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ABSTRACT: It is now widely accepted that in addition to motor coordination, the cerebellum is also involved in the modulation of cognitive and affective processes. Despite alcoholic cerebellar degeneration (ACD) being the most common form of cerebellar disorder, little systematic investigation of cerebellar-mediated cognitive and affective deficits has occurred in chronic alcoholics. Forty-nine chronic alcoholics and 29 healthy control participants underwent testing of cognitive and affective function, along with measurement of cerebellar ataxia using the International Cooperative Ataxia Rating Scale (Trouillas et al., Journal of the Neurological Sciences 145:205-11, 1997). The alcoholic group demonstrated significantly poorer performance as compared to the control group in a number of domains, including visuospatial and language skills, psychomotor speed, new learning and memory, executive functioning, and emotional regulation and affect processing. There were no differences between the alcoholic and control groups in immediate attention and working memory abilities. Years of heavy drinking and total period of abstinence were found to be the best predictors of cognitive and emotional function in the alcoholic group. After accounting for alcohol chronicity, there was still a relationship between the degree of clinical signs of ACD and some areas of cognitive and emotional functioning, including language, executive functioning, processing speed and affect processing. The results suggest that some of the cognitive and affective deficits observed in chronic alcoholics may be mediated, at least in part, by cerebellar dysfunction. These findings add support to the theory of disruption to bidirectional cerebro-cerebellar circuitry underlying cognitive and affective deficits in chronic alcoholics.
The Cerebellum 02/2013; · 3.21 Impact Factor
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ABSTRACT: Piracetam is an AMPAkine drug that may have a range of different mechanisms at the cellular level, and which has been shown to facilitate memory, amongst its other effects. This series of experiments demonstrated that a 10mg/kg dose of piracetam facilitated memory consolidation in the day-old chick when injected from immediately until 120min after weak training (i.e. using a 20% v/v concentration of methyl anthranilate) with the passive avoidance learning task. Administration of piracetam immediately after training led to memory facilitation which lasted for up to 24h following training. This dose of the AMPAkine was not shown to facilitate memory reconsolidation. These findings support the contention that application of the AMPAkine piracetam facilitates memory using a weak training task, and extend the range of actions previously noted with NMDA-related agents to those which also facilitate the AMPA receptor.
Pharmacology Biochemistry and Behavior 08/2012; 103(2):353-358. · 2.53 Impact Factor
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ABSTRACT: BACKGROUND: Alcoholism is the most common cause of cerebellar dysfunction, yet estimates of the incidence of alcoholic cerebellar degeneration (ACD) vary greatly, with differences in methodologies contributing to these disparate findings. This study set out to characterize the frequency and pattern of clinical signs of ACD in an alcoholic group using the International Cooperative Ataxia Rating Scale (ICARS). METHODS: We compared the performance of 49 alcoholics and 29 control participants. The relative contributions of demographic and alcohol consumption variables to ICARS scores in the alcoholic group were also examined. RESULTS: The alcoholic group demonstrated significantly poorer performance on all of the ICARS subscales as compared with the control group. Within the alcoholic group, performance was more impaired on the speech scale than on all of the other scales, except the lower limb component of the kinetic scale, and less impaired on the oculomotor scale compared with all other scales. Years of heavy drinking and lifetime alcohol consumption correlated with total ICARS scores; however, maximum daily consumption was actually negatively correlated with ICARS scores. Of the alcohol history variables, years of heavy drinking was the best predictor of total ICARS scores, making a 19% unique contribution, followed by the period of abstinence from alcohol, which uniquely contributed 7% of the variance. There were high correlations between age and male gender and the alcohol consumption variables; however, age and gender were still found to uniquely contribute 5 and 7% respectively to the variance in total ICARS scores. CONCLUSIONS: ACD may affect up to two-thirds of chronic alcoholics. Assessing the number of years an individual has been drinking beyond a certain threshold can give a good indication of the likelihood of ACD. Age, gender, and the source of the clinical sample may significantly contribute to the prevalence of ACD and require further detailed investigation.
Alcoholism Clinical and Experimental Research 05/2012; · 3.34 Impact Factor
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ABSTRACT: Recent research has pointed to a role for brain-derived neurotrophic factor (BDNF) in long-term potentiation and memory. The present series of experiments examined the effects of the application of exogenous BDNF on memory consolidation and reconsolidation of a weak training stimulus with the day-old chick, using the passive avoidance learning paradigm. Chicks injected intracranially with 12.5 μg/mL recombinant BDNF immediately after a single-trial training event displayed enhanced retention relative to saline up to 24h post-training. Furthermore, this dose was also shown to enhance retention when administered following initial weak training. Thus, exogenous BDNF was shown to enhance both consolidation and reconsolidation of memory when administered acutely to the day-old chick.
