**3.4 N170/Vertex Positive Potential (N170/VPP)**

The N170/VPP complex is a negative peak around 170 ms in the temporal-occipital regions and simultaneously one central-frontal positivity (VPP), functionally equivalent (Joyce and Rossion, 2005). The source of N170 compromises the inferior temporal gyrus and the fusiform gyrus (two neural areas associated with specific face processing). Its amplitude is greater for human faces, compared with objects or other stimuli (Bentin, Allison, Puce, Perez and McCarthy, 1996; Jeffreys, 1989). During the face-processing task, N170 is sometimes followed by a P2, a N250 and an LPP component modulated by other variables. The N170 component has shown amplitude/latency modulation based on race cues (Ibanez et al., 2010c; Ito and Ulrand, 2005; Gonzales et al., 2008), emotional variables (Ashley, Vuilleunier and Swick, 2004) and contextual effects (Ibanez et al. 2011d).

#### **3.5 Early Posterior Negativity (EPN)**

The EPN is a middle-latency component that has been associated with different stages of valence information processing and affective discrimination (Schupp et al., 2004a, 2004b). Di Russo, Taddei, Apnile and Spinelli (2006) suggested that EPN would reflect early valence discrimination and response selection processes. Additionally, Schupp et al. (2004a) have stated that the processing indexed by the EPN is modulated by perceptual features that facilitate further evaluation of arousing stimuli. Different studies have found a modulation differing from the neutral for both emotional (pleasant, unpleasant) categories of pictures (e.g., Dufey et al., 2010; Cuthbert, Schupp, Bradley, Birbaumer and Lang (2000). Nevertheless, specific effects (task or stimuli-dependent) on EPN in relation to valence and the influence of arousal should be further assessed.

### **3.6 P300 (or P3)**

This component has been described as engaging higher-order cognitive operations related to selective attention and resource allocation (Donchin and Coles, 1988). The P3 amplitude may serve as a covert measure of attention that arises independently of behavioral responding (Gray et al., 2004). The component has also been related to a post-decisional "cognitive closure" mechanism (Desmedt, 1980; Verleger, 1998); and to the access of information for consciousness (Picton, 1992). Its amplitude generally varies as a function of the temporal distance between a target and a preceding outgoing stimulus (e.g., Cornejo et al., 2007). There are two sub-components (P3a and P3b). The P3a has a more frontal distribution and is observed after an unexpected event, regardless of the relevance of the stimulus. Usually, it is associated with automatic attentional modulation. The P3b is related to attention, working memory and superior cognitive functions and is observed at centro-parietal sites. This ERP is affected by several psychological processes, the most important of which are motivation and sustained attention.


Contents

### **Preface XI**

Preface

Oxidative stress plays a crucial role in the pathophysiology of various diseases when there is a

disruption of the intracellular redox balance and the homeostatic balance between cellular

oxidants and antioxidants. Reactive oxygen species (ROS), although essential for normal

physiologic processes, are deleterious when produced in excess. Free radicals include not only

ROS but also reactive nitrogen species (RNS) such as nitric oxide and peroxynitrite similarly

leading to nitrosative stress. These molecules react with molecular targets including proteins,

This book intends to provide the readers with an extensive overview of the novel ap‐

proaches and prospects based on oxidative and nitrosative stress in the pathophysiology of

various diseases and in the current treatment strategies with antioxidants, and it is the one

I believe that this book will provide a good grounding in pointing the way to new disciplines

that will contribute to the evolution of strategies for creating, analyzing, and presenting the

**Prof. Dr. Pinar Atukeren**

Cerrahpasa Medical Faculty

Department of Medical Biochemistry

Istanbul University

Turkey

medical information in the future stimulating our colleagues at all multidisciplinary levels.

lipids, and nucleic acids contributing to mitochondrial injury and cellular dysfunction.

to which the authors have made significant contributions in all chapters.