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No Statistical Learning Advantage In Children Over Adults: Evidence From Behaviour And Neural Entrainment., Christine N Moreau, Marc F. Joanisse, Jerrica Mulgrew, Laura J. Batterink

Brain and Mind Institute Researchers' Publications

Explicit recognition measures of statistical learning (SL) suggest that children and adults have similar linguistic SL abilities. However, explicit tasks recruit additional cognitive processes that are not directly relevant for SL and may thus underestimate children's true SL capacities. In contrast, implicit tasks and neural measures of SL should be less influenced by explicit, higher-level cognitive abilities and thus may be better suited to capturing developmental differences in SL. Here, we assessed SL to six minutes of an artificial language in English-speaking children (n = 56, 24 females, M = 9.98 years) and adults (n = 44; 31 females, M …

No Evidence That Portion Size Influences Food Consumption In Male Sprague Dawley Rats, Fabien Naniex, Sophie C. Pinder, Megan Y. Summers, Renee M. Rouleau, Eric Robinson, Kevin P. Myers, James E. Mccutcheon

Faculty Journal Articles

In studies of eating behavior that have been conducted in humans, the tendency to consume more when given larger portions of food, known as the portion size effect (PSE), is one of the most robust and widely replicated findings. Despite this, the mechanisms that underpin it are still unknown. In particular, it is unclear whether the PSE arises from higher-order social and cognitive processes that are unique to humans or, instead, reflects more fundamental processes that drive feeding, such as conditioned food-seeking. Importantly, studies in rodents and other animals have yet to show convincing evidence of a PSE. In this …

Inactivation Of The Medial-Prefrontal Cortex Impairs Interval Timing Precision, But Not Timing Accuracy Or Scalar Timing In A Peak-Interval Procedure In Rats, Catalin V. Buhusi, Marcelo B. Reyes, Cody-Aaron Gathers, Sorinel A. Oprisan, Mona Buhusi

Psychology Faculty Publications

Motor sequence learning, planning and execution of goal-directed behaviors, and decision making rely on accurate time estimation and production of durations in the seconds-to-minutes range. The pathways involved in planning and execution of goal-directed behaviors include cortico-striato-thalamo-cortical circuitry modulated by dopaminergic inputs. A critical feature of interval timing is its scalar property, by which the precision of timing is proportional to the timed duration. We examined the role of medial prefrontal cortex (mPFC) in timing by evaluating the effect of its reversible inactivation on timing accuracy, timing precision and scalar timing. Rats were trained to time two durations in a …

Investigating The Effects Of Sensory Learning In Rats Using Intra And Extra Stimulus Modalities, Ariel M. Kershner

Faculty Curated Undergraduate Works

The purpose of this study was to see what rats learn about the elements of a compound stimulus (a stimulus composed of two different stimuli), and whether their learning differs if the compound is from the same modality (intra-modal), i.e. both visual, or from different modalities (inter-modal), i.e. visual and auditory. We hypothesized that the rats would respond more to the compound stimuli than to the single stimuli (Pearce and Wilson, 1990), more to the compound modality of inter-modal elements than to the compound modality of intra-modal elements (Miller, 1971 and Gingras, 2009), equally to the intra-modal elements (Rescorla, 1972), …

Modified Single Prolonged Stress Reduces Cocaine Self-Administration During Acquisition Regardless Of Rearing Environment, Rebecca S. Hofford, Mark A. Prendergast, Michael T. Bardo

Psychology Faculty Publications

Until recently, there were few rodent models available to study the interaction of post-traumatic stress disorder (PTSD) and drug taking. Like PTSD, single prolonged stress (SPS) produces hypothalamic-pituitary-adrenal (HPA) axis dysfunction and alters psychostimulant self-administration. Other stressors, such as isolation stress, also alter psychostimulant self-administration. However, it is currently unknown if isolation housing combined with SPS can alter the acquisition or maintenance of cocaine self-administration. The current study applied modified SPS (modSPS; two hours restraint immediately followed by cold swim stress) to rats raised in an isolation condition (Iso), enrichment condition (Enr), or standard condition (Std) to measure changes in …

