Neuroscience Test 11

neurulation, fetal, ventricles, nerve

Early Development:

___________

•Formation of the hollow tube that becomes the CNS

•With time, the tube folds, turns, and expands to become the ____ brain

•The hole inside the tube becomes the ________

Neurogenesis

•Generation of new _____ cells occurring in the area right around the ventricle

1.Daughter cell will become a progenitor cell.

2. Daughter cell will migrate.

glial, six,

Early Development

•______ cells provide the scaffolding or “roads” along which nerve cells can migrate to their ultimate destinations.

•By ____ months of gestation, most neurons have been produced.

migration, synapses, linear

Changes in the Brain During Childhood

•Many processes take place during development:

•Cell proliferation & ________

•Development of ________

•Myelination

•Each of these processes has its own time course.

•Development is NOT a ______ progression of growth.

connections, cortical

Synpatogensis

Dramatic increase in the number of neuronal _________ (synapses).

Dendrites in _______ regions increase greatly, providing greater surface area for synaptic connections.

blooming, frontal, overproduction, pruning

Synaptic Blooming and Pruning

•Synapse proliferation (“_______”) is followed by the elimination of synapses (“pruning”)

•The time course varies across cortical regions:

•Earliest = sensory and motor regions

•Latest = ______ cortex (not complete until late adolescence)

•Synaptic _________ allows the brain initially to have maximal capacity to respond to the environment.

•________ allows brain to be sculpted according to experience.

first, stem, integrative, decreases

Myelination

A longer process that varies by region of the nervous system

•Myelination of basic sensory and motor systems: within _____ year after birth

•Myelination of brain ____ occurs first

•Myelination of ________ systems occurs later

Result of Synaptic Pruning and Myelination

During childhood and teenage years, relative amount of white matter increases and gray matter _______

mismatch, limbic, immature, risky

Changes in the Brain During Adolescence

•Developmental “_______” between two systems in adolescence

•_______ structures maturing = creates more powerful incentives to seek exciting reward

•Prefrontal cortex is still _______ = multiple consequences related to executive function

•Likely explains ______ behaviors in adolescence (e.g., fast driving, risky substance use)

adult, emotional, accumbens

Dual-Systems Model

•Evidence supporting model:

•When no reward is involved, adolescents show _____-like logical reasoning skills

•When strong ________ incentives are present, adolescents make riskier choices

•Activity in the nucleus __________ increases in adolescents when anticipating or receiving a reward

expectant, common, language, absent

Influence of the Environment on the Developing Brain

Experience-_________ systems

•Develop in response to experiences are _______ to nearly all members of the species

•E.g., patterned light, presence of caregiver, exposure to ________

•Neural systems develop normally when the expected input is received during sensitive time periods, but are seriously affected when the expected experience is ________.

dependent, universal, juggle

Influence of the Environment on the Developing Brain

Experience-__________ systems

•Develop in response to experiences that are not _______, but vary across people based on their unique experiences

•E.g., musical training early in life, learning to ______, learning to ride a bike

control, social, increase, persist

Environmental Enrichment and Deprivation

Many studies of enrichment have been conducted in other species:

•_______ condition: rat alone in a small plastic cage

•Enriched condition: large area with varied spatial arrangement, toys, and _____ interaction with other rats.

•Enriched environments _________ the number of synapses per neuron, increase neurogenesis, and increase cortical thickness.

•Changes ________ even when the animals are later removed from the enriched setting

white, callosum, plasticity, adolescence

White Matter Development and Exercise

•Higher aerobic fitness in youth is associated with greater _____‑matter integrity (fractional anisotropy, FA) in major tracts (e.g., corpus _______, corona radiata).

Molecular Mechanisms of Exercise-Induced Plasticity

•Exercise triggers molecular and cellular _______ (e.g., BDNF, synaptogenesis, angiogenesis, myelination) which may have especially strong effects during _________ — a period of heightened brain remodeling.

problematic, environment, Bucharest

Environmental Enrichment and Deprivation

•Ethically ________ to conduct true experiments in humans

•Rarely can researchers manipulate a child’s entire ________

•Exception: _________ Early Intervention Project in Romania

little, foster, intelligence, reductions

Bucharest Early Intervention Project

•Orphaned children in state care randomly chosen to receive:

1.Continued care in state-run orphanage (_____ social or intellectual stimulation)

2.Placement with a highly trained _____ family

•Those placed in foster care before 2 yrs of age showed improvements in _________ and normalized EEG activity

•Social isolation associated with ________ in white matter.

sensitive, months, difficult, younger

Developmental Sensitive Periods

•________ period: organism is particularly sensitive to certain external stimuli during a specific developmental period

Examples of sensitive periods in development:•

•Visual system: exposure to visual input in both eyes needed in first ______ of life to develop normal binocular vision

•Language: learning a language becomes more _______ in adulthood

Accuracy on a grammar task is highest when exposure to the language occurred at ________ ages.

increased, later, slower

Brain Development in Autism

•Early in life, the overall brain volume is ___X________

Cortical thickness in autism:

•________ cortical thickness early in development

•Decreased thickness in ______ years of development

White-matter development in autism:

•Increased white matter early in development

•Then _______ rate of myelination, falling behind peers in white-matter development

inattentive, inconsistent, adaptive

Attention-Deficit/Hyperactivity Disorder (ADHD)

•Compared to the average child of the same age, a child with ADHD is either _______, hyperactive/impulsive, or both.

The DSM-5 diagnostic criteria require that:

•Symptoms must be “_________ with developmental level”

•Child must have a clinically significant impairment that interferes with _______ functioning in more than one setting

norepinephrine, inhibitory, delay aversion

ADHD Hypotheses

Different hypotheses about the core deficit in ADHD:

1.Arousal mechanisms dependent on __________ are disrupted, thus difficulty sustaining attention over long periods of time

2.Core deficit in _______ control

3.Deficit in motivational processes, such as _____ _______

dopamine, basalg ganglia, dopaminergic

ADHD and Dopamine

•_________ system is strongly implicated.

