Chapter 3 book Flashcards
Neuroscience
is a branch of science that focuses on the anatomy and physiol-ogy of the nervous system, or the neuroanatomy and neurophysiology, respec-tively.
human nervous system includes
central nervous system and the peripheral nervous system
central nervous system
(CNS, comprising the brain and the spinal cord)
the peripheral nervous system
(PNS, comprising the cranial and spinal nerves, which carry information inward to and outward from the brain and spinal cord).
Developmental neuroscience
Branch of neuroscience focused on identifying how the structures and functions of the nervous system develop and change with time as a function of aging and experience.
Cognitive neuroscience
Branch of neuroscience focused on identifying how the brain structures and functions support higher-level cognitive functions, such as memory, reasoning, problem solving, and language processing.
Neurology
Branch of medicine focused on the nervous system. Neurologists diagnose and treat diseases that disrupt the normal functioning of the nervous system.
Neurosurgery
Branch of surgery focused on the nervous system. Neurosurgeons conduct surgery to prevent and correct diseases of the nervous system, including diseases of the brain and spinal column.
Neuroanatomy
Branch of neuroscience focused on the structures of the nervous system. Neuroanatomists study the architecture of the central and peripheral nervous systems, including the brain, to determine how their individual components work as single units and together as parts of a complex system.
Neurophysiology
Branch of neuroscience focused on the functions of the nervous system structures. Neurophysiologists study how the various units of the nervous system work both as single units and together as parts of larger systems.
Neuropathology
Branch of neuroscience and of medicine focused on identifying diseases of the nervous system, including their causes. Clinical neuropathologists are trained medical doctors who study tissues of the nervous system to identify whether a disease is present.
Neurolinguistics
Branch of neuroscience focused specifically on human language, with a particular interest in understanding how the brain develops and processes spoken, written, and signed language.
MRI, PET, CT and MEG
magnetic resonance imaging (MRI), positron emission to-mography (PET), computerized tomography (CT) scanning, and magnetoencepha-lography (MEG) provide detailed images of the anatomy and/or physiology of the nervous system.
Neuroscience has several subdisciplines, (8)
developmental neuro-science, cognitive neuroscience, neurology, neurosurgery, neuroanatomy, neu-rophysiology, neuropathology, and neurolinguistics.
neurolinguists
who study the structures and functions of the nervous system that relate to language.
Functional magnetic resonance imaging (fMRI)
(fMRI) is a type of brain imaging that allows researchers and cli-nicians to identify the brain structures involved in spe-cific mental functions.
- fMRI is a noninvasive procedure that maps neural activities (i.e., functions) to specific neural regions (i.e., structures) according to changes in blood oxygen levels that correspond to changes in neural activity
horizontal axis
The horizontal axis runs from the anterior (frontal) pole of the brain to the posterior (occipital) pole.
vertical axis
extends from the superior portion of the brain downward along the entire spinal cord.
rostral
refers to the front of the brain,
caudal
refers to the back of the brain.
Dorsal
refers to the top of the brain,
ventral
refers to the bottom of the brain.
On the vertical axis, rostral
refers to the top of the spinal cord (near the brain),
On the vertical axis,caudal
refers to the bottom of the spinal cord (near the coccyx, or tailbone).
On the vertical axis, dorsal
refers to the back of the spinal cord (the side nearest the back),
On the vertical axis,ventral
refers to the front of the spinal cord (the side nearest the belly).
Proximal
re-fers to structures relatively close to a site of reference,
distal
refers to structures relatively far from a site of reference.
anterior
woard the front
posterior
towards the back
superior
towards thetop
inferior
toward bottom
external
toward the outside
internal
toward the inside
efferent
away from brain
afferent
toward brain
Efferent pathways
(also called descending pathways) move away from the brain, carrying motor impulses from the central nervous system to more distal body structures.
