Temporal Dissociation Research Articles

Temporal dynamics of cerebellar and motor cortex physiological processes during motor skill learning

Learning motor tasks involves distinct physiological processes in the cerebellum (CB) and primary motor cortex (M1). Previous studies have shown that motor learning results in at least two important neurophysiological changes: modulation of cerebellar output mediated in-part by long-term depression of parallel fiber-Purkinje cell synapse and induction of long-term plasticity (LTP) in M1, leading to transient occlusion of additional LTP-like plasticity. However, little is known about the temporal dynamics of these two physiological mechanisms during motor skill learning. Here we use non-invasive brain stimulation to explore CB and M1 mechanisms during early and late motor skill learning in humans. We predicted that early skill acquisition would be proportional to cerebellar excitability (CBI) changes, whereas later stages of learning will result in M1 LTP-like plasticity modifications. We found that early, and not late into skill training, CBI changed. Whereas, occlusion of LTP-like plasticity over M1 occurred only during late, but not early training. These findings indicate a distinct temporal dissociation in the physiological role of the CB and M1 when learning a novel skill. Understanding the role and temporal dynamics of different brain regions during motor learning is critical to device optimal interventions to augment learning.

모바일 개인방송 시청 요인 분석 : HMSAM 모델을 중심으로

모바일 기술과 비디오 스트리밍 기술이 발달하고 미디어 플랫폼이 다변화 되면서 ‘페이스북 라이브’, ‘아프리카 TV’와 같은 모바일 개인방송은 기존 IT 시스템과는 다른 수용 패턴을 보이고 있다. 모바일 개인방송 시청 요인에는 오락적 동기가 가장 큰 비중을 차지하므로 기존의 외재적, 생산적 동기 중심의 시스템 수용 이론으로는 연구의 한계가 있다고 판단하였다. 이에 본 연구는 오락적 동기 시스템 수용 분석에 특화된 HMSAM(Hedonic-Motivation System Adoption Model)을 이론적 틀로 활용하여 모바일 개인방송 시청자의 수용 요인에 어떠한 오락적 동기가 작용하는지 실증적으로 알아보고자 하였다. 연구 변인에는 즐거움(Joy), 시간 흐름 미인지(Temporal Dissociation), 현실도피감(Escapism), 몰입(Focused Immersion)과 같은 내재적 동기가 포함되었다. 또한 인지된 사용 용이성(Perceived Ease of Use), 인지된 유용성(Perceived Usefulness), 시청 의도(Intention to Watch) 변인도 포함되었다. 연구 분석은 Multi-indicator 모형의 구조방정식을 통하여 변수들 간의 인과관계와 유의성을 검증하였다. 연구 결과, 모바일 개인방송 시청의 즐거움은 시간 흐름 미인지, 현실도피감, 인지된 사용 용이성과 긍정적(+)인 관계를 맺고, 시청의도와 몰입에도 긍정적(+)인 영향을 주었다. 현실도피감 역시 몰입에 긍정적(+)인 영향을 주었다. 본 연구는 오락적 동기 시스템 수용에 대한 최신 연구인 HMSAM 모델을 이론적 틀로 활용하여 모바일 개인방송 시청 요인들을 새롭게 분석하였다는 점에 의의가 있다. 향후 재미와 오락의 개념을 더 세분화하고, 미디어의 능동적 수용과 수동적 수용을 추가적으로 살펴본다면 더욱 발전된 후속 연구가 진행될 수 있을 것이다.

Temporal dissociation of developmental events in the chick eye under low temperature conditions.

The chick embryonic eye is an excellent model for the study of vertebrate organogenesis. Key events in eye development involve thickening, invagination and cytodifferentiation of the lens primordium. While these events occur successively at different developmental stages, the extent to which these events are temporally related is largely unknown. Here we show that the lens invagination is highly sensitive to temperature. Lowering of incubation temperature to 29°C at embryonic day 2 delayed the onset of invagination of the lens, but not thickening and cytodifferentiation, leading to abnormal protrusion of the eye. The temperature shift also delayed the inward bending of the underlying retinal primordium, even in the absence of the lens. Taken together, our results suggest that lens invagination is initiated independently of thickening and cytodifferentiation, possibly by mechanisms associated with morphogenesis of the primordial retina.

