Person: Fortier, Catherine
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Fortier
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Catherine
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Fortier, Catherine
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Publication Spared Discrimination and Impaired Reversal Eyeblink Conditioning in Patients with Temporal Lobe AmnesiaCarrillo, M.C.; Fortier, Catherine; Gabrieli, John; Hopkins, Robin; McGlinchey-Berroth, R; Kesner, R; Disterhoft, JasonThe effect of medial temporal lobe damage on a two tone delay discrimination and reversal paradigm was examined in human classical eyeblink conditioning. Eight medial temporal lobe amnesics and their demographically matched controls were compared. Amnesics were able to distinguish between two tones during the initial discrimination phase of the experiment almost as well as control participants. Amnesic patients were not able to reverse the previously acquired two tone discrimination. In contrast, the control participants showed improved discrimination performance after the reversal of the tones. These findings support the hypothesis that the hippocampus, and associated temporal lobe regions, play a role in eyeblink conditioning that becomes essential in more complex versions of the task, such as the reversal of an acquired two tone discrimination.Publication Temporal Discrimination Learning in Abstinent Chronic Alcoholics(Wiley, 2002-06) McGlinchey, Regina; Fortier, Catherine; Cermak, Laird S.; Disterhoft, John F.Background: Converging evidence from varied experimental paradigms has demonstrated that the cerebellum is involved in the timing of learned behavior. Given the documented neurological changes secondary to chronic alcoholism, particularly cerebellar degeneration, the ability of recovered chronic alcoholics to learn a temporal discrimination was assessed by using delayed eyeblink classical conditioning. Methods: Twelve abstinent alcoholic participants and 12 matched control participants were randomly presented 2 clearly discriminable tone conditioned stimuli that were individually paired with 2 different interstimulus intervals. Results: The data revealed a significant alteration in the abstinent alcoholics’ peak latency measure at the long interstimulus intervals and an overall impairment in their level of acquisition of conditioned responses. No group differences in extinction were observed. Conclusions: It was speculated that cerebellar cortical atrophy caused by years of alcohol abuse resulted in the peak latency alteration and that atrophy extending into deep cerebellar nuclei caused the overall impairment in conditioned response acquisition.Publication Effects of OEF/OIF-Related Physical and Emotional Co-Morbidities on Associative Learning: Concurrent Delay and Trace Eyeblink Classical Conditioning(MDPI, 2014) McGlinchey, Regina; Fortier, Catherine; Venne, Jonathan R.; Maksimovskiy, Arkadiy L.; Milberg, WilliamThis study examined the performance of veterans and active duty personnel who served in Operation Enduring Freedom and/or Operation Iraqi Freedom (OEF/OIF) on a basic associative learning task. Eighty-eight individuals participated in this study. All received a comprehensive clinical evaluation to determine the presence and severity of posttraumatic stress disorder (PTSD) and traumatic brain injury (TBI). The eyeblink conditioning task was composed of randomly intermixed delay and trace conditioned stimulus (CS) and unconditioned stimulus (US) pairs (acquisition) followed by a series of CS only trials (extinction). Results revealed that those with a clinical diagnosis of PTSD or a diagnosis of PTSD with comorbid mTBI acquired delay and trace conditioned responses (CRs) to levels and at rates similar to a deployed control group, thus suggesting intact basic associative learning. Differential extinction impairment was observed in the two clinical groups. Acquisition of CRs for both delay and trace conditioning, as well as extinction of trace CRs, was associated with alcoholic behavior across all participants. These findings help characterize the learning and memory function of individuals with PTSD and mTBI from OEF/OIF and raise the alarming possibility that the use of alcohol in this group may lead to more significant cognitive dysfunction.Publication Silent Trace Eliminates Differential Eyeblink Learning in Abstinent Alcoholics(Molecular Diversity Preservation International (MDPI), 2009) Maksimovskiy, Arkadiy L.; Fortier, Catherine; Venne, Jonathan Ryan; Lafleche, Ginette; McGlinchey, ReginaChronic alcoholism has profound effects on the brain, including volume reductions in regions critical for