Afferent pathways
(also called ascending pathways) move toward the brain, carrying sensory information from the distal body structures to the brain.
neurons
The billions of highly specialized cells that compose the nervous system
neuron is functionally divided into four components:
cell body, axon, presynaptic terminal, and dendrites.
cell body
the center of the neuron, containing its nucleus; the nucleus contains DNA material (genes, chromosomes) and proteins. The human brain uses an estimated 30,000–40,000 genes
The axon and the dendrites are
extensions from the cell body, serving as vehicles for the cell body to receive and transmit information from other neurons,
information carried by neurons is in the form
of electrochemi-cal nerve impulses; these impulses transmit information to and away from the cell body.
the axon,
single efferent nerve extension, the axon, which carries nerve impulses away from the cell body. The axon extends from the cell body for a distance of 1 mm to 1 m, at which point it arborizes into a number of terminal branches
presyn-aptic terminal
The distal end of each terminal branch
Dendrites
the afferent extensions of a neuron, meaning they bring nerve impulses into the cell body from the axonal projections of other neurons.
synapse
is the site where two neurons meet. For the two neurons to communicate, the nerve impulse must cross the synapse.
Neu-rotransmitters
are chemical agents that help transmit information across the synap-tic cleft,
synap-tic cleft
which is the space between the axon of the transmitting neuron and the dendrite of the receiving neuron.
synaptogenesis
When a synapse is created, that is, when one neu-ron forges a connection with another neuron,
Gray matter
consists of the cell bodies of neurons and the dendrites.
- gray matter is where information is generated and processed,
White matter
is the tissue that carries information among gray matter, consisting primarily of ax-onal fibers that carry information among gray matter tissues.
- white matter serves as an information conduit.
myelin
Neurons are sheathed in a coating
- to the rapid relay of nerve impulses, particularly within white matter. This sheath also helps protect the neuron.
Myelinization
refers to the growth of the myelin sheath, a slow process that is not complete until late childhood.
Innervate
is the term in neuroscience that means “to sup-ply nerves” to a particular region or part of the body
cranial nerves
The 12 pairs of nerves that emerge from the brain
spinal nerves
The 31 pairs of nerves that emerge from the spinal cord
The brain is essentially the chief executive operator of the entire CNS:
It initiates and regulates virtually all motor, sensory, and cognitive processes.
The spinal cord acts primarily as a conduit of
information, carrying not only sensory information from the body to the brain through afferent pathways, but also motor commands from the brain to the rest of the body through efferent pathways.
CNS protective shields
- Bone: skull and Werebral column
- layered membranes: Meninges ( 3 layers)
- Cerebrospinal fluid (CSF)
pia mater
1st
tightly wraps around the brain and spinal cord and carries the blood vessels
- transparent shield that gives the brain its bright pink color
arachnoid mater,
2nd layer
- a delicate membrane separated from the pia mater by the subarachnoid space
dura mater
3td and outermost layer
- consists of thick, fibrous tissue that com-pletely encases the brain and the spinal cord.
CSF
carries chemicals important to metabolic processes, but it is also an important buffer against jolts to the CNS.
spinal tap
Also called a lumbar punc-ture, a spinal tap involves inserting a needle between two of the lower (lumbar) vertebrae and extracting CSF from the subarachnoid space.
- used to diagnose meningitis
Peripheral Nervous System
The PNS is the system of nerves connected to the brainstem and the spinal cord. These nerves carry sensory information to the CNS and motor commands away from the CNS, thus controlling nearly all voluntary and involuntary activity of the human body.
- PNS consists of two sets of nerves: cranial nerves and spinal nerves.
The cranial nerves
transmit information concerning four of the five senses (vision, hearing, smell, and taste) to the brain.
- also carry motor impulses from the brain to the face and neck muscles, including those activating the tongue and the jaw
The seven cranial nerves most closely involved with speech and language production are :
Trigeminal (V) Facial (VII) Glossopharyngeal (IX Vagus (X) Accessory (XI) Hypoglossal (XII):
Trigeminal (V):
Facial sensation; jaw movements, including chewing
Facial (VII):
Taste sensation; facial movements, including smiling
Acoustic (VIII):
Hearing and balance
Glossopharyngeal (IX):
Tongue sensation; palatal and pharyngeal movement, including gagging
Vagus (X):
Taste sensation; palatal, pharyngeal, and laryngeal movement, in-cluding voicing
Accessory (XI):
Palatal, pharyngeal, laryngeal, head, and shoulder movement
Hypoglossal (XII):
Tongue movement
The 31 pairs of spinal nerves
These nerves mediate re-flexes, sensory activity, and conscious (volitional) motor activity
contralateral
ms, damage to the left side of the brain will affect the functioning of the right side of the body.
neocortex
meaning “new cortex”
- is the enlargement of the outer layers of the brain.
