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Definition
“Decade of the Brain:” stimulated brain research of the 1990s under then-President George H. Bush
Improved knowledge of how the brain works provides unprecedented promise for helping us improve treatments for a variety of neurological conditions |
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Term
| What are Neuroanatomy and Nuerophysiology? |
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Definition
Neuroscience: branch of science that focuses on the anatomy and physiology of the nervous system
Neuroanatomy: anatomy of the nervous system
Neurophysiology: physiology of the nervous system
Human nervous system = central nervous system + peripheral nervous system |
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| What are Neuroanatomy and Nuerophysiology?, cont |
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Definition
Central nervous system: brain and spinal cord
Peripheral nervous system: cranial and spinal nerves that carry information inward to and outward from the brain and spinal cord
Neuroscientists study:
Anatomical structures of the nervous system
How the structures work together as a complex unit and as separate, distinct biological units |
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| What are Neuroanatomy and Nuerophysiology?, cont |
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Definition
Neuroscience: focused branch of the more general disciplines of anatomy and physiology.
Anatomists: physical characteristics of bodily structures; how they relate to other structures to form anatomical systems.
Physiologists: way in which bodily structures function, both by themselves and in concert with other structures to form physiological systems
Hippocrates: “father of medicine” |
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| What are Neuroanatomy and Nuerophysiology?, cont |
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Definition
Neurolinguists: structures and functions of the nervous system that related to language
Linguistics: language as a developmental and ecological phenomenon
Psycholinguistics: cognitive processes involved with developing, processing, and producing human language. |
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Term
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Definition
Human nervous system organized along 2 axes
Horizontal axis
Vertical axis
Comprise the T-shaped neuraxis
Horizontal axis: anterior (frontal) pole of brain to the posterior (occipital) pole of the brain
Vertical axis: superior portion of the brain downward along the entire spinal cord
Horizontal axis:
Rostral = front of the brain
Caudal = back of the brain
Dorsal = top of the brain
Ventral = bottom of the brain
Vertical axis:
Rostral = top of the spinal cord (near the brain)
Caudal = bottom of the spinal cord (near the coccyx)
Dorsal = back of the spinal cord (backside)
Ventral = front of the spinal cord (bellyside)
(Bhatnagar & Andy, 1995) |
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| Directional and Positional Terms |
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Definition
Proximal: relatively close to a site of reference
Distal: relatively far from a site of reference
Anterior: toward the front
Posterior: toward the back
Superior: toward the top
Inferior: toward the bottom
External: toward the outside
Internal: toward the inside |
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| Directional and Positional Terms, cont |
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Definition
Efferent: away from the brain
Afferent: toward the brain (Zemlin, 1988)
Efferent pathways (descending pathways): carry motor impulses from the central nervous system to more distal structures of the body
Afferent pathways (ascending pathways): carry sensory information from the distal structures of the body to the brain |
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Term
| Research Paradigms: fMRI studies |
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Definition
Functional magnetic resonance imaging (FMRI): brain imaging used to identify brain structures involved with specific mental functions
Examines changes in blood oxygen levels that correspond to changes in neural activity
Different from magnetic resonance imaging (MRI): examines brain activity when individuals are engaged in a specific processing task
Requires no injections of radioactive materials
Images can be collected relatively quickly
Resultant images are of very high resolution
Weismer and colleagues study, 2005 |
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Term
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Definition
Human nervous system:
Complex anatomical and physiological structure that includes the brain, spinal cord, and sets of nerves that carry information to and from the brain and spinal cord.
Mediates nearly all aspects of human behavior with few exceptions |
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Term
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Definition
Neurons: billions of highly specialized cells that make up the nervous system
Carry electrical-chemical nerve impulses
4 components:
Cell body: center of the neuron, containing its nucleus
Axon: single efferent nerve extension which carries nerve impulses away from the cell body
Presynaptic terminal: distal end of each terminal branch; sites at which the axonal connection of one neuron corresponds with the dendritic extension of another neuron.