•Dopaminergic cells project both to the ______ ______ and prefrontal cortex, regions whose activity is altered in ADHD.

•Drugs used to treat ADHD influence the dopamine system

•Genes implicated in ADHD are generally genes that influence __________ neurotransmission

stimulant, reuptake, high, behavioral

Treatment of ADHD
•_______ drugs, such as Methylphenidate (Ritalin), influence the dopamine system by slowing the rate of _________

Treatment with methylphenidate affects network patterns:

•Incraeases activity in “_____ attention network” and decreases activity in “low attention network”

•Ideally, individuals with ADHD would also be given _________ modification strategies.

representation, loss, somatosensory, reorganize

Brain Plasticity in Adulthood

•Changes in experience in adulthood can lead to changes in the ___________ of information in the brain.

•______ of input of a certain kind can cause representations to wither away

•E.g., in the case of an amputation, the map in __________ cortex is reorganized; territory previously corresponding to lost part is now responsive to a neighboring part of the body.

The somatosensory cortex can ________ after amputation.

continual, changes, phantom, new

Reorganization of Function

“Maps” in sensory cortex are maintained only through ________ sensory input

•When input changes systematically, the map _______

Example: _________ sensations in people who lost a limb

•Some amputees continue to perceive sensations that can be distracting and painful

•Phantom limb sensations may occur when cells used to code for the lost limb are now being stimulated by _____ input from a different body location

cross, rededicated, Braille, non-visual

______-Modal Plasticity

•Cortex normally dedicated for one purpose can be _________ to an entirely different purpose.

Example: “visual” cortex in people blind from birth

•No visual input – but is activated by _______ reading, other tactile stimulation, and some auditory and verbal tasks

•Indicates that the “visual” cortex can reorganize to respond to ________ information in congenitally blind people

necrosis, transneuronal, edema, fluid

Dysfunction Following Brain Injury

•________: cells begin to die at site of lesion

•____________ degeneration: cell loss can extend to more distal neurons

•_______: swelling which increases pressure within skull (can be life threatening)

•Dead cells broken down, _____ fills the spaces where cells had been

neurogenesis, angiogenesis, axonal

Cellular-level Changes that Aid Recovery

•Generation of new cells: _________ and Gliogenesis

•_____________: new blood vessels grow and reestablish blood supply

•_______ sprouting connecting regions that had not previously been connected

-New synapses form

surrounding, large, parallel,

Recovery of Function

Damage to a discrete region of brain tissue affects:

•Cells in that immediate area, ___________ tissue, and more distant brain tissue

•When the damaged area within the primary motor cortex is relatively ______, there may not be enough intact tissue in that hemisphere to support recovery of function. In such a case, function may be partly taken over by the _______ region of the opposite hemisphere

premotor, varies, original, compensation

Recovery of Function

Damage to primary motor cortex (M1) affects primary somatosensory cortex (S1) and _______ cortex (PM), as well as connecting pathways.

Variables Impacting Recovery of Function

•Degree of recovery from traumatic brain damage ______ from person to person.

'

Recovery vs. Compensation

•True recovery: the _______ function is restored

•____________: the person learns a work-around, to do task in a new way

motor, repeated, stimulaiton, contralateral

Interventions to Promote Recovery

•Specific training programs

•e.g., physical therapy for ______ difficulties following stroke

•e.g., emphasis on _______ use of limb, or speech

•_________ methods (e.g., TMS, tDCS)

•e.g., stimulate damaged hemisphere

•e.g., inhibit _________ hemisphere to reduce competition

earlier, left, aphasia, spatial

Recovery of Function and the Kennard Principle

•The idea that the ________ in life damage is sustained, the better the recovery.

Damage to young brain does still have consequences:

•Early _____-hemisphere damage: No _______, but still deficits in phonology, syntax, and linguistic semantics

•Early right-hemisphere damage: Difficulties in ______ cognition, analogous to those of right-hemisphere-damaged adult.

complex, crowding, damaged

Crowding Hypothesis

•Children that sustain damage earlier in life typically have ___X____ outcomes for recovery

•However, deficits may emerge later as the child is expected to demonstrate more _______ skills

•________ hypothesis: intact areas of the child’s brain are now expected to carry out the functions that they would normally implement, as well as the functions that the ______ area would normally have implemented

general, increases, regulation, temporal

Cognitive Changes with Aging

•“_______ decline” viewpoint: all abilities decline with age

•Results of a general reduction in mental resources or a general slowing in processing speed

•Reality: some aspects decline more with age than others:

•Novel problem solving declines; accumulated knowledge _________

•Emotion _________ improves

•Cognitive functions within frontal and _______ regions show greater decline with age.

increased, prefrontal, harder

Age-Related Changes in Functional Activity

•In some cases, older adults show ________ brain activation compared to younger adults

•Especially in regions that are most affected by aging, such as ________ cortex

•These regions may be inefficient: “working _______” because they are working poorly, leading to increased activation

localization, compensate, taxed

Dedifferentiation

•Idea that _________ of function becomes less defined with age

•Attempt to recruit more brain regions to _________ for lost functionality

•Similar pattern seen in younger adults when cognitive resources are very _______

blood, oxygen mentally, dendritic

Slowing the Effects of Aging

1.Aerobic exercise

•Has multiple benefits

•Produces a greater proliferation of _____ vessels to the brain, resulting in enhanced _____ supply

 

2.Remaining intellectually active

•________ stimulating environment produces an elaboration of ________ trees, allowing more numerous and varied synaptic connections.