Predictive smooth eye pursuit in a population of young men: II. Effects of schizotypy, anxiety and depression.

Cognition and Action Group, Neurology Department, Medical School, Aeginition Hospital, National and Kapodistrian University of Athens, Athens, Greece.
Experimental Brain Research (Impact Factor: 2.17). 12/2011; 215(3-4):219-26. DOI: 10.1007/s00221-011-2888-4
Source: PubMed

ABSTRACT Smooth pursuit eye movement dysfunction is considered to be a valid schizophrenia endophenotype. Recent studies have tried to refine the phenotype in order to identify the specific neurophysiological deficits associated with schizophrenia. We used a variation of the smooth eye pursuit paradigm, during which the moving target is occluded for a short period of time and subjects are asked to continue tracking. This is designed to isolate the predictive processes that drive the extraretinal signal, a process previously reported to be defective in schizophrenia patients as well as their healthy relatives. In the current study, we investigated the relationship between predictive pursuit performance indices and age, education, non-verbal IQ, schizotypy and state anxiety, depression in 795 young Greek military conscripts. State anxiety was related to better predictive pursuit performance (increase in residual pursuit gain), while disorganized schizotypy was related to deficient predictive pursuit performance (decreased residual gain). This effect was independent of the effect of disorganized schizotypy on other oculomotor functions supporting the hypothesis that predictive pursuit might be specifically affected in schizophrenia spectrum disorders and could be considered as a distinct oculomotor endophenotype.

1 Bookmark
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper introduces a model of oculomotor control during the smooth pursuit of occluded visual targets. This model is based upon active inference, in which subjects try to minimise their (proprioceptive) prediction error based upon posterior beliefs about the hidden causes of their (exteroceptive) sensory input. Our model appeals to a single principle - the minimisation of variational free energy - to provide Bayes optimal solutions to the smooth pursuit problem. However, it tries to accommodate the cardinal features of smooth pursuit of partially occluded targets that have been observed empirically in normal subjects and schizophrenia. Specifically, we account for the ability of normal subjects to anticipate periodic target trajectories and emit pre-emptive smooth pursuit eye movements - prior to the emergence of a target from behind an occluder. Furthermore, we show that a single deficit in the postsynaptic gain of prediction error units (encoding the precision of posterior beliefs) can account for several features of smooth pursuit in schizophrenia: namely, a reduction in motor gain and anticipatory eye movements during visual occlusion, a paradoxical improvement in tracking unpredicted deviations from target trajectories and a failure to recognise and exploit regularities in the periodic motion of visual targets. This model will form the basis of subsequent (dynamic causal) models of empirical eye tracking measurements, which we hope to validate, using psychopharmacology and studies of schizophrenia.
    PLoS ONE 10/2012; 7(10):e47502. · 3.53 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The influence of anxiety on ocular motor control and gaze has received less research attention than its effects on postural control and locomotion. This review summarizes research on trait anxiety, state anxiety, anxiety disorders, ocular motor reflexes, and gaze. It applies these findings to clinical problems of visually induced unsteadiness and dizziness (VUD, also known as visual vertigo), fear of falling (FoF), and chronic subjective dizziness (CSD). Humans are inherently more sensitive to vertical heights than horizontal distances. Vertical height intolerance is reported by one-quarter to one-third of the general population. Humans also possess a gaze bias toward potentially threatening stimuli in the visual field, more prominent in individuals with higher versus lower trait anxiety and increased by state anxiety. This bias may drive hypervigilance-avoidance gaze patterns in patients with social anxiety disorder and specific phobias. Trait and state anxiety also appear to adversely affect gaze control, reducing gaze stability on visual targets. This may be one mechanism underlying persistent VUD and visual symptoms of CSD. Anxiety-related gaze diversion may increase gait instability in patients with FoF. Anxiety affects ocular motor reflexes and gaze control in ways that may contribute to clinically significant visual and visual-vestibular syndromes.
    Current opinion in neurology 12/2013; · 5.73 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Neuregulins (NRGs) comprise a large family of growth factors that stimulate ERBB receptor tyrosine kinases. NRGs and their receptors, ERBBs, have been identified as susceptibility genes for diseases such as schizophrenia (SZ) and bipolar disorder. Recent studies have revealed complex Nrg/Erbb signaling networks that regulate the assembly of neural circuitry, myelination, neurotransmission, and synaptic plasticity. Evidence indicates there is an optimal level of NRG/ERBB signaling in the brain and deviation from it impairs brain functions. NRGs/ERBBs and downstream signaling pathways may provide therapeutic targets for specific neuropsychiatric symptoms.
    Neuron 07/2014; 83(1):27-49. · 15.77 Impact Factor

Full-text (3 Sources)

Available from
May 21, 2014