Dr. Lars Schwabe - Stress, Memory, and Behavioral Flexibility with

In this episode of the Research Bites Podcast, Dr. Kristina Spaulding talks with Dr. Lars Schwabe about what happens to learning and memory when the brain is under stress—and why those changes matter for behavior, training, and mental health.

They begin by unpacking how memory works in the first place, walking through the stages of encoding, consolidation, and retrieval. From there, they explore the still-debated idea of reconsolidation—the possibility that when memories are retrieved, they may briefly become modifiable. Dr. Schwabe discusses the evidence behind this concept, along with early attempts to reduce the emotional intensity of memories in conditions such as addiction and PTSD.

The conversation then turns to the physiology of stress. Dr. Schwabe explains how acute stress activates the sympathetic nervous system and the HPA axis, releasing cortisol and reshaping how the brain prioritizes information. Under these conditions, the amygdala tends to amplify emotionally salient details. As a result, stress can strengthen central aspects of emotional and threat-related learning while weakening contextual information and working memory.

These shifts have important behavioral consequences. When stress is high, certain types of learning becomes stronger—one possible pathway to fear generalization. Dr. Schwabe also discusses how stress can change the type of behavior we rely on. Goal-directed behavior—associated with the prefrontal cortex—allows flexible updating based on outcomes. Habitual behavior, more closely tied to other brain areas, is faster but less flexible. Under stress, the balance can shift toward habits and away from flexible decision-making.

Throughout the conversation, Dr. Spaulding and Dr. Schwabe explore what these findings might mean for animal training, resilience, learned helplessness, and the treatment of stress-related disorders. They also emphasize an important reality of scientific work: translating laboratory findings into real-world practice is complex, and individual differences play a major role in how stress affects learning and beha

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Transcript

[00:00:00] 

Speaker 5: Hello and welcome. I'm Dr. Kristina Spalding, and this is the Research Bys Podcast brought to you by Science Matters Academy of Animal Behavior. We foster conversations about science and its application to animal training and behavior. In an effort to improve wellbeing for animals and the people they live with, please enjoy geeking out about the science of behavior.

Host: Hi Lars. Thank you so much for joining me today. 

Guest: Yeah, hi Kristina. Nice to meet you. 

Host: I'm really looking forward to this. I want start by, before we get into the details of, of what you're working on I just want to start by thanking you for the work that you do, because you do a lot of work on stress and memory.

And this has actually been very, very helpful. In the work that [00:01:00] we do with dogs and helping us to understand how to change behavior. Okay. 'cause I actually think in certain contexts a lot of the behavior that we see with dogs is related to habit for one thing. Mm-hmm. 

And so understanding how habit works, which we'll get into today, has helped.

Us understand how we can change some of these behaviors that we're seeing that often are very resistant to behavior change. So I don't know if you knew that, but your work has been 

Guest: very No, it's, it's, it's good to hear. I, I think I didn't know before, but yeah, it's, it's great to hear. 

Host: So, as I said, you do a lot of work on memory and stress, so can you just talk a little bit about how you came to this subject and why you study it?

Guest: Yeah, well, I mean, to, to be honest, I came into that topic quite by chance when I was looking for PhD positions 20 years [00:02:00] ago. And there was one professor who offered a project on, on stress and memory, and I was right away, pretty fascinated by this topic. And I'm still fascinated by this topic.

I think it's extremely relevant. I think it's telling us a lot about how learning and memory works in general, but it has also important practical educations for mm-hmm. For example, understanding psychopathology for educational contexts and as I've just learned also for dock owners, which is also great.

Host: Yeah. Yeah, I agree. I think it is fascinating and has a lot of practical implications.

 Can you start by talking about what memory is, because I think people have a, like, they think they know what memory is, but there's actually multiple different components to it, and we're gonna be talking about mm-hmm. Those components today. So can you just explain the basics of how it works? 

Guest: Yeah. So, uh, memories are actually built in [00:03:00] stages.

So that means we start with encoding. So. Learning new information, acquiring new information. Once you hear something, once you see something. In order make those last for a longer time, it needs to be consolidated. So that's a second important stage after which then leads to a transfer from a short term or temporary store towards a longer term memory store.

And once this phase of consolidation has been completed, uh, then we should be able to recall or retrieve the memory at later stages. So these are the three main stages, encoding. Consolidation and retrieval. 

Host: Okay. And then there's also reconsolidation, right? 

Guest: Exactly. I mean, that's, that's a more debated topic I would say.

Oh, okay. So the idea is that, um, once we retrieve, uh, a consolidate memory, that this memory would reenter [00:04:00] a state, a fragile state 

Host: mm-hmm. 

Guest: From which it needs to be stabilized and new. During a process called reation. And the really interesting, uh, thing is that it's assumed that during this transient, uh, reconsolidation window, memories would be modifiable.

So susceptible to change. So that means that once we retrieve, we recall a certain previous event, even if that happened years ago, we should be able to modify our memory for this event. And I think that's pretty fascinating. That has, of course, very important indications also when you think about clinical, uh, situations, unwanted memories, highly stressful memories.