Dendrites: afferent extensions of a neuron; bring nerve impulses into the cell body from the axonal projections of other neurons
Spines: increase the surface area of the neuron’s afferent connections
Synapse: site where two neurons meet
Nerve impulse must cross the synapse in order to communicate
Neurotransmitters: chemical agents that help transmit information across the synaptic cleft
Synaptic cleft: space between the axon of the transmitting neuron and the dendrite of the receiving neuron
Nervous tissue: formed by the linkages of thousands of neurons
Grey matter: cell bodies of neurons and the dendrites; where information is generated and processed
White matter: carries information among grey matter
Myelin: neuron coating
Rapid relay of nerve impulses, particularly within white matter; protects the neuron
Myelinization: growth of the myelin sheath; slow process not complete until late in childhood |
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Term
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Definition
Central nervous system (CNS)
Brain and spinal cord
Peripheral nervous system (PNS)
Nerves that emerge from the brain and the spinal cord to innervate the rest of the body
Innervate: supply of nerves to a particular region or part of the body
Cranial nerves: emerge from brain; 12 pairs
Spinal nerves: emerge from spinal cord; 31 pairs
Cranial and spinal nerves carry information back and forth between brain, spine, and rest of body
Sensory information carried to the brain via afferent pathwaysa
Motor information carried away from brain via efferent pathways |
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Term
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Definition
Brain: chief operator of the entire CNS
Spinal cord: conduit of information
Protective shields:
Bone: skull covers the brain and vertebral column covers the spinal cord
Layered membranes: menignes, 3 layers:
Pia matter: inside layer, carries blood vessels that serve the brain
Arachnoid matter: second layer
Dura matter: 3rd and outermost layer, encases brain and spinal cord
Cerebrospinal fluid (CSF): circulates between innermost two layers of meninges; carries chemicals important to metabolic processes and serves as important buffer for any jolts to CNS. |
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Term
| Peripheral Nervous System |
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Definition
System of nerves connected to brainstem and spinal cord
Carries sensory information to the CNS and motor commands away from the CNS
Controls nearly all voluntary and involuntary activity of the human body
12 pairs of cranial nerves:
Important for speech, language, and hearing
Transmit information concerning 4 of 5 senses to the brain (vision, hearing, smell, taste)
Carry motor impulses from the brain to the muscles of the face and neck, including those activating the tongue and jaw (involved with speech)
7 cranial nerves most closely involved in speech and language production include:
Trigeminal (V)
Facial (VII)
Acoustic (VIII)
Glossopharyngeal (IX)
Vagus (X)
Accessory (XI)
Hypoglossal (XII)
31 pairs of spinal nerves:
Mediate reflexes and volitional sensory and motor activity |
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Term
| What are the Major Structures of the Brain? |
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Definition
Growth of the human brain in both size and weight represents one of the most significant evolutionary changes in the anatomy of the human species
Proportionally, the relative size of the human brain and its sheer demand for energy (1/5 of the body’s metabolic resources) far exceeds that of any other mammal (Lieberman, 1991)
Enlargement of the outer layers of the brain
Neocortex: enlarged regions which have grown over the original human brain
Controls most of the functions we consider to exemplify human thought and language
3 major sections
Cerebrum
Brain stem
Cerebellum |
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Term
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Definition
Cerebrum, or cerebral cortex: crucial roles in “language, conceptual thinking, creativity, planning, and the ways in which we give form and substance to our thoughts” (Noback et al., 2005, p. 439)
40% of the brain’s weight and contains over 100 billion neurons
Allocortex: original and older human brain (10% of brain matter)
Neocortex: newly-evolved outer structures (90% of brain matter)
Two mirror-image hemispheres
Right hemisphere
Left hemisphere
Longitudinal fissure: long cerebral crevice separating two hemispheres
Corpus collosum: band of fibers that connects two hemispheres, serving as a conduit for communication between the hemispheres |
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Term
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Definition
6 lobes of 4 types
1 frontal lobe
1 occipital lobe
2 temporal lobes
2 parietal lobes |
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Definition
Largest lobe of the human brain
Most anterior part of the brain, behind the forehead
2 key functions:
Activating and controlling fine and complex motor activities, including speech output
Controlling human “executive functions”
Executive functions: problem-solving, planning, creating, reasoning, decision-making, social awareness, and rationalizing
Prefrontal cortex: most anterior portion of the frontal lobe
Affective aspects of sensations, including gloom, elation, calmness, and friendliness
“Regulator of the depth of feeling” (Noback, et al., 2005, p. 452)
Primary motor cortex: controls the initiation of skilled, delicate, voluntary movements, including movements of the extremities and those used in speech