Nmda Receptor Blockade Specifically Impedes The Acquisition Of Incentive Salience Attribution, Jonathan J. Chow, Joshua S. Beckmann

Psychology Faculty Publications

Glutamatergic signaling plays an important role in learning and memory. Using Pavlovian conditioned approach procedures, the mechanisms that drive stimulus-reward learning and memory have been investigated. However, there are instances where reward-predictive stimuli can function beyond being solely predictive and can be attributed with “motivational value” or incentive salience. Using a Pavlovian conditioned approach procedure consisting of two different but equally predictive stimuli (lever vs. tone) we investigated the role NMDA receptor function has in the attribution of incentive salience. The results revealed that the administration of MK-801, an NMDA receptor antagonist, during acquisition of Pavlovian conditioned approach promoted goal-tracking …

Effects Of Environmental Enrichment On Self-Administration Of The Short-Acting Opioid Remifentanil In Male Rats, Rebecca S. Hofford, Jonathan J. Chow, Joshua S. Beckmann, Michael T. Bardo

Psychology Faculty Publications

Background

Opioid abuse is a major problem around the world. Identifying environmental factors that contribute to opioid abuse and addiction is necessary for decreasing this epidemic. In rodents, environmental enrichment protects against the development of low dose stimulant self-administration, but studies examining the effect of enrichment and isolation (compared to standard housing) on the development of intravenous opioid self-administration have not been conducted. The present study investigated the role of environmental enrichment on self-administration of the short-acting μ-opioid remifentanil.

Methods

Rats were raised in an enriched condition (Enr), standard condition (Std), or isolated condition (Iso) beginning at 21 days of …

(Re)Grounding Grounded Theory: A Close Reading Of Theory In Four Schools, Tavis Apramian, Sayra Cristancho, Chris Watling, Lorelei Lingard

Health and Rehabilitation Sciences Publications

The debate over what counts as theory has dominated methodological conversations in grounded theory research for decades. Four of the schools of thought in that debate – Glaserian, Straussian, Charmazian, and Clarkeian – hold different assumptions about what theory is and how it is made. The first two schools understand theory as an abstraction that exactingly accounts for exceptions. The second two schools understand theory as a process of describing voices hidden from public view. While Glaserian and Straussian coding processes focus on coding exceptions, Charmazian and Clarkeian coding processes focus on building a story of the participants or social …

Bk Channels Mediate Synaptic Plasticity Underlying Habituation In Rats., Tariq Zaman, Cleusa De Oliveira, Mahabba Smoka, Chakravarthi Narla, Michael O Poulter, Susanne Schmid

Brain and Mind Institute Researchers' Publications

Habituation is a basic form of implicit learning and represents a sensory filter that is disrupted in autism, schizophrenia, and several other mental disorders. Despite extensive research in the past decades on habituation of startle and other escape responses, the underlying neural mechanisms are still not fully understood. There is evidence from previous studies indicating that BK channels might play a critical role in habituation. We here used a wide array of approaches to test this hypothesis. We show that BK channel activation and subsequent phosphorylation of these channels are essential for synaptic depression presumably underlying startle habituation in rats, …

Adolescent Cannabinoid Exposure Induces A Persistent Sub-Cortical Hyper-Dopaminergic State And Associated Molecular Adaptations In The Prefrontal Cortex., Justine Renard, Laura G Rosen, Michael Loureiro, Cleusa De Oliveira, Susanne Schmid, Walter J Rushlow, Steven R Laviolette

Brain and Mind Institute Researchers' Publications

Considerable evidence suggests that adolescent exposure to delta-9-tetrahydrocanabinol (THC), the psychoactive component in marijuana, increases the risk of developing schizophrenia-related symptoms in early adulthood. In the present study, we used a combination of behavioral and molecular analyses with in vivo neuronal electrophysiology to compare the long-term effects of adolescent versus adulthood THC exposure in rats. We report that adolescent, but not adult, THC exposure induces long-term neuropsychiatric-like phenotypes similar to those observed in clinical populations. Thus, adolescent THC exposure induced behavioral abnormalities resembling positive and negative schizophrenia-related endophenotypes and a state of neuronal hyperactivity in the mesocorticolimbic dopamine (DA) pathway. …