eyeblink classical conditioning (EBCC). The current study challenged abstinent alcoholics using delay (n = 20) and trace (n = 17) discrimination/reversal EBCC. Comparisons revealed a significant difference between delay and trace conditioning performance during reversal (t (35) = 2.08, p < 0.05). The difference between the two tasks for discrimination was not significant (p = 0.44). These data support the notion that alcoholics are increasingly impaired in the complex task of reversing a previously learned discrimination when a silent trace interval is introduced. Alcoholics’ impairment in flexibly altering learned associations may be central to their continued addiction.Publication Conditional Discrimination Learning in Patients with Bilateral Medial Temporal Lobe Amnesia(American Psychological Association (APA), 2003-12) Fortier, Catherine; Disterhoft, John F.; Capozzi, Stephen; Kilduff, Patrick; Cronin-Golomb, Alice; McGlinchey, ReginaThe ability of bilateral medial temporal lobe amnesic patients (MT; n = 8) and normal participants (NC; n = 8) to acquire a conditional discrimination in trace and delay eyeblink conditioning paradigms was investigated. Experiment 1 assessed trace conditional discrimination learning by using a light conditional stimulus (S+/S−) and tone conditioned stimulus (CS) separated by a 1-s trace. NCs responded differentially on S+ trials (mean percent conditioned responses = 66) versus S− trials (30), whereas MTs were impaired in their acquisition of the conditional discrimination (S+ = 51, S− = 43). In Experiment 2, the temporal separation was eliminated. NCs acquired the conditional discrimination (S+ = 70, S− = 29). MTs were unable to respond differentially (S+ = 42, S− = 37). The findings indicate that the hippocampal system is essential in acquiring a conditional discrimination, even in a delay paradigm.Publication Procedural Memory System Supports Single Cue Trace Eyeblink Conditioning in Medial Temporal Lobe Amnesia(American Psychological Association (APA), 2008-03) McGlinchey, Regina; Capozzi, Stephen M.; Fortier, Catherine; Disterhoft, John F.A number of studies investigating trace eyeblink conditioning have found impaired, but not eliminated, acquisition of conditioned responses (CRs) in both animals and humans with hippocampal removal or damage. The underlying mechanism of this residual learning is unclear. The present study investigated whether the impaired level of learning is the product of residual hippocampal function or whether it is mediated by another memory system that has been shown to function normally in delay eyeblink conditioning. Performance of bilateral medial temporal lobe amnesic patients who had a prior history of participating in eyeblink conditioning studies was compared to a control group with a similar training history and to an untrained control group in a series of single cue trace conditioning tasks with 500 ms, 250 ms, and 0 ms trace intervals. Overall, patients acquired CRs to a level similar to the untrained controls, but were significantly impaired compared to the trained controls. The pattern of acquisition suggests that amnesic patients may be relying on the expression of previously acquired, likely cerebellar based, procedural memory representations in trace conditioning.Publication Delay Discrimination and Reversal Eyeblink Classical Conditioning in Abstinent Chronic Alcoholics(American Psychological Association (APA), 2008-03) Fortier, Catherine; Steffen, Elizabeth M.; LaFleche, Ginette; Venne, Jonathan R.; Disterhoft, John F.; McGlinchey, ReginaEvidence has shown that alcoholism leads to volume reductions in brain regions critical for associative learning using the eyeblink classical conditioning paradigm (EBCC). Evidence indicates that cerebellar shrinkage causes impairment in simple forms of EBCC, whereas changes in forebrain structures result in impairment in more complex tasks. In this study, the ability of abstinent alcoholics and matched control participants to acquire learned responses during delay discrimination and discrimination reversal was examined and related to severity of drinking history and neuropsychological performance. During discrimination learning, one tone (CS+) predicted the occurrence of an airpuff (unconditioned stimulus), and another tone (CS−) served as a neutral stimulus; then the significance of the tones was reversed. Alcoholics who learned the initial discrimination were impaired in acquiring the new CS+ after the tones reversed; this is a function that has previously been linked to forebrain structures. It is suggested that a factor important to alcoholic addiction may be the presence of alcoholic-related