The Effect of Propranolol and Midazolam on the Reconsolidation of a Morphine Place Preference in Chronically Treated Rats

A stable memory can be disrupted if amnestic treatment is applied in conjunction with memory reactivation. Recent findings in the conditioned place preference (CPP) model suggest that blocking reconsolidation attenuates the ability of environmental cues to induce craving and relapse in drug addicts, but the impact of prior physical dependence has not been described. We examined the effect of post-reactivation amnestic treatment on reconsolidation of a CPP for morphine, in animals naïve to morphine, under chronic morphine experience or abstinent. Chronic morphine experience was induced by escalating doses of morphine from 10 mg/kg/day (s.c.), and maintained on 30 mg/kg/day during the course of conditioning and reactivation procedures, or conditioning alone. Naïve and morphine-experienced animals were trained in a three-compartment apparatus by four morphine (5 mg/kg, s.c.) and four saline experiences paired with either of two large conditioning compartments. The memory was then reactivated by a CPP test, and immediately afterward animals received an injection of the beta-adrenergic antagonist propranolol (10 mg/kg, s.c.), the GABAa agonist midazolam (1 mg/kg, i.p.), or saline. Morphine-naïve rats received only a single reconsolidation-blocking treatment (Experiment 1), while chronic morphine rats were given eight reactivation sessions each followed by amnestic treatment, either before (Experiment 2) or after 10 days of withdrawal (Experiment 3). Propranolol and midazolam disrupted reconsolidation in morphine-naïve rats, but failed to disrupt the CPP when rats were trained under chronic morphine treatment, even if they were recovered from chronic opiate exposure before reactivation. In fact, propranolol increased the preference for the drug-paired context in animals trained while maintained on chronic morphine. Midazolam had little effect. Morphine experience may produce neurochemical changes which alter memory storage processes and reduce the impact of amnestic treatments on reconsolidation

Maintaining fixation does not increase demands on working memory relative to free viewing

The comparison of memory performance during free and fixed viewing conditions has been used to demonstrate the involvement of eye movements in memory encoding and retrieval, with stronger effects at encoding than retrieval. Relative to conditions of free viewing, participants generally show reduced memory performance following sustained fixation, suggesting that unrestricted eye movements benefit memory. However, the cognitive basis of the memory reduction during fixed viewing is uncertain, with possible mechanisms including disruption of visual-mnemonic and/or imagery processes with sustained fixation, or greater working memory demands required for fixed relative to free viewing. To investigate one possible mechanism for this reduction, we had participants perform a working memory task—an auditory n-back task—during free and fixed viewing, as well as a repetitive finger tapping condition, included to isolate the effects of motor interference independent of the oculomotor system. As expected, finger tapping significantly interfered with n-back performance relative to free viewing, as indexed by a decrease in accuracy and increase in response times. By contrast, there was no evidence that fixed viewing interfered with n-back performance relative to free viewing. Our findings failed to support a hypothesis of increased working memory load during fixation. They are consistent with the notion that fixation disrupts long-term memory performance through interference with visual processes

Detection of foot-and-mouth disease virus in milk samples by real-time reverse transcription polymerase chain reaction: Optimisation and evaluation of a high-throughput screening method with potential for disease surveillance

This study aimed to evaluate the utility of milk as a non-invasive sample type for the surveillance of foot-and-mouth disease (FMD), a highly contagious viral disease of cloven-hooved animals. Four milking Jersey cows were infected via direct-contact with two non-milking Jersey cows that had been previously inoculated with FMD virus (FMDV: isolate O/UKG/34/2001). Milk and blood were collected throughout the course of infection to compare two high-throughput real-time reverse transcription polymerase chain reaction (rRT-PCR) protocols with different RT-PCR chemistries. Using both methods, FMDV was detected in milk by rRT-PCR one to two days before the presentation of characteristic foot lesions, similar to detection by virus isolation. Furthermore, rRT-PCR detection from milk was extended, up to 28 days post contact (dpc), compared to detection by virus isolation (up to 14 dpc). Additionally, the detection of FMDV in milk by rRT-PCR was possible for 18 days longer than detection by the same method in serum samples. FMDV was also detected with both rRT-PCR methods in milk samples collected during the UK 2007 outbreak. Dilution studies were undertaken using milk from the field and experimentally-infected animals, where for one sample it was possible to detect FMDV at 10 . Based on the peak C values detected in this study, these findings indicate that it could be possible to identify one acutely-infected milking cow in a typical-sized dairy herd (100-1000 individuals) using milk from bulk tanks or milk tankers. These results motivate further studies using milk in FMD-endemic countries for FMD surveillance

Classification of general and personal semantic details in the Autobiographical Interview

