Timing of puberty and EEG coherence during photic stimulation

Author(s): Gruzelier, J. H.

Journal/Book: Int J Psychophysiol. 1996; 21: PO Box 211, 1000 AE Amsterdam, Netherlands. Elsevier Science BV. 135-149.

Abstract: Selective elimination of a large proportion of cortical synapses constitutes the last major stage in brain development which is linked to sexual maturation. Various neurodevelopmental theories have proposed an association between schizophrenia and late brain maturational events. Based on epidemiological and psychopharmacological data, Saugstad hypothesised a relationship between timing of puberty, synaptic density and psychosis proneness. Early puberty should result in an earlier end to synaptic pruning, a larger number of surviving connections and an increased risk for affective psychosis, In contrast, in late maturers prolonged synapse elimination should lead to lower synaptic density which constitutes a diathesis for schizophrenia. We used EEG coherence as a neurophysiological measure of cortico-cortical connectivity, Late maturers were expected to show higher coherence, especially for short-distance connections where lower synaptic density should lead to decreased local differentiation. EEG was recorded from 12 bipolar derivations in 19 early and 19 late maturing subjects of both sexes under conditions of rest and photic stimulation at different flicker frequencies, Whereas there were no coherence differences between early and late maturers during rest, both groups differed during flicker stimulation, As hypothesised, late maturers were found to Late maturers were also found to have higher intrahemispheric long-distance coherence. These findings were restricted to delta, alpha and beta 2 bands and were more pronounced in males, Our findings are interpreted in terms of a structural difference in neuronal connectivity between extreme early and late maturers.

Note: Article J Kaiser, Charing Cross & Westminster Med Sch, Dept Psychiat, Lab Neuropsychophysiol, St Dunstans Rd, London W6 8RF, England

Keyword(s): EEG coherence; timing of puberty; synaptic pruning; schizophrenia; photic stimulation; HUMAN CEREBRAL-CORTEX; SYNAPTIC DENSITY; SCHIZOPHRENIC-PATIENTS; VISUAL-CORTEX; MATURATION; CHILDREN; ELIMINATION; CHILDHOOD; EMOTIONS; SYMPTOMS

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