat

Retrograde Cholera Toxin B placed in the nucleus accumbens labelled neurons in the ventral tegmental area; a larger share of these NAc-projecting VTA cells were cFos positive after 10-Hz phasic than after 25-Hz tonic locus coeruleus stimulation.

Supplementary Fig. S6 (described in Results, last paragraph)

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BLA (basal amygdaloid nucleus) UBERON:0002887 projects to CEA (central amygdaloid nucleus) UBERON:0002883 · Rat

Cholera Toxin B conjugated to a green fluorophore injected into the central amygdala retrogradely labelled neurons in the basolateral amygdala; labelled cell numbers were comparable across stimulation groups, and about 54% of odor-activated BLA cells were CeA-labelled after 25-Hz tonic LC stimulation versus about 11% in no-light controls.

Fig. 7A–C, F; Methods (CTB infusions)

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LC (Locus ceruleus) UBERON:0002148 functionally connects to VTA (Ventral tegmental area) UBERON:0002691 · Rat

Optogenetic 10-Hz phasic activation of ChR2-expressing locus coeruleus neurons paired with an odor raised the number of cFos-positive cells in the ventral tegmental area and the fraction of tyrosine-hydroxylase-positive VTA neurons expressing cFos, relative to odor-only controls; 10-Hz tonic activation of the same site produced no such increase.

Fig. 4D–H

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BLA (basal amygdaloid nucleus) UBERON:0002887 projects to ACB (Nucleus accumbens) UBERON:0001882 · Rat

Cholera Toxin B conjugated to a red fluorophore injected into the nucleus accumbens retrogradely labelled a population of neurons in the basolateral amygdala, which the authors counted and compared with cFos labelling. In no-light controls about 11% of activated BLA cells were NAc-labelled, rising to roughly 37% after 10-Hz phasic LC stimulation.

Fig. 7A–C, F; Methods (CTB infusions)

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