The brain includes three major sections:
the cerebrum, the brainstem, and the cerebellum
cerebrum, or cerebral cortex
- the cerebrum is the largest, comprising 40% of the weight of the brain and containing more than 100 billion neurons
- reasoning, problem solving, planning, and hypothesizing,
longitudinal fissure
The two hemispheres are separated by a long cerebral crevice (or fissure)
corpus callosum
is a band of fibers that connects the two hemispheres, serving as a conduit for com-munication between them.
cerebrum is organized into six lobes of four types:
one frontal lobe, one oc-cipital lobe, two temporal lobes, and two parietal lobes.
Frontal lobe
- largest lobe of the human brain; it resides in the most anterior part of the brain, behind the forehead.
- activating and controlling both fine and complex motor ac-tivities, including speech output,
- controlling human “executive functions.
- theory of mind (ToM).
Executive functions sometimes called higher-order cognitive abilities.
functions because they govern the organized, goal-directed, and controlled execution of critical human behaviors.
ToM
is one’s ability to attribute mental states to others, which is neces-sary to take the perspective of another
- the understanding that other people have thoughts and feelings of their own, and it appears to be a human-specific attribute.
prefrontal cortex
-is the most anterior portion of the frontal lobe.
- It is the part of the brain that evolved most recently in the human species and is most developed rela-tive to that of other species
- serves as a “regulator of the depth of feeling”
-
the primary motor cortex and the premotor cortex
- frontal lobe
- ## both important for human speech, as well as other motor functions.
the primary motor cortex
The pri-mary motor cortex controls the initiation of skilled, delicate voluntary movements, including not only movements of the extremities (e.g., fingers, hands, toes), but also movements used in speech.
The premotor cortex
also involved with con-trol of skilled motor functions, including control of musculature and programming patterns and sequences of movements
homunculus (motor strip.)
- frontal lobe
- shows the loca-tion of various motor functions in the motor cortex.
Broca’s area
left frontal lobe
- important region of the brain for spoken communication.
Occipital Lobe.
posterior portion of the brain.
- specialized for visual reception and processing.
- primary visual cortex: receives and processes visual information
Parietal lobes
- posterior to the frontal lobe on the left and right sides (above the ears).
- perceiving and integrating sensory and perceptual information, comprehending oral and written language, and performing mathematical calculations.
- contain primary somatosensory cortex and sensory association cortex
- especially important to working memory,
primary somatosensory cortex
It receives and processes sensory experiences of pain, temperature, touch, pressure, and movement from receptors throughout the body
inferior part of the sensory system of the left parietal lobe
is tied to lan-guage ability, particularly reading and naming abilities, as well as mathematic ability
temporal lobes
-sit posterior to the frontal lobe but inferior to the parietal lobes (behind the ears).
-they contain the functions for process-ing auditory information and language comprehension.
-
Heschl’s gyrus
specialized for processing speech, particularly its temporal (time) aspects.
word deafness
- Bilateral damage to both the right and the left audi-tory cortices can result
- has intact process-ing of nonword auditory stimuli, but cannot understand spoken words.
Wernicke’s area
- left temporal lobe
- receptive speech area
- located in the superior portion of the left temporal lobe
- Wernicke’s area is damaged by stroke or other brain injury, individuals typi-cally exhibit significant difficulty with processing and producing coherent language in both spoken and written form. Wernickes aphasia or “jargon aphasia”
brainstem
sits directly on top of the spinal cord and serves as a conduit between the rest of the brain and the spinal cord.
brainstem three primary functions
- key transmitter of sensory information to the brain and of motor information away from the brain.
