Pupil and dopamine

AIMS: Pupillography is a noninvasive and cost-effective method to determine autonomic nerve activity. Genetic variants in cytochrome P450 (CYP), dopamine receptor (DRD2, DRD3), serotonin receptor (HTR2A, HTR2C) and ATP-binding cassette subfamily B (ABCB1) genes, among others, were previously associated with the pharmacokinetics and pharmacodynamics of antipsychotic drugs. Our aim was to evaluate the effects of aripiprazole and olanzapine on pupillary light reflex related to pharmacogenetics...

Organisms use rewards to navigate and adapt to (uncertain) environments. Error-based learning about rewards is supported by the dopaminergic system, which is thought to signal reward prediction errors to make adjustments to past predictions. More recently, the phasic dopamine response was suggested to have two components: the first rapid component is thought to signal the detection of a potentially rewarding stimulus; the second, slightly later component characterizes the stimulus by its reward prediction error...

Individuals differ in how they learn from experience. In Pavlovian conditioning models, where cues predict reinforcer delivery at a different goal location, some animals-called sign-trackers-come to approach the cue, whereas others, called goal-trackers, approach the goal. In sign-trackers, model-free phasic dopaminergic reward-prediction errors underlie learning, which renders stimuli 'wanted'. Goal-trackers do not rely on dopamine for learning and are thought to use model-based learning. We demonstrate this double dissociation in 129 male humans using eye-tracking, pupillometry and functional magnetic resonance imaging informed by computational models of sign- and goal-tracking...

Taking into account the fact that factors of intra-school environment are of great importance when forming health of pupils, this study aimed to investigate the main kinds of metabolism among pupils of secondary educational institutions depending on the organization of educational process and food services. MATERIAL AND METHODS: The observing group comprised of 137 students of Secondary School focusing on physico-mathematical sciences at the age of 12.9±1.3 years; the comparison group consisted of 131 students of Secondary School at the age of 12...

PURPOSE: Daily administration of 0.01% atropine eye drops is a promising approach for myopia control. The mechanism of action is believed to involve the dopaminergic system of the retina, triggering an increased release of dopamine. Previous studies in psychiatric condition such as major depression suggest that pattern electroretinogram (PERG) amplitudes are modulated by changes in retinal dopamine. It is thus plausible that atropine eye drops could have an effect on PERG amplitudes. The present study was designed to test this, assessing the difference in amplitude between contrast levels and the ratio of amplitudes between check sizes as primary endpoints...

The brain is adapted to learn from interactions with the environment that predict or enable the procurement of rewards (Schultz, 2010). For infants, the main caregiver (often the mother) is most associated with primary biological rewards such as food and warmth, as well as the most likely provider of emotional and social rewards such as comfort and responsiveness. In this study we capitalize on the reward value of mother to examine reward learning mechanisms in infancy using multiple eye-tracking measures. Converging lines of research have demonstrated links between reward-related striatal dopamine activity and measurable changes in spontaneous eye-blink rate (EBR) and pupil dilation (Eckstein et al...

The cultural transmission of behaviour depends on the ability of the pupil to identify and emulate an appropriate tutor1-4 . How the brain of the pupil detects a suitable tutor and encodes the behaviour of the tutor is largely unknown. Juvenile zebra finches readily copy the songs of the adult tutors that they interact with, but not the songs that they listen to passively through a speaker5,6 , indicating that social cues generated by the tutor facilitate song imitation. Here we show that neurons in the midbrain periaqueductal grey of juvenile finches are selectively excited by a singing tutor and-by releasing dopamine in the cortical song nucleus HVC-help to encode the song representations of the tutor used for vocal copying...

Parkinson's disease (PD) is one of the most common neurodegenerative disorders and the second leading cause of dementia worldwide. With an aging population, the prevalence of the disease has dramatically increased. Clinical management has advanced through recent developments in dopaminergic imaging and genetic risk profiling. However, early and accurate diagnosis of the disorder remains a challenge, largely because of the lack of noninvasive and inexpensive reliable diagnostic tests. Besides the well-studied cerebral neurodegeneration that underlies the cardinal symptoms of PD (ie, bradykinesia, tremor, rigidity, and postural instability), ocular changes have also been described in PD, including visual dysfunction, pupil abnormality, lens opacity, and retinal neuronal loss and dysfunction...

BACKGROUND: Pupillometry is used for the detection of autonomic dysfunction related to numerous diseases and drug administration. Genetic variants in cytochrome P450 ( CYP2D6, CYP3A4), dopamine receptor ( DRD2, DRD3), serotonin receptor ( HTR2A, HTR2C) and ATP-binding cassette subfamily B ( ABCB1) genes were previously associated with aripiprazole response. AIMS: Our aim was to evaluate if aripiprazole affects pupil contraction and its relationship with pharmacokinetics and pharmacogenetics...

Dopamine (DA) and noradrenaline (NA) are important neurotransmitters, which are suggested to play a vital role in modulating the neural circuitry involved in the executive control of cognition. One way to investigate the functions of these neurotransmitter systems is to assess physiological indices of DA and NA transmission. Here we examined how variations of spontaneous eye-blink rate and pupil size, as indirect measures of DA and NA activity, respectively, are related to performance in a hallmark aspect of executive control: attentional set shifting...