Premotor cortex: control of skilled motor functions, including control of musculature and programming patterns and sequences of movements
Organized topographically: specific motor functions correspond to specific sites in the cortices
Homunculus: map that illustrates the location of specific human functions
“Motor strip:” motor functions organized along a strip
Contralateral: right premotor cortex controls the left side of the body, and vice versa
Broca’s Area: motor cortex of the left frontal lobe
Responsible for the fine coordination of speech output
Named after French physician Paul Broca |
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Term
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Definition
One lobe
Posterior portion of the brain
Visual reception and processing
Primary visual cortex: posterior pole of the occipital lobe
Receives and processes visual information received from the eyes, fusing information on depth, space, shape, movement, and color into a single visual image |
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Term
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Definition
Two lobes
Sit posterior to the frontal lobe on the left and right sides (above the ears)
Key functions:
Perceiving and integrating sensory and perceptual information
Comprehending oral and written language and calculation for mathematics
Primary somatosensory cortex (primary sensory cortex): “sensory strip”
Sensory association cortex
Inferior part of the left parietal lobe’s sensory system tied to language ability, especially reading and naming abilities (Bhatnagar & Andy, 1995)
Important to working memory: essential for most higher-order executive functions and or acquiring and accessing one’s lexicon |
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Term
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Definition
Two lobes
Sit posterior to the frontal lobe but inferior to the parietal lobes (behind the ears)
Contain functions for processing auditory information as well as language comprehension
Heschl’s gyrus: small region of the left temporal lob that appears specialized for the processing of speech, particularly the temporal aspects of speech
Wernicke’s area (receptive speech area): language comprehension
Sits in the superior portion of the left temporal lobe near the intersection of the parietal, occipital, and temporal lobes
Point of convergence for receiving and integrating associations from throughout the brain
Wernicke’s aphasia: damage to Wernicke’s area; significant challenges in processing and producing coherent language in both spoken and written form |
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Term
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Definition
Sits directly on top of the spinal cord
Conduit between brain and spinal cord
Consists of midbrain, pons, medulla oblongata
3 primary functions:
Key transmitter of sensory information to the brain and motor information away from the brain
Major relay station for the cranial nerves supplying the head and face and for controlling the visual and auditory senses
Associated with metabolism and arousal
3 major reflex centers:
Cadiac center (heart)
Vasometer center (blood vessels)
Respiratory center (breathing) |
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Term
| Multicultural Focus: International Adoption and Neurophysiological Sensitive Periods |
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Definition
Foreign-birth adoption: a child is adopted from overseas, often from an institutionalized setting
Experience-expectant plasticity for acquiring language during the sensitive period, even when it has a late start |
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Term
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Definition
Oval-shaped “little brain”
Sits posterior to the brainstem
Regulates motor and muscular activity
Coordination of motor movements
Maintenance of muscle tone
Monitoring of movement range and strength
Maintenance of posture and equilibrium |
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Term
| How Does the Human Brain Process and Produce Language? |
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Definition
Connectionist models
Network of distributed processors that interact with one another via excitatory and inhibitory connections (McClelland, Rumelhart, & Hinton, 1986)
Connectivity among units critical for understanding how information is processed |
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Term
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Definition
Knowledge of words; internal lexicon
Lexical knowledge is distributed across the brain
Semantic knowledge is a distributed modality
Distributed neural networks transcending the frontal and temporal lobes
Frontal lobe: executive elements of word knowledge
Temporal lobe: storage and organization of semantic memories and categories (Bookheimer, 2002; Frackowiak et al., 2004)
s
Semantic knowledge is left lateralized
Consistently activates regions of the left hemisphere, particularly left inferior portions of the frontal lobe and regions across the entire left temporal lobe
Some aspects of semantic knowledge involve right-hemisphere processing
Processing of figurative and abstract language
Processing involved more holistic interpretation of meaning, rather than one-to-one mappings of words to meanings |
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Term
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Definition
“Language instinct” (Pinker, 1994) and “language acquisition device” (Chomsky, 1978):
Rapidly and automatically process the rules of syntax and morphology (morphosyntax)
Genetically-based adaptation of the human brain to process the universal grammar of language
