Term
| 5 stages of neurodevelopment in fetus? |
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Definition
Induction of neural plate
Neural proliferation
Cellular migration & aggregation
Axon grown & synapse formation
Neuronal death & synapse rearrangement |
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Term
| When does neural plate differentiate? |
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Definition
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Term
| Which germ cell layer does the neural plate differentiate from? What is the organizer layer? |
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Definition
ECTODERM = layer it develops from
MESODERM = organizer layer; sends out chemical signals to induce change |
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Term
| Difference between totipotent & multipotent? |
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Definition
Totipotent - before neural plate induction; can be ANY cell in body
Multipotent - after neural plate induction; can be either neural or glial cells |
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Term
| 2 criteria necessary to be called stem cells? |
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Definition
Unlimited self renewal
Able to develop into different types of mature cells |
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Term
| Hollow inside of the neural tube eventually becomes.... |
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Definition
| The central canal of the SC which is continuous with the cerebral vencticles |
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Term
| When do the forebrain, midbrain, and hindbrain emerge as swellings from the neural tube? |
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Definition
| At 40 days post conception (about 5th or 6th week) |
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Term
| During neural proliferation, the site of greatest cellular division is the _______ |
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Definition
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Term
| Two different methods of neural cell migration? |
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Definition
Somal Translocation - can be radial or tangential
Glial Mediated Translocation - always RADIAL |
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Term
| Cortical development appear to occur by an ________________ pattern |
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Definition
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Term
| A growth cone is present at the growing tip of neurites, and extends/retracts a cytoplasmic extension called _________ |
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Definition
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Term
| Chemoaffinity Hypothesis of Axon Development |
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Definition
Proposed by Sperry after frog eye experiment
Believed postsynaptic surfaces in NS release specific chemical which attracts each axon
Later revised to account for exact same circuitous path each axon takes while regenerating (release chemicals along the way of growth) |
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Term
| _______________ is the tendency of developing axons to grow along paths established by proceeding axons' ____________ |
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Definition
Fasciculation is the tendency......
.....by proceeding axons' pioneer growth cones |
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Term
| What type of glial cell is synaptogenesis particularly dependent on? |
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Definition
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Term
| Where does neurogenesis primarily continue in adulthood? |
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Definition
| In OLFACTORY BULB & HIPPOCAMPUS |
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Term
| Postnatal growth of the brain results from which 3 other kinds of growth: |
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Definition
1) Synaptogenesis
2) Myelination of axons
3) Increased dendritic branching |
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Term
| When are peak levels of synaptogenesis reached in visual cortex vs. frontal cortex? |
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Definition
Visual cortex - 7-8 months
Frontal cortex - 2 yrs |
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Term
| Difference in growth of cortical grey vs. white matter in postnatal brain? |
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Definition
WHITE - grows slowly until early adulthood (myelination of PFC is slowest)
GREY - grows to larger volume than it will be eventually, then reduces in size |
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Term
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Definition
| Tendency to continue making a formerly correct response when it is currently incorrect |
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Term
| What did Diamond hypothesize was causing the perseveration errors made by children in reaching experiments? |
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Definition
| Caused by incomplete wiring of PFC |
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Term
| Difference between CRITICAL and SENSITIVE periods in development? |
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Definition
Critical - essential for experience to occur during a certain time interval; experience will have no developmental effect if outside this period
Sensitive - experience has greater effect if during this period, and will have a lesser effect if experienced outside of this period |
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Term
| Where does neurogenesis occur in olfactory bulb vs. hippocampus? |
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Definition
OB - occurs in subventricular zone; cells migrate to OB
Hippoc. - occurs in dentate gyrus, present in hippocampus |
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Term
| In neurogenesis in adult mammals, what do new neurons produced in the olfactory bulb and hippocampus become |
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Definition
OB - produced in SVZ, become INTERNEURONS
Hippocampus - produced in dentate, become GRANULE cells |
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Term
| 3 core symptoms of AUTISM: |
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Definition
Reduced ability to infer emotions of others
Reduced capacity for social interaction
Preoccupation/fixation with single activity |
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Term
| What are the most prevalent childhood neurological disorders? |
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Definition
| Autism spectrum disorders |
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Term
| Structures implicated in MRI studies of autism patients? |
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Definition
| Cerebellum, amygdala, frontal cortex |
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Term
| What is the most noticeable feature in Williams Syndrome? |
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Definition
Language abilities - delay in language development; but still exceptional skills given avg IQ = 60
Those with Williams Syndrome thought to be opposite to ASD individuals (talkative, empathetic, sociable) |
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Term
| Physical facial appearance of individuals with Williams syndrome? |
