Adult neurogenesis, or the addition of new neurons to the brain after development, is an incompletely understood process with potential implications for learning and memory. The zebra finch (Taeniopygia guttata) song system, which receives new neurons during adulthood and is involved in an auditory learning process that in many ways parallels that of humans, makes them a useful model for investigating these putative roles.
While some suggest that new neurons are activated during learning in much the same way as the general neuronal population, others argue that new neurons have a more plastic role in learning and memory. To probe this question, we examined auditory learning in the songbird caudomedial nidopallium (NCM, analogous to the mammalian auditory association cortex), a region that plays a role in auditory processing. Neurons in the NCM express the immediate early gene zenk, a correlate of neural activity, when exposed to novel conspecific song, but the response lessens as the song is repeated. This habituation is specific and long-lasting, suggesting that the NCM is specialized for learning and forming memories of new songs quickly.
To assess the degree to which new neurons participate in song learning, we compared the habituation rate in adult-born neurons and the general neuronal population. One group of birds was repeatedly exposed to a novel conspecific song to induce NCM habituation, while another group heard the song for the first time immediately prior to sacrifice. We used a triple-labeling protocol to stain for a cell birth marker (BrdU), a neuronal marker (Hu), and an activity-dependent immediate early gene protein product (ZENK). With this protocol, a triple-labeled cell was an adult-born neuron activated during song exposure.
Comparing the habituation rates of new and old neurons could reveal their relative roles in song learning. If new neurons habituate at a similar rate as the general neuronal population, this would indicate that they are incorporated into existing auditory learning circuitry and play similar roles as existing neurons. If the drop in new neuron response with song repetition is significantly more than in old neurons, this could point to a more plastic role for adult-born neurons in the NCM. We hypothesized that we would see evidence for the latter possibility. Additionally, we predicted greater activation in response to novel song in the new neuronal population than in the general neuronal population, which would also indicate relatively high plasticity. Our preliminary results support these hypotheses, and also indicate that adult-born neurons have higher baseline activity than general population neurons. Further work must be done to elaborate these findings, but they are suggestive of a role for young adult-born neurons in learning and memory., 2018, Old URL: https://wesscholar.wesleyan.edu/etd_hon_theses/2058, In Copyright – Non-Commercial Use Permitted (InC-NC)
Cummings, Jennifer Anne (Jennifer Anne Cummings) (Author), (John Kirn) (Thesis advisor)
The cortical pre-motor nucleus HVC plays a key role in regulating song learning, production, and maintenance in oscine birds. The HVC is located at the center of both major pathways involved in song learning and is believed to work as the implicit timekeeper of the song system. During the critical period, a time early in development during which a bird must be exposed to its species-specific song if it is to learn to sing, the HVC experiences high rates of neurogenesis that decrease considerably once the critical period has ended around 60 to 90 days post-hatch, although the nucleus continues to recruit new neurons throughout life. If a bird is isolated during the critical period so that it has no exposure to a male tutor, high rates of neuron addition to the HVC are prolonged and the bird can learn to copy another male’s song later into adulthood, although isolates generally produce a more variable song regardless of eventual tutor exposure.
To date, investigations into the nature of neurogenesis to the HVC have focused on the addition of excitatory projection neurons that connect to RA, another nucleus involved in vocal production. However, it has been shown that inhibitory interneurons are also added to the HVC, at least during the critical period. Since parvalbumin-expressing interneurons are associated with plasticity in other sensory systems and have even been shown to induce ocular dominance plasticity in mice after the critical period has ended, we wondered what role parvalbumin-positive interneuron addition may play in regulating plasticity of the song system. To investigate this question, we quantified the rates of parvalbumin-expressing neuron addition to the zebra finch HVC during and directly after the critical period and analyzed these trends in relation to vocal learning.
Neurons were birth-dated using thymidine analog injections at 20, 40, 60, or 120 days post-hatch in male zebra finches raised with male tutors. Birds were perfused at least 60 days after injection, and immunohistochemical techniques were used to quantify new parvalbumin-positive neurons added at these different time points. Before perfusion, birdsong was recorded, and computer-driven similarity scores between a bird’s song and its tutor’s were used to analyze the degree to which a bird had effectively copied its tutor. In addition, rates of parvalbumin-positive neurogenesis were investigated in a population of birds isolated from male tutors.