So that's a very interesting and important topic. I would say. We, and also some other colleagues found some evidence, uh, suggesting that supporting the idea of a. To, uh, mention it well as well, that [00:05:00] there's also some evidence that is questioning the idea of, uh, memory, uh, reconsolidation. So it's a question.

Mainly the key question of this debate is whether you actually changed the original memory or whether you are just forming a new competing memory trace at the time of retrieval. 

Host: Right. Okay, that makes sense. And for reconsolidation to happen, does that require like a verbal recall or is this something you can see going on in like rodents as well, for example?

Guest: Well, it has been demonstrated in rodents and also, uh, in, in other species. So it's possible to reactivate the memory trace, uh, also via relatively subtle. Reminder cues. So by just presenting, for example, the context in which a specific event had been ENC quoted or, uh, some other cues that were associated with the original, uh, event.

So it doesn't need to [00:06:00] be, uh, a verbal reactivation. 

Host: And then once you've recalled that memory, are we trying to sort of change the emotional response, for example, to change how it is reconsolidated. 

Guest: Exactly. So that would be, uh, the idea. And I mean, there are different approaches to that. So, I mean, initially, , many studies talked about, for example, pharmacological interventions, 

Host: right?

Guest: So we know. Order to, um, to have this, uh, memory boost for emotionally arousing events, you typically need, uh, an increase in, in activity of a neurotransmitter called Marin. And, um, there are certain, , drugs that can interfere with the action of this, uh, neurotransmitter. And there are some evidence suggesting that if you administer those drugs after retrieval, so during the potentiation, window.

Emotionality or the emotional that comes with a specific [00:07:00] event.

Host: Yeah. Really, really fascinating work. I've, I've seen some of that going on and it's, yeah, it's super, super interesting. The implications of that. That is still, I think, very much at the experimental stages, right? Not being used clinically. 

Guest: Well, I mean there, there have been first attempts, for example, in drug addicts or also in PTSDs patients, but I would say it's, it's still preliminary data.

So it's, it's not really that we're at the stage that we could really, do that in, in, in clinical se settings as a standard treatment. So, uh, we're not that far yet. 

Host: Maybe coming in the future, 

Guest: hopefully. 

Host: So you talk about four different domains where stress impacts memory, and it's actually quite complex.

I remember I, I have a book that I wrote on stress in Dogs, and I just, but I was working on the stress and memory section. It was just, it was a lot to try [00:08:00] and sort through, but I think it seems like the thinking on this has maybe become a little bit more clear. Recently. So the first effect is how stress impacts memory formation or encoding.

And we, we already know that highly emotional or stressful events tend to be remembered better. So can you talk about. Happens when an animal is stressed during memory and coding. 

Guest: Yeah, so I think it's, uh, very important to really understand what's going on If an, uh, individual animal or human, uh, is stressed, and what happens is that several physiological response systems, uh, get.

So, uh, there's a very rapid, immediate response within seconds that is mediated primarily via the autonomic or sympathetic nervous system. So, uh, this leads, for example, to the increase in heart rate or to this, that we all know from our [00:09:00] own, uh, stressful situations. 

Host: Mm-hmm. 

Guest: And that's due to the release of adrenaline and, uh, no adrenaline.

From the Adrenal Me doula, in, uh, response to stress. So that happens really within seconds. And in addition, there is a parallel slower response and endocrinal hormonal response, that's immediate by the by. It's a complicated term, but, but aam pituitary adrenal axis. So that's a, an axis that leads in the end to the release of, uh, glucocorticoid such as cortisol, immune.

So cortisol, people might have heard about that before. So that's in hormone. And that's, uh, typically released only, uh, peak levels. That's. To after the onset of a stressful event. So relatively, late. But the important thing about, uh, cortisol is that it can cross the blood brain barrier and act directly on the brain.

And it acts primarily on, regions such as the prefrontal cortex or areas of the media temporal lobe, [00:10:00] including theus. And, and these are exactly those brain regions where we know that these are highly relevant for. Learning for memory, for decision making. So for these higher order, uh, cognitive processes and it's idea that through the action of these neurotransmitters and hormones, stressful events can impact the way we encode information.

Yeah. 

Host: Right. And so we have this so that adrenaline, uh, or noradrenaline, maybe causes this increased activation of the amygdala. Correct. Do I have that right? 

Guest: Well, that, that's, that's also one important idea. Exactly. 

Host: Yeah. And then the amygdala is, if I'm remembering back to my learning neuroscience from 10 years ago, the amygdala is the one that is responsible for that increased encoding of the emotional memories.

Guest: Yeah, exactly. So the Amala definitely plays a critical role, and it's the idea that there's indeed, um, an [00:11:00] increased amygdala activity in situation in highly stressful situations. And that's also driven by, by, uh, no adrenaline, uh, and cortical such as cortisol appear to amplify this module in the fact. And then the amala, um, would modulate memory, uh, storage processes in other brain regions such as, uh, the hippocampus.

