Instrumental conditioning for food reinforcement in the spontaneously hypertensive rat model of attention deficit hyperactivity disorder.

BACKGROUND: The spontaneously hypertensive rat is thought to show good validity as a model of attention deficit hyperactivity disorder, in part because of impaired delayed reinforcement behaviour, corresponding to the dynamic developmental theory of the disorder. However, some previous studies may have been confounded use of fluid reward. Therefore, the objective of this study was to assess the spontaneously hypertensive rat and two comparison strains (Wistar and Wistar Kyoto) using a non-delayed food reinforcement paradigm in an attempt to advance knowledge of basic learnt behaviour in this strain, without potentially confounding reward sensitivity, which could impact on motivation to learn. Rats were trained on a fixed ratio 1 two choice discrimination schedule, extinction, reacquisition and reversal. We also tested non-reinforced spontaneous alternation to facilitate data interpretation. RESULTS: The spontaneously hypertensive rat displayed slower shaping and reduced on task activity during task acquisition, contrasting with previous results which indicate either enhanced responding and an impairment only when a delay is used; we suggest several reasons for this. In line with previous work, the same strain exhibited poor extinguishing of behaviour but were not impaired to the same extent on reversal of the discrimination. Finally, non-reinforced alternations on a Y-maze were also reduced in the spontaneously hypertensive rat. CONCLUSIONS: In sum, the spontaneously hypertensive rat appear to show poor response inhibition in reinforced and non-reinforced contexts. However, impaired response inhibition was reduced during reversal when an opposite response produced food reward alongside presentation of the conditioned stimulus. We discuss the possibility of enhanced attribution of incentive salience to cues in this strain and highlight several points of caution for researchers conducting behavioural assessments using the spontaneously hypertensive rat and their associated comparison strains.

Is there a link between previous exposure to sport injury psychology education and UK sport injury rehabilitation professionals' attitudes and behaviour towards sport psychology?

OBJECTIVES: The use of sport psychology strategies during sport injury rehabilitation can lead to several positive outcomes such as improved adherence and self-efficacy. The purpose of this study was to compare the sport psychology related attitudes and behaviours of UK sport injury rehabilitation professionals (SIRPs) who had studied the psychological aspects of sport injury to those who had not. PARTICIPANTS AND DESIGN: Ninety-four SIRPs (54 physiotherapists and 40 sports therapists with a mean of 9.22 years' experience of working in sport) completed an online survey and were grouped according to their level of previous exposure to sport injury psychology education at an undergraduate/postgraduate level. Analyses were undertaken to establish whether there were any differences in sport psychology related attitude (MANOVA), usage (MANOVA), and referral behaviours (chi square) between the groups. RESULTS: The MANOVA and chi square tests conducted revealed that those who had studied the psychological aspects of sport injury reported using significantly more sport psychology in their practice and making more referrals to sport psychologists. CONCLUSIONS: It was concluded that sport injury psychology education appears to be effective in increasing the sport psychology related behaviours (use of sport psychology and referral) of SIRPs and should be integrated into professional training.

Auditory responses in a rodent model of Attention Deficit Hyperactivity Disorder.

A central component of Attention Deficit Hyperactivity Disorder (ADHD) is increased distractibility in response to visual and auditory stimuli, which is linked to the superior colliculus (SC). Furthermore, there is now mounting evidence of altered collicular functioning in ADHD and it is proposed that a hyper-responsive SC could mediate symptoms of ADHD, including distractibility. In the present study we conducted a systematic characterisation of the intermediate and deep layers of the SC in the most commonly used and well-validated model of ADHD, the spontaneously hypertensive rat (SHR), building on prior work showing increased distractible behaviour in this strain using visual distractors. We examined collicular-dependent orienting behaviour, local field potential (LFP) and multiunit activity (MUA) in response to auditory stimuli in the anaesthetised rat, and morphological measures, in the SHR in comparison to the Wistar Kyoto (WKY) and Wistar (WIS). We found no evidence of increased distractibility in the behavioural data but suggest that this may arise due to cochlear hearing loss in the SHR. Furthermore, the electrophysiology data indicate that the SC in the SHR may still be hyper-responsive, normalising the amplitude of auditory responses that would otherwise be reduced due to the hearing impairment. The morphological measures of collicular volume, cell density and ratios did not indicate this potential hyper-responsiveness had a basis at the structural level examined. These findings have implications for future use of the SHR in auditory processing studies and may represent a limitation to the validity of this animal model.

Sport psychology education for sport injury rehabilitation professionals: a systematic review.