Neuroscience Letters 04/2012; 516(1):119-23. · 2.11 Impact Factor
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ABSTRACT: Memantine is a non-competitive N-methyl-d-aspartate (NMDA) receptor antagonist that has been approved for the treatment of the cognitive deficits noted in Alzheimer's disease. While there is a body of research that supports memantine's facilitative action upon memory compromise, this series of studies aimed to investigate the effects of this drug in healthy animals with intact memory functioning. A 0.1 mM dose of memantine injected immediately after a weakly aversive training event (i.e. 20% v/v methyl anthranilate) was found to enhance passive avoidance learning for this event in day-old chicks up to 24 h following training. The same dose of memantine was also observed to enhance memory for the training event when it was administered in conjunction with a reminder trial. These results suggest that memantine is capable of facilitating both memory consolidation as well as memory reconsolidation. It was concluded that memantine's mechanism may involve the short-term or intermediate memory phases of the Gibbs and Ng model of memory, and that the current findings represent enhancement of intact memory, rather than amelioration of memory compromise.
Neurobiology of Learning and Memory 03/2012; 97(4):380-5. · 3.42 Impact Factor
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ABSTRACT: Anonclinical sample of 41 participants were subjected to heightened levels of physiological arousal and measured on a number of neuropsychological measures of attention. The participants completed the measures under both 75dB and 95dB white noise. Examination of the performance on the Corsi Block Tapping Task, the Trail Making Test Part B, and the Digit Symbol Substitution Test showed significant decrements in performance on these tasks as a result of the high levels of physiological arousal. Tests that failed to show performance deficits included the Trail Making Test Part A, the Symbol Search, and measures of reaction time. These results indicate that the effect of heightened arousal on test performance is on the more complex indices of attention. It is suggested that heightened levels of arousal can influence performance in the clinical assessment situation, and collateral measurement of anxiety state may be helpful in determining the effect of this factor in conducting assessment in both clinical and nonclinical samples.
Australian Psychologist 03/2011; 36(3):239 - 243. · 0.61 Impact Factor
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ABSTRACT: This study investigated episodic and procedural memory performance in early and late pregnancy. Twenty-six women in the third trimester of pregnancy, 20 women in the first trimester of pregnancy, and 24 nonpregnant controls were administered a battery of verbal and visual episodic memory tasks and two procedural memory tasks. Results indicated that compared to controls, both pregnant groups had reduced scores on immediate and delayed verbal episodic memory tasks, but were unimpaired on visual and procedural memory tasks. Verbal memory differences could not be accounted for by mood state or attention; however, progesterone level accounted for a small amount of the variation. Although memory differences were minor, the perception of memory problems may have implications for everyday living for pregnant women.
Journal of Clinical and Experimental Neuropsychology 03/2011; 33(6):680-91. · 2.13 Impact Factor
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ABSTRACT: Anecdotal reports of sleep disturbance during pregnancy are abundant; however, objective measurement of sleep changes has so far produced conflicting results.
To objectively measure sleep architecture and investigate subjective sleep quality in the first and third trimester of pregnancy, when compared to the nonpregnant state.
Twenty-seven women in the third trimester of pregnancy, 21 women in the first trimester of pregnancy and 24 nonpregnant control women underwent overnight polysomnography and completed questionnaires regarding sleep quality and mood.
Women in the third trimester of pregnancy had poorer sleep efficiency, more awakenings, less stage 4 sleep, more stage 1 sleep and fewer minutes in rapid eye movement sleep when compared to the control group. Cortical arousals were seen more often during pregnancy, particularly in response to respiratory events and limb movements. Sleep during the first trimester was affected to a lesser extent, with more wake time after sleep onset and less stage 4 sleep when compared to the controls.
Sleep during pregnancy is compromised by higher amounts of wake and cortical arousals leading to sleep fragmentation, with greater amounts of light sleep and less deep sleep. Mood state did not have an effect on sleep. Given the impact of sleep on well-being, this study increases our understanding of the characteristics of sleep during pregnancy, to help recognise when severe sleep disruption may warrant referral to a specialist for appropriate diagnosis and treatment.