So it's idea that the amala is not the storage site itself, but it's modulating memory processes in other regions. So it's telling, for example, the hippocampus, Hey, this is important. You should better store that for the future, 

Host: right? 'cause the amygdala is also important for salience. So it's, 

Guest: yeah, definitely 

Host: flagging it.

Yep, that makes sense. So when we're talking about this stress enhancement of memory, does that apply to all types of memory or only like episodic memory, for example? 

Guest: Yeah, that's, it's a very, uh, a good question. So, um, it's actually fairly complex, I have to admit. So, [00:12:00] um, mean, it's typically assumed that episodic memories are indeed enhanced.

So. You have better episodic memory for what was happening during a stressful event. But even this is not a global enhancement. So it's not that everything that you encoded under stress is later better remembered. But it seems that really the. Key element, the central features of these, of this, uh, stressful, uh, episode.

This is what is later better remembered, but other aspects of, uh, the stressful encounter, such as contextual background, some other things that going on, but that the focus of attention, that there's actually reduced memory for, for these, what we call peripheral types of information. I think that's also important, uh, uh, to know that it's also balancing, right?

So it's, uh, prioritization of the most relevant aspects of a situation. So that's, uh, when, when it comes to, episodic memory, and we [00:13:00] know that other forms of memory as we might discuss, uh, uh, later on, uh, even impaired. By such as memory, rie working memory processes, typically by stressful events. Yeah.

And. Learning memory that are enhanced by stress. For example, q, dependent learning and memory processes. So associating, for example, a threat exposure to threat with a specific stimulus that's typically enhanced. I'm not stressed. or also, uh, as we might, uh, translate your on also habit formation is assumed to be enhanced.

Host: And we will definitely, um, get to those things because I think those are very, very relevant for what we do, when we're working on dog behavior and other species too. Um, when it comes to fear and things like that. and I should have done this first, but so episodic memory, 'cause not everyone knows what episodic memory is.

episodic memory is sort of this autobiographical type memory that we have of sort [00:14:00] of what, why. Where, et cetera. And then working memory, you can probably define this better than I can. Can you just clarify what working memory is? 

Guest: So memory is what is, in late terms, often referred to as, it's called short term memory.

So that means, uh, maintaining certain information for a relatively short period of time, but it's a name, uh, working memory suggests it's not just about some passive maintenance, but it's also doing something, with, uh, with this, uh, maintained information. So. One, uh, good example is mental arithmetic or, if you, uh, cook something and you've read something in the, uh, recipe book and, uh, then you go to your part and you try to implement things, and so you have to combine information.

So that's what, what working memory is doing and what it's for. So it's extremely important. 

Host: Right, and it's also important for the audience to understand that it's, this is something that does come into play in non-humans too. And so, as [00:15:00] I understand it, you know, something like remembering a cue 

Guest: absolutely 

Host: might be an example of working memory and, and staying focused on if, you know, if you're queued to do something that maybe has multiple steps that you can stay focused on that as you're going through these different activities and there's distractions happening around you.

Guest: Absolutely. Yeah. 

Host: Why don't we go to context memory next. You talked about this a little bit already. Mm-hmm. In terms of the difference between the, the remembering cues and context. But one of the things that we think is happening in PTSD. Is that fear becomes over generalized. And this is related to how stress affects context memory.

So can you, can you talk a little bit more about that distinction between context and Q and then how that's impacted by stress? 

Guest: Yeah, absolutely. So it's, uh, another, uh, very important distinction. So, um, let's imagine the very following scenario. You are walking your dog. Somewhere and let's say in a [00:16:00] park and then all of a sudden, uh, you or a dog is, is attacked by another dog.

And, then, uh, you could, uh, learn different things. You could associate the threat of this other aggressive dog. The park that you're in. And that would be an example of context memory. So you are associating specific stimuli in your environment with a specific, um, experience. Uh, you form relational or we call relational maps.

So associations between multiple Jews, or you could just associate. Threatening encounter with a specific stimulus. For example, the, um, the look of the specific, uh, dark or the barking that you heard before or things like that, and the letter, if you associate a specific experience, just the single stimuli, that's what we call two dependent learning or two dependent threat learning.

Whereas if you associated it with the multiple stimuli. In the [00:17:00] environment, then this is referred to as contextual memory or contextual learning. And what we, and also others, uh, also different species could, uh, show is that under stress. And when stress hormone levels are high, typically this contextual learning is impaired.

Two dependent, uh, learning and memory is enhanced. So it's this balance of contextual and two dependent, uh, learning is altered in favor of their dependent learning under stress. And that might be indeed highly relevant in the context of PTS because people show them these, extreme emotional responses.

Context. Context. So also in contexts that are actually safe, because the memory is not bound to the context any longer, but they show it in multiple contexts. They generalize, as you, uh, mentioned, and they just respond to specific cues that were associated with traumatic events. Uh, suggest certain orders or [00:18:00] tones or even certain words.

