**4. Discussion**

Paedophilic and non paedophilic men exhibit a frontal and subcortical activation during processing of sexually relevant stimuli. The paedophiles show more activation in subcortical regions during sex relevant images processing (in hippocampus, amygdala, thalamus, septal areas), regions that are implicated in the modulation of sexual behaviours and genital responses. The activation of these subcortical areas is more intense in paedophiles in comparison to controls that exhibit more activation of prefrontal cortex, the essential structure in the control of the information processing and to co-ordinate behaviour and inhibition of urges impulses.

The findings of the neuroimaging studies in paedophilia suggest that paedophilic and no paedophilic men may differ more fundamentally in the brain function during processing of sexually relevant stimuli. They differ in the brain areas that are activated and not in the brain areas that are implied. In paedophilia this different neural activation in comparison with healthy controls men (without paedophilia) could be owe principally to an alterations in the association fibres of brain that connect different cortical and subcortical areas that realize visual processing or to a structural alteration in neural areas that are important in the development of sexual behaviour (for example in the frontal cortex, amygdala, hypothalamus and septal regions). Too the data of the structural studies could indicate an atypical brain development in paedophiles that could lead to an atypical processing in relation to sexual stimuli and sexual behaviour. But it is necessary to be cautious in the interpretation of the results of these studies. Since some of these works, as the study of Walter et al. (2007) finds a differential activation of subcortical regions in relation to other works that find different evidence. For what it is very necessary to increase the knowledge in this field with new studies.

The results of these studies offer a new perspective on paedophilia and can provide the bases for the development of more sophisticated diagnostic tools and new therapeutic approaches to the treatment of this disorder. Although in relation with the methodology of the works realized up to the date, will be of importance that future studies include a more number of persons with diagnosis of paedophilia, for what works with greater statistical power would be desirable to observe if the findings continue being after of to increase the sample. Also future researchs with a larger sample size would aid in the discovery of other possible differences.

Regarding the groups to include in later studies, would be suitable the incorporation of different groups as sexual non-paedophile aggressors group and of other groups of offenders for if there is some type of alteration that can be due to the sexual aggression or the delinquency in general. Finally, the study of the entire brain might be a method of study more succeeded to try to discover possible differences that the studies that have centred on regions of interest could have overlooked. It is necessary to bear in mind that the area of study, for the social repercussions that carries among other things, is a difficult area for planning some type of study and especially for obtaining the necessary sample.
