Papers by Jessica Elizabeth
Neuroscience Research, 2016
By saying "Anyone who has never made a mistake has never tried anything new", Albert Einstein him... more By saying "Anyone who has never made a mistake has never tried anything new", Albert Einstein himself allegedly implied that the making and processing of errors are essential for behavioral adaption to a new or changing environment. These essential error-related cognitive and neural processes are likely influenced by reward value. However, previous studies have not dissociated accuracy and value and so the distinct effect of reward on error processing in the brain remained unknown. Therefore, we set out to investigate this at various points in decision-making. We used functional magnetic resonance imaging to scan participants while they completed a random dot motion discrimination task where reward and non-reward were associated with stimuli via classical conditioning. Pre-error activity was found in the medial frontal cortex prior to response but this was not related to reward value. At response time, error-related activity was found to be significantly greater in reward than non-reward trials in the midcingulate cortex. Finally at outcome time, error-related activity was found in the anterior cingulate cortex in non-reward trials. These results show that reward value enhances post-decision but not pre-decision error-related activities and these results therefore have implications for theories of error correction and confidence.
Depressive disorders contribute heavily to global disease burden; This is possibly because patien... more Depressive disorders contribute heavily to global disease burden; This is possibly because patients are usually treated homogeneously, despite having heterogeneous symptoms with differing underlying neural mechanisms. On the contrary, treatment that directly influences the neural circuit relevant to an individual patient’s subset of symptoms might more precisely and thus effectively aid in the alleviation of their specific symptoms. We tested this hypothesis, using fMRI functional connectivity neurofeedback to target a neural biomarker that objectively relates to a specific subset (melancholic) of depressive symptoms and that is generalizable across independent cohorts of patients. The targeted biomarker was the functional connectivity between the left dorsolateral prefrontal cortex and left precuneus, which has been shown in a data-driven manner to be less anticorrelated in patients with melancholic depression than in healthy controls. We found that the more a participant normalize...
Molecular Psychiatry, 2020
Patients with posttraumatic stress disorder (PTSD) appear to manifest two opposing tendencies in ... more Patients with posttraumatic stress disorder (PTSD) appear to manifest two opposing tendencies in their attentional biases and symptoms. However, whether common neural mechanisms account for their opposing attentional biases and symptoms remains unknown. We here propose a model in which reciprocal inhibition between the amygdala and ventromedial prefrontal cortex (vmPFC) predicts synchronized alternations between emotional under- and overmodulatory states at the neural, behavioral, and symptom levels within the same patients. This reciprocal inhibition model predicts that when the amygdala is dominant, patients enter an emotional undermodulatory state where they show attentional bias toward threat and manifest re-experiencing symptoms. In contrast, when the vmPFC is dominant, patients are predicted to enter an emotional overmodulatory state where they show attentional bias away from threat and avoidance symptoms. To test the model, we performed a behavioral meta-analysis (total N = 4...
Frontiers in Neuroscience, 2020
Olfaction is an evolutionary ancient sense, but it remains unclear to what extent it can influenc... more Olfaction is an evolutionary ancient sense, but it remains unclear to what extent it can influence routine human behavior. We examined whether a threat-relevant predator odor (2-methyl-2-thiazoline) would contextually enhance the formation of human fear memory associations. Participants who learned to associate visual stimuli with electric shock in this predator odor context later showed stronger fear responses to the visual stimuli than participants who learned in an aversiveness-matched control odor context. This effect generalized to testing in another odor context, even after extinction training. Results of a separate experiment indicate that a possible biological mechanism for this effect may be increased cortisol levels in a predator odor context. These results suggest that innate olfactory processes can play an important role in human fear learning. Modulatory influences of odor contexts may partly explain the sometimes maladaptive persistence of human fear memory, e.g., in post-traumatic stress disorders.
medRxiv, 2021
Depressive disorders contribute heavily to global disease burden; This is possibly because patien... more Depressive disorders contribute heavily to global disease burden; This is possibly because patients are usually treated homogeneously, despite having heterogeneous symptoms with differing underlying neural mechanisms. On the contrary, treatment that directly influences the neural circuit relevant to an individual patient’s subset of symptoms might more precisely and thus effectively aid in the alleviation of their specific symptoms. We tested this hypothesis, using fMRI functional connectivity neurofeedback to target a neural biomarker that objectively relates to a specific subset (melancholic) of depressive symptoms and that is generalizable across independent cohorts of patients. The targeted biomarker was the functional connectivity between the left dorsolateral prefrontal cortex and left precuneus, which has been shown in a data-driven manner to be less anticorrelated in patients with melancholic depression than in healthy controls. We found that the more a participant normalized this biomarker, the more related (brooding and more general depressive), but not unrelated (trait anxiety), symptoms were reduced. Thus, one-to-one correspondence between a normalized neural network and decreased depressive symptoms was demonstrated. These results were found in two experiments that took place several years apart by different experimenters, indicating their reproducibility. Indicative of their potential clinical utility, effects remained one-two months later.