And that is really an, a very prominent, uh, example of the strength. Dependent, uh, learning or as we sometimes say, stimulus response, learning and not stress. 

Host: Right. And again, something, I mean, I love that you used a dog example, right? Because this is something we talk a lot about in the animal training world, is that they have this context learning.

and that idea that it under stress, that that context learning isn't quite working as well. I don't know if that's necessarily how we would put it, because it's, there's an adaptive value to it, right? So we say it's not working. Yeah, absolutely. But there's actually a function to that as well. 

Guest: Yeah.

Yeah, absolutely. And I think that that's also very, uh, important, um, aspect, right? Because I mean, we assume that, how our brain responds, to stressful events that this is in general, highly adaptive, uh, it has developed, um, over hundreds or thousands of years. And, um, that's really important for [00:19:00] coping with those situations.

Think about stressful, potentially life-threatening situations. It's really essential to prioritize the most salient, the most relevant, uh, information. And then if it's about those life-threatening events, we're better safe than sorry, right? So it's better to really make sure that you're appropriately, appropriately responding to, uh, to the potentially threatening.

Sti then thinking too long about whether it might be relevant or not. 

Host: And if there's a, you know, if we're attacked by a dog and the thing that you learn the most is the park, but then you encounter that dog somewhere else, you're not gonna have, you know, the same response. And that might be end up being important if you don't respond appropriately,

there's. There's a difference between the, I mean, as you know, but there's a difference between the acute stress response and [00:20:00] chronic stress. So how much do we understand about differences between the effects of acute and chronic stress on memory? Because once again, for the listeners, once an animal is under chronic stress, things change a lot.

And sometimes they have. Chronically elevated levels of glucocorticoids, but sometimes they actually don't. And if those glucocorticoids are part of what's having these memory influences for me mm-hmm. It gets very hard to predict or understand what chronic stress might be doing to memory. 

Guest: Yeah. So, um, I.

At least in humans, there's significantly more research on the effects of acute stress, and that's just for the simple reason that you can induce acute stress in the lab. And that's for obvious ethical reasons, not possible chronic stress. You can only do some correlations asking people, questionnaires, how stressed they felt over a couple of months, period of a couple of [00:21:00] months.

But it's. Not possible to induce it experimentally, however, in animals there is, um, actually, um, also research where, for example, rats or mice were exposed to feathers repeatedly and for a prolonged period of time. Uh, so we knew a, uh, know also a little bit about, uh, the effects of, uh, chronic stress. And the pretty clear picture is that chronic stress is detrimental for memory.

So that's pretty well established. So, um. You can, uh, even show that after periods of, uh, prolonged and intensive, uh, stress, there's a decreased in brain volume. So gray meta volume in, regions that are really key for learning and memory. Uh, also for what's we call inhibitory controls. So, um, being able to inhibit certain responses.

Host: Yep. 

Guest: So might, might be also, uh, important. There's. There's also some evidence, uh, in humans, again, not [00:22:00] experimental, but , what was done, for example, is that, some colleagues, , tested students, university students that were preparing for medical exams. So, uh, it's also, . Very stressful period. The students were tested during this Heidi stressful, extended, stress period and also afterwards.

And, um, they could also show that, , even in these, math students, there's decreased volume in, , regions such as the prefrontal cortex news. Once, , those, periods of extended stress were over there was also recovery. So, um, that, there was again, a certain, , increase in, uh, brain volume in these, , regions that I would assume that something very similar is happening in, in, uh, dogs and in other animals as well.

So, um.

I think I would say in, in virtually all cognitive processes. But the good thing is that it's apparently reversible. 

Host: Is that true [00:23:00] in j Just in adults though. What about developmental chronic stress and memory that that has longer lasting effects? Correct. 

Guest: I mean, yeah. We, we know that, uh, there are certain periods of brain, uh, developed.

Spend that are particularly critical. So we refer to them also as critical. For example, during childhood, these are critical period. Intense, uh, stressful events were, uh, also extended stress during those periods. It has particularly detrimental effects, so that's also really well documented effects of, for example, childhood, childhood adversity and so forth.

So that has, uh, unfortunately, very long, long-lasting negative. It does not mean that we can't do anything. So I mean, there might be certain therapeutic interventions that might, uh, improve the situation, but it's difficult for sure. So you are right. It might depend also on the, the period of brain [00:24:00] development.

Host: I think we've already talked about this a little bit. 'cause it all, you know, it's all related. Yeah. The, so the impacts on retrieval, I mean, I think we really have talked about this, but just if there's anything you wanna add, let me know. So stress and retrieval, it has a, if I understand it correctly, there's a negative impact on aspects.

Of that memory that may not be directly related to the sort of traumatic or stressful thing that happened, but mm-hmm. You're more likely to recall things that were directly related, or at least the brain thought were directly related. 

Guest: Yeah. Yeah. I mean, it's um, generally assumed and also repeated has been repeatedly shown that acute stress impairs.