Australian and New Zealand Journal of Obstetrics and Gynaecology 02/2011; 51(1):38-46. · 1.24 Impact Factor
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ABSTRACT: Given the prevalence of mild traumatic brain injury (mTBI) and enduring subjective complaints known as postconcussion symptoms (PCS), it is important to investigate the nature and extent of these difficulties. This study used meta-analytic techniques to integrate the available information on the emotional symptoms associated with mTBI. Small effect sizes were found across all domains (depression, anxiety, coping, and psychosocial disability); however, significance depended upon the weighting method employed. The results indicate that mTBI had a small to negligible effect on emotional symptom reporting. This has implications for the etiology of PCS, the delivery of therapeutic interventions, and medico-legal disputations.
Journal of Clinical and Experimental Neuropsychology 06/2010; 32(5):463-73. · 2.13 Impact Factor
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ABSTRACT: This series of experiments investigated the role of protein translation and RNA synthesis on consolidation and reconsolidation of passive avoidance learning (PAL) in day-old chicks. Although it is well established that protein translation is required after a reminder, there are conflicting reports in the literature concerning the requirement for RNA synthesis at this time. Day-old male New HampshirexWhite Leghorn chicks were trained on a single trial passive avoidance task. The results confirmed the requirement for protein translation during reconsolidation with memory deficits induced by anisomycin (ANI) (10mg/kg) detected at 60min post-reminder. It was also established that RNA synthesis was required for consolidation of PAL through inhibition by 5,6-Dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB) (0.075microg/kg), administered at or after training. The same dose of DRB was also found to inhibit memory post-reactivation. However injections were required before the reminder trial and memory deficits were evident by 60min, consistent with that found for ANI post-reminder. As with ANI, the DRB-induced memory deficit post-reminder was also transient, and resolved by 24h post-reminder. For both reconsolidation drug studies, the memory deficit was wholly dependent on the memory being reactivated by a reminder-trial. The study highlights an important role for RNA synthesis following memory reactivation.
Pharmacology Biochemistry and Behavior 10/2009; 94(3):438-46. · 2.53 Impact Factor
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ABSTRACT: There is an increasing evidence that long-term alcohol intake can promote damage to most of the body's major organs. However, regular consumption of a small-moderate amount of alcohol is often recommended as being beneficial to health and of concern is that the effect of ingesting commercially available alcohol products on steroid hormone synthesis under variable nutritional conditions has not been thoroughly investigated. Many individuals consume alcohol alone prior to a meal and the aim of the present study was to assess the effect of consuming a small-moderate amount of commercially available alcohol on the level of salivary cortisol and salivary dehydroepiandrosterone sulfate (DHEAS) before and after a meal. A total of 24 males aged 19-22 years participated in the current investigation. The experimental procedure required participants to fast for 6 h before being asked to ingest either 40 g alcohol in the form of red wine (n=8), low alcohol and high beer (n=8), white wine (n=8) or the equivalent amount of placebo over a 135-min period before consuming food for 45-min. The level of blood alcohol, salivary cortisol and salivary DHEAS was assessed upon arrival and then at regular 45-min intervals during the 180-min experimental period. The results showed that the consumption of alcohol and placebo can significantly lower the level of salivary cortisol. However, the effect of consuming a small-moderate amount of commercially available alcohol on the level of salivary DHEAS was dependent on the nutritional content of the beverage with red wine promoting no change, white wine promoting a significant decrease, and beer having a variable effect on salivary DHEAS concentration when compared to placebo. It was concluded that the effect of commercially available alcohol on the HPA axis is not the same for all alcohol products and both the nutritional status of participants and the nutritional content of the alcoholic beverage being administered should be taken into consideration when investigating the effect of alcohol on the HPA axis.
Pharmacology Biochemistry and Behavior 06/2009; 93(2):170-6. · 2.53 Impact Factor
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ABSTRACT: This paper reports two studies which investigated the effect of interference on delayed recall scores of the WMS-III and other commonly used memory measures. In Study 1, participants completed the immediate and delayed components of the WMS-III, with or without the introduction of conceptually similar memory tasks between the recall trials. In Study 2, this order of administration was reversed, with the WMS-III subtests used as the interference items. The results indicated that the introduction of interference items during the delay negatively affected delayed recall performance on almost all sub-tests. In addition, equal effects of proactive and retroactive interference were demonstrated. These findings raise concerns regarding the standardization process for memory tasks and highlight the need to consider interference effects in clinical practice, and stand as a caution in the use of memory-related materials during the delay interval in memory testing.