Molecular Psychiatry, 2020
Patients with posttraumatic stress disorder (PTSD) appear to manifest two opposing tendencies in ... more Patients with posttraumatic stress disorder (PTSD) appear to manifest two opposing tendencies in their attentional biases and symptoms. However, whether common neural mechanisms account for their opposing attentional biases and symptoms remains unknown. We here propose a model in which reciprocal inhibition between the amygdala and ventromedial prefrontal cortex (vmPFC) predicts synchronized alternations between emotional under-and overmodulatory states at the neural, behavioral, and symptom levels within the same patients. This reciprocal inhibition model predicts that when the amygdala is dominant, patients enter an emotional undermodulatory state where they show attentional bias toward threat and manifest re-experiencing symptoms. In contrast, when the vmPFC is dominant, patients are predicted to enter an emotional overmodulatory state where they show attentional bias away from threat and avoidance symptoms. To test the model, we performed a behavioral meta-analysis (total N = 491), analyses of own behavioral study (N = 20), and a neuroimaging meta-analysis (total N = 316). Supporting the model, we found the distributions of behavioral attentional measurements to be bimodal, suggesting alternations between the states within patients. Moreover, attentional bias toward threat was related to re-experiencing symptoms, whereas attentional bias away from threat was related with avoidance symptoms. We also found that the increase and decrease of activity in the left amygdala activity was related with re-experiencing and avoidance symptoms, respectively. Our model may help elucidate the neural mechanisms differentiating nondissociative and dissociative subtypes of PTSD, which usually show differential emotional modulatory levels. It may thus provide a new venue for therapies targeting each subtype.
Frontiers in Neuroscience, 2020
Olfaction is an evolutionary ancient sense, but it remains unclear to what extent it can influenc... more Olfaction is an evolutionary ancient sense, but it remains unclear to what extent it can influence routine human behavior. We examined whether a threat-relevant predator odor (2-methyl-2-thiazoline) would contextually enhance the formation of human fear memory associations. Participants who learned to associate visual stimuli with electric shock in this predator odor context later showed stronger fear responses to the visual stimuli than participants who learned in an aversiveness-matched control odor context. This effect generalized to testing in another odor context, even after extinction training. Results of a separate experiment indicate that a possible biological mechanism for this effect may be increased cortisol levels in a predator odor context. These results suggest that innate olfactory processes can play an important role in human fear learning. Modulatory influences of odor contexts may partly explain the sometimes maladaptive persistence of human fear memory, e.g., in post-traumatic stress disorders.
Neuroscience Research, 2016
By saying " Anyone who has never made a mistake has never tried anything new " , Albert Einstein ... more By saying " Anyone who has never made a mistake has never tried anything new " , Albert Einstein himself allegedly implied that the making and processing of errors are essential for behavioral adaption to a new or changing environment. These essential error-related cognitive and neural processes are likely influenced by reward value. However, previous studies have not dissociated accuracy and value and so the distinct effect of reward on error processing in the brain remained unknown. Therefore, we set out to investigate this at various points in decision-making. We used functional magnetic resonance imaging to scan participants while they completed a random dot motion discrimination task where reward and non-reward were associated with stimuli via classical conditioning. Pre-error activity was found in the medial frontal cortex prior to response but this was not related to reward value. At response time, error-related activity was found to be significantly greater in reward than non-reward trials in the mid-cingulate cortex. Finally at outcome time, error-related activity was found in the anterior cingulate cortex in non-reward trials. These results show that reward value enhances post-decision but not pre-decision error-related activities and these results therefore have implications for theories of error correction and confidence.
Frontiers in Psychology, 2015
In a complex and uncertain world, how do we select appropriate behavior? One possibility is that ... more In a complex and uncertain world, how do we select appropriate behavior? One possibility is that we choose actions that are highly reinforced by their probabilistic consequences (model-free processing). However, we may instead plan actions prior to their actual execution by predicting their consequences (model-based processing). It has been suggested that the brain contains multiple yet distinct systems involved in reward prediction. Several studies have tried to allocate model-free and model-based systems to the striatum and the lateral prefrontal cortex (LPFC), respectively. Although there is much support for this hypothesis, recent research has revealed discrepancies. To understand the nature of the reward prediction systems in the LPFC and the striatum, a series of single-unit recording experiments were conducted. LPFC neurons were found to infer the reward associated with the stimuli even when the monkeys had not yet learned the stimulus-reward (SR) associations directly. Striatal neurons seemed to predict the reward for each stimulus only after directly experiencing the SR contingency. However, the one exception was "Exclusive Or" situations in which striatal neurons could predict the reward without direct experience. Previous single-unit studies in monkeys have reported that neurons in the LPFC encode category information, and represent reward information specific to a group of stimuli. Here, as an extension of these, we review recent evidence that a group of LPFC neurons can predict reward specific to a category of visual stimuli defined by relevant behavioral responses. We suggest that the functional difference in reward prediction between the LPFC and the striatum is that while LPFC neurons can utilize abstract code, striatal neurons can code individual associations between stimuli and reward but cannot utilize abstract code.
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Papers by Jessica Elizabeth