THE EFFECT OF WEBSITE QUALITY FEATURES AND COGNITIVE ABSORPTION ON SOCIAL NETWORK SITE USAGE: A CROSS-NATIONAL STUDY

Social network sites (SNSs) have become an essential interpersonal communication tool, and the number of global SNSs users is increasing at an astonishing rate. To fill the research gap on SNSs, this study examined the rarely discussed influence of website quality features and cognitive absorption on SNS acceptance. This cross-sectional study focused on comparing 250 users from Taiwan and 200 users from Indonesia to contribute to the growing field of information system (IS) and information technology (IT) literature on SNSs. Structural equation modeling (SEM) and multi-group analysis were used to analyze the data. results indicated similarities and differences between the two countries, confirming that the effect of country moderates the SNS usage. This study demonstrated that website quality features attract users based on the perceived ease of use and perceived usefulness. Feelings of temporal dissociation, heightened enjoyment, and curiosity also arouse users’ intentions to use SNSs. To cite this document: Ya-Hui Hsu, Chien-Kuo Li, Chien-Ming Li, and Na-Ting Liu, The effect of website quality features and cognitive absorption on social network site usage: A cross-national study , International Journal of Electronic Commerce Studies, Vol.7, No.2, pp.156-188, 2016. Permanent link to this document: http://dx.doi.org/10.7903/ijecs.1448 Â

Temporal dissociation between the focal and orientation components of spatial attention in central and peripheral vision

Selective attention, i.e. the ability to concentrate one's limited processing resources on one aspect of the environment, is a multifaceted concept that includes different processes like spatial attention and its subcomponents of orienting and focusing. Several studies, indeed, have shown that visual tasks performance is positively influenced not only by attracting attention to the target location (orientation component), but also by the adjustment of the size of the attentional window according to task demands (focal component). Nevertheless, the relative weight of the two components in central and peripheral vision has never been studied.We conducted two experiments to explore whether different components of spatial attention have different effects in central and peripheral vision. In order to do so, participants underwent either a detection (Experiment 1) or a discrimination (Experiment 2) task where different types of cues elicited different components of spatial attention: a red dot, a small square and a big square (an optimal stimulus for the orientation component, an optimal and a sub-optimal stimulus for the focal component respectively). Response times and cue-size effects indicated a stronger effect of the small square or of the dot in different conditions, suggesting the existence of a dissociation in terms of mechanisms between the focal and the orientation components of spatial attention. Specifically, we found that the orientation component was stronger in periphery, while the focal component was noticeable only in central vision and characterized by an exogenous nature.

Stroke risk assessment in atrial fibrillation: risk factors and markers of atrial myopathy

Atrial fibrillation (AF) is a complex phenomenon associated with electrical, mechanical, and structural abnormalities of the atria. Ischaemic stroke in AF is only partially understood, but the mechanisms are known to be related to the atrial substrate as well as the atrial rhythm. The temporal dissociation between timing of AF and occurrence of stroke has led to the hypothesis that fibrotic, prothrombotic atrial tissue is an important cause of thrombus formation in patients with AF, independent of the atrial rhythm. Current stroke risk scores are practical, but limited in their capacity to predict stroke risk accurately in individual patients. Stroke prediction might be improved by the addition of emerging risk factors, many of which are expressions of atrial fibrosis. The use of novel parameters, including clinical criteria, biomarkers, and imaging data, might improve stroke risk prediction and inform on optimal treatment for patients with AF and perhaps individuals only at risk of AF.

