This chapter summarizes findings from structural and functional neuroimaging studies in individuals with idiopathic rapid eye movement (REM) sleep behavior disorder (iRBD). In humans, functional brain imaging has been used to evaluate the neural mechanisms and structures that regulate REM sleep. Dysfunction of the REM sleep atonia network forms the neuropathological basis for RBD. In humans, iRBD is diagnosed when a patient with videopolysomnographic confirmation of REM sleep without atonia has no evidence of a neurological disease or other possible causes. The chapter summarizes the neuroimaging abnormalities that have been identified in Parkinson disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA). Several neuroimaging studies have evaluated the morphological and functional state of the substantia nigra in iRBD. These studies have evaluated the echogenicity of the substantia nigra with transcranial sonography (TCS) and the nigrostriatal dopaminergic system with functional imaging.

Emotions are often expressed or signaled via postures and movements of the whole body or its parts. This chapter surveys the smaller but important corpus of research devoted to investigating the perception of bodily expressed emotions and its neural substrate. It focuses on the visual cues underlying body and bodily emotion perception. The chapter begins with a consideration of what constitutes a bodily expression or signal of emotion, highlighting a difference between actions that directly convey an emotion and actions that do not but are nevertheless performed in an emotional way. It then briefly summarises studies that have demonstrated the ability of human observers to distinguish between and identify a range of emotions from body posture and movement stimuli. The chapter surveys the current state of knowledge about how the brain processes visual information relating to other people's bodies and bodily expressions of emotion.

Value-based decision making is the process of selecting actions from among several alternatives to maximize future possible rewards and minimize future possible punishers. Underlying this capacity are a number of distinct neural signals, which include: outcome value, chosen value, decision value and action value. This chapter considers each of these signals and evaluates evidence about the contribution of specific neural circuits to these functions. It briefly reviews evidence for the existence of comparison signals that resemble the outcome of such a decision process. The chapter talks about the post-decision value signals, which serve as an input for generating prediction error signals that are then subsequently used to update the value signals needed to compute future choice. Furthermore, it is likely that decisions emerge as a function of the interaction among a number of additional regions such as the amygdala, striatum, and intra-parietal cortex.

This chapter discusses the contributions of functional imaging to our understanding of how action and tool concepts are represented and processed in the human brain. It is framed within the feature-based account of semantic memory. This approach assumes that conceptual knowledge is represented in a large distributed network, indexing a range of semantic features. Neurophysiological studies in non-human primates have suggested that the frontoparietal circuitry may play a role in visuomotor transformations and action matching, imitation and understanding. Studies of action observation and semantic retrieval provide converging evidence that left posterior middle temporal gyrus (LPMT) activation is commonly increased for hand manipulation and whole-body movements. The chapter revisits several themes that have emerged from functional imaging studies of tool and action processing. It evaluates the positive evidence for the feature-based account of semantic memory, and concludes by highlighting future directions to investigate the neural mechanisms of tool and action processing.

Inappropriate aggression and violence is a pervasive feature of contemporary society. The great advances in the authors' knowledge of brain function have helped our understanding of the neural mechanisms underlying behaviour. This chapter focuses on what the authors know of these as they apply to aggression. It is axiomatic that the brain plays a central role in aggression, both by recognizing aggression-provoking stimuli, and formulating aggressive responses. The regulation of aggression is a distributed function of the brain. There are many anatomical areas associated with aggression, though whether there are specific 'aggressive' nuclei remains doubtful. There are also a plethora of neurochemical systems implicated in aggression. The challenge to those studying aggression in children is to identify the interplay between specific genes and critical elements of the social and physical environment that, together, determine long-lasting patterns of aggressive behaviour.