associative responses that interfere with the ability to learn new more adaptive associations.Publication Reduced Cortical Thickness in Abstinent Alcoholics and Association with Alcoholic Behavior(Wiley, 2011-12) Fortier, Catherine; Leritz, Elizabeth; Salat, David; Venne, Jonathan R.; Maksimovskiy, Arkadiy; Williams, Victoria; Milberg, William; McGlinchey, ReginaBackground Chronic misuse of alcohol results in widespread damage to the brain. Prior morphometric studies have examined cortical atrophy in individuals with alcoholism; however, no previous studies have examined alcohol-associated atrophy using cortical thickness measurements to obtain regional mapping of tissue loss across the full cortical surface. Methods We compared cortical thickness measures from 31 abstinent individuals with a history of prior alcohol abuse to 34 healthy nonalcoholic control participants (total sample size = 65). Cortical surface models were created from high-resolution T1-weighted images, and cortical thickness was then estimated as the distance between the gray matter/white matter boundary and the outer cortical surface. Results Abstinent alcoholics showed reduced whole-brain thickness as compared to nonalcoholic participants. Decreases in thickness were found bilaterally in (i) superior frontal, (ii) precentral, (iii) postcentral, (iv) middle frontal, (v) middle/superior temporal, (vi) middle temporal, and (vii) lateral occipital cortical regions. Decreased cortical thickness in the alcoholic group was associated with severity of alcohol abuse. Conclusions These findings demonstrate widespread reduction in cortical thickness as a consequence of chronic alcoholism, with most severe reductions in frontal and temporal brain regions.Publication Distinct Functional Networks Within the Cerebellum and Their Relation to Cortical Systems Assessed With Independent Component Analysis(Elsevier BV, 2012-05-01) Dobromyslin, Vitaly I.; Salat, David; Fortier, Catherine; Leritz, Elizabeth; Beckmann, Christian F.; Milberg, William; McGlinchey, ReginaCerebellar functional circuitry has been examined in several prior studies using resting fMRI data and seed-based procedures, as well as whole-brain independent component analysis (ICA). Here, we hypothesized that ICA applied to functional data from the cerebellum exclusively would provide increased sensitivity for detecting cerebellar networks compared to previous approaches. Consistency of group-level networks was assessed in two age- and sex-matched groups of twenty-five subjects each. Cerebellum-only ICA was compared to the traditional whole-brain ICA procedure to examine the potential gain in sensitivity of the novel method. In addition to replicating a number of previously identified cerebellar networks, the current approach revealed at least one network component that was not apparent with the application of whole brain ICA. These results demonstrate the gain in sensitivity attained through specifying the cerebellum as a target structure with regard to the identification of robust and reliable networks. The use of similar procedures could be important in further expanding on previously defined patterns of cerebellar functional anatomy, as well as provide information about unique networks that have not been explored in prior work. Such information may prove crucial for understanding the cognitive and behavioral importance of the cerebellum in health and disease.Publication Implicit Memory in Korsakoff’s Syndrome: A Review of Procedural Learning and Priming Studies(Springer Science and Business Media LLC, 2012-05-17) Hayes, Scott M.; Fortier, Catherine; Levine, Andrea; Milberg, William; McGlinchey, ReginaKorsakoff’s syndrome (KS) is characterized by dense anterograde amnesia resulting from damage to the diencephalon region, typically resulting from chronic alcohol abuse and thiamine deficiency. This review assesses the integrity of the implicit memory system in KS, focusing on studies of procedural learning and priming. KS patients are impaired on several measures of procedural memory, most likely due to impairment in cognitive functions associated with alcohol-related neural damage outside of the diencephalon. The pattern of performance on tasks of implicit priming suggests reliance on a residual, non-flexible memory operating more or less in an automatic fashion. Our review concludes that whether measures of implicit memory reveal intact or impaired performance in individuals with KS depends heavily on specific task parameters and demands, including timing between stimuli, the specific nature of the stimuli used in a task, and the integrity of supportive cognitive functions necessary for performance.