Re or ability to recall certain past events and typically also those events that are not directly related to the ongoing stressor. So, um, that has been repeatedly, uh, shown and it's of course, also highly relevant. For example, in exam situations, it might explain the, the blackouts [00:25:00] that some, students, uh, experienced from, uh, time to time.

Uh, so it's also a really relevant, uh, fact and, um. The other aspect that they mentioned. Um, so to what extent there's actually increased, uh, memory or at least unimpaired memory for those aspects that are key to the stressor. That's also something that I would say, um, it's. Research is still ongoing. Uh, so, um, we are also planning some research on this, uh, because it has not been really systematically studied.

So the classical study is really that you expose people to a certain stressor and then you task memory for certain pictures or words that people have learned before. So really unrelated material, but also finding something that's really directly related to the stressor in an experimental setting. But I think it's important to have really, um, yeah, more fine grained and maybe [00:26:00] also in a more appropriate view on, uh, how, uh, stress actually affects re processes.

Host: Yeah. Because it's not, anytime we're talking about behavior, things get very complicated very quickly. So this brings us to the part that I think is the most fascinating, which is the relationship between memory and stress and flexibility. And so I do think before we jump into that, we need to define a few things.

So we're gonna be talking about habit and goal directed behavior. Can you define each of those for the listeners? 

Guest: Yeah. Yeah. So these are two, distinct modes of, uh, what we call instrumental learning. So instrumental learning is about learning. How to act to achieve certain desirable outcomes where I avoid, uh, unpleasant outcomes.

And, uh, this might be another control of two different mechanisms or [00:27:00] processes. One is goal-directed learning. So goal-directed learning means we are learning the causal association between a certain action and the specific outcome. Yeah. And that's typically under the control of the prefrontal cortex.

Uh, there might be a different process, and that's a habitual process. And the habitual process learn association between a certain stimulus and a certain response. So it's more or less independent of the outcome that's following the response or the action, but it's just stimulus. Response. And, uh, this typically develops with practice.

So the things that we've done a hundred times before, we don't reflect anymore what, uh, this is actually, uh, leading to, but we just do it in a certain situation in response to certain, and that's habitual learning. And, uh, both there both highly relevant. And I think [00:28:00] it's important to, to keep the wound balanced.

Host: Yeah. And so habitual learning is very, because it's this really strong relationship between the stimulus and the response, or as many animal trends would call it, the antecedent and the behavior. 

Guest: Mm-hmm. 

Host: It becomes very, very tightly sort of connected to or controlled by the environmental cues, and therefore it's less flexible.

Right? Mm-hmm. When we talk about it being less flexible, what we mean is that it's not as responsive to the outcome, or again, we would call it the consequence. But, and this is what I mean when I first learned about this, this kind of blew my mind, is that 

Guest: mm-hmm. 

Host: The behavior will continue in the absence of reinforcement, correct.

Guest: Yeah, exactly. So that's, that's, uh, the, the key element of it, that it really becomes independent of, the outcome of the reinforcement. Um, and it's really automatic in a way. And this leads also then to the, uh, [00:29:00] inflexibility to the, uh, reduced flexibility, right? Because you cannot adjust the behavior if the environment changes, but you're just doing what you've learned before.

Host: Right. And this is the piece that we have found to be very helpful in our field because you can take like, so one example of a behavior that I think can become very habitual, I don't think it always is, but is barking and lunging on leash. You know, when you see dogs that are barking and lunging at other dogs or bicycles or something, I think there are aspects of that that can become habitual.

And so if we remove the dog. From their typical environments, if they have a typical place where they go to be walked and we can bring them to a novel environment, it seems like the behavior becomes more flexible and more responsive to training. Mm-hmm. And I suspect that's because it's habitual. Yeah. 

Guest: I mean that, that might well be the case that there's uh, um, the association between that specific context [00:30:00] and the response pattern, the barking, uh, et cetera.

So that might well be that there's a strong connection between, Yeah. 

Host: And then goal directed behavior, on the other hand, is much more flexible.

So. When I first started talking about goal-directed behavior, I got the question a lot about whether or not animals can actually have goals. But we, I mean, we do see what we call goal-directed behavior in non-human animals, correct? 

Yes.

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Guest: Absolutely. So it has been, shown in, in rodents, but also in other animals.

So I think it's then also a question how you define goal-directed behavior, right? And, , this context, it's, really defined as behavior that is sensitive to the motivational value of a certain outcome or reinforcer. So, um. If the animal changes its behavior, depending on whether it wants a certain outcome or it doesn't want, , this outcome.

And, , this has been really, , nicely demonstrated. , And I'm pretty sure [00:32:00] that. 

Host: I'm fully convinced that they, they do show that distinction between those two different kinds of behaviors. So, before we get into stress, uh, I have one question that I've mm-hmm. I think I know the answer to, but I would like to confirm.

