The participation of cortical amygdala in innate, odour-driven behaviour

Abstract

Innate behaviors are observed in naïve animals without prior learning or experience, suggesting that the neural circuits that mediate these behaviors are genetically determined and stereotyped. The neural circuits that convey olfactory information from the sense organ to the cortical and subcortical olfactory centers have been anatomically defined1-3 but the specific pathways responsible for innate responses to volatile odors have not been identified. We have devised genetic strategies that demonstrate that a stereotyped neural circuit that transmits information from the olfactory bulb to cortical amygdala is necessary for innate aversive and appetitive behaviors. Moreover, we have employed the promoter of the activity-dependent gene, arc, to express the photosensitive ion channel, channelrhodopsin, in neurons of the cortical amygdala activated by odors that elicit innate behaviors. Optical activation of these neurons leads to appropriate behaviors that recapitulate the responses to innate odors. These data indicate that the cortical amygdala plays a critical role in the generation of innate odor-driven behaviors but do not preclude the participation of cortical amygdala in learned olfactory behaviors.

The Nucleus Accumbens: Mechanisms of Addiction across Drug Classes Reflect the Importance of Glutamate Homeostasis

“…Much like the experiments discussed above, this strategy has produced exciting results. For example, recent work deciphering the role of the cortical amygdala in odordriven behavior has shown that the after isolation of odor-related ensembles, activation of these neuronal populations in the absence of odor recapitulates responses observed previously during odor exposure (Root et al, 2014). Furthermore, using the same mouse model, deactivating fear-related neural circuits in the hippocampus inhibits freezing behavior after exposure to a fear-inducing context .…”

Combinatorial effects of odorants on mouse behavior

“…1C and Fig. S4) (29)(30)(31)(32)35). Some odorant classes (azines, terpenes, thiols) included odorants with different behavioral effects whereas others (camphors and thiazoles) included only aversive odorants and still others (esters, ketones, and vanillin-like compounds) were uniformly neutral (Figs.…”

“…Innate odor responses, such as aversive responses to predator odors (3,21,23,(27)(28)(29)(30)(31)(32), are similar among individuals. The stereotyped nature of these responses suggests the existence of genetically determined neural circuits in which olfactory sensory input from a given receptor or combination of receptors has a high probability of eliciting a specific response.…”

Manipulating neural activity in physiologically classified neurons: triumphs and challenges

“…Moreover, photoactivation of these ensembles elicited approach and avoidance behaviours, respectively. Thus, the authors were able to identify neuronal representations in cortical amygdala that comprise determined neural circuits for the generation of innate olfactory responses [50].…”

“…This connectivity has been proposed to provide an anatomical substrate for innate and learned olfactory behaviours, respectively. Root et al labelled and manipulated neurons responsive to innately appetitive and aversive odours by using the Arc promoter to drive expression of the light-activated cation channel, channelrhodopsin [50]. The authors injected an AAV encoding a Cre-dependent channelrhodopsin fused to enhanced yellow fluorescent protein (ChR2-EYFP) into the cortical amygdala of a transgenic mouse in which the Arc promoter drives the expression of a tamoxifen-dependent Cre-recombinase (CreER rstb.royalsocietypublishing.org Phil.…”