Archives of Clinical Neuropsychology 03/2009; 24(1):105-12. · 2.18 Impact Factor
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ABSTRACT: Gamma-butyrolactone (GBL) is a prodrug to gamma-hydroxybutyric acid (GHB) and metabolises to GHB when ingested. Discrimination stimulus studies report generalisation of effects of GHB to GBL. While amnesia is one of the most commonly reported symptoms of GHB's ingestion in human users, as yet few studies have examined this effect. Although an endogenous GHB specific receptor is present in the brain, several studies have indicated that the clinical effects of exogenous doses of GBL/GHB are due to its action on GABA(B) receptors rather than on the GHB receptor. In this series of studies, New Hampshire x White leghorn cockerels were trained using a modified version of the passive avoidance learning task. Subcutaneous injections of GBL induced a memory deficit by 10 min post-training, which persisted for at least 24 h. No effect on memory was seen with administration of the specific GHB agonist NCS-356 (gamma-p-chlorophenyl-trans-4-hydroxycrotonate). The GBL-induced memory deficit appeared similar to the deficit produced by baclofen, where the antagonist facilitated learning. Additionally, GBL-induced memory deficit was ameliorated by application of a GABA(B) antagonist. The results support the hypothesis that GBL exerts its influence on memory via the GABA(B) receptor rather than by the specific GHB receptor.
Behavioural brain research 11/2008; 197(2):347-55. · 3.22 Impact Factor
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ABSTRACT: Cyclin-dependent kinase 5 (CDK-5) is reported to phosphorylate the NMDA receptor prior to the induction of long-term potentiation (LTP), among its many other effects. Application of CDK-5 inhibitors disrupts LTP and results in impaired task acquisition in behaving animals. In this study, we investigated the effect of exogenously applied roscovitine, a potent CDK-5 inhibitor, on consolidation and reconsolidation processes in day-old male chicks. New Hampshire x White leghorn cockerels were trained using a modified version of the passive avoidance learning task. Intracranial injections of roscovitine (2.5 microM) administered immediately after training induced a memory deficit that evolved from 5-minute post-training and persisted until at least 24 h following training. Injections of roscovitine (2.75 microM) administered immediately after the reminder trial induced a memory deficit observed by 30-minute post-reminder which had resolved by 24 h following the reminder. The comparison between consolidation and reconsolidation demonstrates differences both in the time of the onset of the memory deficit as well as in the permanence of this deficit. The results suggest an important, although different role for CDK-5 in consolidation and reconsolidation processes following passive avoidance learning.
Pharmacology Biochemistry and Behavior 11/2008; 91(1):59-66. · 2.53 Impact Factor
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ABSTRACT: Both NMDA and non-NMDA receptors participate in the consolidation of passive avoidance learning (PAL) in the day-old chick. NMDA antagonists have also been implicated in reconsolidation processes following reminder-trials. In this study, we examined the effect of administering 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), a non-NMDA receptor antagonist, on reconsolidation following memory reactivation. New Hampshire x White leghorn cockerels were trained using a modified version of the PAL task. When CNQX was administered 20 min following a reminder trial, a retention deficit was detected at 90 min, but this had resolved by 24 h following the reminder. The parameters of the reconsolidation deficit were similar to those induced by CNQX injections post-training with the exception of their transience. This finding suggests that the action of non-NMDA receptors may perform a similar role in both consolidation and reconsolidation processes.
Neuroscience Letters 09/2008; 442(3):244-8. · 2.11 Impact Factor
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ABSTRACT: A one-trial learning task, where chicks learn that a bead of a particular shape and/or colour has a bitter taste (because it has been coated in 100% methyl anthranilate, MeA) and subsequently avoids it on test, has been widely used by research groups across the world. However, there are some differences in the results reported by different research laboratories. One important difference is found when chicks are trained with a diluted bitter taste on the bead (10 or 20% MeA); memory is not consolidated and fades, lasting for different times. At Monash and La Trobe Universities, memory lasts for 30 min but at the Open University (OU), memory lasts for 4-6h before fading. Differences in protocol that may explain this apparent discrepancy are whether the chicks have seen the bead before (novelty) and whether the colour or the shape of the bead is an important feature. In this review, we discuss these and other factors that may contribute to the differences in the characteristics of memory processing at Monash and at the OU, such as chick strain, hatchery or laboratory incubated chicks, age at training. It is clear that there is a difference between passive avoidance and discriminative avoidance protocols and this may explain the differences in duration of the memory with weakly reinforced learning. Is the OU task a more salient experience because of the novelty of the bead and therefore a 'stronger' learning experience? The different protocols may allow different questions to be addressed.