Examination Of Methamphetamine Reinstatement In Female And Male Rats: A Pre-Clinical Model Of Relapse, Steven T. Pittenger

Department of Psychology: Dissertations, Theses, and Student Research

Methamphetamine (meth) dependence is often characterized by persistent and chronic relapse (i.e., return to drug use). There is growing pre-clinical and human evidence suggesting females are at greater risk to relapse. The set of studies presented in this dissertation extended this limited evidence by identifying sex-dependent neural substrates correlated with meth-triggered reinstatement (Experiment 1) and by examining sex-differences in reinstatement triggered by drugs of abuse that are commonly co-abused with meth (Experiment 2). Female and male rats were trained to self-administer meth, received subsequent extinction sessions, and then tested for reinstatement. In Experiment 1, rats were perfused following reinstatement testing …

Differential Effect Of Clomipramine On Habituation And Prepulse Inhibition In Dominant Versus Subordinate Rats., Alvin Yang, Tahira Daya, Karen Carlton, Jin Hui Yan, Susanne Schmid

Brain and Mind Institute Researchers' Publications

Many patients with depression have comorbidities associated with an impairment of sensorimotor gating, such as e.g. schizophrenia, Parkinson Disease, or Alzheimer disease. Anti-depressants like clomipramine that modulate serotonergic or norepinephrinergic neurotransmission have been shown to impact sensorimotor gating, it is therefore important to study potential effects of clomipramine in order to rule out an exacerbation of sensorimotor gating impairment. Prior studies in animals and humans have been inconclusive. Since serotonin and norepinephrine levels are closely related to anxiety and stress levels and therefore to the social status of an animal, we tested the hypothesis that acute and chronic effects of …

Bursts And Heavy Tails In Temporal And Sequential Dynamics Of Foraging Decisions, Kanghoon Jung, Hyeran Jang, Jerald D. D. Kralik, Jaeseung Jeong

Dartmouth Scholarship

A fundamental understanding of behavior requires predicting when and what an individual will choose. However, the actual temporal and sequential dynamics of successive choices made among multiple alternatives remain unclear. In the current study, we tested the hypothesis that there is a general bursting property in both the timing and sequential patterns of foraging decisions. We conducted a foraging experiment in which rats chose among four different foods over a continuous two-week time period. Regarding when choices were made, we found bursts of rapidly occurring actions, separated by time-varying inactive periods, partially based on a circadian rhythm. Regarding what was …

Attention Deficit Associated With Early Life Interictal Spikes In A Rat Model Is Improved With Acth, Amanda E. Hernan, Abigail Alexander, Pierre-Pascal Lenck-Santini, Rod C. Scott

Dartmouth Scholarship

Children with epilepsy often present with pervasive cognitive and behavioral comorbidities including working memory impairments, attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder. These non-seizure characteristics are severely detrimental to overall quality of life. Some of these children, particularly those with epilepsies classified as Landau-Kleffner Syndrome or continuous spike and wave during sleep, have infrequent seizure activity but frequent focal epileptiform activity. This frequent epileptiform activity is thought to be detrimental to cognitive development; however, it is also possible that these IIS events initiate pathophysiological pathways in the developing brain that may be independently associated with cognitive deficits. These …

Activation Of Mglur2/3 Receptors In The Ventro-Rostral Prefrontal Cortex Reverses Sensorimotor Gating Deficits Induced By Systemic Nmda Receptor Antagonists., Bridget Valsamis, Michael Chang, Marei Typlt, Susanne Schmid

Brain and Mind Institute Researchers' Publications

Prepulse inhibition (PPI) of acoustic startle is an operational measure of sensorimotor gating, which is disrupted in schizophrenia. NMDA receptor (NMDAR) antagonist induced PPI disruption has become an important pharmacological model for schizophrenia; however, knowledge of the underlying mechanism remains incomplete. This study examines the role of NMDAR in the caudal pontine reticular nucleus (PnC) and the medial prefrontal cortex (mPFC) in NMDARs antagonist induced PPI deficits, as well as the NMDA receptor subtypes involved. We administered the NMDA antagonist MK-801 locally into the caudal pontine reticular formation (PnC), where the PPI mediating pathway converges with the primary startle pathway, …