Sport psychology education has been shown to have a positive impact on the practice of sport injury rehabilitation professionals (SIRPs). The purpose of this paper is to review recommendations relating to such education. The paper presents a review of existing literature relating to the content and mode of delivery for a sport psychology education programme for SIRPs. The review seeks to address four questions: (1) What topic areas do researchers suggest should be integrated into the sport psychology education of SIRPs? (2) What topic areas are currently being recommended by professional bodies? (3) What are the findings of research examining the impact of sport psychology education on SIRPs? and (4) What do researchers recommend to be the most appropriate mode of delivery for sport psychology education for SIRPs? The findings of the review suggest that in order to maximise adherence amongst already qualified SIRPs sport psychology education should be delivered in a flexible short duration package. Additionally three broad areas that sport psychology education should cover emerged: (1) understanding of the psychological impact of injury, (2) interventions and psychological skills/techniques, and (3) referral and professional boundaries. This has important implications for the future training of SIRPs.

Psychological and physical correlates of musculoskeletal symptoms in male professional divers and offshore workers.

BACKGROUND: Underwater divers are more likely to complain of musculoskeletal symptoms than a control population. Accordingly, we conducted a study to determine whether musculoskeletal symptoms reflected observable physical disorder, to ascertain the relationship between symptoms and measures of mood, memory and executive function and to assess any need for future screening. METHODS: A 10% random sample of responders to a prior postal health questionnaire was examined (151 divers, 120 non-diving offshore workers). Participants underwent physical examination and a neuropsychological test battery for memory and executive function. Participants also completed the Hospital Anxiety and Depression Scale for anxiety (HADSa) and depression (HADSd), and questionnaires for physical health-related quality of life (SF36 PCS), mental health-related quality of life (SF36 MCS), memory (Cognitive Failures Questionnaire (CFQ), Prospective and Retrospective Memory Questionnaire (PRMQ)), executive function (dysexecutive syndrome questionnaire (DEX)), musculoskeletal symptoms (MSS) and general unrelated symptom reporting. RESULTS: Of participants with moderate/severe musculoskeletal symptoms, 52% had physical signs, and of participants with no symptoms, 73% had no physical signs. There was no difference in the prevalence of signs or symptoms between groups. Musculoskeletal symptoms were associated with lower SF36 PCS for both groups. In divers, musculoskeletal symptoms were associated with higher general unrelated symptom reporting and poorer scoring for HADSa, PRMQ, CFQ and DEX with scores remaining within the normative range. A positive physical examination was associated with general unrelated symptom reporting in divers. There were no differences in neuropsychological test scores attributable to either group or musculoskeletal symptoms. CONCLUSIONS: Musculoskeletal symptoms were associated with physical signs, but this was not a strong effect. Reporting of musculoskeletal symptoms by the divers studied was also associated with a tendency to report symptoms generally or somatisation, and caution should be exercised regarding their interpretation as an indication of physical disease or their use for health screening.

The effects of methylphenidate on cognitive performance of healthy male rats.

WE AIMED TO INVESTIGATE THE EFFECTS OF METHYLPHENIDATE (MPH) IN HEALTHY RATS ON TWO DISTINCT RADIAL MAZE TASKS WHICH RELY ON BRAIN STRUCTURES AND NEUROTRANSMITTERS KNOWN TO BE AFFECTED BY MPH: the Random Foraging Non-Delay Task (RFNDT) and the Delayed Spatial Win Shift Task (DSWT). Hooded Lister rats were trained to complete either the RFNDT or the DSWT having received oral treatment of either a vehicle or MPH (3.0 mg/kg and 5.0 mg/kg for RFNDT, 3.0 mg/kg for DSWT). We found no effect of MPH on the RFNDT relative to the control group. However, those treated with 5.0 mg/kg MPH did take significantly longer to reach criterion performance than those treated with the 3.0 mg/kg MPH, suggesting some doses of MPH can have detrimental effects. For the DSWT, if MPH was present in both phases, performance did not differ from when it was absent in both phases. However, when present in only one phase there was an increase in errors made, although this only reached significance for when MPH was present only in the test-phase. These data suggest that MPH may have detrimental effects on task performance and can result in state-dependent effects in healthy individuals.

Appetitive and consummative responding for liquid sucrose in the spontaneously hypertensive rat model of attention deficit hyperactivity disorder.

The spontaneously hypertensive rat (SHR) is one proposed animal model of attention deficit hyperactivity disorder (ADHD) argued to show strong face validity on the basis of behavioural characteristics. However, SHR may have fundamental alterations to the sensitivity of fluid reward due to altered renal function that has the potential to affect performance in complex reinforced behavioural tests. This could particularly confound determination of operant motivational alterations in the SHR. We assessed baseline bodyweight, home cage lab chow and water intake in the SHR and their typical control strains: Wistar and Wistar Kyoto. We also assessed sucrose preference, and appetitive and consummative positive and negative contrast for sucrose (4% versus 20%) on a motivational runway. As expected, SHR showed enhanced water intake compared to Wistar and Wistar Kyotos but comparable lab chow intake at baseline. SHR exhibited sucrose preference for 4% and 20%, as did both control strains, but the preference for 4% was enhanced in the SHR. SHR showed significant negative and positive contrast in sucrose consumption on the runway, as did Wistar Kyotos. Wistars exhibited neither. Appetitive contrast was not measurable in the SHR due to a robust locomotor velocity increase at the age of testing. The enhanced fluid intake found in the SHR argues against using fluid reinforcers in behavioural tests. We suggest the presence of both forms of contrast in the SHR is unusual for rats tested in ad lib. food conditions while the contrast pattern in Wistars indicate abnormalities in reward sensitivity in this control strain.

