Science posts

See science posts on page 28 below.

    • 2008
    • Jeffrey W. Dalley et al.
    • Neurobehavioral mechanisms of impulsivity: Fronto-striatal systems and functional neurochemistry
    • Impulsive acts and decisions are a part of everyday normal behavior. However, in its pathological forms, impulsivity can be a debilitating disorder often associated with a number of neuropsychiatric disorders, including attention-deficit hyperactivity disorder (ADHD). This article reviews recent progress in our understanding of the neurobiology of impulsivity using examples from recent investigations in experimental animals. Evidence is reviewed from several well-established paradigms with putative utility in assessing distinct forms of impulsive behavior in rodents, including the 5-choice serial reaction time (5CSRT) task and the delay discounting paradigm. We discuss, in particular, recent psychopharmacological and in-vivo neurochemical data in task-performing rats showing functional heterogeneity of the forebrain dopamine (DA), noradrenaline (NA), serotonin (5-HT) and acetylcholine (ACh) systems and identify how these systems normally function to facilitate flexible goal-directed ..
    • 2015
    • Jørgen Assar Mortensen et al.
    • Evidence for an antagonistic interaction between reward and punishment sensitivity on striatal activity: A verification of the Joint Subsystems Hypothesis
    • The Reinforcement Sensitivity Theory proposes that the Behavioral Approach System (BAS) comprises dopaminergic brain regions and underpins reward sensitivity causing impulsivity. It has been shown in a supraliminal priming task that highly reward sensitive subjects have a larger reaction time (RT) priming effect and make more commission errors to prime-incongruent targets. We adapted a similar task to event-related fMRI and hypothesized that (1) high reward sensitivity is associated with increased activation in dopaminergic brain regions, the ventral striatum in particular, (2) that BAS related personality traits predict impulsivity and (3) that the BAS effects are larger after adjusting for the interactive influence of trait avoidance, as predicted by the Joint Subsystems Hypothesis. Fourteen healthy females participated in the fMRI experiment and were scored on sensitivity to reward (SR) and trait avoidance, i.e., sensitivity to punishment (SP) and neuroticism (N). SR scores were a..
    • 2015
    • Martin Reuter et al.
    • A new measure for the revised reinforcement sensitivity theory: psychometric criteria and genetic validation
    • Jeffrey Gray's Reinforcement Sensitivity Theory (RST) represents one of the most influential biologically-based personality theories describing individual differences in approach and avoidance tendencies. The most prominent self-report inventory to measure individual differences in approach and avoidance behavior to date is the BIS/BAS scale by Carver and White (1994). As Gray and McNaughton (2000) revised the RST after its initial formulation in the 1970/80s, and given the Carver and White measure is based on the initial conceptualization of RST, there is a growing need for self-report inventories measuring individual differences in the revised behavioral inhibition system (BIS), behavioral activation system (BAS) and the fight, flight, freezing system (FFFS). Therefore, in this paper we present a new questionnaire measuring individual differences in the revised constructs of the BIS, BAS and FFFS in N = 1814 participants (German sample). An English translated version of the new mea..
    • 2011
    • Anja Leue et al.
    • Reinforcement Sensitivity and Conflict Processing
    • The revised reinforcement sensitivity theory relates individual differences in conflict processing to aversive reinforcement. Conflict monitoring was modulated by means of three reinforcement-related conflict levels in a Go/Nogo task. The small conflict level entailed aversive verbal-nonmonetary feedback, the medium conflict level provided verbal and monetary loss feedback, and the high conflict level included verbal and monetary gain and loss feedback. In a sample of N = 91 students, treatment-induced changes of ERP data were reflected by an early N2 factor that occurred in a spatiotemporal principal component analysis including all conflict levels. The results indicate that the Nogo N2 was more negative following verbal-monetary reinforcement compared to verbal-nonmonetary reinforcement, whereas a ceiling effect probably occurred for the gain and loss condition. Low trait-BIS individuals showed more negative N2 scores on this factor in the medium and high compared to the small conf..
    • 2004
    • Philip J Corr
    • Reinforcement sensitivity theory and personality
    • A fully fledged neuroscience of personality is beginning to emerge, shaped and guided in large measure by the seminal work of Jeffrey A. Gray over a period of 40 years. In this Festschrift, I trace the theoretical development of Gray's approach—now known as Reinforcement Sensitivity Theory (RST)—out of the Eysenckian tradition to its most recent articulation. Experimental attempts to test RST are reviewed and the theoretical problems raised by this literature discussed. Also presented are data relating to a recent clarification of RST, viz. the joint subsystems hypothesis, which postulates a fundamental interdependence of appetitive and aversive systems in the typical human laboratory. The value of Gray's general approach to building behavioural theories on the bases of both the conceptual nervous system and the real nervous system is validated in personality, which has long been thought a philosophical mystery rather than a standard problem to be tackled by scientific me..
