Hockenbury Discovering Psychology 5th txtbk

A Guided Tour of the Brain71HypothalamusLinks brain and endocrinesystem; regulates hunger, thirst,sleep, and sexual behaviorThalamusProcesses and integratessensory information; relays sensoryinformation to cerebral cortexFigure 2.18 Key Structures of theForebrain and Limbic System In the crosssectionalview shown here, you can see thelocations and functions of four importantsubcortical brain structures. In combination,these structures make up the limbicsystem, which regulates emotional control,learning, and memory.AmygdalaInvolved in memory andemotion, especially fearand angerHippocampusInvolved in formingnew memoriesThe Hippocampus The hippocampus is a large structure embedded in the temporallobe in each cerebral hemisphere (see Figure 2.18). The word hippocampuscomes from a Latin word meaning “sea horse.” If you have a vivid imagination,the hippocampus does look a bit like the curved tail of a sea horse. The hippocampusplays an important role in your ability to form new memories of eventsand information. As noted earlier, neurogenesis takes place in the adult hippocampus.The possible role of new neurons in memory formation is an activearea of neuroscience research (see Gould, 2007; Lledo & others, 2006). InChapter 6, we’ll take a closer look at the role of the hippocampus and other brainstructures in memory.The Thalamus The word thalamus comes from a Greek word meaning “innerchamber.” And indeed, the thalamus is a rounded mass of cell bodies located withineach cerebral hemisphere. The thalamus processes and distributes motor informationand sensory information (except for smell) going to and from the cerebral cortex.Figure 2.19 depicts some of the neural pathways going from the thalamus to the differentlobes of the cerebral cortex. However, the thalamus is more than just a sensoryrelay station. The thalamus is also thought to be involved in regulating levels ofawareness, attention, motivation, and emotional aspects of sensations.Figure 2.19 The Thalamus Almost allsensory and motor information going toand from the cerebral cortex is processedthrough the thalamus. This figure depictssome of the neural pathways from differentregions of the thalamus to specificlobes of the cerebral cortex.The Hypothalamus Hypo means “beneath” or “below.” As itsPrimary somatosensory cortexname implies, the hypothalamus is located below the thalamus. Primary motor cortexAlthough it is only about the size of a peanut, the hypothalamuscontains more than 40 neural pathways. These neuralpathways ascend to other forebrain areas and descend to the Frontal cortexmidbrain, hindbrain, and spinal cord. The hypothalamus is involvedin so many different functions, it is sometimes referredto as “the brain within the brain.”The hypothalamus regulates both divisions of the autonomicnervous system, increasing and decreasing such functions asheart rate and blood pressure. It also helps regulate a variety ofbehaviors related to survival, such as eating, drinking, frequencyof sexual activity, fear, and aggression.One area of the hypothalamus, called the suprachiasmatic nucleus(SCN), plays a key role in regulating daily sleep–wake cycles and otherrhythms of the body. We’ll take a closer look at the SCN in Chapter 4.ThalamusParietal lobePrimaryvisual cortex