Excitatory and inhibitory lateral interactions effects on contrast detection are modulated by tRNS.

Contrast sensitivity for a Gabor signal is affected by collinear high-contrast Gabor flankers. The flankers reduce (inhibitory effect) or increase (facilitatory effect) sensitivity, at short (2λ) and intermediate (6λ) target-to-flanker separation respectively. We investigated whether these inhibitory/facilitatory sensitivity effects are modulated by transcranial random noise stimulation (tRNS) applied to the occipital and frontal cortex of human observers during task performance. Signal detection theory was used to measure sensitivity (d') and the Criterion (C) in a contrast detection task, performed with sham or tRNS applied over the occipital or the frontal cortex. After occipital stimulation results show a tRNS-dependent increased sensitivity for the single Gabor signal of low but not high contrast. Moreover, results suggest a dissociation of the tRNS effect when the Gabor signal is presented with the flankers, consisting in a general increased sensitivity at 2λ where the flankers had an inhibitory effect (reduction of inhibition) and a decreased sensitivity at 6λ where the flankers had a facilitatory effect on the Gabor signal (reduction of facilitation). After a frontal stimulation, no specific effect of the tRNS was found. We account for these complex interactions between tRNS and flankers by assuming that tRNS not only enhances feedforward input from the Gabor signal to the cortex, but also enhances the excitatory or inhibitory lateral intracortical input from the flankers. The boosted lateral input depends on the excitation-inhibition (E/I) ratio, namely when the lateral input is weak, it is boosted by tRNS with consequent modification of the contrast-dependent E/I ratio.

[Pre- and postoperative color Doppler ultrasonography of myocutaneous flaps in reconstructive surgery of the breast]. / L'eco color-Doppler nello studio pre e postoperatorio dei lembi miocutanei in chirurgia ricostruttiva della mammella.

The authors present their experience in the study of blood supply of flaps. The machine used to study both pre and postoperatively the myocutaneous flap is the echo-color Doppler, a brand new device which has recently been used in investigating the morphology and the blood supply. The use of such method has provided us with the following information: detailed ultrasound structure of the skin, subcutaneous and muscular tissues of the examined flap; localization of vessels within the flap; size of the vessel in its whole length; quality and speed of both the arterial and venous flow. Such information is very important for the surgeon to plan in detail the reconstruction by knowing the blood supply of myocutaneous flap.

[Cryosurgery in the treatment of condylomatosis]. / La criochirurgia nel trattamento della condilomatosi.

The authors report their personal experience of the treatment of condylomas in both male and female patients using cryosurgery. The temperature of -80 degrees C which can be obtained using hyperdry nitrogen monoxide equipment allow radical treatment to be performed without pain in an outpatient setting without general or loco-regional anesthesia. The characteristics of this treatment allow patients to be regularly monitored, thus eliminating all signs of recidivation of those lesions which were too small to be seen at the start of treatment. The patient is considered cured after an interval of approximately 30-40 days after the disappearance of all condylomas.

[Cryosurgery in the treatment of verrucae]. / La criochirurgia nel trattamento delle verruche.

The paper reports the A. experience of 1460 cases of verrucae treated with cryosurgery. A hyperdry nitrogen monoxide method was used which enables a temperature of approximately -80 degrees C to be obtained. The large number of cases treated allowed the A. to present a statistical picture which was highly significant with regard to the mean number of applications, mean freezing time and, lastly, the mean healing time for different types of verrucae. The study confirms that cryosurgery is the elective treatment for this type of pathology.