The Cognitive Brain Neurons: The Building Blocks of the Brain Structure of the Nervous System The Peripheral Nervous System The Cerebral Cortex Subcortical Areas Chapter 1

Neurons: The Building Blocks of the Brain Chapter 1

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Structure of the Nervous System The nervous system is traditionally considered to have two major parts, the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS consists of the brain and spinal cord; the PNS consists of the skeletal nervous system and the autonomic nervous system (ANS). We start with the more basic, and (in evolution­ary terms) older PNS and then turn to the brain itself. (p. 18) Chapter 1

The Peripheral Nervous System The autonomic nervous system (ANS) is traditionally divided into two major parts, the sympathetic and parasympathetic nervous systems. The sympathetic nervous system prepares an animal to respond more vigorously and accurately during an emergency. increases the heart rate (so more oxygen and nutrients are delivered to organs). increases the breathing rate (thus providing more oxygen) dilates the pupils (resulting in greater sensitivity to light). causes the palms of the hands to become moist (thus providing better grip). reduces digestive functions, including salivation (putting them “on hold”). relaxes the bladder (suspending another function that isn’t crucial in an emergency). These changes prepare an organism for successful challenge or successful escape, and are often called the fight-or-flight response. Why should we care about this response in a book on cognition? For one thing, the events surrounding this response can ac­tually improve memory (Chapter 5), while at the same time they can disrupt reason­ing (Chapter 10). (p. 19) The parasympathetic nervous system in many ways counters the sympathetic nervous system. Whereas the sympathetic system tends to rev things up, the parasympathetic system dampens them down. Moreover, whereas the sympathetic system causes a whole constellation of effects (producing arousal in general), the parasympathetic system targets single organs or small sets of organs. In a job inter­view, you are grateful when the interviewer moves onto another part of your résumé where you are on rock-solid ground—and the parasympathetic system then dampens down the fight-or-flight response you were struggling to contain. (p. 19) Chapter 1

The Cerebral Cortex Chapter 1

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Subcortical Areas Chapter 1

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Studying Cognition Converging Evidence for Dissociations and Associations Behavioral Methods Correlational Neural Methods: The Importance of Localization Causal Neural Methods Modeling Neural-Network Models Cognition is investigated in several fields, each of which uses a different approach. When first conceived, cognitive psychology focused exclusively on the level of infor­mation processing (e.g., Lindsay & Norman, 1977; Neisseç 1967). Artificial intelli­gence (AI), concentrating at the same level of analysis, is the field in which Studying Cognition researchers attempt to program computers to perform cognitive tasks. Many AI researchers believe that cognition is so complicated that figuring out how to build a processing system that performs comparably to humans will lend insight into human cognition (Minsky, 1986). Neither early cognitive psychology nor AI pays much at­tention to the way such information processing takes place in the brain. But even computer buffs have noted that it isn’t quite right to assume that information pro­cessing is independent of the machine itself: some programs rely on specific features of the hardware, such as the presence of a certain amount of RAM or a particular graphics or sound card. Studying the hardware can lead to insights about what the machine does and how it functions. (p. 24 – 25) Chapter 1

Converging Evidence for Dissociations and Associations Converging evidence: different types of results that imply the same conclusion, lies at the heart of successful investigations in cognitive psychology. Many of the methods in cognitive psychology are used to accomplish two general types of goals: Dissociation: to establish that an activity or a variable affects the performance of one task (or aspect of one task) but not of another. Double dissociation: an activity or variable affects one process but not another and a second activity or variable has the reverse properties. Association: occurs when the effects of an activity or variable on one task are accompanied by effects on another task. The first thing you will notice as we continue is that there are a lot of different meth­ods. No one method is ideal; they all have limitations and potential problems. But— and this is a critical point—they have different limitations and potential problems. (p. 25) Chapter 1

Behavioral Methods A behavioral method measures directly observable behavior such as the time to respond or the accuracy of a response. Researchers attempt to draw inferences about internal representation and processing from such directly observable responses. Chapter 1

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Correlational Neural Methods: The Importance of Localization Cognitive psychology has become extraordinarily exciting during the past decade because researchers have developed relatively inexpensive, high-quality methods for assessing how the human brain functions. These methods are correlational: although they reveal the pattern of brain activity that accompanies information processing, they do not show that activation in specific brain areas actually results in the task’s being carried out. Correlation does not necessarily imply causation. Chapter 1

Correlational Neural Methods: The Importance of Localization We can evaluate the various correlational neural methods on four dimensions: (1) Spatial resolution, how precisely they localize the brain area that produces a signal. (2) Temporal resolution, how precisely they track changes in brain activity over time. (3) Invasiveness, the degree to which they require introduction of foreign substances into the brain. (4) Cost, both for the equipment (and any special facilities) and for its use in each participant test. The three most important neuroimaging. Chapter 1

Correlational Neural Methods: The Importance of Localization Chapter 1

An fMRI scan in progress. A PET scan in progress. An fMRI scan in progress. Chapter 1

Causal Neural Methods Chapter 1 Researchers have depended on other types of studies to establish causal connections between brain activation and performance. Such methods, summarized in Table 1–3, show that activity in a particular brain area actually gives rise to specific representa­tions or carries out specific processes. (p. 37) Chapter 1