Memory During Anesthesia: the Role of Stress Hormones

1. To investigate whether the auditory stimulation causes changes in hormones levels (cortisol+prolactin) during general anesthesia. 2. To determine if there is a correlation between hormones levels (cortisol+prolactin) and dreams recall. 3. To investigate whether, in patients receiving auditory stimulation, there is a correlation between hormones levels (cortisol+prolactin), serum remifentanil concentration and detection of implicit memory. 4. To investigate the presence of primary auditory cortex activation (temporal lobe) in patients with implicit memory and in those with dreams recall using the EEG-ERP 128 channels GES300 EGI system.