2: The Brain
- Page ID
- 54071
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)- 2.1: The Central and Peripheral Nervous Systems
- The nervous system consists of the central nervous system (CNS) and peripheral nervous system (PNS). The CNS includes the brain and spinal cord, while the PNS encompasses other neural elements. Neurons and glial cells are the primary cell types in nervous tissue. Neurons have a soma and processes like axons and dendrites. CNS structures with cell bodies are called nuclei, while in the PNS, they are ganglia. Axonal bundles are tracts in the CNS and nerves in the PNS.
- 2.2: Lower-Level Structures of the Brain
- The lower-level structures of the brain include the brain stem, spinal cord, and cerebellum, primarily located in the hindbrain, midbrain, and diencephalon. These structures manage basic survival functions. The hindbrain, comprising the medulla oblongata, pons, and cerebellum, controls respiration and movement. The midbrain supports motor and sensory functions, while the diencephalon's thalamus and hypothalamus regulate emotions and behaviors.
- 2.3: Lobes - Cerebral Hemispheres and Lobes of the Brain
- The brain is divided into two hemispheres with distinct functions, known as lateralization; the left hemisphere primarily manages language and logical reasoning, while the right focuses on spatial tasks. The corpus callosum connects the hemispheres for communication. The brain consists of four lobes: the frontal lobe (executive functions), temporal lobe (memory, language comprehension), occipital lobe (visual processing), and parietal lobe (sensory integration, spatial processing).
- 2.4: Limbic System and Other Brain Areas
- The page provides an overview of key brain structures, focusing on the limbic system, midbrain, and hindbrain. It explains the roles of the thalamus, limbic system structures like the hippocampus, amygdala, and hypothalamus, and the vital functions they manage. Cases like Henry Molaison highlight the impacts of brain surgery on memory. It also explores midbrain functions and highlights the somatosensory and motor cortex, illustrating sensory processing and response pathways.
- 2.5: Somatosensory and Motor Cortex
- The cerebral cortex maintains a sensory topography mirroring the body's receptor positions, exemplified by the somatosensory cortex, where body parts are mapped onto the cortex in a sensory homunculus. This mapping emphasizes areas with greater sensitivity, such as fingers and the face, while less sensitive areas occupy smaller cortical regions. Sensory processing begins in the primary sensory cortex and integrates into multimodal areas to create seamless perceptions.
- 2.6: Hemispheres
- The page provides an overview of the brain's structure and functions, focusing on lateralization, where certain functions are predominantly managed by one hemisphere. The brain, part of the central nervous system along with the spinal cord, is divided into two hemispheres connected by the corpus callosum. The text also discusses brain plasticity and how studying brain damage, such as strokes, contributes to understanding brain function.
- 2.7: Split-Brain Measures-severing the corpus callosum
- The page discusses neuroplasticity, neurogenesis, and brain lateralization, explaining their roles in brain function and adaptation. Neuroplasticity is the brain's ability to reorganize itself by forming new neural connections in response to learning and damage. Neurogenesis refers to the formation of new neurons, which may aid brain repair. Brain lateralization explores the specialization of the left and right hemispheres, as evidenced by split-brain studies.
- 2.8: Trauma
- The page discusses cortical responses, emphasizing how sensory stimuli are initially processed in different areas of the cerebral cortex before moving to the motor processing stages led by the frontal lobe. The prefrontal areas within the frontal lobe play a crucial role in executive functions, affecting goal-directed behavior and personality. It highlights Phineas Gage's case, whose personality seemed altered after a prefrontal cortex injury.