In normally raised birds, rates of parvalbumin-positive neuron addition reflected what is known about neurogenesis to the HVC during the critical period, with a peak at 40 days post-hatch and a gradual decline thereafter. Rates of parvalbumin-positive neuron addition to the HVC at 60 days post-hatch positively correlated with tutor song copying. The addition of neurons expressing parvalbumin occurred at a higher rate in isolates than in birds reared with a tutor, and by 180 days post-hatch, isolated birds displayed significantly more parvalbumin-positive neurons throughout the HVC than birds reared with a tutor. These data suggest that parvalbumin-expressing neurons are at least one factor mediating plasticity in the zebra finch vocal learning system., 2016, Old URL: https://wesscholar.wesleyan.edu/etd_hon_theses/1532, In Copyright – Non-Commercial Use Permitted (InC-NC)
Sensory systems are constantly inundated with sensory noise, including self-generated noise (reafference) resulting from the animal’s own behaviors. Selective filtering of irrelevant reafferent signals facilitates the detection of relevant, external stimuli from the environment. In the dorsal octavolateralis nucleus (DON) of the hindbrain in Leucoraja erinacea, suppression of reafferent electrosensory signals is accomplished, in part, by an adaptive filter mechanism. Ascending efferent neurons (AENs), the principal cells of the cerebellar-like DON, receive both primary sensory inputs and a wide array of centrally generated predictive inputs related to the animal’s movements. The predictive inputs are transmitted by parallel fibers in the molecular layer. Through a process of associative synaptic plasticity, the weights of the parallel fiber inputs are adjusted to suppress AEN responses to predictable, reafferent signals. AENs have been shown to selectively ignore electrosensory stimuli repeatedly coupled to their own movements. AEN responses to electrosensory stimuli consistently coupled to ventilatory motor commands and passive fin movements have previously been shown to be progressively eliminated. Here, I show that swimming motor commands may also serve as a predictive signal for the suppression of coupled electrosensory stimuli. Furthermore, I demonstrate that a cancellation signal develops for a predictable, coupled stimulus but not when the same stimulus is free-running. Finally, by coupling stimuli to both swimming and ventilatory motor commands, I demonstrate that two cancellation signals can independently develop in a single AEN to suppress reafference associated with the two distinct behaviors., 2017, Old URL: https://wesscholar.wesleyan.edu/etd_hon_theses/1906, In Copyright – Non-Commercial Use Permitted (InC-NC)
Electroencephalography (EEG) is a non-invasive neuroimaging method that records fluctuations in bioelectrical activity from the scalp. Oscillations in EEG activity can be categorized by bands of activity that are prevalent during different states of consciousness. Neurofeedback is a subset of biofeedback that uses real-time quantitative EEG metrics to help individuals regulate their own brain activity. Alpha waves (8-12 Hz) are EEG oscillations that are especially prominent during periods of relaxation with closed eyes. It has been shown that up-regulation of alpha activity through neurofeedback can decrease anxiety symptoms (Kamiya, 1969; Hammond, 2005), usually following hours of neurofeedback training. In this study, participants underwent a single fifteen-minute session of alpha-enhancement neurofeedback training to assess changes in self-reported anxiety, as measured by the State-Trait Anxiety Inventory. An auditory neurofeedback stimulus was represented as sine tone whose pitch was inversely correlated to the ratio of alpha amplitude to the average amplitudes of all frequency bands. A control group received sham feedback that was recorded from another subject. Experimental subjects showed a reduction in self- reported anxiety, although this reduction was not significant and not significantly different from changes in control-group anxiety. In addition, differences in alpha ratio pre and post training were not significant in either group, and changes in alpha ratio were not significantly correlated to changes in anxiety. More subjects, lower stimulus latency, and longer neurofeedback sessions would benefit future experiments aiming to reduce anxiety through alpha-enhancement neurofeedback., 2015, Old URL: https://wesscholar.wesleyan.edu/etd_hon_theses/1483, In Copyright – Non-Commercial Use Permitted (InC-NC)
There is growing evidence that the rise in overweight and obese people is, in part, an environmentally motivated trend. This study was designed to investigate the effects of a junk food diet on cue-motivated behavior, or âincentive salience.â Other measures investigated include: physiological modulation of motivation, context-reward association, hedonic âlikingâ reactions in the absence of motivated behavior, and anxiety. Tests were carried out in three offspring populations that were exposed to junk food, standard chow, or both prenatally through the mother and maintained on the diet throughout life. Each group showed a conditioned place preference for contexts paired with junk food, regardless of physiological state. Each group showed similar levels of reactivity toward reward-related cues during autoshaping and extinction, regardless of physiological state. Diet did, however, trend towards having an effect on hedonic âlikingâ reactions to concentrations of sucrose water. Animals maintained on a junk food diet displayed a blunted sensitivity to increasing concentrations of sucrose, whereas standard chow animals displayed more hedonic âlikingâ reactions to higher concentrations of sucrose. These observations contribute to the literature concerning effects of high fat food by investigating prenatal as well as long-term lifetime exposure to human junk food., 2015, Old URL: https://wesscholar.wesleyan.edu/etd_hon_theses/1359, In Copyright – Non-Commercial Use Permitted (InC-NC)
We make hundreds of decisions on a daily basis, many involving a choice
between two or more alternatives. These decisions are often complicated when they are infused with an element of uncertainty, and not all outcomes of our potential choices are fully known. Over time, our brains have evolved various mechanisms that help us assess uncertain alternatives and make decisions that are informed by weighing risk versus payoff in a beneficial manner. However, when these mechanisms go awry, it is possible for our decisions to become increasingly irrational and risky, as is often observed in the case of patients suffering from Problem Gambling (also known as gambling disorder).