Focused, not lost: the mediating role of Temporal Dissociation and Focused Immersion on Problematic Internet Use

ABSTRACTThe internet has become an irreplaceable instrument for people of the twenty-first century. In light of Activity Theory, it can be considered the technological element in functional organs which augment a person’s ability to carry out activities and achieve specific goals. In its capacity as a tool, the internet can lead to the risk of ‘inverse instrumentality’ – the process by which people lose their sense of self-directedness and experience a passive and uncontrolled approach to technology. Past research has stressed the importance of cognitive involvement in technology for a healthy use of the internet. Nevertheless, it remains unclear whether cognitive involvement does indeed protect against the misuse of new media, or whether it is antecedent to it. In this study, two dimensions of the Cognitive Absorption Scale (Focused Immersion (FI) and Temporal Dissociation (TD)) were used as mediators between antecedents of internet misuse (Self-control, Mindfulness and Self-esteem) and Problematic Internet Use. Only TD was found to act as a mediator. Furthermore, the scores on the FI scale were positively predicted by levels of Self-esteem and Self-control. This suggests that certain ways of experiencing cognitive involvement are more risky than others. Implications for professionals and ideas for future research are also discussed.

Phasic and sustained brain responses in the amygdala and the bed nucleus of the stria terminalis during threat anticipation

Several lines of evidence suggest that the amygdala and the bed nucleus of the stria terminalis (BNST) are differentially involved in phasic and sustained fear. Even though, results from neuroimaging studies support this distinction, a specific effect of a temporal dissociation with phasic responses to onset versus sustained responses during prolonged states of threat anticipation has not been shown yet. To explore this issue, we investigated brain activation during anticipation of threat in 38 healthy participants by means of functional magnetic resonance imaging. Participants were presented different visual cues indicated the temporally unpredictable occurrence of a subsequent aversive or neutral stimulus. During the onset of aversive versus neutral anticipatory cues, results showed a differential phasic activation of amygdala, anterior cingulate cortex (ACC), and ventrolateral prefrontal cortex (PFC). In contrast, activation in the BNST and other brain regions, including insula, dorsolateral PFC, ACC, cuneus, posterior cingulate cortex, and periaqueductal grey was characterized by a sustained response during the threat versus neutral anticipation period. Analyses of functional connectivity showed phasic amygdala response as positively associated with activation, mainly in sensory cortex areas whereas sustained BNST activation was negatively associated with activation in visual cortex and positively correlated with activation in the insula and thalamus. These findings suggest that the amygdala is responsive to the onset of cues signaling the unpredictable occurrence of a potential threat while the BNST in concert with other areas is involved in sustained anxiety. Furthermore, the amygdala and BNST are characterized by distinctive connectivity patterns during threat anticipation.

Dissociating sensory from decision processes in human perceptual decision making.

A key question within systems neuroscience is how the brain translates physical stimulation into a behavioral response: perceptual decision making. To answer this question, it is important to dissociate the neural activity underlying the encoding of sensory information from the activity underlying the subsequent temporal integration into a decision variable. Here, we adopted a decoding approach to empirically assess this dissociation in human magnetoencephalography recordings. We used a functional localizer to identify the neural signature that reflects sensory-specific processes, and subsequently traced this signature while subjects were engaged in a perceptual decision making task. Our results revealed a temporal dissociation in which sensory processing was limited to an early time window and consistent with occipital areas, whereas decision-related processing became increasingly pronounced over time, and involved parietal and frontal areas. We found that the sensory processing accurately reflected the physical stimulus, irrespective of the eventual decision. Moreover, the sensory representation was stable and maintained over time when it was required for a subsequent decision, but unstable and variable over time when it was task-irrelevant. In contrast, decision-related activity displayed long-lasting sustained components. Together, our approach dissects neuro-anatomically and functionally distinct contributions to perceptual decisions.

The Effects of Electrical and Optical Stimulation of Midbrain Dopaminergic Neurons on Rat 50-kHz Ultrasonic Vocalizations.