So when we're talking about habitual behavior, it's not completely immune to extinction. Isn't, is it like it'll eventually does it, I mean. If the behavior continues in the absence of reinforcement indefinitely, do we eventually see a decrease in the strength of that behavior, even if it's habitual? 

Guest: Yeah, I mean, I would, I would agree that one would expect.

A pattern. I mean, from a theoretical perspective, it's not that clear cut because this operational definition of go directed or habitual responding doesn't really say something about the resistance to extinction. But [00:33:00] still in, in practical terms, if we would run this, uh, experiment, I would also assume that then at some point, the behavior.

reduced to some degree again. So what we would refer to, um, extinction. Extinction, the critical aspect is really the sensitivity to, uh, for example, outcome, , devaluation. And so one would need to. Repeatedly test the sensitivity of behavior to, um, outcome, uh, devaluation, and then, uh, see to what extent it's still there or not.

I think a critical aspect might be also whether the behavior has been shown repeatedly in between or not. So for example, this dock and park example, if you manage repeatedly that the dork does not sure this. Behavior, uh, in the park, and it might be really established. And it might be really, uh, routine and, uh, then it maybe does not [00:34:00] require the, the return of, reinforcement or so just because you have then this strong association between the new behavior and, uh, the context again.

Right. So that, 

Host: right, 

Guest: that would be then a, a favor habit, 

Host: right? Yeah. And I think, yeah, and I mean, my experience too, right, is that it's not like. There's goal directed. I mean, people can't see what I'm doing in the recording, but it's not like on one end we have goal directed behavior. and then there's habit.

And those are two completely separate categories. I mean, we we're going to see overlap in the middle where it has some elements of both. 

Guest: Yeah, I mean, classically there was really a pretty clear cut distinction, but more recent research shows that it's not that distinct and that there might be also so in between states, let's call it like that.

Right? So, uh, that it's more a continuum 

Host: that makes sense. The one other thing that I just wanted to clarify for people is that habit and goal directed learning, I mean, this is not just a semantic distinction because they actually [00:35:00] occur in different brain areas, correct? 

Guest: Yeah, absolutely. So, uh, the goal directed, uh, uh, learning behavior is mainly.

Dependent on the prefrontal cortex, whereas the habitual behavior relies more on what we call the basal ganglia. So the stri, so the fairly deep and, uh, evolutionary old brain area. So, and you can, uh, also really nicely see that if behavior is more and more frequently shown and more often repeated, that you can see.

The 

Host: That's you the of I. It can really help us differentiate between behaviors that can be a lot harder to, distinguish between by just observing the behavior. 

Guest: Mm-hmm. 

Host: So when I see that, okay, there's different brain areas that are involved in these different behaviors and that's really [00:36:00] important information to me, that they're actually different behaviors.

And that they probably, from a behavior modification standpoint, we may need to address them differently because different parts of the brain are, yeah. 

Guest: Yeah, absolutely. And, uh, we need also then really sophisticated tasks showing that, uh, these are actually different behaviors. Because also if, if you talk about goal-directed and habitual behavior, if you just.

At what, for example, participant or also dog or a rat is doing in a certain task. The behavior might, might look quite the same and it's very difficult to distinguish, but only by changing. Then there are contingencies or the environmental conditions. You see that it's actually a different. That's, uh, indeed fascinating and I agree that also, for example, brain imaging or other techniques, uh, might help here or can help, definitely can help that really show, uh, that there are different processes going on.

Host: Okay, so now we can get back to stress and memory flexibility. [00:37:00] 

Guest: Yeah, 

Host: and I spent a lot of time in my work talking about resilience and. And the fact that flexibility is an important component of resilience because if animals cannot flexibly respond to change or stress, it's then harder for them to cope with stress.

But at the same time, stress can reduce flexibility in a number of ways. What happens to memory flexibility when animals experience acute stress? And if you can also talk a little bit about. What exactly is memory flexibility? 'cause I don't know if people are gonna have a clear idea of what that means.

Guest: Yeah, yeah. So I mean, there are different, different views on that. So, so one perspective is that there, there is actually not just one single memory system, but there are multiple memory systems that have a different neural basis and that work, um, based on different Yeah, operational characteristics as we say.

So we talked about some of them, , already. So for example, contextual versus q [00:38:00] dependent. Or, um, goal directed, versus habitual. So you have some forms of a memory that, require some relational processing, some linking of a different elements, and some cognitive reflection. So some also, yeah, consciousness or awareness.

That then allows you also to adjust the behavior once environment changes in certain environmental conditions change and this ability to flexibly adjust your behavior or your responses. That's, I think, an essential element of a memory flexibility. Whereas these other more rigid processes, these are really.

Repeating the routines that you've done a thousand times before where it's just some automatic responding to certain cues. And this is then lacking the flexibility because you show that in all contacts, in all situations. So that's, uh, the distinction. And [00:39:00] as we discussed before, they're also different neural substrates, the, uh, neural substrates, the neuro basis of memory flexibility or more broadly.