    • 2014
    • Eric M. Miller et al.
    • Dissociating Motivation from Reward in Human Striatal Activity
    • Neural activity in the striatum has consistently been shown to scale with the value of anticipated rewards. As a result, it is common across a number of neuroscientific subdiscliplines to associate activation in the striatum with anticipation of a rewarding outcome or a positive emotional state. However, most studies have failed to dissociate expected value from the motivation associated with seeking a reward. Although motivation generally scales positively with increases in potential reward, there are circumstances in which this linkage does not apply. The current study dissociates value-related activation from that induced by motivation alone by employing a task in which motivation increased as anticipated reward decreased. This design reverses the typical relationship between motivation and reward, allowing us to differentially investigate fMRI BOLD responses that scale with each. We report that activity scaled differently with value and motivation across the striatum. Specificall..
    • 2004
    • René Marois et al.
    • The Neural Fate of Consciously Perceived and Missed Events in the Attentional Blink
    • Cognitive models of attention propose that visual perception is a product of two stages of visual processing: early operations permit rapid initial categorization of the visual world, while later attention-demanding capacity-limited stages are necessary for the conscious report of the stimuli. Here we used the attentional blink paradigm and fMRI to neurally distinguish these two stages of vision. Subjects detected a face target and a scene target presented rapidly among distractors at fixation. Although the second, scene target frequently went undetected by the subjects, it nonetheless activated regions of the medial temporal cortex involved in high-level scene representations, the parahippocampal place area (PPA). This PPA activation was amplified when the stimulus was consciously perceived. By contrast, the frontal cortex was activated only when scenes were successfully reported. These results suggest that medial temporal cortex permits rapid categorization of the visual input, whi..
    • 2007
    • E E Forbes et al.
    • Genetic variation in components of dopamine neurotransmission impacts ventral striatal reactivity associated with impulsivity
    • Individual differences in traits such as impulsivity involve high reward sensitivity and are associated with risk for substance use disorders. The ventral striatum (VS) has been widely implicated in reward processing, and individual differences in its function are linked to these disorders. Dopamine (DA) plays a critical role in reward processing and is a potent neuromodulator of VS reactivity. Moreover, altered DA signaling has been associated with normal and pathological reward-related behaviors. Functional polymorphisms in DA-related genes represent an important source of variability in DA function that may subsequently impact VS reactivity and associated reward-related behaviors. Using an imaging genetics approach, we examined the modulatory effects of common, putatively functional DA-related polymorphisms on reward-related VS reactivity associated with self-reported impulsivity. Genetic variants associated with relatively increased striatal DA release (DRD2 −141C deletion)..
    • 2012
    • Thomas D. Albright
    • On the Perception of Probable Things: Neural Substrates of Associative Memory, Imagery, and Perception
    • Cognitive models of attention propose that visual perception is a product of two stages of visual processing: early operations permit rapid initial categorization of the visual world, while later attention-demanding capacity-limited stages are necessary for the conscious report of the stimuli. Here we used the attentional blink paradigm and fMRI to neurally distinguish these two stages of vision. Subjects detected a face target and a scene target presented rapidly among distractors at fixation. Although the second, scene target frequently went undetected by the subjects, it nonetheless activated regions of the medial temporal cortex involved in high-level scene representations, the parahippocampal place area (PPA). This PPA activation was amplified when the stimulus was consciously perceived. By contrast, the frontal cortex was activated only when scenes were successfully reported. These results suggest that medial temporal cortex permits rapid categorization of the visual input, whi..
    • 2015
    • Rebecca L. Jackson et al.
    • The Nature and Neural Correlates of Semantic Association versus Conceptual Similarity
    • The ability to represent concepts and the relationships between them is critical to human cognition. How does the brain code relationships between items that share basic conceptual properties (e.g., dog and wolf) while simultaneously representing associative links between dissimilar items that co-occur in particular contexts (e.g., dog and bone)? To clarify the neural bases of these semantic components in neurologically intact participants, both types of semantic relationship were investigated in an fMRI study optimized for anterior temporal lobe (ATL) coverage. The clear principal finding was that the same core semantic network (ATL, superior temporal sulcus, ventral prefrontal cortex) was equivalently engaged when participants made semantic judgments on the basis of association or conceptual similarity. Direct comparisons revealed small, weaker differences for conceptual similarity > associative decisions (e.g., inferior prefrontal cortex) and associative > co..

Related

You might be interested in.