Rationale: Adult rats emit ultrasonic vocalizations (USVs) at around 50-kHz; these commonly occur in contexts that putatively engender positive affect. While several reports indicate that dopaminergic (DAergic) transmission plays a role in the emission of 50-kHz calls, the pharmacological evidence is mixed. Different modes of dopamine (DA) release (i.e., tonic and phasic) could potentially explain this discrepancy.Objective: To investigate the potential role of phasic DA release in 50-kHz call emission.Methods: In Experiment 1, USVs were recorded in adult male rats following unexpected electrical stimulation of the medial forebrain bundle (MFB). In parallel, phasic DA release in the nucleus accumbens (NAcc) was recorded using fast-scan cyclic voltammetry. In Experiment 2, USVs were recorded following response-contingent or non-contingent optogenetic stimulation of midbrain DAergic neurons. Four 20-s schedules of optogenetic stimulation were used: fixed-interval, fixed-time, variable-interval, and variable-time.Results: Brief electrical stimulation of the MFB increased both 50-kHz call rate and phasic DA release in the NAcc. During optogenetic stimulation sessions, rats initially called at a high rate comparable to that observed following reinforcers such as psychostimulants. Although optogenetic stimulation maintained reinforced responding throughout the 2-h session, the call rate declined to near zero within the first 30 min. The trill call subtype predominated following both electrical and optical stimulation.Conclusion: The occurrence of electrically-evoked 50-kHz calls, time-locked to phasic DA (Experiment 1), provides correlational evidence supporting a role for phasic DA in USV production. However, in Experiment 2, the temporal dissociation between calling and optogenetic stimulation of midbrain DAergic neurons suggests that phasic mesolimbic DA release is not sufficient to produce 50-kHz calls. The emission of the trill subtype of 50-kHz calls potentially provides a marker distinguishing positive affect from positive reinforcement.

Social networking’s peril: Cognitive absorption, social networking usage, and depression

Social networking has become commonplace in today’s always-connected world. Due to this ubiquity, researchers have sought to explore the positive and negative effects that can result from usage of social networking. This research has shown many effects on an individual's psychological well-being, with one of the most concerning being mixed results of how usage relates to depression. In this study, we further examine the relationship between usage and depression for social networking users. In addition, we posit that aspects of cognitive absorption, namely temporal dissonance, focused immersion, and heightened enjoyment, have a direct effect on the amount of usage. A survey of 251 social networking users reveals that temporal dissociation and heightened enjoyment are associated with increased usage, and usage was found to be associated with greater levels of depression. Further, prior research has shown a significant difference between genders in Internet usage and social networking. Therefore, we report our findings as an overall analysis and as a gender-based between-groups analysis. This analysis shows that more variance is explained for females than males in most relationships. Implications for research and society are discussed along with future research directions.

Neural activation patterns underlying basolateral amygdala influence on intra-accumbens opioid-driven consummatory versus appetitive high-fat feeding behaviors in the rat.

The present study explored the role of the amygdala in mediating a unique pattern of feeding behavior driven by intra-accumbens (intra-Acb) opioid activation in the rat. Temporary inactivation of the basolateral amygdala (BLA), via GABAA agonist muscimol administration prevents increased consumption following intra-Acb opioid administration of the selective μ-opioid agonist D-Ala2, NMe-Phe4, Glyol5-enkephalin (DAMGO), yet leaves food approach behaviors intact, particularly after consumption has ended. One interpretation is that inactivation of the BLA selectively blocks neural activity underlying DAMGO-driven consummatory (consumption) but not appetitive (approach) behaviors. The present experiments take advantage of this temporal dissociation of consumption and approach behaviors to investigate their associated neural activity. Following either intra-Acb saline or DAMGO administration, with or without BLA muscimol administration, rats were given 2-hr access to a limited amount of high-fat diet. Immediately following the feeding session, rats were sacrificed and brains assayed for neural activity patterns across critical brain regions known to regulate both appetitive and consummatory feeding behaviors. The results show that intra-Acb DAMGO administration increased c-Fos activation in orexin neurons within the perifornical area of the hypothalamus and that this increase in activation is blocked by BLA muscimol inactivation. Intra-Acb DAMGO administration significantly increased c-Fos activation within dopaminergic neurons of the ventral tegmental area, compared to saline controls, and BLA inactivation had no effect on this increase. Overall, these data provide underlying circuitry that may mediate the selective influence of the BLA on driving consummatory, but not appetitive, feeding behaviors in a model of hedonically driven feeding behavior.