Is to a large extent prefrontal cortex. And we know that the prefrontal cortex is highly sensitive to stress hormones, to neurotransmitters that are released in times of stress. And this is, I think, a main mechanism by which stress, uh, stress events may interfere with a behavioral and, uh, monic, uh, flexibility.

Host: I find this whole thing. So fascinating because when we're looking at, when we're looking at mental health disorders and people, and as well as when we're looking at, you know, behavioral issues in dogs, which sometimes is defined by the dog's welfare and sometimes by the humans not liking what the dog is doing.

But when we see, so if we focus, I would say on the decreased welfare of the dog, when they have something going on [00:40:00] that is decreasing their welfare, so sort of, um, an equivalent to like a mental health disorder in humans, I very much. You feel like they, they get stuck. Right, and they're, they're responding.

It's, they seem to be almost, in some cases, responding in. Sort of isolation to everything else that is going on around them. Like they're not, it doesn't appear like they're necessarily processing everything. Right? Yeah. Yeah. And that really fits with what you are saying, the research says about this relational processing and the ability to connect things to together.

And then, um, and you've also talked about in your. About decreased integration of information and also the decreased ability to sort of update or incorporate new information. And that to me seems like that must be very connected to mental health disorders and things like, you know. PTSD or other mental health disorders where you [00:41:00] have, like, someone may have an experience that's not as negative as they thought it would be, and yet that doesn't seem to be updated.

Am I mm-hmm. On the right track at all here? 

Guest: Yeah. Yeah, absolutely. I would absolutely agree. So, uh, I mean it's, uh, memory, uh, reduced max, uh, memory flexibility under stress is indeed reflected in a reduced updating capacity in a reduced. Integration of different, uh, events and memories. Um, also in the. To update knowledge, and this is exactly what we see, for example, in patients suffering from major depression or also in anxiety disorders.

Absolutely. That's also what these patients, report, that's what we see in clinical studies in which, , tasks with,, those, patient, , populations. So absolutely. . You can see that. And, uh, you can also see that once, once there's an improve in clinical symptoms,, if there's some, , [00:42:00] treatment, , success that you see, also an improvement in exactly those, processes and the flexibility, , of thinking and onic, flexibility.

So that seems to be highly relevant in this context. And.

Not directly, but uh, also what, what you're describing, uh, the observations it seems to suggest, suggest that there are very similar processes and mechanisms going on in, uh, dogs. And, uh, yeah, I can well imagine that that is highly relevant here as well. 

Host: I mean, certainly from our experience, I say our, you know, me and other professionals I've talked to, this does seem to be a big component.

And so if we think about that. Is there, is it possible to create a buffering effect by, you know, if, if, if we can, if an individual has higher cognitive flexibility to begin with, does that tend to buffer them against later stress? 

Guest: [00:43:00] Yeah, I mean, one would hope so. I mean, definitely there are individual differences.

You're referring to, uh, resilience before and. That there are, uh, some individuals that are highly resilient. So even to fairly extreme stressors as others are obviously not, and there are many, many components. So of course genetics plays a role, certain developmental experiences. Then of course a general, uh, level of cognitive functioning, let's call it like that, is a relevant factor.

We did actually a fairly recently one study where we, um, tried to test. Of cognitive training can also, uh, buffer detrimental effects. stress on certain, uh, cognitive functions. So what we did is we tested people's working memory capacity at baseline. And, uh, then, uh, we, gave them, uh, I think it was a six or even eight week, uh, training, daily training.

so it was an app [00:44:00] based, uh, training that was really directed at, strengthening, Memory related cognitive functions. And then after that, a training period, we exposed them either to stress or a control and tested them working memory, performance. And, uh, we saw that those that received, uh, the extended cognitive training indeed showed, um, somewhat reduced stress related impairments in working.

So it seems that some sort of training. Might be helpful here, and I mean, it doesn't need to be this lab based, fairly artificial training, but it's just. Right. So being mentally active doing tasks and that this might be something, uh, productive. 

Host: Yeah, I, I have a hypothesis that the amount of sort of control that we exert over dogs' lives and the amount of decisions that we make for them, and the limitations on exploration and things like that.

My [00:45:00] hypothesis. I mean, it hasn't been tested. If you ever wanna test, you know, test this on dogs. But my hypothesis is that because we limit their ability to interact and explore and make decisions on their own, I think that probably makes them less resilient to stress in the long run. And so there are a group of trainers and behavior consultants that are trying to encourage people.

It doesn't mean they don't have any rules, right? But just to do things like. Let them smell things as long as they want to and let them check out. Things that spook them until they can satisfy themselves that it's not actually dangerous. 

Guest: Yeah, yeah, absolutely. I mean, uh, what you're saying reminds me of a phenomenon that's called learned helplessness.

Host: Yeah. 

Guest: So that's an extremely, uh, influential, uh, phenomenon that was actually also for the first time demonstrated at Docs. 

Host: Right. 

Guest: And, uh, that's, uh, uh, a phenomenon. Briefly summarize it's idea that you first have a certain experience. It might be an aversive experience, but [00:46:00] also a more neutral one. And ation here is whether you learn that can control certain.