Abnormal air righting behaviour in the spontaneously hypertensive rat model of ADHD.

The spontaneously hypertensive rat (SHR) is the most commonly used model of attention-deficit hyperactivity disorder (ADHD), displaying the main symptoms of the disorder which are responsive to psychostimulant treatments. Research to date has focused on behavioural tests investigating functioning of the striatum or prefrontal cortex in these rats. However, there is now evidence that the superior colliculus, a structure associated with head and eye movements, may also be dysfunctional in ADHD. Therefore, the aim of this study was to investigate whether the SHR demonstrated impairment in collicular-dependent behaviour. To this end, we examined air righting behaviour, which has previously been shown to be modulated in a height-dependent manner reliant on a functional superior colliculus. We assessed SHR, Wistar Kyotos and Wistars on static righting and air righting at 50 and 10 cm drop heights. There were no differences in static righting, indicating that there were no gross motor differences that would confound air righting. Qualitative analysis of video footage of the righting did not reveal any changes previously associated with collicular damage, unique to the SHR. However, the SHR did show impairment in height-dependent modulation of righting in contrast to both control strains, such that the SHR failed to modulate righting latency according to drop height. This failure is indicative of collicular abnormality. Given that many rodent tests of attentional mechanisms involve head and eye orienting, which are heavily dependent on the colliculus, a collicular dysfunction has strong implications for the type of attentional task used in this strain.

The pedunculopontine tegmental nucleus and the nucleus basalis magnocellularis: do both have a role in sustained attention?

BACKGROUND: It is well established that nucleus basalis magnocellularis (NbM) lesions impair performance on tests of sustained attention. Previous work from this laboratory has also demonstrated that pedunculopontine tegmental nucleus (PPTg) lesioned rats make more omissions on a test of sustained attention, suggesting that it might also play a role in mediating this function. However, the results of the PPTg study were open to alternative interpretation. We aimed to resolve this by conducting a detailed analysis of the effects of damage to each brain region in the same sustained attention task used in our previous work. Rats were trained in the task before surgery and post-surgical testing examined performance in response to unpredictable light signals of 1500 ms and 4000 ms duration. Data for PPTg lesioned rats were compared to control rats, and rats with 192 IgG saporin infusions centred on the NbM. In addition to operant data, video data of rats' performance during the task were also analysed. RESULTS: Both lesion groups omitted trials relative to controls but the effect was milder and transient in NbM rats. The number of omitted trials decreased in all groups when tested using the 4000 ms signal compared to the 1500 ms signal. This confirmed previous findings for PPTg lesioned rats. Detailed analysis revealed that the increase in omissions in PPTg rats was not a consequence of motor impairment. The video data (taken on selected days) showed reduced lever orientation in PPTg lesioned rats, coupled with an increase in unconditioned behaviours such as rearing and sniffing. In contrast NbM rats showed evidence of inadequate lever pressing. CONCLUSION: The question addressed here is whether the PPTg and NbM both have a role in sustained attention. Rats bearing lesions of either structure showed deficits in the test used. However, we conclude that the most parsimonious explanation for the deficit observed in PPTg rats is inadequate response organization, rather than impairment in sustained attention. Furthermore the impairment observed in NbM lesioned rats included lever pressing difficulties in addition to impaired sustained attention. Unfortunately we could not link these deficits directly to cholinergic neuronal loss.

Excitotoxic lesions of the pedunculopontine tegmental nucleus in rats impair performance on a test of sustained attention.

Recent research has suggested that the pontomesencephalic tegmentum might be an important part of a network underlying sustained attention. The largest structure of the pontomesencephalic tegmentum is the pedunculopontine tegmental nucleus, which has ascending connections to thalamus and with corticostriatal systems. In this experiment we examined the performance of rats following bilateral excitotoxic lesions of the pedunculopontine tegmental nucleus on a test of sustained attention previously used to examine frontal cortical function. After an initial period of darkness, the rats had to attend continuously to a dim stimulus light that would, at unpredictable intervals, become transiently brighter. During this period of increased stimulus brightness the rats could press a lever to obtain a food reward. Rats were trained to a criterion level of performance before lesions were made. After surgery, sham lesioned rats (n=7) resumed accurate responding, with an average successful detection rate of approximately 70%. Pedunculopontine lesioned rats (n=7), however, only achieved a successful detection rate of approximately 40%. When the duration of the bright target stimulus was increased from 1.5 to 4 s, the performance of the pedunculopontine lesioned rats significantly improved. The observation that an increase in brightness duration caused a marked improvement in lesioned rats' performance suggests strongly that the impairment was in attention rather than motor ability or simple sensory processing. These data are taken to be consistent with the hypothesis that the pedunculopontine tegmental nucleus is an important part of a network maintaining attention.