41 research outputs found

    Reconsolidation and extinction are dissociable and mutually exclusive processes: behavioral and molecular evidence.

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    Memory persistence is critically influenced by retrieval. In rats, a single presentation of a conditioned fear stimulus induces memory reconsolidation and fear memory persistence, while repeated fear cue presentations result in loss of fear through extinction. These two opposite behavioral outcomes are operationally linked by the number of cue presentations at memory retrieval. However, the behavioral properties and mechanistic determinants of the transition have not yet been explored; in particular, whether reconsolidation and extinction processes coexist or are mutually exclusive, depending on the exposure to non-reinforced retrieval events. We characterized both behaviorally and molecularly the transition from reconsolidation to extinction of conditioned fear and showed that an increase in calcineurin (CaN) in the basolateral amygdala (BLA) supports the shift from fear maintenance to fear inhibition. Gradually increasing the extent of retrieval induces a gradual decrease in freezing responses to the conditioned stimulus and a gradual increase in amygdala CaN level. This newly synthesized CaN is required for the extinction, but not the reconsolidation, of conditioned fear. During the transition from reconsolidation to extinction, we have revealed an insensitive state of the fear memory where NMDA-type glutamate receptor agonist and antagonist drugs are unable either to modulate CaN levels in the BLA or alter the reconsolidation or extinction processes. Together, our data indicate both that reconsolidation and extinction are mutually exclusive processes and also reveal the presence of a transitional, or "limbo," state of the original memory between these two alternative outcomes of fear memory retrieval, when neither process is engaged.This research was supported by aUK Medical Research Council Programme Grant (no. 9536855) to B.J.E., and was conducted in the Department of Psychology and the Medical Research Council/Wellcome Trust Behavioural and Clinical Neuroscience Institute. E.M. was supported by a Royal Society Newton International Fellowship. A.L.M. was partly supported by the Ferreras-Willetts Fellowship in Neuroscience at Downing College, Cambridge University.This is the final version of the article. It first appeared from Society for Neuroscience via http://dx.doi.org/10.1523/JNEUROSCI.4001-13.2014

    Assessing the treatment effects in apraxia of speech: introduction and evaluation of the Modified Diadochokinesis Test

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    Background: The number of reliable and valid instruments to measure the effects of therapy in apraxia of speech (AoS) is limited. Aims: To evaluate the newly developed Modified Diadochokinesis Test (MDT), which is a task to assess the effects of rate and rhythm therapies for AoS in a multiple baseline across behaviours design. Methods: The consistency, accuracy and fluency of speech of 24 adults with AoS and 12 unaffected speakers matched for age, gender and educational level were assessed using the MDT. The reliability and validity of the instrument were considered and outcomes compared with those obtained with existing tests. Results: The results revealed that MDT had a strong internal consistency. Scores were influenced by syllable structure complexity, while distinctive features of articulation had no measurable effect. The testretest and intra- and inter-rater reliabilities were shown to be adequate, and the discriminant validity was good. For convergent validity different outcomes were found: apart from one correlation, the scores on tests assessing functional communication and AoS correlated significantly with the MDT outcome measures. The spontaneous speech phonology measure of the Aachen Aphasia Test (AAT) correlated significantly with the MDT outcome measures, but no correlations were found for the repetition subtest and the spontaneous speech articulation/prosody measure of the AAT. Conclusions & Implications: The study shows that the MDT has adequate psychometric properties, implying that it can be used to measure changes in speech motor control during treatment for apraxia of speech. The results demonstrate the validity and utility of the instrument as a supplement to speech tasks in assessing speech improvement aimed at the level of planning and programming of speech

    Magnetic resonance imaging of the brain and vocal tract:Applications to the study of speech production and language learning