Affective Politics, Debility and Hearing Voices: Towards a Feminist Politics of Ordinary Suffering

This paper is an intervention within feminist and queer debates that have re-posed so-called negative states of being as offering productive possibilities for political practice and social transformation. What is sometimes called the politics of negative affect or analyses of political feeling has sought to de-pathologise shame, melancholy, failure, depression, anxieties and other forms of ‘feeling bad’, to open up new ways of thinking about agency, change and transformation. Ann Cvetkovich's recent memoir explores depression as a public feeling and argues that ‘feeling bad might, in fact, be the ground for transformation’. As she suggests, the question, ‘how do I feel’ could usefully be reframed as ‘how does capitalism feel’? This performative staging of political forms of psychosocial reflexivity opens up new strategies for survival, new visions of the future, and importantly de-medicalises feeling beyond an individual expression of psychopathology. The grounds for affective politics might be found within new feminist futures that are attentive to the relations between emotion, affect, feelings and politics. This paper will be situated within these debates and the challenge of thinking about the productive possibilities of negative states of being. However, rather than focus on depression, I will turn my attention to experiences such as psychosis and temporal dissociation, based on my long-standing research with the Hearing Voices Network. In the context of discussions of disability and capability I will discuss the value of concepts such as debility, and ‘living in prognosis’, and respond to the call to think through what such states might offer for feminist and queer practice.

Imaging Agonist-Induced D2/D3 Receptor Desensitization and Internalization In Vivo with PET/fMRI.

This study investigated the dynamics of dopamine receptor desensitization and internalization, thereby proposing a new technique for non-invasive, in vivo measurements of receptor adaptations. The D2/D3 agonist quinpirole, which induces receptor internalization in vitro, was administered at graded doses in non-human primates while imaging with simultaneous positron emission tomography (PET) and functional magnetic resonance imaging (fMRI). A pronounced temporal divergence between receptor occupancy and fMRI signal was observed: occupancy remained elevated while fMRI responded transiently. Analogous experiments with an antagonist (prochlorperazine) and a lower-affinity agonist (ropinirole) exhibited reduced temporal dissociation between occupancy and function, consistent with a mechanism of desensitization and internalization that depends upon drug efficacy and affinity. We postulated a model that incorporates internalization into a neurovascular-coupling relationship. This model yielded in vivo desensitization/internalization rates (0.2/min for quinpirole) consistent with published in vitro measurements. Overall, these results suggest that simultaneous PET/fMRI enables characterization of dynamic neuroreceptor adaptations in vivo, and may offer a first non-invasive method for assessing receptor desensitization and internalization.

TP53 Silencing Bypasses Growth Arrest of BRAFV600E-Induced Lung Tumor Cells in a Two-Switch Model of Lung Tumorigenesis.

Lung carcinogenesis is a multistep process in which normal lung epithelial cells are converted to cancer cells through the sequential acquisition of multiple genetic or epigenetic events. Despite the utility of current genetically engineered mouse (GEM) models of lung cancer, most do not allow temporal dissociation of the cardinal events involved in lung tumor initiation and cancer progression. Here we describe a novel two-switch GEM model for BRAF(V600E)-induced lung carcinogenesis allowing temporal dissociation of these processes. In mice carrying a Flp recombinase-activated allele of Braf (Braf(FA)) in conjunction with Cre-regulated alleles of Trp53, Cdkn2a, or c-MYC, we demonstrate that secondary genetic events can promote bypass of the senescence-like proliferative arrest displayed by BRAF(V600E)-induced lung adenomas, leading to malignant progression. Moreover, restoring or activating TP53 in cultured BRAF(V600E)/TP53(Null) or BRAF(V600E)/INK4A-ARF(Null) lung cancer cells triggered a G1 cell-cycle arrest regardless of p19(ARF) status. Perhaps surprisingly, neither senescence nor apoptosis was observed upon TP53 restoration. Our results establish a central function for the TP53 pathway in restricting lung cancer development, highlighting the mechanisms that limit malignant progression of BRAF(V600E)-initiated tumors.