Brain research bulletin 07/2008; 76(3):198-207. · 2.18 Impact Factor
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ABSTRACT: It has been one of the unshakeable orthodoxies of memory research that memory is initially laid down in a labile form for a short period following the experience and that over time the memory is "fixed" or "consolidated" into the physical structure of the brain. Over the last decade a large body of data has gathered which demonstrates that a "consolidated" memory can be returned to a labile state following retrieval of material from the store, which can then be re-consolidated, incorporating the newly acquired information into the representation of the world. The process of re-consolidation thus provides a sensible means for the crucial process of memory updating to occur. The paper focuses on pharmaco-behavioural experiments undertaken in our laboratories as well as in those of other groups which use the day-old chick as subject and the passive avoidance learning (PAL) task to examine the behavioural and metabolic parameters of re-consolidation. The data indicate that the consolidation and the re-consolidation processes are similar but not identical physiological processes. The re-processing of the memory following a re-consolidation involves each of the glutamatergic, adrenergic and dopaminergic neurotransmitter systems as well as re-activation of protein synthesis associated with the respective traces. In the chick model system, the ability to undertake re-consolidation is transient, and is observed only for a maximum of 24-48 h following the initial training event. Controversy persists as to whether the re-consolidated memory represents a new memory or whether it is a modification of the original memory processing.
Brain research bulletin 07/2008; 76(3):192-7. · 2.18 Impact Factor
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ABSTRACT: This study investigated the effect of ouabain, an inhibitor of NA(+) and K(+) ATPase, on consolidation and reconsolidation of a passive avoidance learning task in the day-old chick. In the consolidating trace, ouabain is thought to inhibit an intermediate-term memory phase, some aspects of which acts as a "trigger" for long-term stabilisation of the trace by new protein synthesis. It was hypothesised that a similar process may initiate the protein synthesis observed following reminder-activated reconsolidation in the young chick. Chicks were trained on a single trial passive avoidance task. A dose of 0.2 ug/kg ouabain was administered intracranially either 5 min post-training (consolidation processes) or 5 min post-reminder (reconsolidation processes). Consistent with previous research, ouabain administration induced a memory deficit following the initial learning trial. However, contrary to expectation, ouabain did not disrupt memory processing post-reactivation. This finding provides further evidence for the notion that consolidation and reconsolidation are associated with similar, but distinct, stages of processing.
Neuroscience Letters 09/2007; 423(2):123-7. · 2.11 Impact Factor
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ABSTRACT: To investigate the relationship of working memory, processing speed and verbal comprehension with FAS performance in individuals who had sustained a traumatic brain injury (TBI).
Sixty-three patients with a TBI were grouped according to the presence of impaired verbal fluency performance and then compared on a number of cognitive and demographic variables.
Following a TBI, working memory and processing speed had the greatest influence on verbal fluency performance. For those individuals who have not sustained a TBI, education, verbal intelligence, working memory and speed of information processing were related to FAS performance.
The findings of the study indicate that FAS performance was related to verbal intelligence, working memory ability, attention and speed of information processing. The results further suggest that different variables are related to FAS performance following a TBI as compared with control group performances.
Brain Injury 07/2007; 21(7):709-19. · 1.36 Impact Factor
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ABSTRACT: Anecdotal and experimental evidence has demonstrated that humans and animals exhibit physiological and cognitive alterations in response to sickness and injury. It is now clear that these changes are due to the actions of proinflammatory cytokines. The current study examined the effects of peripheral administration of polyinosinic:polycytidylic acid, a synthetic double-stranded viral RNA, on the memory processes of day-old chicks trained on a single trial passive avoidance task. Polyinosinic:polycytidylic acid impaired performance on the passive avoidance task in a dose-dependent manner. Maximal deficits were observed when 5 g/kg polyinosinic:polycytidylic acid was administered 120 min before training. Tests for retention revealed that interference in memory consolidation appeared between 30 and 40 min after training. These results indicate an inhibitory effect of polyinosinic:polycytidylic acid on the processes of memory formation at the transition from intermediate-term memory phase (A) to intermediate-term memory phase (B) of the Gibbs and Ng model of memory formation. The study also investigated the pyrogenic actions of polyinosinic:polycytidylic acid, and examined the effect of pretreatment with ketoprofen, a cyclooxygenase inhibitor. Significant rises in body temperature were observed 30 min after injection of polyinosinic:polycytidylic acid. Inhibition of cyclooxygenase by ketoprofen ameliorated the polyinosinic:polycytidylic acid-induced deficits in retention and attenuated the increase in body temperature. These results demonstrate that polyinosinic:polycytidylic acid induces memory processing deficits and is pyrogenic in the day-old chick and that these effects are cyclooxygenase-dependent.
Behavioural Pharmacology 03/2007; 18(1):19-27. · 2.72 Impact Factor