Innate, species-specific ability to represent the discrete rule-governed syntactic rules of universal grammar
Possibility of a distinct morphosyntactic brain module
Language-learning in non-human primates
Specific impairments in morphosyntax as a function of focal brain damage
Increased activation of the language areas of the left hemisphere: Wernicke’s area, Broca’s area, parietal lobes
Complex cognitive ability served by a variety of separate and specialized cortical areas transcending the right and left hemispheres |
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Term
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Definition
Phonetic module: human brain as a specialized processor designed specifically for phonetic segments of speech (Mattingly & Lieberman, 1988)
Rapid analysis of temporal characteristics of speech sounds occurs in the auditory centers of the left temporal lobes
Processing of spectral characteristics of speech sounds occurs in the right temporal lobe
Brain research failure to identify a single structure or location in the brain that is specialized only for the processing of speech |
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Term
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Definition
Use of language as a social tool; understanding the rules of communication
Draws primarily upon functions of the frontal lobe
Organized, goal-directed, and controlled use of language as a means for communication with others
Willful attention: maintain attention to a given task even when competing stimuli are present (Frackowiak et al., 2004)
Parietal lobe processes incoming stimuli; frontal lobe forces attention to particular stimulus selected for attention (Frackowiak et al., 2004) |
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| Theory to Practice: Differential Diagnosis of Language Disorders Using Neurophysiological Models of Language Processing |
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Definition
Theoretical models of language disorders: specific weakness in verbal working memory, specifically processing capacity
Active engagement of working memory
Differential diagnosis: differentiating a suspected disorder from all other possible disorders |
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Term
| What is a Sensitive Period? |
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Definition
Sensitive period: timeframe of development corresponding to growth or change in a particular aspect of neuroanatomy or neurophysiology that underlies a given sensory or motoric capacity
Studies of pregnant women in Nagasaki and Hiroshima in WWII
Correspond to a period of active neuroanatomical and neurophysiological change
Change is possible beyond the period of sensitivity (Bruer, 2001)
Sensitive periods represent a phase of not only opportunity, but also of risk
Sensitive periods have a beginning and an endpoint, and the length of this period varies for different aspects of neuroanatomy and neurophysiology |
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Term
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Definition
Synaptogenesis: the formation of synaptic connections
Driven by our sensory and motoric experiences after birth; occurs most rapidly in the first year of life (Huttonlocher, 2002)
Synaptic pruning: pruning of excess synapses
Neural plasticity: malleability of the central nervous system
Capacity for the sensory and motor systems to organize and reorganize themselves by generating new synaptic connections, or by using existing synapses for alternative means
Experience-expectant plasticity: changes in brain structures that occur due to normal experiences
Develops “obligatory cortical functions” (Huttonlocher, 2002, p. 176) that organize basic sensory-motor neural systems
Once the sensitive period for a given experience-expectant brain function has passed, environmental experiences no longer readily modify cortical circuits |
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Term
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Definition
Experience-dependent plasticity: unique to a given individual; requires highly-specific types of experiences for change
Utilizes 3 mechanisms:
Formation of new synaptic connections among neurons (dendritic sprouting)
Generation of new neurons
Increase in synaptic strength (Huttonlocher, 2002)
Brain capacity available independent of age
Vocabulary growth
Hart and Risley (1995) |
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Term
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Definition
Occurs when a child develops with little or no exposure to spoken or signed language
“Feral children:” children deprived of language exposure due to abuse and neglect
Provide support for a sensitive period of language acquisition |
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Term
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Definition
Johnson and Newport (1989): English abilities of Asian immigrants to the U.S. whose exposure to English occurred sometime between 3 and 39 years of age
English abilities negatively associated with age of English learning
Better English skills associated with earlier exposure
Hakuta (2002): failure to identify a specified end point for the sensitive period of language acquisition |
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Term
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Definition
Inability of researchers to identify a putative endpoint to the sensitive period of language acquisition
Reflects the experience-dependent capabilities of the human brain to adapt and modify itself in response to the environment |
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