Spatial serial order processing in schizophrenia

Fraser, David A.; Park, Sohee; Clark, Gina; Yohanna, Daniel; Houk, James C.

doi:10.1016/j.schres.2003.09.019

Cited by 33 publications

(26 citation statements)

References 40 publications

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“…Crow and colleagues have made the case for an evolutionary link between the origin of language and the etiology of schizophrenia (Berlim et al 2003). This is interesting because people with schizophrenia show a major deficit in their capacity for dealing with serial order, which has been attributed to a deficit in the cortical-basal ganglionic portion of the BA46-DPM (Fraser et al 2004). I would further attribute this to a problem with the competitive pattern classification operation discussed earlier in this paper.…”

Section: Discussionmentioning

confidence: 99%

Agents of the mind

2005

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The higher order circuitry of the brain is comprised of a large-scale network of cerebral cortical areas that are individually regulated by loops through subcortical structures, particularly through the basal ganglia and cerebellum. These subcortical loops have powerful computational architectures. Using, as an example, the relatively well-understood processing that occurs in the cortical/basal ganglionic/cerebellar distributed processing module that generates voluntary motor commands, I postulate that a network of analogous agents is an appropriate framework for exploring the dynamics of the mind.

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Section: Discussionmentioning

confidence: 99%

Agents of the mind

2005

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“…A decrease in the NMDA/ AMPA ratio may lead to a reduction in the number or specificity of afferent ensembles that can be represented by each cell, because more inputs per cell would be required to reach the up state. This reduction may be associated with the loss of active parallel pathways through the striatum and may correlate with the reduction of potential serial memory tasks in schizophrenia (Fraser et al, 2004). During addiction, the increase in the NMDA/AMPA ratio may play a role in the effect of dominance of a single behavioral pathway over others, leading to such findings as cocaine-sensitive cells in the NAcb (Carelli, 2002;Kelley, 2004;Peoples et al, 2004).…”

Section: Implications For Pathologymentioning

confidence: 99%

NMDA/AMPA Ratio Impacts State Transitions and Entrainment to Oscillations in a Computational Model of the Nucleus Accumbens Medium Spiny Projection Neuron

Wolf¹,

Moyer²,

Lazarewicz³

et al. 2005

J. Neurosci.

169

196

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We describe a computational model of the principal cell in the nucleus accumbens (NAcb), the medium spiny projection (MSP) neuron. The model neuron, constructed in NEURON, includes all of the known ionic currents in these cells and receives synaptic input from simulated spike trains via NMDA, AMPA, and GABA A receptors. After tuning the model by adjusting maximal current conductances in each compartment, the model cell closely matched whole-cell recordings from an adult rat NAcb slice preparation. Synaptic inputs in the range of 1000 -1300 Hz are required to maintain an "up" state in the model. Cell firing in the model required concurrent depolarization of several dendritic branches, which responded independently to afferent input. Depolarization from action potentials traveled to the tips of the dendritic branches and increased Ca 2ϩ influx through voltage-gated Ca 2ϩ channels. As NMDA/AMPA current ratios were increased, the membrane showed an increase in hysteresis of "up" and "down" state dwell times, but intrinsic bistability was not observed. The number of oscillatory inputs required to entrain the model cell was determined to be ϳ20% of the "up" state inputs. Altering the NMDA/AMPA ratio had a profound effect on processing of afferent input, including the ability to entrain to oscillations in afferent input in the theta range (4 -12 Hz). These results suggest that afferent information integration by the NAcb MSP cell may be compromised by pathology in which the NMDA current is altered or modulated, as has been proposed in both schizophrenia and addiction.

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“…It is important to note that sequence learning has also been shown to be impaired in schizophrenia. 17,18 In the present study, we aimed to elucidate the cognitive underpinnings and consequences of imitation impairments in schizophrenia. Learning via imitation requires successful integration of multiple perceptual and cognitive processes.…”

Section: Introductionmentioning

confidence: 99%

Gesture Imitation in Schizophrenia

Matthews

Gold

Sekuler

et al. 2011

Schizophrenia Bulletin

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Recent evidence suggests that individuals with schizophrenia (SZ) are impaired in their ability to imitate gestures and movements generated by others. This impairment in imitation may be linked to difficulties in generating and maintaining internal representations in working memory (WM). We used a novel quantitative technique to investigate the relationship between WM and imitation ability. SZ outpatients and demographically matched healthy control (HC) participants imitated hand gestures. In Experiment 1, participants imitated single gestures. In Experiment 2, they imitated sequences of 2 gestures, either while viewing the gesture online or after a short delay that forced the use of WM. In Experiment 1, imitation errors were increased in SZ compared with HC. Experiment 2 revealed a significant interaction between imitation ability and WM. SZ produced more errors and required more time to imitate when that imitation depended upon WM compared with HC. Moreover, impaired imitation from WM was significantly correlated with the severity of negative symptoms but not with positive symptoms. In sum, gesture imitation was impaired in schizophrenia, especially when the production of an imitation depended upon WM and when an imitation entailed multiple actions. Such a deficit may have downstream consequences for new skill learning.

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Spatial serial order processing in schizophrenia

Cited by 33 publications

References 40 publications

Agents of the mind

Agents of the mind

NMDA/AMPA Ratio Impacts State Transitions and Entrainment to Oscillations in a Computational Model of the Nucleus Accumbens Medium Spiny Projection Neuron

Gesture Imitation in Schizophrenia

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