Past research with humans has shown that visual cues in our environment can play a role in affecting our preferences for risky or safe alternatives by priming past memories. Other studies have implicated specific brain regions such as the Anterior Insular cortex (AIC) and the Orbitofrontal cortex (OFC) in the process of evaluating risk. In the present study, we report that, like humans, rats appear to indicate sensitivity to priming cues, becoming more risky following exposure to cues that are associated with past wins, and less risky following exposure to cues that are associated with past losses. We also report that optogenetic inhibition of the AIC seems to either increase or decrease risk preference, depending on when during the task said inhibition is administered. Inhibition of the OFC, on the other hand, returned inconclusive results. These observations contribute to the literature on risky decision- making by investigating the effects of environmental cues on risky choices, and by building upon our knowledge of the neural mechanisms behind the process., 2016, Old URL: https://wesscholar.wesleyan.edu/etd_hon_theses/1653, In Copyright – Non-Commercial Use Permitted (InC-NC)
Siegelman, Matthew E. (Matthew E. Siegelman) (Author), (Matthew Kurtz) (Thesis advisor)
The negative symptoms of schizophrenia (SCZ) are disabling, poorly understood, and weakly responsive to current treatments. Increasing evidence suggests that motivational deficits specifically represent a substantial problem within the negative symptom domain. Thus treating or minimizing the harmful effects of amotivation could have major therapeutic benefits. Unfortunately, a lack of clinical measurement approaches has limited research as to how amotivation in schizophrenia relates to disease pathology, functional outcome, or treatment options. One successful approach has been the use of computerized behavioral tasks designed to translate subjective human decision-making into an objective measure of motivation. This study utilized a computerized Effort Discounting Task (EDT) to assess motivational differences between SCZ patients and healthy controls. While prior studies have employed similar tasks to investigate reward valuation, this study uniquely included a newly programmed loss aversion EDT (L-EDT) task in addition to a gain seeking EDT (G-EDT) in order to dually examine participants’ motivation to either earn or prevent the loss of a monetary reward. Deficits in the SCZ group and a greater sensitivity to losses in both groups were observed, as evidenced by task performance. EDT results were also associated with survey measures related to negative symptoms and motivated behavior in the SCZ group. These results suggest that separate gain and loss EDTs could be used in future work to identify clinically meaningful motivational differences between SCZ and healthy populations. The reliability of the L-EDT was lower than expectation and requires further investigation., 2016, Old URL: https://wesscholar.wesleyan.edu/etd_hon_theses/1584, In Copyright – Non-Commercial Use Permitted (InC-NC)
Parkinson’s disease (PD) is associated with a loss of internal cueing systems, affecting rhythmic motor tasks such as walking. To address this deficit, researchers have pursued methods of supplementing rhythmic cueing in patients with PD. Rhythmic auditory stimulation has been shown to improve motor deficits in some individuals; these findings have inspired the development of dance programs for PD. In further investigating the effects of music and auditory stimulation on movement, it has been shown that musical groove is related to ease of sensorimotor coupling in a simple tapping task. We were curious to see how PD individuals attending weekly dance classes respond to differing levels of musical groove. Additionally, while PD symptoms have been shown to improve from dance therapy, it is unknown whether these effects are modulated by groove and sensorimotor experience, and if previous experience with music and dance affect these relationships.
We assessed tapping to high- and low-groove songs, music and dance experience, and disease severity using the Unified Parkinson’s Disease Rating Scale (UPDRS) in PD individuals before and after four months of weekly dance classes. We tested the hypothesis that groove and sensorimotor experience, as quantified by music and dance experience, affect the therapeutic outcome of dance classes for PD. We found associations between dance experience, sensorimotor coupling ability, and improvement in disease severity from baseline to four months. The presence of dance experience (>1 year of training) resulted in enhanced sensorimotor coupling ability during tapping to both high [F(1,118)=18.6, p<0.001***] and low [F(1,118)=5.98, p=0.016*] groove songs. Variability in tapping performance was negatively correlated with improvement in UPDRS scores from baseline to 4 months for high (r=-0.465, p< 0.001***) and low (r=-0.585, p<0.001***) groove songs, indicating that more accurate sensorimotor coupling was associated with greater UPDRS improvements. Furthermore, participants with dance experience also exhibited greater improvements in UPDRS scores [F(1,94)=73.4, p<0.001***]. These data suggest that dance experience predicts rhythmic movement consistency and may contribute to motor improvement following a dance intervention. Together, our findings suggest that dance and sensorimotor experience act as predictors of the therapeutic outcome of four months of dance classes for PD., 2019, Old URL: https://wesscholar.wesleyan.edu/etd_hon_theses/2102, In Copyright – Non-Commercial Use Permitted (InC-NC)
This study aimed to identify neural correlates of procedural learning on a Serial Reaction Time (SRT) task using Event-Related Potentials (ERPs). This SRT paradigm was designed specifically for future use with children with low-functioning autism, as procedural learning impairments have been proposed as an etiology of autism. ERPs were recorded as typically-developing children and adults watched pattern and random SRT stimuli. Results showed that, for adults, P1 amplitudes trended toward being enhanced for random stimuli, while the opposite trend was observed in children. In adults, there was also a significant effect of stimulus condition on P3 amplitude. There was a significant interaction between group and stimulus condition for the P1 and N1 peaks. These findings could indicate that children and adults processed the patterned stimuli in contrasting manners. The success of this paradigm with young children suggests the study can be effectively extended to children with autism., 2010, Old URL: https://wesscholar.wesleyan.edu/etd_hon_theses/426, In Copyright – Non-Commercial Use Permitted (InC-NC)
Introduction: More than half of disordered gamblers (60.4%) report comorbid tobacco dependence (compared to only 16.8% of the general population), suggesting a common mechanism for the pathology of these disorders. Furthermore, 41.3% of disordered gamblers report the diagnosis of an anxiety disorder (compared to only 10% of the general population), which is implicated as a risk factor for relapse, and is thought to promote the maintenance of maladaptive gambling and smoking behaviors. One of the most important characteristics common to all gambling games is the uncertainty associated with the probability of reward delivery and the magnitude of the reward. Evidence suggests that this uncertainty may powerfully enhance attraction to cues, such as the flashing lights and celebratory sounds of casino slot machines, and at times, may sensitize reward pathways in the brain. Nicotine is implicated in attention, particularly for cues. However, it is unknown how nicotine or anxiety might contribute to cue-attraction.
Methods: In the present study, we investigate the effects of nicotine (0.3 mg/kg, s.c.) on the desire for cues associated with uncertain rewards in male and female Long-Evans rats. Rats received injections of either nicotine or saline 15-minutes prior to each conditioning session. In an autoshaping task, rats learned to associate lever and tone cues (CS) with the delivery of sucrose pellet rewards (UCS) on either a certain or uncertain reward contingency. Under certain reward conditions, each CS presentation was immediately followed by the delivery of a single sucrose pellet (100%-1). In contrast, under uncertain conditions, only half of all CS presentations were rewarded by a sucrose pellet, with the remaining half being unrewarded. When the CS presentation was followed by UCS delivery, the reward was either 1, 2 or 3 pellets (with equal probability) (50%-1-2-3), which resulted in the same total number of CS and UCS presentations as in the certain condition. Sign-tracking and goal-tracking behaviors were recorded as a measure of attraction to either the lever cue or the sucrose delivery dish. Subsequently, we tested the ability of gambling-like cues to serve as a conditioned reinforcer, and to promote motivation for the sucrose reward during a progressive ratio task. Finally, the Elevated Plus Maze was used to measure the effects of anxiety and its interaction with nicotine and uncertainty.