Temporal Dissociation of Striatum and Prefrontal Cortex Uncouples Anhedonia and Defense Behaviors Relevant to Depression in 6-OHDA-Lesioned Rats

The dorsolateral striatum (DLS) processes motor and non-motor functions and undergoes extensive dopaminergic degeneration in Parkinson's disease (PD). The nigrostriatal dopaminergic degeneration also affects other brain areas including the pre-frontal cortex (PFC), which has been associated with the appearance of anhedonia and depression at pre-motor phases of PD. Using behavioral, neurochemical, and electrophysiological approaches, we investigated the temporal dissociation between the role of the DLS and PFC in the appearance of anhedonia and defense behaviors relevant to depression in rats submitted to bilateral DLS lesions with 6-hydroxydopamine (6-OHDA; 10μg/hemisphere). 6-OHDA induced partial dopaminergic nigrostriatal damage with no gross motor impairments. Anhedonic-like behaviors were observed in the splash and sucrose consumption tests only 7days after 6-OHDA lesion. By contrast, defense behaviors relevant to depression evaluated in the forced swimming test and social withdrawal only emerged 21days after 6-OHDA lesion when anhedonia was no longer present. These temporally dissociated behavioral alterations were coupled to temporal- and structure-dependent alterations in dopaminergic markers such as dopamine D1 and D2 receptors and dopamine transporter, leading to altered dopamine sensitivity in DLS and PFC circuits, evaluated electrophysiologically. These results provide the first demonstration of a dissociated involvement of the DLS and PFC in anhedonic-like and defense behaviors relevant to depression in 6-OHDA-lesioned rats, which was linked with temporal fluctuations in dopaminergic receptor density, leading to altered dopaminergic system sensitivity in these two brain structures. This sheds new light to the duality between depressive and anhedonic symptoms in PD.

Temporal dissociation between sodium depletion and sodium appetite appearance: Involvement of inhibitory and stimulatory signals

Our aim was to analyze the participation of inhibitory and stimulatory signals in the temporal dissociation between sodium depletion (SD) induced by peritoneal dialysis (PD) and the appearance of sodium appetite (SA), particularly 2h after PD, when the rats are hypovolemic/natremic but SA is not evident. We investigated the effects of bilateral injections of the serotonin (5-HT) receptor antagonist, methysergide, into the lateral parabrachial nucleus (LPBN) on hypertonic NaCl and water intake 2h vs. 24h after PD. We also studied plasma renin activity (PRA) and aldosterone (ALDO) concentration 2h vs. 24h after PD. Additionally, we combined the analysis of brain Fos immunoreactivity (Fos-ir) with the detection of double immunoreactivity in 5HT and oxytocinergic (OT) cells 2h after PD. Bilateral LPBN injections of methysergide (4μg/200nl at each site) increased NaCl intake when tested 2h after PD compared to controls. We found a significant increase in PRA and ALDO concentration after PD but no differences between 2 and 24h after PD. We also found for the first time a significant increase 2h after PD in the number of Fos-ir neurons in the brainstem nuclei that have been shown to be involved in the inhibition of SA.In summary, the results show that 5HT-mechanisms in the LPBN modulate sodium intake during the delay of SA when the renin angiotensin aldosterone system (RAAS) is increased. In addition, the activation of brainstem areas previously associated with the satiety phase of SA is in part responsible for the temporal dissociation between SD and behavioral arousal.