Assessing Empathy In Rats: The Role Of Shared Experience, Dylan Richmond

Summer Research

Previous research has searched for empathy in rats (Rattus norvegicus) by placing a trapped rat inside a restricting tube, and giving a donor rat the opportunity to free it (Ben-Ami Bartal et al., 2011; Silberberg et al., 2014). It is unclear if freeing behavior is due to empathetic responses by donors, or if it is motivated by desire for social contact, or some other factor. The current study utilized a novel method to measure empathy in rats. Donors had the opportunity to free trapped rats from a restricting tube into an adjacent chamber. Half the donor rats spent …

Bdnf In The Dentate Gyrus Is Required For Consolidation Of "Pattern-Separated" Memories., Pedro Bekinschtein, Brianne A Kent, Charlotte A Oomen, Gregory D Clemenson, Fred H Gage, Lisa M Saksida, Timothy J Bussey

Brain and Mind Institute Researchers' Publications

Successful memory involves not only remembering information over time, but also keeping memories distinct and less confusable. The computational process for making representations for similar input patterns more distinct from each other has been referred to as "pattern separation." In this work, we developed a set of behavioral conditions that allowed us to manipulate the load for pattern separation at different stages of memory. Thus, we provide experimental evidence that a brain-derived neurotrophic factor (BDNF)-dependent pattern separation process occurs during the encoding/storage/consolidation, but not the retrieval stage of memory processing. We also found that a spontaneous increase in BDNF in …

The Touchscreen Operant Platform For Assessing Executive Function In Rats And Mice., Adam C Mar, Alexa E Horner, Simon R O Nilsson, Johan Alsiö, Brianne A Kent, Chi Hun Kim, Andrew Holmes, Lisa M Saksida, Timothy J Bussey

Brain and Mind Institute Researchers' Publications

This protocol details a subset of assays developed within the touchscreen platform to measure various aspects of executive function in rodents. Three main procedures are included: extinction, measuring the rate and extent of curtailing a response that was previously, but is no longer, associated with reward; reversal learning, measuring the rate and extent of switching a response toward a visual stimulus that was previously not, but has become, associated with reward (and away from a visual stimulus that was previously, but is no longer, rewarded); and the 5-choice serial reaction time (5-CSRT) task, gauging the ability to selectively detect and …

The Touchscreen Operant Platform For Testing Working Memory And Pattern Separation In Rats And Mice., Charlotte A Oomen, Martha Hvoslef-Eide, Christopher J Heath, Adam C Mar, Alexa E Horner, Timothy J Bussey, Lisa M Saksida

Brain and Mind Institute Researchers' Publications

The automated touchscreen operant chamber for rats and mice allows for the assessment of multiple cognitive domains within the same testing environment. This protocol presents the location discrimination (LD) task and the trial-unique delayed nonmatching-to-location (TUNL) task, which both assess memory for location. During these tasks, animals are trained to a predefined criterion during ∼20-40 daily sessions. In LD sessions, touching the same location on the screen is rewarded on consecutive trials, followed by a reversal of location-reward contingencies. TUNL, a working memory task, requires animals to 'nonmatch' to a sample location after a delay. In both the LD and …

The Touchscreen Operant Platform For Testing Learning And Memory In Rats And Mice., Alexa E Horner, Christopher J Heath, Martha Hvoslef-Eide, Brianne A Kent, Chi Hun Kim, Simon R O Nilsson, Johan Alsiö, Charlotte A Oomen, Andrew Holmes, Lisa M Saksida, Timothy J Bussey

Brain and Mind Institute Researchers' Publications

An increasingly popular method of assessing cognitive functions in rodents is the automated touchscreen platform, on which a number of different cognitive tests can be run in a manner very similar to touchscreen methods currently used to test human subjects. This methodology is low stress (using appetitive rather than aversive reinforcement), has high translational potential and lends itself to a high degree of standardization and throughput. Applications include the study of cognition in rodent models of psychiatric and neurodegenerative diseases (e.g., Alzheimer's disease, schizophrenia, Huntington's disease, frontotemporal dementia), as well as the characterization of the role of select brain regions, …