Results: Here, we demonstrate differences in cue attraction and motivation for certain versus uncertain rewards in the presence of nicotine. For example, during the autoshaping task, nicotine enhanced attraction to CS cues for certain conditions, but not for uncertain ones. Conversely, in the progressive ratio task, nicotine enhanced motivation to obtain the reward in uncertain conditions, but not for certain conditions. Females, in particular, appear to be vulnerable to the combined effects of nicotine and reward uncertainty on motivation to obtain rewards. While not significant, anxiety appears to play a role in moderating attraction-related behaviors, as rats in the uncertain condition exhibited higher levels of anxiety compared to rats in the certain condition.
Discussion: Understanding the effects of nicotine and uncertainty on cue-reactivity might provide insight into the comorbid relationship between pathological gambling and tobacco use. Here, nicotine increased attraction for cues associated with certain reward outcomes, and increased motivation to obtain rewards associated with uncertain outcomes. Since motivation to obtain rewards appears to be greater in females injected with nicotine, comorbidity rates may be sex specific rather than uniform across both sexes. Future studies should consider these sex-dependent effects when developing successful intervention programs for comorbid disordered gambling and tobacco behaviors. Additionally, the finding that uncertainty increases anxiety behavior suggests an interplay between anxiety and nicotine, which should be considered when treating patients with a comorbid anxiety diagnosis, GD diagnosis, and nicotine dependence. Since anxiety is a known contributor to the relapse and maintenance of maladaptive behaviors, it is crucial to understand its ability to promote attraction to uncertain rewards in the presence of nicotine., 2017, Old URL: https://wesscholar.wesleyan.edu/etd_hon_theses/1799, In Copyright – Non-Commercial Use Permitted (InC-NC)
Reuman, Hannah Sophie (Hannah Sophie Reuman) (Author), (Janice Naegele) (Thesis advisor)
BACKGROUND: Autism spectrum disorders (ASD) are a group of pervasive developmental brain disorders characterized by three hallmark symptoms: deficits in sociability, difficulties with communication, and restricted, stereotyped, and repetitive patterns of behavior. The prevalence of ASD diagnoses increases each year. Now more than ever, more effective treatments are needed. Recent research has shown that a highly restrictive, 6:1 ketogenic diet (fat: carbohydrate + protein composition) significantly alleviates the three core symptoms of autism in the BTBR T+ tf/J (BTBR) mouse model of autism (Masino et al. 2012). Although these findings are promising, implementing this stringent diet in the ASD clinical population could be quite challenging. The purpose of this current study was to evaluate whether a less stringent diet comprised of a 3.2:1 (fat: carbohydrate + protein) ratio significantly reduces behavioral symptoms of autism in BTBR T+ tf/J mice., 2013, Old URL: https://wesscholar.wesleyan.edu/etd_hon_theses/980, In Copyright – Non-Commercial Use Permitted (InC-NC)
Despite the growing number of treatments for epilepsy, patients with drug resistant epilepsy still have limited options beyond invasive surgical intervention. Recent developments in animal research have highlighted the therapeutic potential of optogenetic and chemogenetic therapy. While the anticonvulsant effect of optogenetic silencing techniques have been robustly demonstrated in mouse models of epilepsy, the same effect has not been as extensively explored with chemogenetic silencing techniques. We investigated whether hippocampal expression of a modified drug-activated glycine receptor reduced limbic seizures. Adult mice received stereotaxic injections of an AAV2 containing mutated glycine receptor (iGlyR) activated by Ivermectin (IVM) into multiple sites in the hippocampal formation. After allowing several weeks for viral expression, acute seizures were induced in mice using a modified pilocarpine seizure induction protocol. Seizure activity was monitored by continuous video-EEG recordings from several hours prior to IVM injection to four hours after pilocarpine injection. Serenia Pro Seizure detection software was used to quantify the latency, incidence, and severity of the seizures. Viral-mediated expression was analyzed and quantified based on immunohistochemical staining and confocal microscopy. Treated groups displayed decreased time to ictal events compared to all controls. The high dose treated group displayed increased number of seizures per minute before status epilepticus or death and decreased seizure durations. We observed expression of iGlyR in all layers of the dentate gyrus and cornus ammonis. These results indicate successful modulation of ictal activity through the activation of iGlyR during pilocarpine induced limbic seizures., 2017, Old URL: https://wesscholar.wesleyan.edu/etd_hon_theses/1832, In Copyright – Non-Commercial Use Permitted (InC-NC)
Even among skilled readers, there is a considerable degree of variability in specific sub-skills and processing proficiency. A number of behavioral and physiological tests have been designed and implemented in an attempt to uncover the foundations of these differences. The Compound Remote Associates Test (CRAT) was designed in 2003 (Bowden & Jung-Beeman, 2003a; Bowden & Jung-Beeman, 2003b), examining participants’ ability to identify and comprehend compound words in the English language. That study was designed to examine problem-solving aspects related to insight and conscious analysis. The purpose of the current study is to determine if a modified version of this test can be used as a measure of variability in reading profiles.