The pupil response under constant illumination can be used as a marker of cognitive processes. In the past, pupillary responses have been studied in the context of arousal and decision-making. However, recent work involving Parkinson's patients suggested that pupillary responses are additionally affected by reward sensitivity. Here, we build on these findings by examining how pupil responses are modulated by reward and loss while participants (N = 30) performed a Pavlovian reversal learning task. In fast (transient) pupil responses, we observed arousal-based influences on pupil size both during the expectation of upcoming value and the evaluation of unexpected monetary outcomes...

Attention-deficit/hyperactivity disorder (ADHD) diagnosis is based on reported symptoms, which carries the potential risk of over- or under-diagnosis. A biological marker that helps to objectively define the disorder, providing information about its pathophysiology, is needed. A promising marker of cognitive states in humans is pupil size, which reflects the activity of an 'arousal' network, related to the norepinephrine system. We monitored pupil size from ADHD and control subjects, during a visuo-spatial working memory task...

This review provides an introduction to two eyetracking measures that can be used to study cognitive development and plasticity: pupil dilation and spontaneous blink rate. We begin by outlining the rich history of gaze analysis, which can reveal the current focus of attention as well as cognitive strategies. We then turn to the two lesser-utilized ocular measures. Pupil dilation is modulated by the brain's locus coeruleus-norepinephrine system, which controls physiological arousal and attention, and has been used as a measure of subjective task difficulty, mental effort, and neural gain...

UNLABELLED: Neurophysiological evidence suggests that neuromodulators, such as norepinephrine and dopamine, increase neural gain in target brain areas. Computational models and prominent theoretical frameworks indicate that this should enhance the precision of neural representations, but direct empirical evidence for this hypothesis is lacking. In two functional MRI studies, we examine the effect of baseline catecholamine levels (as indexed by pupil diameter and manipulated pharmacologically) on the precision of object representations in the human ventral temporal cortex using angular dispersion, a powerful, multivariate metric of representational similarity (precision)...

A brief historical background on Autism & some of the important symptoms associated with Autism are summarized. Using strong Electro Magnetic Field Resonance Phenomenon between 2 identical molecules with identical weight (which received U.S. Patent) non-invasively & rapidly we can detect various molecules including neurotransmitters, bacteria, virus, fungus, metals & abnormal molecules. Simple non- invasive measurement of various molecules through pupils & head of diagnosed or suspected Autism patients indicated that in Autism patients following changes were often found: 1) Acetylcholine is markedly reduced; 2) Alzheimer's disease markers (i...

Motivation determines multiple aspects of behavior, including action selection and energization of behavior. Several components of the underlying neural systems have been examined closely, but the specific role of the different neuromodulatory systems in motivation remains unclear. Here, we compare directly the activity of dopaminergic neurons from the substantia nigra pars compacta and noradrenergic neurons from the locus coeruleus in monkeys performing a task manipulating the reward/effort trade-off. Consistent with previous reports, dopaminergic neurons encoded the expected reward, but we found that they also anticipated the upcoming effort cost in connection with its negative influence on action selection...

In this randomized controlled trial, 508 5-year-old kindergarten children participated, of whom 257 were delayed in literacy skills because they belonged to the lowest quartile of a national standard literacy test. We tested the hypothesis that some children are more susceptible to school-entry educational interventions than their peers due to their genetic makeup, and thus whether the dopamine receptor D4 gene moderated intervention effects. Children were randomly assigned to a control condition or one of two interventions involving computer programs tailored to the literacy needs of delayed pupils: Living Letters for alphabetic knowledge and Living Books for text comprehension...

There are ∼20 types of retinal ganglion cells (RGCs) in mice, each of which has distinct molecular, morphological, and physiological characteristics. Each RGC type sends axon projections to specific brain areas that execute light-dependent behaviors. Here, we show that the T-box transcription factor Tbr2 is required for the development of several RGC types that participate in non-image-forming circuits. These types are molecularly distinct, project to non-image-forming targets, and include intrinsically photosensitive RGCs...

Recent epidemiological evidence suggests that children who spend more time outdoors are less likely to be, or to become myopic, irrespective of how much near work they do, or whether their parents are myopic. It is currently uncertain if time outdoors also blocks progression of myopia. It has been suggested that the mechanism of the protective effect of time outdoors involves light-stimulated release of dopamine from the retina, since increased dopamine release appears to inhibit increased axial elongation, which is the structural basis of myopia...

PURPOSE: To report the ophthalmic findings in young patients with dopamine β-hydroxylase deficiency and to assess them in the context of other reports in an attempt to discern if ophthalmic criteria may assist in early detection of this debilitating, yet treatable, disorder. DESIGN: Prospective, observational case series. METHODS: An ophthalmic examination, including measuring intraocular and systemic blood pressures while supine, sitting, and standing, and eyelid function and pupillary function testing, was completed on 3 young patients with recently documented dopamine β-hydroxylase deficiency at a single institution...