Nicole M. Gage

Consciousness and attention

This chapter discusses consciousness and attention that can be considered as complementary processes. Conscious contents often are thought to involve the widespread distribution of focal contents, like the sight of a rabbit. As soon as a person sees a rabbit (consciously), he/she can also judge whether its real, if its somebodys pet, he/she can laugh or scream for fear of being bitten, and try to remember if rabbits carry rabies. The point is that a great variety of brain events can be evoked by a conscious object, including a great variety of unconscious processes. Conversely, a person can focus cognitive resources on any topic to which he/she decide to devote attention. Consciousness typically involves a small amount of content at any given moment, like the sight of a rose bush, which may recruit and mobilize many unconscious brain functions.

Social cognition: Perceiving the mental states of others

This chapter investigates one aspect of human cognition that makes human beings unique among its mammalian relatives—the ability to understand each other as conscious beings with internal mental states. Social cognition abilities in human beings are complex and multifaceted. They are supported by multiple systems of interconnected cortical and subcortical areas. During evolution, the simpler valuation and behavioral system of the limbic brain was overlaid by the growing cerebral cortices that make complex cognition possible. It is very likely that the large and complex cerebral cortices evolved in part due to selective pressures by the increasing complexity of human society and the demands of social cognition. Increased social and cognitive complexity in the environment leads to increased complexity in correlated brain systems.

Chapter 13 – Emotion

Publisher Summary This chapter discusses the emotion systems of the brain and their interactions with cognitive processing. Mammals have separate emotional systems in the brain, each with patterned, innate responses to stimuli in the expected environment of the species related to survival. Systems such as the fear system and the reward system are shown to have both unconditioned and conditioned responses to significant “calling conditions” supported by separate neural networks—fear relying on the amygdala and its connections, and the reward system relying heavily on the mesolimbic and mesocortical pathways of the VTA. Each of these systems can come under cognitive control and also reciprocally influence higher decision making, appraisal systems, and consciousness. Each system is capable of elaborating distinctly different subjective feelings.

Mind and brain

This chapter provides an overview of cognitive neuroscience that is the combined study of mind and brain. To understand the mind-brain, it helps to have an idea of its orders of magnitude, the powers of ten that tells the basic units of interest. Human beings function over a great range of time scales. Behaviorally, one-tenth of a second (100 ms) is an important unit to keep in mind. The fastest (simple) reaction time to a stimulus is about 100 milliseconds and the time it takes for a sensory stimulus to become conscious is typically a few hundred milliseconds. This makes sense in the environment in which human beings evolved. Most imaging experiments use standard cognitive tasks, so there is a growing integration of behavioral and brain evidence. The implications for brain functioning in health and disease are immense.

Chapter 2 – A framework

Publisher Summary This chapter introduces a framework that helps to organize a good deal of cognitive neuroscience. It presents a diagram that combines a large body of brain and psychological evidence. Each aspect of the functional framework is described. The senses all begin from receptor surfaces containing millions of receptors, like the retina at the back of the eye. All sensory pathways terminate in the rear half of the cortex. Each of the classical senses is believed to have a brief storage ability called a sensory buffer. The body senses; like touch, pain, and proprioception, are also well understood. Sensory activities are flexibly enhanced by selective attention; attention has a “bottom-up” component, to reflect the times when the sensory experience is captured by a flash or a bang, or more subtly by the sight of someones face. A range of events can be focused upon voluntarily, in a “top-down” fashion. While there continues to be debate about brain regions involved in selective attention, recent evidence shows that cortical regions for visual attention show marked overlap with eye movement control.

Learning and Remembering

This chapter explores the processes of learning and remembering. First, both episodic and semantic memory is defined with examples. The chapter describes the brain areas involved in learning and memory. The brain changes that occur during learning are then described in easy-to-understand steps. A central debate in the study of learning and memory is presented next: is consciousness needed for episodic learning? A description of the difference between unconscious learning and implicit learning is presented next, with examples of each taken from our everyday lives. We then take a look at the interactive roles of working memory and executive function in learning and memory processes—bringing the notion of the control of memory to the discussion of conscious and unconscious learning and memory. Next, a description of patients who developed memory loss is presented, along with a discussion of the types of amnesia and why they occur.

Attention and Consciousness

This chapter covers a wide range of topics, from a discussion of the “waking state” to dreaming to exceptional states of mind. Throughout the chapter, the notion of consciousness as a brain variable is woven through each discussion. The chapter opens with a description of how brain rhythms differ during differing levels of awareness. Next, the impact of attention—both voluntary and involuntary—on brain processes is described. Brain functions that make up the “central executive” of our brain are discussed; these provide a cognitive control network for dealing with daily life. But what about when we are asleep? The chapter closes with a description of the brain bases of “exceptional states of mind”—from out-of-body experiences to the role of neurofeedback.

Disorders of Consciousness

The chapter, Disorders of Consciousness , describes both normal and abnormal states of unconsciousness. We drift into deep unconsciousness as a normal stage of sleep each night and reemerge each morning. If needed, anesthesia can provide controlled, reversible unconsciousness that may seem like a sleep stage but differs sharply in brain activity patterns. After traumatic brain injury or disease, we may lapse into a deep unconscious state of coma. Patients may transition from this state to a vegetative state (VS), a minimally conscious state, a confusional state, to a fully conscious state. Not all patients make this transition, however. Treatment of persistent VS patients and end-of-life decisions are difficult and painful to make. New progress has been made on determining the levels of awareness and wakefulness in patients with disorders of consciousness, with specific brain regions that provide evidence for awareness despite a lack of overt, observable signs.

Humans Are Social Beings

In this chapter, we explore the brain bases of social cognition. The social brain involves a network of cortical and subcortical regions that are especially sensitive to social situations. The chapter is organized around four central aspects of social cognition: theory of mind , empathy , social perception , and social behavior . Just where in the brain do we process social information such as shared attention to an object, decoding facial expressions, understanding body language? As we step through their neural bases, we will build a basis for the key brain regions that provide the neural mechanisms for our social selves. The chapter concludes with a discussion of impairments in social cognition—which range from mild to severe and span many types of brain diseases, disorders, and damage.

Decisions, Goals, and Actions

Abstract This chapter describes the many complex functions of the frontal lobes. The frontal lobes are a vast mosaic of cell types and cortical regions, diverse in their cell structures, anatomical features, and connectivity patterns. Unlike regions in the sensory cortex, the frontal lobes do not have a single job to do; they are not specialized for decoding speech sounds or recognizing faces. Rather, the frontal lobes are engaged in almost all aspects of human cognitive function. The frontal lobe is “home” to executive processes that allow us to make plans and revise them, action processes where physical actions are planned and motor system activity is initiated, and personality processes where social maturity and morality systems are developed. The chapter concludes with a discussion of the many frontal lobe syndromes that occur when the frontal lobes are damaged due to injury or brain disease.