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    The human vocal system is highly plastic, allowing for the flexible expression of language, mood and intentions. However, this plasticity is not stable throughout the life span, and it is well documented that adult learners encounter greater difficulty than children in acquiring the sounds of foreign languages. Researchers have used magnetic resonance imaging (MRI) to interrogate the neural substrates of vocal imitation and learning, and the correlates of individual differences in phonetic “talent”. In parallel, a growing body of work using MR technology to directly image the vocal tract in real time during speech has offered primarily descriptive accounts of phonetic variation within and across languages. In this paper, we review the contribution of neural MRI to our understanding of vocal learning, and give an overview of vocal tract imaging and its potential to inform the field. We propose methods by which our understanding of speech production and learning could be advanced through the combined measurement of articulation and brain activity using MRI – specifically, we describe a novel paradigm, developed in our laboratory, that uses both MRI techniques to for the first time map directly between neural, articulatory and acoustic data in the investigation of vocalisation. This non-invasive, multimodal imaging method could be used to track central and peripheral correlates of spoken language learning, and speech recovery in clinical settings, as well as provide insights into potential sites for targeted neural interventions

    An EMA analysis of the effect of increasing word length on consonant production in apraxia of speech: A case study

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    The effect of increasing word length on the articulatory dynamics (i.e. duration, distance, maximum acceleration, maximum deceleration, and maximum velocity) of consonant production in acquired apraxia of speech was investigated using electromagnetic articulography (EMA). Tongue-tip and tongue-back movement of one apraxic patient was recorded using the AG-200 EMA system during word-initial consonant productions in one, two, and three syllable words. Significantly deviant articulatory parameters were recorded for each of the target consonants during one, two, and three syllables words. Word length effects were most evident during the release phase of target consonant productions. The results are discussed with respect to theories of speech motor control as they relate to AOS

    Lingual kinematic strategies used to increase speech rate: Comparisons between younger and older adults

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    The primary objective of this study was to assess the lingual kinematic strategies used by younger and older adults to increase rate of speech. It was hypothesised that the strategies used by the older adults would differ from the young adults either as a direct result of, or in response to a need to compensate for, age-related changes in the tongue. Electromagnetic articulography was used to examine the tongue movements of eight young (M526.7 years) and eight older (M567.1 years) females during repetitions of /ta/ and /ka/ at a controlled moderate rate and then as fast as possible. The younger and older adults were found to significantly reduce consonant durations and increase syllable repetition rate by similar proportions. To achieve these reduced durations both groups appeared to use the same strategy, that of reducing the distances travelled by the tongue. Further comparisons at each rate, however, suggested a speed-accuracy trade-off and increased speech monitoring in the older adults. The results may assist in differentiating articulatory changes associated with normal aging from pathological changes found in disorders that affect the older population

    Online intervention, 'MePlusMe', supporting mood, wellbeing, study skills, and everyday functioning in students in higher education: A protocol for a feasibility study

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    Background: Psychological and study skill difficulties faced by students in higher education can lead to poor academic performance, sub-optimal mental health, reduced study satisfaction, and drop out from study. At the same time, higher education institutions' support services are costly, oversubscribed, and struggle to meet demand whilst facing budget reductions. The purpose of the proposed study is to evaluate the acceptability of a new online intervention, MePlusMe, aimed at students in higher education facing mild to moderate psychological and/or study skill difficulties. The study will also assess the feasibility of proposed recruitment and outcome assessment protocols for a future trial of effectiveness. The system supports self-management strategies alongside ongoing monitoring facilitated by a messaging service, as well as featuring a built-in community of student users. It is based on current clinical guidelines for the management of common mental health problems, together with best practice from the educational field. Methods/design: Two hundred and forty two students will be recruited to a within-subjects, repeated measures study conducted over 8 weeks. Self-report measures of depression and anxiety symptoms, mental wellbeing, academic self-efficacy, and everyday functioning will be collected at baseline, and then at 2, 4, and 8 weeks. During this period, students will have access to the intervention system. UK higher education institutions Bournemouth University and University of Warwick will participate in the study. Data on student satisfaction and engagement will also be collected. Study findings will help to determine the most appropriate primary outcome and the required sample size for a future trial. Discussion: This study will evaluate the acceptability of an online intervention system for students facing psychological and/or study skill difficulties and will test recruitment procedures and outcome measures for a future trial of effectiveness. The system is designed to be implemented as a stand-alone service or a service complementary to student support services, which is accessible to the majority of students and effective in improving student experience at higher education institutions. © 2015 Papadatou-Pastou et al
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