- a major relay station for the cranial nerves supplying the head and face, and for controlling the visual and auditory senses.
- metabolism and arousal.
Three major reflex centers are located in the brainstem:
the cardiac center, which controls the heart; the vasomotor center, which controls the blood vessels; and the respiratory center, which controls breathing.
cerebellum
oval-shaped “little brain” that resides posterior to the brain-stem.
- responsible for regulating motor and muscular ac-tivity,coordinating motor movements, maintaining muscle tone, monitoring movement range and strength, and maintaining posture and equilibrium.
connectionist models
attempt to represent the com-putational architecture of the brain as it processes various types of information, particularly that which is specific to higher-order human cognition
many basic language processes (e.g., word retrieval) are distributed throughout the
sensory and motor cortices of the brain and are not confined to a single structure
Semantics
- involves an individual’s knowledge of words, or internal lexicon.
Semantic knowledge is left-lateralized
Semantic processing consistently activates left-hemisphere regions, particularly left inferior portions of the frontal lobe and regions across the entire left temporal lobe.
semantics knowledge is distributed modality:
Word storage involves dis-tributed neural networks transcending the frontal and temporal lobes, with some activation in the parietal lobes.
Some aspects of semantic knowledge involve right-hemisphere processing.
the right hemisphere also contributes to semantic processing, particularly the processing of figurative and abstract language.
- Wernicke’s area remain an important locus for word storage
Syntax and morphology
- complex interconnections of the parietal, temporal, and frontal lobes
phonology
- the capacity of the human brain to process sequences of non-speech sounds is fairly limited (about 7–9 units/second), speech processing occurs at much higher rates (50–60 units/second
- both hemi-spheres seem to be involved in speech–sound processing, although the auditory re-gions of the left temporal lobe appear to be critical locations for phonetic analyses of speech sounds
phonetic module
designed specifically for processing the phonetic segments of speech
phonological processing
- which occurs in Broca’s area,
- it involves analyzing phonological seg-ments and working memory.
- brocas and heschls gyrus work with it too
pragmatics
- using language as a social tool
- the quantity, quality, manner, and relevance of language during com-munication.
- pragmatic ability draws primarily on frontal lobe functions.
sensitive period
is a time frame of development during which a particular aspect of neuroanatomy or neu-rophysiology underlying a given sensory or motoric capacity undergoes growth or change.
sensitive period have 3 features
- Sensitive periods correspond to a time of active neuroanatomical and neuro-physiological change.
- Sensitive periods are a phase not only of opportunity but also of risk.
- Sensitive periods have a beginning and an end point, and the length of a period varies for different aspects of neuroanatomy and neurophysiology
12 years for the development of grammar
synaptic pruning
At about the end of the first year, the infant’s brain contains approximately twice as many synaptic connections as an adult’s; from this time to adolescence, excess synapses are pruned,
Neural plasticity
is a term pertaining to the malleability of the CNS, and it re-lates primarily to the capacity of 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
- refers to the ongoing sculpting of brain structures that occur as a result of normal experiences.
- uses the basic hardware that is provided to sculpt the brain as experiences amass.
- develops “obligatory cortical functions” that organize basic sensorimotor neural systems, such as vision, hearing, and language.
- Acquisition of language grammar occurs as a function of experience- expectant plasticity
experience-dependent plas-ticity
- is unique to a given individual; this type of functional brain modification requires highly specific types of experiences for change.
- brain capacity available independent of age because, through time, the human brain retains most of its capacity to learn through experience and to adapt to change.
Learning new information requires three mechanisms:
the formation of new synaptic connections among neurons (dendritic sprouting), the generation of new neurons, and an increase in synaptic strength
Linguistic isolation
occurs when a child develops with little or no exposure to a spoken or sign language.
feral children
children depried of language exposure as a result of abuse and neglect
sensitive period for language acuisition
Such evidence points to the period of birth through early adolescence as a sensitive period for language acquisition. Although language skills can be acquired after this period, many individuals are unlikely to acquire nativelike fluency.
2nd language learners
- accents seemed to be gover by a sensitive period
- did not affect syntax
