compound stimulus
Recently Published Documents


TOTAL DOCUMENTS

88
(FIVE YEARS 9)

H-INDEX

18
(FIVE YEARS 1)

2021 ◽  
Author(s):  
Shruti Shridhar ◽  
Vikrampal Singh ◽  
Richa Bhatt ◽  
Sankhanava Kundu ◽  
Balaji Jayaprakash

Memory of an ordered sequence of distinct events requires encoding the temporal order as well as the intervals that separates these events. In this study, using order place association task where the animal learns to associate the location of the food pellet to the order of entry into the event arena, we probe the nature of temporal order memory in mice. In our task, individual trials, become distinct events, as the animal is trained to form unique association between entry order and a correct location. The inter-trial intervals (> 30 mins) are chosen deliberately to minimise the working memory contributions. We develop this paradigm initially using 4 order place associates and later extend it to 5 paired associates. Our results show that animals not only acquire these explicit (entry order to place) associations but also higher order associations that can only be inferred implicitly from the temporal order of these events. As an indicator of such higher order learning during the probe trail the mice exhibit predominantly prospective errors that declines proportionally with temporal distance. On the other hand, prior to acquiring the sequence the retrospective errors are dominant. Additionally, we also tested the nature of such acquisitions when temporal order CS is presented along with flavour as a compound stimulus comprising of order and flavour both simultaneously being paired with location. Results from these experiments indicate that the animal learns both order-place and flavour-place associations. Comparing with pure order place training, we find that the additional flavour in compound training did not interfere with the ability of the animals to acquire the order place associations. When tested remotely, pure order place associations could be retrieved only after a reminder training. Further higher order associations representing the temporal relationship between the events is markedly absent in the remote time.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Michael S. Totty ◽  
Naomi Warren ◽  
Isabella Huddleston ◽  
Karthik R. Ramanathan ◽  
Reed L. Ressler ◽  
...  

AbstractEnvironmental contexts can inform animals of potential threats, though it is currently unknown how context biases the selection of defensive behavior. Here we investigated context-dependent flight responses with a Pavlovian serial-compound stimulus (SCS) paradigm that evokes freeze-to-flight transitions. Similar to previous work in mice, we show that male and female rats display context-dependent flight-like behavior in the SCS paradigm. Flight behavior was dependent on contextual fear insofar as it was only evoked in a shock-associated context and was reduced in the conditioning context after context extinction. Flight behavior was only expressed to white noise regardless of temporal order within the compound. Nonetheless, rats that received unpaired SCS trials did not show flight-like behavior to the SCS, indicating it is associative. Finally, we show that pharmacological inactivation of two brain regions critical to the expression of contextual fear, the central nucleus of the amygdala (CeA) and bed nucleus of the stria terminalis (BNST), attenuates both contextual fear and flight responses. All of these effects were similar in male and female rats. This work demonstrates that contextual fear can summate with cued and innate fear to drive a high fear state and transition from post-encounter to circa-strike defensive modes.


2021 ◽  
Author(s):  
Michael S. Totty ◽  
Naomi Warren ◽  
Isabella Huddleston ◽  
Karthik R. Ramanathan ◽  
Reed L. Ressler ◽  
...  

ABSTRACTEnvironmental contexts and associative learning can inform animals of potential threats, though it is currently unknown how contexts bias defensive transitions. Here we investigated context-dependent flight responses in the Pavlovian serial-compound stimulus (SCS) paradigm. We show here that SCS-evoked flight behavior in male and female rats is dependent on contextual fear. Flight was reduced in the conditioning context after context extinction and could be evoked in a different shock-associated context. Although flight was exclusive to white noise stimuli, it was nonetheless associative insofar as rats that received an equal number of unpaired USs did not show flight-like behavior. Finally, we found that inactivation of either the central nucleus of the amygdala (CeA) or bed nucleus of the stria terminalis (BNST) attenuated both contextual fear and flight responses. This work demonstrates that contextual fear summates with cued and innate fear to drive a high fear state and freeze-to-flight transitions.