The empirical data was collected at Wesleyan University during the fall of 2015. Participants (N= 70) completed four separate assessments of reading sub-skills; a modified CRAT, the vocabulary and reading comprehension portions of the Nelson- Denny Reading Test (NDRT), and a spelling dictation task. Results revealed that 20.9% of the variability in CRAT performance could be accounted for by the other measures which were used. Multiple regression analyses revealed that spelling was a significant predictor of CRAT performance and vocabulary a moderate predictor when performance on the other measures was accounted for. Additionally, a marginal effect of solution type emerged whereby Type 2 solutions were most readily completed. Together, results indicate that the modified CRAT is indeed a useful tool for determining individual differences in reading, and may be indicative of variability in lexical expertise and morphological awareness., 2016, Old URL: https://wesscholar.wesleyan.edu/etd_hon_theses/1545, In Copyright – Non-Commercial Use Permitted (InC-NC)
Maximizing tendency-an individual difference in the desire to choose optimal options rather than ones that are merely sufficient-has been associated with greater search for alternatives prior to choice commitment. However, recent work has shown that when search came with the risk of losing some existing alternatives, maximizers explored fewer alternatives before selection, the inverse of the established pattern (Patalano, Weizenbaum, Lolli, & Anderson, 2015). In the central study of this thesis, I investigated the relationship between maximizing tendency and search behavior in a serial search task in which choices were presented sequentially and immediately became unavailable if rejected. This common decision situation has elements from each previously studied context. In both this study and a baseline study (in which no sequentially presented options became unavailable), maximizing tendency predicted more extensive search. The results suggest that when loss of rejected options is definite and unavoidable, maximizing tendency is associated with greater, rather than lesser, search for choice alternatives., 2015, Old URL: https://wesscholar.wesleyan.edu/etd_hon_theses/1528, In Copyright – Non-Commercial Use Permitted (InC-NC)
Lofaro, Olivia Maria (Olivia Maria Lofaro) (Author), (Mike Robinson) (Thesis advisor)
Drug addiction involves compulsive pursuit of a reward that persists even in the face of adverse consequences. Previous research has established that optogenetic stimulation of the central amygdala (CeA) generates an addiction-like preference for laser-paired reward that persists in the face of external punishment. The present study however aims to examine whether CeA stimulation-induced reward preference is maintained despite internal physiological consequences using sodium depletion and conditioned taste aversion (CTA). To this end, rats infused with light-activated Channelrhodopsin (ChR2) or control virus (EYFP) were trained to press levers for either a sucrose reward paired with CeA laser stimulation, or an unpaired salt pellet. During the sodium depletion experiment, rats developed a strong preference for the sucrose pellet, and were then repeatedly sodium-depleted in order to shift preference towards the salt reward. Here, EYFP rats shifted their behavior while ChR2 rats did not, maintaining a focused preference for the laser-paired reward despite their growing sodium appetite. In the CTA experiment, rats were presented with two novel sugar pellet flavors, one of which was repeatedly paired with the aversive agent lithium chloride. ChR2 and EYFP rats were then given the option to lever press for the aversive reward paired with laser stimulation, or the unpaired alternative flavored reward. Here, EYFP rats demonstrated a stronger avoidance of the aversive pellet and reduction in laser preference compared to ChR2 rats. These results suggest that CeA stimulation produces a powerful compulsion that can overcome intense physiological motivation, which could provide insight into why addicts forego their own health and biological needs to pursue their preferred reward., 2017, Old URL: https://wesscholar.wesleyan.edu/etd_hon_theses/1881, In Copyright – Non-Commercial Use Permitted (InC-NC)