Dataset Information

When to hold that thought: an experimental study showing reduced inhibition of pre-trained associations in schizophrenia.

ABSTRACT: Schizophrenia encompasses a wide variety of cognitive dysfunctions, a number of which can be understood as deficits of inhibition. To date, no research has examined 'conditioned inhibition' in schizophrenia--the ability of a stimulus that signals the absence of an expected outcome to counteract the conditioned response produced by a signal for that outcome (a conditioned excitor). A computer-based task was used to measure conditioned excitation and inhibition in the same discrimination procedure, in 25 patients with a confirmed diagnosis of schizophrenia and a community-based comparison sample. Conditioned inhibition was measured by a ratio score, which compared the degree to which the inhibitory stimulus and a neutral control stimulus reduced conditioned responding to the excitatory cue: the lower the ratio, the greater the inhibitory learning. At test the ratios were 0.45 and 0.39 for patient and control groups respectively, and the relevant interaction term of the ANOVA confirmed that the degree of inhibition was reduced in the patient group, with an effect size of r = 0.28.These results demonstrate for the first time that inhibitory learning is impaired in schizophrenia. Such an impairment provides an attractive framework for the interpretation of the positive symptoms of schizophrenia. However, we were unable to demonstrate any relationship between the level of conditioned inhibition and medication. Similarly, in the present study it must be emphasised that the available data did not demonstrate any relationship between individual variation in inhibitory learning and the level of positive symptoms as measured by the PANSS. In fact inhibitory learning impairment was relatively greater in participants with a predominantly negative symptom profile and their excitatory learning was also reduced. Accordingly the next step will be to investigate such relationships in a larger sample with a priori defined sub-groups displaying predominantly positive versus predominantly negative symptoms.

SUBMITTER: He Z

PROVIDER: S-EPMC3408477 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

When to hold that thought: an experimental study showing reduced inhibition of pre-trained associations in schizophrenia.

He Zhimin Z Cassaday Helen J HJ Park S Bert G SB Bonardi Charlotte C

PloS one 20120730 7

Schizophrenia encompasses a wide variety of cognitive dysfunctions, a number of which can be understood as deficits of inhibition. To date, no research has examined 'conditioned inhibition' in schizophrenia--the ability of a stimulus that signals the absence of an expected outcome to counteract the conditioned response produced by a signal for that outcome (a conditioned excitor). A computer-based task was used to measure conditioned excitation and inhibition in the same discrimination procedure ...[more]

PMID: 22860074

Similar Datasets

Project description:Breath-hold divers (BHD) experience repeated bouts of severe hypoxia and hypercapnia with large increases in blood pressure. However, the impact of long-term breath-hold diving on cerebrovascular control remains poorly understood. The ability of cerebral blood vessels to respond rapidly to changes in blood pressure represents the property of dynamic autoregulation. The current investigation tested the hypothesis that breath-hold diving impairs dynamic autoregulation to a transient hypotensive stimulus. Seventeen BHD (3 women, 11?±?9 yr of diving) and 15 healthy controls (2 women) completed two or three repeated sit-to-stand trials during spontaneous breathing and poikilocapnic conditions. Heart rate (HR), finger arterial blood pressure (BP), and cerebral blood flow velocity (BFV) from the right middle cerebral artery were measured continuously with three-lead electrocardiography, finger photoplethysmography, and transcranial Doppler ultrasonography, respectively. End-tidal carbon dioxide partial pressure was measured with a gas analyzer. Offline, an index of cerebrovascular resistance (CVRi) was calculated as the quotient of mean BP and BFV. The rate of the drop in CVRi relative to the change in BP provided the rate of regulation [RoR; (?CVRi/?T)/?BP]. The BHD demonstrated slower RoR than controls (P ? 0.001, d?=?1.4). Underlying the reduced RoR in BHD was a longer time to reach nadir CVRi compared with controls (P = 0.004, d?=?1.1). In concert with the longer CVRi response, the time to reach peak BFV following standing was longer in BHD than controls (P = 0.01, d?=?0.9). The data suggest impaired dynamic autoregulatory mechanisms to hypotension in BHD. NEW & NOTEWORTHY Impairments in dynamic cerebral autoregulation to hypotension are associated with breath-hold diving. Although weakened autoregulation was observed acutely in this group during apneic stress, we are the first to report on chronic adaptations in cerebral autoregulation. Impaired vasomotor responses underlie the reduced rate of regulation, wherein breath-hold divers demonstrate a prolonged dilatory response to transient hypotension. The slower cerebral vasodilation produces a longer perturbation in cerebral blood flow velocity, increasing the risk of cerebral ischemia.

Project description:Orbitofrontal Cortex (OFC) structural abnormality in schizophrenia has not been well characterized, probably due to marked anatomical variability and lack of consistent definitions. We previously reported OFC sulcogyral pattern alteration and its associations with social disturbance in schizophrenia, but OFC volume associations with psychopathology and cognition have not been investigated. We compared chronically treated schizophrenia patients with healthy control (HC) subjects, using a novel, reliable parcellation of OFC subregions and their association with cognition, especially the Iowa Gambling Task (IGT), and with schizophrenic psychopathology including thought disorder. Twenty-four patients with schizophrenia and 25 age-matched HC subjects underwent MRI. OFC Regions of Interest (ROI) were manually delineated according to anatomical boundaries: Gyrus Rectus (GR); Middle Orbital Gyrus (MiOG); and Lateral Orbital Gyrus (LOG). The OFC sulcogyral pattern was also classified. Additionally, MiOG probability maps were created and compared between groups in a voxel-wise manner. Both groups underwent cognitive evaluations using the IGT, Wisconsin Card Sorting Test, and Trail Making Test (TMT). An 11% bilaterally smaller MiOG volume was observed in schizophrenia, compared with HC (F(1,47) = 17.4, P = 0.0001). GR and LOG did not differ, although GR showed a rightward asymmetry in both groups (F(1,47) = 19.2, P < 0.0001). The smaller MiOG volume was independent of the OFC sulcogyral pattern, which differed in schizophrenia and HC (chi2 = 12.49, P = 0.002). A comparison of MiOG probability maps suggested that the anterior heteromodal region was more affected in the schizophrenia group than the posterior paralimbic region. In the schizophrenia group, a smaller left MiOG was strongly associated with worse 'positive formal thought disorder' (r = -0.638, P = 0.001), and a smaller right MiOG with a longer duration of the illness (r = -0.618, P = 0.002). While schizophrenics showed poorer performance than HC in the IGT, performance was not correlated with OFC volume. However, within the HC group, the larger the right hemisphere MiOG volume, the better the performance in the IGT (r = 0.541, P = 0.005), and the larger the left hemisphere volume, the faster the switching attention performance for the TMT, Trails B (r = -0.608, P = 0.003). The present study, applying a new anatomical parcellation method, demonstrated a subregion-specific OFC grey matter volume deficit in patients with schizophrenia, which was independent of OFC sulcogyral pattern. This volume deficit was associated with a longer duration of illness and greater formal thought disorder. In HC the finding of a quantitative association between OFC volume and IGT performance constitutes, to our knowledge, the first report of this association.

Dataset Information

When to hold that thought: an experimental study showing reduced inhibition of pre-trained associations in schizophrenia.

Publications

When to hold that thought: an experimental study showing reduced inhibition of pre-trained associations in schizophrenia.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets