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Enhanced semantic priming in schizophrenia: a computer model based on excessive pruning of local connections in association cortex

  • Peter J. Siekmeier (a1) and Ralph E. Hoffman (a2)

Abstract

Background

Many studies have found that people with schizophrenia exhibit abnormally high levels of semantic priming. Post-mortem and neuroimaging studies of schizophrenia suggest a reduction of neuritic processes (dendrites and synapses).

Aims

To demonstrate that reductions in neuritic processes can produce excessive priming in patients with schizophrenia.

Method

Associative memory was simulated using a computer-based neural network system consisting of two interactive neural groups, one coding for individual memories and the other for the category to which each memory belonged.

Results

Variation of a single parameter determining the density of local connections within the two neuronal groups gave a close approximation to levels of memory access and semantic priming previously reported in normal subjects and in patients with schizophrenia.

Conclusions

This study suggests that schizophrenia arises from excessive pruning of local connections in association cortex. Its findings shed light on the mechanisms underlying cognitive priming more generally, and how it might emerge developmentally.

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Copyright

Corresponding author

Dr Ralph Hoffman, Yale – New Haven Psychiatric Hospital, 20 York Street, New Haven, CT 06504, USA

Footnotes

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Declaration of interest

None.

Footnotes

References

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Amit, D. J., Gutfreund, H. & Sompolinsky, H. (1987) Information storage in neural networks with low levels of activity. Physical Review A – General Physics, 35, 22932303.
Barch, D. M., Cohen, J. D., Servan-Schreiber, D., et al (1996) Semantic priming in schizophrenia: an examination of spreading activation using word pronunciation and multiple SOAs. Journal of Abnormal Psychology, 105, 592601.
Benes, F. M., McSparren, J., Bird, E. D., et al (1991) Deficits in small interneurons in prefrontal and cingulate cortices of schizophrenic and schizoaffective patients. Archives of General Psychiatry, 48, 9961001.
Bressler, S. L. (1995) Large-scale cortical networks and cognition. Brain Research Reviews, 20, 288304.
Carrie, J. R. G. (1993) Evaluation of a neural network model of amnesia in diffuse cerebral atrophy. British Journal of Psychiatry, 163, 217222.
Collins, A. M. & Loftus, E. (1975) A spreading activation theory of semantic processing. Psychological Review, 82, 407428.
Eastwood, S. L. & Harrison, P. J. (1995) Decreased synaptophysin in the medial temporal lobe in schizophrenia demonstrated using immunoautoradiography Neuroscience, 69, 339343.
Feinberg, I. (1982) Schizophrenia: caused by a fault in programmed synaptic elimination during adolescence? Journal of Psychiatric Research, 17, 319334.
Friston, K. J. (1996) Theoretical neurobiology and schizophrenia. British Medical Bulletin, 52, 644655.
Glantz, L. A. & Lewis, D. A. (2000) Decreased dendritic spine density on prefrontal cortical pyramidal neurons in schizophrenia. Archives of General Psychiatry, 57, 6573.
Grunze, H. C., Rainnie, D. G., Hasselmo, M. E., et al (1996) NMDA-dependent modulation of CAI local circuit inhibition. Journal of Neuroscience, 16, 23042343.
Henik, A., Nissimov, E., Priel, B., et al (1995) Effects of cognitive load on semantic priming in patients with schizophrenia. Journal of Abnormal Psychology, 104, 576584.
Hermann, M., Ruppin, E. & Usher, M. (1993) A neural model of the dynamic activation of memory. Biological Cybernetics, 68, 455463.
Hinton, G. E. (1992) How neural networks learn from experience. Scientific American, September, 145151.
Hoffman, R. E. & Dobscha, S. K. (1989) Cortical pruning and the development of schizophrenia: a computer model. Schizophrenia Bulletin, 15, 477490.
Hoffman, R. E. & McGlashan, T. H. (1997) Synaptic elimination, neurodevelopment, and the mechanism of hallucinated ‘voices’ in schizophrenia. American Journal of Psychiatry, 154, 16831689.
Horn, D., Ruppin, E., Usher, M., et al (1993) Neural network modeling of Alzheimer's Disease. Neural Computation, 5, 736749.
Huttenlocher, P. R. (1979) Synaptic density in human frontal cortex – developmental changes and the effects of aging. brain Research, 163, 195205.
Kwapil, T. R., Hegley, D. C., Chapman, L. J., et al (1990) Facilitation of word recognition by semantic priming in schizophrenia. Journal of Abnormal Psychology, 99, 215221.
Lewis, D. A. & Gonzalez-Burgos, G. (2000) Intrinsic excitatory connections in the prefrontal cortex and the pathophysiology of schizophrenia. Brain Research Bulletin, 52, 309317.
Maher, B. A. (1983) A tentative theory of schizophrenic utterance. In Progress in Experimental Personality Research, vol. XI (eds Maher, B. & Maher, W), pp. 152. San Diego: Academic Press.
Maher, B. A., Manschreck, T. C., Hoover, T. M., et al (1987) Thought disorder and measured features of language production in schizophrenia. In Positive and Negative Symptoms in Psychosis (eds Harvey, P. & Walker, E.), pp. 195215. Hillsdale, NJ: Lawrence Erlbaum.
Maher, B. A., Manschreck, T. C., Redmond, D., et al (1996) Length of illness and the gradient from positive to negative semantic priming in schizophrenic patients. Schizophrenia Research, 22, 127132.
Manschreck, T., Maher, B. A., Milavetz, J. J., et al (1988) Semantic priming in thought disordered schizophrenic patients. Schizophrenia Research, 1, 6166.
Meilijson, T. & Ruppin, E. (1992) History-dependent Attractor Neural Networks. Technical Report 261/92. Tel-Aviv: School of Mathematical Sciences, Tel-Aviv University.
Meyer, D. E. & Schvaneveldt, R. W. (1971) Facilitation in recognizing pairs of words: evidence of a dependence between retrieval operations. Journal of Experimental Psychology, 20, 227234.
Mitrushina, M., Abara, J. & Blumenfeld, A. (1996) A comparison of cognitive profiles in schizophrenia and other psychiatric disorders. Journal of Clinical Psychology, 52, 177190.
Moritz, S., Andresen, B., Domin, F., et al (1999) Increased spreading activation in healthy subjects with elevated scores in a scale assessing schizophrenic language disturbances. Psychological Medicine, 29, 161170.
Ruppin, E. & Reggia, J. A. (1995) A neural model of memory impairment in diffuse cerebral atrophy. British Journal of Psychiatry, 166, 1928.
Selemon, L. D., Rajowska, G. & Goldman-Rakic, P. S. (1995) Abnormally high neuronal density in the schizophrenic cortex. A morphometric analysis of prefrontal area 9 and occipital area 17. Archives of General Psychiatry, 52, 305318.
Spitzer, M., Weisker, I., Winter, M., et al (1994) Semantic and phonological priming in schizophrenia. Journal of Abnormal Psychology, 103, 485494.
Woo, T. U., Pucak, M. L., Kye, C. H., et al (1997) Peripubertal refinement of the intrinsic and associational circuitry in monkey prefrontal cortex. Neuroscience, 80, 11491158.

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Enhanced semantic priming in schizophrenia: a computer model based on excessive pruning of local connections in association cortex

  • Peter J. Siekmeier (a1) and Ralph E. Hoffman (a2)
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