Investigation of temporal dissociation and focused immersion as moderators of satisfaction–continuance intention relationship: Smartphone as an example

Previous studies have suggested that the influence of customer satisfaction on loyalty is more complex than it might seem at first sight. The IS Continuance Theory states that satisfaction leads to continuance intention. Through the context of users using the applications of smartphone, this study found that temporal dissociation moderates the satisfaction–continuance intention relationship negatively. However, focused immersion is not a moderator. There is a paucity of research into the implication of cognitive absorption for continued IT usage and the moderating role of temporal dissociation and focused immersion on relationship between satisfaction and continuance intention. This study fills these literature gaps. Though temporal absorption and focused immersion are often treated as two of the dimensions of cognitive absorption, handling them separately can provide useful insights on their dynamics. This study suggests that with many competing smartphone applications serving as substitutes, application software developers should not ignore the moderating role of temporal dissociation. They can design more applications that lead users to be unaware of the passage of time when using them. Such kind of applications may compete and “win” other applications with higher satisfaction but weak temporal dissociation content, thus resulting in continuance usage.

Different time scales of motion integration for anticipatory smooth pursuit and perceptual adaptation.

When repeatedly exposed to moving stimuli, the oculomotor system elicits anticipatory smooth pursuit (ASP) eye movements, even before the stimulus moves. ASP is affected oppositely to perceptual speed judgments of repetitive moving stimuli: After a sequence of fast stimuli, ASP velocity increases, whereas perceived speed decreases. These two effects--perceptual adaptation and oculomotor priming--could result from adapting a single common internal speed representation that is used for perceptual comparisons and for generating ASP. Here we test this hypothesis by assessing the temporal dependence of both effects on stimulus history. Observers performed speed discriminations on moving random dot stimuli, either while pursuing the movement or maintaining steady fixation. In both cases, responses showed perceptual adaptation: Stimuli preceded by fast speeds were perceived as slower, and vice versa. To evaluate oculomotor priming, we analyzed ASP velocity as a function of average stimulus speed in preceding trials and found strong positive dependencies. Interestingly, maximal priming occurred over short stimulus histories (∼two trials), whereas adaptation was maximal over longer histories (∼15 trials). The temporal dissociation of adaptation and priming suggests different underlying mechanisms. It may be that perceptual adaptation integrates over a relatively long period to robustly calibrate the operating range of the motion system, thereby avoiding interference from transient changes in stimulus speed. On the other hand, the oculomotor system may rapidly prime anticipatory velocity to efficiently match it to that of the pursuit target.

Temporal Dissociation between Disease Activity Reduction and Improvements in Fatigue and Physical Function After Infliximab in Rheumatoid Arthritis

Objective: To evaluate the temporal responses to infliximab in fatigue and other selected parameters of physical function, inflammation, disease activity, and QOL in a cohort of rheumatoid arthritis patients. Methods: A prospective study was conducted. At baseline (PRE), after two (POST 2) and six (POST 6) months of treatment with infliximab (3 mg/Kg), fatigue, muscle function and strength, quality of life, disease activity, and markers of inflammation were assessed in 25 consecutive patients. Results: Infliximab treatment resulted in a significant reduction in fatigue at POST 2 and POST 6 when evaluated by both Chalder and the Global Fatigue VAS scale. Similarly, improvements in physical function at POST 2 and POST 6 as assessed by both the timed-stands test and SF-36 physical functioning domain was also observed. Conversely, disease activity, as assessed by DAS-28, remained unchanged at POST 2 and improved only at POST 6. The reduction in clinical markers of inflammation (i.e. CRP and ERS) did not reach significance at POST 2 or at POST 6, except for a trend in CRP after 6 months of treatment. Muscle strength remained unchanged throughout the trial. Additionally, no significant correlations were found between delta changes of either disease activity or inflammation parameters and physical function and fatigue parameters. Conclusion: These findings clearly reveal a temporal dissociation between the improvements in fatigue, physical function, and quality of life and the reduction in disease activity in response to infliximab in rheumatoid arthritis patients. The predictive value of these early response factors merits further investigations.