[autismo-biologia] Fw: [2282] Autismo: 20% in piu' di connessioni cerebrali

[Stefano Palazzi]

Riguardo al ruolo della sinaptogenesi, come è interessante che un  
deficit di potatura sinaptica nei primi mesi di vita porti  
all'autismo, così lo è pure che un eccesso di potatura in adolescenza  
possa portare a schizofrenia:

J Psychiatr Res. 1994 May-Jun;28(3):239-65.

Is schizophrenia due to excessive synaptic pruning in the prefrontal  
cortex? The
Feinberg hypothesis revisited.

Keshavan MS, Anderson S, Pettegrew JW.

Department of Psychiatry, Western Psychiatric Institute and Clinic,  
Pittsburgh,
PA 15213.

Several lines of evidence support the notion that a substantial  
reorganization of
cortical connections, involving a programmed synaptic pruning, takes  
place during
adolescence in humans. A review of neurobiological abnormalities in  
schizophrenia
indicates that the neurobiological parameters that undergo peripubertal
regressive changes may be abnormal in this disorder. An excessive  
pruning of the
prefrontal corticocortical, and corticosubcortical synapses, perhaps  
involving
the excitatory glutamatergic inputs to pyramidal neurons, may underlie
schizophrenia. A reciprocal failure of pruning in certain subcortical  
structures,
such as lenticular nuclei, may also occur. Several developmental  
trajectories,
related to early brain insults as well as genetic factors affecting  
postnatal
neurodevelopment, could lead to the illness. These models would have  
heuristic
value and may be consistent with several known facts of the  
schizophrenic
illness, such as its onset in adolescence and the gender differences  
in its onset
and natural course. The relationship between these models and other  
etiological
models of schizophrenia are summarized and approaches to test relevant  
hypotheses
are discussed.


PMID: 7932285 [PubMed - indexed for MEDLINE]