The Autobiographical Interview (AI) separates internal (episodic) and external (non-episodic) details from transcribed protocols using an exhaustive and reliable scoring system. While the details comprising the internal composite are centered on elements of episodic memory, external details are more heterogeneous as they are meant to capture a variety of non-episodic utterances: general semantics, different types of personal semantics details, metacognitive statements, repetitions, and details about off topic events. Elevated external details are consistently observed in aging and in neurodegenerative diseases. In the present study, we augmented the AI scoring system to differentiate subtypes of external details to test whether the elevation of these details in aging and in frontotemporal lobar degeneration (including mixed frontotemporal/semantic dementia [FTD/SD] and progressive non-fluent aphasia [PNFA]) would be specific to general and personal semantics or would concern all subtypes. Specifically, we separated general semantic details from personal semantic details (including autobiographical facts, self-knowledge, and repeated events). With aging, external detail elevation was observed for general and personal semantic details but not for other types of external details. In frontotemporal lobar degeneration, patients with FTD/SD (but not PNFA) generated an excess of personal semantic details but not general semantic details. The increase in personal but not general semantic details in FTD/SD is consistent with prevalent impairment of general semantic memory in SD, and with the personalization of concepts in this condition. Under standard AI instructions, external details were intended to capture off-topic utterances and were not intended as a direct measure of semantic abilities. Future investigations concerned with semantic processing in aging and in dementia could modify standard instructions of the AI to directly probe semantic content

Eye Movements Relate to Episodic Detail Retrieval during Recall of Autobiographical Memories

Eye movements have been shown to benefit the encoding and retrieval of memories in laboratory experiments. However, the ecological validity of laboratory memory is questionable, necessitating the use of naturalistic methods to assess episodic autobiographical memory (AM) – recollection of past events from people’s everyday lives. Several studies have related eye movements to AM, but with notable limitations, including a lack of eye movement monitoring (EMM) and the use of subjective methods. The goal of this dissertation was to examine whether eye movements benefitted recall of AMs using EMM in combination with an objective measure – the Autobiographical Interview – which quantifies the number of details recalled. I developed a novel EMM paradigm in which participants recalled AMs while viewing a blank screen according to (1) free viewing and (2) fixed viewing conditions. In Experiment 1, a working memory task was used to validate that free and fixed viewing were comparable in their demands on executive resources, as compared to a finger-tapping condition in which participants demonstrated reduced accuracy on the task. In Experiment 2, participants recalled self-selected AMs during free and fixed viewing. Fixation rate was predictive of the number of internal (episodic) but not external (non-episodic) details recalled across both viewing conditions. In Experiment 3, I tested recall of a staged event to see if individual differences in AM moderated the effect of fixations on internal details. High AM individuals demonstrated the positive effect of fixations on number of internal (not external) details observed in Experiment 2, whereas low AM individuals did not show a relationship between eye movements and recall. Overall, eye movements appear to relate to retrieval of episodic details during AM recall, possibly through exploration of recollected visual images. In anatomical studies, connectivity between oculomotor, memory, and posterior visual regions suggest neural network that could mediate the relationship of eye movements, memory retrieval, and possibly mental imagery. As a next step in this research, neuroimaging studies are needed to assess this hypothesized mechanism linking eye movements to AM.Ph.D.2020-11-16 00:00:0

The Effects of Memory Remoteness on Recall and Recognition: Development of a Novel Measure of Naturalistic Memory

The current study introduced a new measure for the study of naturalistic memory, which involved the use of a homogeneous, controlled event for all participants. We tested participants’ memory for this so-called staged event with both the Autobiographical Interview (AI) and our novel receiver operating characteristic (ROC) task. Statistical analyses indicated that scores on the AI and on our new ROC measure showed time sensitivity consistent with the literature. These data were difficult to interpret, however, because of a confound of age. We will need to age-match our groups before drawing any major conclusions. That said, we found a significant positive correlation between measures of recollection on both the AI and ROC task, which was a promising finding in terms of validating the new measure against an established procedure. Overall, our results suggest that assessing recall and recognition for a staged event is a viable method for studying naturalistic memory.MAS

Untangling competition between epitaxial strain and growth stress through examination of variations in local oxidation

The corrosion properties of engineering alloys are strongly influenced by local variations seen at the micro level. Here, the authors demonstrate how the metal grain orientation can influence the protectiveness of the oxide, which provides a possible route for improving corrosion performance

Construction of dual-labelled E. coli strains to study the effects of antibiotics and microbiota on the horizontal transfer of ESBL genes in the in vitro chicken caecal microbiota

Short Term Missions (STMs) are small travel grants with the aim of sharing scientific expertise, methodologies, equipment and facilities to harmonise the existing approaches and methodologies within the large OHEJP network, and to drive the research forward in a collaborative and non-duplicative fashion to strengthen both the scientific capacity within the OHEJP and also future prevention, preparedness, detection and response of the EU to foodborne and other emerging threats across human-animal-environmental sectors