Or whether you cannot. Right. And those who, uh, cannot. Then in a subsequent, uh, situation where all individuals, all docs can actually control the situation and do something to reduce, for example, aversive stimulation. Also, those who have experienced before. Their behavior has no influence on the environment.

No influence on the outcomes that they were affected at several levels at the effecti level. So, uh, they had increased negative affect at the cognitive level, so they were less able to learn that they can now actually change the situation. And also motivational. So they even tried less to, really avoid negative outcomes and so forth due to this initial situation where they'd, uh, learned that, they can't do anything about, what, what's happening to them.

[00:47:00] and this is more or less what you're describing. So, uh, yeah, it's uh, an interesting, so again, highly relevant also in clinical context. It has been 

Host: right. 

Guest: It's highly influential factor in the context of depression or anxiety disorders. I mean, there's a more nuanced, uh, debate and perspective on that now, but, um, I think it's, it's a highly relevant phenomen 

Host: Yeah, absolutely.

Fascinating information. And I think, it's for people who aren't in this field and thinking really deeply about this, they probably don't necessarily think about memory as being. So important for kind of like emotional health, but it, it's really critical for that. 

Guest: Certainly. Uh, it's about learning that you can control what's happening to you.

So, uh, it might be, uh, really relevant emotionally relevant outcomes. But even the, the neutral ones, I mean. There are also some, studies in, in, uh, healthy, uh, participants, where it's just about solving anagram tasks. Yeah. So a fairly neutral [00:48:00] task, but even if you go, uh, give people a certain unsolved, uh, gram tasks, so where they.

Do not experience any control, of, uh, the outcome. Then you can show later that they have impairments in other unrelated cognitive tasks. Yeah. So it's really the experience of control that matters. 

Host: Yeah, it's really important. So despite this increasingly detailed understanding of the influence of stress on memory and the link to PTSD and other mental health conditions, it's been difficult.

To translate that information into clinical applications, particularly I think medications. Yeah. Can you talk a little bit about why that might be? 

Guest: Yeah. I mean it's, it's a tough question, but a very important one, and I think there are. Many answers to that. So, I mean, one part of it might be that, uh, in the lab we tend to use fairly artificial tasks.

I mean that's also for, for good reasons, because we wanna [00:49:00] control many, uh, variables, right? And wanna have it as clean as possible. But obviously in everyday life you rarely find, find such, uh, conditions. So it's about the matching of the lab tasks and the real life situation. I think that's one aspect.

Important one is that typically in lab studies we look at, group level differences. And much of what might be really relevant might be really at the individual level and that individual differences. So coming again back to resilience. Yeah. And a certain vulnerability factor. Factors. These might be really, really important.

And to really have a better understanding of such vulnerability or resilience sectors, you have to study, a large number of people, typically larger sample sizes than. Typically do in many of oral lab based study. But I think if you do that and let then look into individual differences, then uh, you get an impression of what might be going [00:50:00] on yearend.

That it's not that a gear cut that stress does A or stress does B, but that it might also really depend on the individual. And I think a better understanding of these individual differences might be also, uh, be important. 

Host: Yeah, that makes sense. And that takes a really long time to get right because we have to do so many studies to figure out.

What the different factors are. I mean, unless we get really lucky in the beginning, but you know, we're trying to figure out and you test it and then it's, you don't see the results that you were, you know, looking for. And yeah, that's a really hard thing to figure out. Okay, so the last question is, I always love this question.

What unanswered questions are at the top of your mind right now, and what do you think research should focus on? 

Guest: Yeah, I mean. Directly relates to what we just, uh, had discussed before. So I think looking into individual differences is important. And I mean, I, I've now been working in this, uh, field of stress and memory for more than 15 years.

Years. And I mean, I'm still very [00:51:00] fascinated by it, but also.

 Clinical relevance and what we can do to modulate these processes in order to help patients or to help people in educational settings. I mean, that's definitely something that I'd be, uh, interested in. And we're just currently planning our first studies really in patient populations. So that will be also very important and exciting.

But then on the other hand, also.

Who, who hear about that for the first time, then I think, wow, there's so much going on. And they know so much. But actually for someone working in the theater of impression, so, so did, so I mean, if you would ask me what are the detailed brain mechanisms, how, stress connects with this effects would say, well, I have a rough idea, but really no detailed understanding.

And this requires also this translation [00:52:00] across levels. Right? So from really very. In animals, uh, the, the behavioral cognitive neuroscience studies and then also of course the clinical, uh, studies and this translation across. Levels is extremely difficult, but mm-hmm. Also extremely important. 

Host: Yeah. Yeah. I agree.

I, I, I tell people that one of the most important things that I learned in graduate school was how little I know. 

Guest: Yeah. 

Host: How much we still have to learn. 

Guest: Absolutely. 

Host: Well, thank you very much. I really appreciate you taking the time to come talk about your work, which is really influential and, and fascinating, so.

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