Rats Acquire Stronger Preference For Flavors Consumed Towards The End Of A High-Fat Meal, Kevin P. Myers

Faculty Journal Articles

Rats learn to prefer flavors associated with postingestive effects of nutrients. The physiological signals underlying this postingestive reward are unknown. We have previously shown that rats readily learn to prefer a flavor that was consumed early in a multi-flavored meal when glucose is infused intragastrically (IG), suggesting rapid postingestive reward onset. The present experiments investigate the timing of postingestive fat reward, by providing distinctive flavors in the first and second halves of meals accompanied by IG fat infusion. Learning stronger preference for the earlier or later flavor would indicate when the rewarding postingestive effects are sensed. Rats consumed sweetened, calorically-dilute …

Rats Acquire Stronger Preference For Flavors Consumed Towards The End Of A High-Fat Meal, Kevin P. Myers

Faculty Journal Articles

Rats learn to prefer flavors associated with postingestive effects of nutrients. The physiological signals underlying this postingestive reward are unknown. We have previously shown that rats readily learn to prefer a flavor that was consumed early in a multi-flavored meal when glucose is infused intragastrically (IG), suggesting rapid postingestive reward onset. The present experiments investigate the timing of postingestive fat reward, by providing distinctive flavors in the first and second halves of meals accompanied by IG fat infusion. Learning stronger preference for the earlier or later flavor would indicate when the rewarding postingestive effects are sensed. Rats consumed sweetened, calorically-dilute …

Iptakalim Preferentially Decreases Nicotine-Induced Hyperlocomotion In Phencyclidine-Sensitized Rats: A Potential Dual Action Against Nicotine Addiction And Psychosis, Nick Volf, Gang Hu, Ming Li

Department of Psychology: Faculty Publications

Objective: Iptakalim is a putative ATP-sensitive potassium (KATP) channel opener. It is also a novel nicotinic acetylcholine receptor (nAChR) blocker and can antagonize nicotine-induced increase in dopamine release in the nucleus accumbens. Our recent work also shows that iptakalim exhibits a clozapine-like atypical antipsychotic profile, indicating that iptakalim may possess a dual action against nicotine addiction and schizophrenia.

Methods: The present study examined the potential therapeutic effects of iptakalim on nicotine use in schizophrenia. We created an animal model of comorbidity of nicotine addiction and schizophrenia by injecting male Sprague-Dawley rats with nicotine (0.40 mg/kg, subcutaneously［sc］) or saline, in combination …

Just Say “Nootropic”: The Effects Of Nicotine On Memory And Learning, Elyse N. Goveia

Psychology Honors Papers

This study investigated the effects of nicotine on memory and learning in adolescent and adult male Fischer-344 rats. Rats were given 0.2 mg/kg/day of either nicotine or saline chronically for 2 weeks and were tested in the Morris water maze as adolescents (Phase 1) and then again 4 months later as adults (Phase 2). There were 4 main groups: nicotine/nicotine, nicotine/saline, saline/nicotine, and saline/saline. In Phase 2 rats were tested for c-Fos and BrdU expression in the dentate gyrus of the hippocampus. Behavioral data indicated that as adults, rats given nicotine were significantly improved at the water maze task compared …

Perceptual Functions Of Perirhinal Cortex In Rats: Zero-Delay Object Recognition And Simultaneous Oddity Discriminations., Susan J Bartko, Boyer D Winters, Rosemary A Cowell, Lisa M Saksida, Timothy J Bussey

Brain and Mind Institute Researchers' Publications

The perirhinal cortex (PRh) is widely accepted as having an important role in object recognition memory in humans and animals. Contrary to claims that PRh mediates declarative memory exclusively, previous evidence suggests that PRh has a role in the perceptual processing of complex objects. In the present study, we conducted an examination of the possible role of PRh in perceptual function in rats. We examined whether bilateral excitotoxic lesions of PRh or PPRh (perirhinal plus postrhinal cortices) in the rat would cause deficits in a zero-delay object-recognition task and a simultaneous oddity discrimination task. Both of these tasks measured spontaneous …

Paradoxical Facilitation Of Object Recognition Memory After Infusion Of Scopolamine Into Perirhinal Cortex: Implications For Cholinergic System Function., Boyer D Winters, Lisa M Saksida, Timothy J Bussey