2020 ◽  
Vol 393 ◽  
pp. 112774
Author(s):  
Mohamed L. Drame ◽  
Maria Balaet ◽  
Jonathan L.C. Lee

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Sarah Hersman ◽  
David Allen ◽  
Mariko Hashimoto ◽  
Salvador Ignacio Brito ◽  
Todd E Anthony

Assessing the imminence of threatening events using environmental cues enables proactive engagement of appropriate avoidance responses. The neural processes employed to anticipate event occurrence depend upon which cue properties are used to formulate predictions. In serial compound stimulus (SCS) conditioning in mice, repeated presentations of sequential tone (CS1) and white noise (CS2) auditory stimuli immediately prior to an aversive event (US) produces freezing and flight responses to CS1 and CS2, respectively (Fadok et al., 2017). Recent work reported that these responses reflect learned temporal relationships of CS1 and CS2 to the US (Dong et al., 2019). However, we find that frequency and sound pressure levels, not temporal proximity to the US, are the key factors underlying SCS-driven conditioned responses. Moreover, white noise elicits greater physiological and behavioral responses than tones even prior to conditioning. Thus, stimulus salience is the primary determinant of behavior in the SCS paradigm, and represents a potential confound in experiments utilizing multiple sensory stimuli.


2020 ◽  
Author(s):  
Mohamed L. Drame ◽  
Maria Balaet ◽  
Jonathan L. C. Lee

AbstractStudies of memory reconsolidation of pavlovian memories have typically employed unimodal conditioned stimuli, despite the use of multimodal compound stimuli in other settings. Here we studied sign-tracking behaviour to a compound audiovisual stimulus. First, we observed not unexpectedly that sign-tracking was poorer to the audiovisual compound than to unimodal visual stimuli. Then, we showed that, depending on the parameters of compound stimulus re-exposure at memory reactivation, systemic MK-801 treatment either impaired extinction to improve signtracking at test, or disrupted reconsolidation to impair test behaviour. When memory reactivation consisted of re-exposure to only the auditory component of the compound stimulus, we observed sign-tracking impairments following MK-801 treatment, but only under certain test conditions. This was in contrast to the consistent impairment following reactivation with the full audiovisual compound. Moreover, the parameters of auditory stimulus presentation to enable MK-801-induced impairment at test varied depending on whether the stimulus was presented within or outside the training context. These findings suggest that behaviour under the control of appetitive pavlovian compound stimuli can be modulated by targeting both extinction and reconsolidation, and that it is not necessary to re-expose to the full compound stimulus in order to achieve a degree of modulation of behaviour.


2019 ◽  
Author(s):  
Mengyuan Gong ◽  
Taosheng Liu

AbstractSelective attention is a core cognitive function for efficient processing of information. Although it is well known that attention can modulate neural responses in many brain areas, the computational principles underlying attentional modulation remain unclear. Contrary to the prevailing view of a high-dimensional, distributed neural representation, here we show a surprisingly simple, biased neural representation for feature-based attention in a large dataset including five human fMRI studies. We found that when participants selected one feature from a compound stimulus, voxels in many cortical areas responded consistently higher to one attended feature over the other. This univariate bias was robust at the level of single brain areas and consistent across brain areas within individual subjects. Importantly, this univariate bias showed a progressively stronger magnitude along the cortical hierarchy. In frontoparietal areas, the bias was strongest and contributed largely to pattern-based decoding, whereas early visual areas lacked such a bias. These findings suggest a gradual transition from a more analog to a more abstract representation of attentional priority along the cortical hierarchy. Biased neural responses in high-level areas likely reflect a low-dimensional neural code that facilitates robust representation and simple read-out of cognitive variables.


2018 ◽  
Author(s):  
Sarah Hersman ◽  
Todd E. Anthony

SUMMARYAnimals exhibit distinct patterns of defensive behavior according to their perceived imminence of potential threats. Ethoexperimental [1, 2] and aversive conditioning [3-5] studies indicate that as the probability of directly encountering a threat increases, animals shift from behaviors aimed at avoiding detection (e.g. freezing) to escape (e.g. undirected flight). What are the neural mechanisms responsible for assessing threat imminence and controlling appropriate behavioral responses? Fundamental to addressing these questions has been the development of behavioral paradigms in mice in which well-defined threat-associated sensory stimuli reliably and robustly elicit passive or active defensive responses [6, 7]. In serial compound stimulus (SCS) fear conditioning, repeated pairing of sequentially presented tone (CS1) and white noise (CS2) auditory stimuli with footshock (US) yields learned freezing and flight responses to CS1 and CS2, respectively [6]. Although this white noise-induced transition from freezing to flight would appear to reflect increased perceived imminence due to the US being more temporally proximal to CS2 than CS1, this model has not been directly tested. Surprisingly, we find that audio frequency properties and sound pressure levels, not temporal relationship to the US, determine the defensive behaviors elicited by SCS conditioned auditory stimuli. Notably, auditory threat stimuli that most potently elicit high imminence behaviors include frequencies to which mouse hearing is most sensitive. These results argue that, as with visual threats [8], perceived imminence and resulting intensity of defensive responses scale with the salience of auditory threat stimuli.


Sign in / Sign up

Export Citation Format

Share Document