Brain and Mind Institute Researchers' Publications

The cholinergic system has long been implicated in learning and memory, yet its specific function remains unclear. In the present study, we investigated the role of cortical acetylcholine in a rodent model of declarative memory by infusing the cholinergic muscarinic receptor antagonist scopolamine into the rat perirhinal cortex during different stages (encoding, storage/consolidation, and retrieval) of the spontaneous object recognition task. Presample infusions of scopolamine significantly impaired object recognition compared with performance of the same group of rats on saline trials; this result is consistent with previous reports supporting a role for perirhinal acetylcholine in object information acquisition. Scopolamine infusions …

Glutamate Receptors In Perirhinal Cortex Mediate Encoding, Retrieval, And Consolidation Of Object Recognition Memory., Boyer D Winters, Timothy J Bussey

Brain and Mind Institute Researchers' Publications

Object recognition is consistently impaired in human amnesia and animal models thereof. Results from subjects with permanent brain damage have revealed the importance of the perirhinal cortex to object recognition memory. Here, we report evidence from rats for interdependent but distinct stages in object recognition memory (encoding, retrieval, and consolidation), which require glutamate receptor activity within perirhinal cortex. Transient blockade of AMPA receptor-mediated synaptic transmission within perirhinal cortex disrupted encoding for short- and long-term memory as well as retrieval and consolidation. In contrast, transient NMDA receptor blockade during encoding affected only long-term object recognition memory; NMDA receptor activity was also …

Transient Inactivation Of Perirhinal Cortex Disrupts Encoding, Retrieval, And Consolidation Of Object Recognition Memory., Boyer D Winters, Timothy J Bussey

Brain and Mind Institute Researchers' Publications

Damage to perirhinal cortex (PRh) impairs object recognition memory in humans, monkeys, and rats when tested in tasks such as delayed nonmatching to sample, visual paired comparison, and its rodent analog, the spontaneous object recognition task. In the present study, we have capitalized on the discrete one-trial nature of the spontaneous object recognition task to investigate the role of PRh in several distinct stages of object recognition memory. In a series of experiments, transient inactivation of PRh was accomplished with bilateral infusions of lidocaine directly into PRh immediately before the sample phase (encoding), immediately before the choice phase (retrieval), or …

Double Dissociation Between The Effects Of Peri-Postrhinal Cortex And Hippocampal Lesions On Tests Of Object Recognition And Spatial Memory: Heterogeneity Of Function Within The Temporal Lobe., Boyer D Winters, Suzanna E Forwood, Rosemary A Cowell, Lisa M Saksida, Timothy J Bussey

Brain and Mind Institute Researchers' Publications

It is widely believed that declarative memory is mediated by a medial temporal lobe memory system consisting of several distinct structures, including the hippocampus and perirhinal cortex. The strong version of this view assumes a high degree of functional homogeneity and serial organization within the medial temporal lobe, such that double dissociations between individual structures should not be possible. In the present study, we tested for a functional double dissociation between the hippocampus and peri-postrhinal cortex in a single experiment. Rats with bilateral excitotoxic lesions of either the hippocampus or peri-postrhinal cortex were assessed in tests of spatial memory (radial …

Cyclic Changes In Estradiol Regulate Synaptic Plasticity Through The Map Kinase Pathway, Ruifen Bi, Michael R. Foy, Rose-Marie Vouimba, Richard F. Thompson, Michel Baudry

Psychological Science Faculty Works

Hippocampal synaptic structure and function exhibit marked variations during the estrus cycle of female rats. Estradiol activates the mitogen-activated protein (MAP) kinase pathway in numerous cell types, and MAP kinase has been shown to play a critical role in the mechanisms underlying synaptic plasticity. Here, we report that endogenous estrogen produces a tonic phosphorylation/activation of extracellular signal-regulated kinase 2 (ERK2)/MAP kinase throughout the female rat brain and an increase in tyrosine phosphorylation of NR2 subunits of N-methyl-D-aspartate (NMDA) receptors. Moreover, cyclic changes in estrogen levels during the estrus cycle of female rats are associated with corresponding changes in the levels …