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Definition
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Term
| Differences between hypoplasia vs. ectopsia vs. dysplasia? |
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Definition
Hypoplasia - error in cell proliferation
Ectopsia - error in cell migration
Dysplasia - error in cell differentiation |
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Term
| What error in neurodevelopment is seen in fetal alcohol syndrome cases? |
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Definition
| Error in ectopsia (migration) - cortex lacks distinct layers; see heterotopia |
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Term
| All meningiomas are ____________ tumors |
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Definition
ENCAPSULATED (grow within own membrane)
Therefore, almost always benign tumors (contained w/in own membrane so cannot metastasize) |
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Term
| _____% of brain tumors do not originate in the brain |
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Definition
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Term
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Definition
Area surrounding a cerebral infarct
Goal of stroke treatment is to SAVE THE PENUMBRA |
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Term
| What are the 3 main causes of ischemic strokes? |
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Definition
Arteriosclerosis
Embolism
Thrombosis |
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Term
| Much of the brain damage associated with a stroke is associated with excessive release of what neurotransmitter? |
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Definition
GLUTAMATE
Get excessive Glu release from hypoxic neurons, which overactivates Glu receptors, causing Ca influx into postsyn cell and additional Glu release |
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Term
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Definition
| Closed-head injury that causes cerebrovascular damage (damage of BVs) |
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Term
| Most contusions are usually __________ injuries |
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Definition
| Contrecoup (occur on opposite side of head as to the one that was struck) |
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Term
| What is Punch Drunk Syndrome |
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Definition
| Common in athletes & boxers; repeated concussions leading to dementia (dementia pugilistic) and cerebral scarring |
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Term
| Epilepsy is believed to be caused by a pathology at ____________ synapses, causing synchronous neuronal burst firing |
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Definition
| Occur at inhibitory GABA synapses |
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Term
| Difference between Generalized & Partial seizures? |
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Definition
Generalized - involve ENTIRE brain
Partial - stay in one hemisphere of brain |
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Term
| Difference between simple vs. complex partial seizures? |
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Definition
Simple - primarily involved with motor/sensory abnormalities; called "Jacksonian seizures"
Complex - often restricted to temporal lobes (more issues with perception); people appear conscious but have no recollection; presence of automatisms |
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Term
| What is characteristic in the EEG of petit mal seizures? |
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Definition
| 3-per-second spike and wave discharge |
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Term
| Biggest risk factor for Parkinson's? Most common symptoms of PD? |
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Definition
AGE
Symptoms - resting tremor, muscle rigidity, akinesia, postural instability |
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Term
| The _______________ pathway appears to have a loss of DA neurons in PD |
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Definition
| Nigrostriatal (SN to striatum) |
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Term
| The gene mutations identified as contributors to PD development are all associated with... |
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Definition
| Mitochondrial dysfunction |
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Term
| DBS treatment for PD is aimed at... |
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Definition
| Subthalamic nucleus (used to increase activity through basal ganglia pathway) |
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Term
| Onset of Huntington's is typically associated with? |
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Definition
| CHOREA - rapid, complex, jerky movements |
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Term
| What is the repeat seen in the Huntingtin gene that can cause disorder? |
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Definition
CAG repeats
36-39 = borderline
>40 = positive for Huntington's |
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Term
| Mutant huntingtin protein causes which losses of function and which gains of function in the brain? |
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Definition
LoF = increased apoptosis, lower BDNF levels
GoF = faster progression, neural inclusions in neurons |
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Term
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Definition
| 3: 1 female to male ratio |
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Term
| Incidence of MS is higher in regions ___________ |
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Definition
farther away from equator
Involvement of vitamin D? |
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Term
| What are 2 defining molecular markers for Alzheimer's? |
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Definition
Amyloid plaques - found extracellularly
Neurofibrillary tangles - found intracellularly; due to phosphorylation of Tau protein |
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Term
| Neurofibrillary tangles are formed from... |
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Definition
| Hyperphosphorylation of the Tay protein |
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Term
| Where are the areas of peak neuronal loss & pathogenesis in Alzheimer's? |
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Definition
Medial temporal lobe structures - hippocampus, amygdala
Frontal cortex - PFC, IT, posterior parietal |
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Term
| Where are neurofibrillary tangles typically first seen in Alzheimer's? |
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Definition
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Term
| What is the primary theory of Alzheimer's pathology? |
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Definition
| Amyloid hypothesis - amyloid plaques are primary symptom, and cause all other symptoms |
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Term
| What is the amyloid precursor protein and what is its relevance in Alzheimer's pathology? |
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Definition
Processed by alpha, beta, gamma secretases
alpha-secretase mutations cause increased incidence of B-amyloid plaques
Note that plaque formation PRECEDES cellular damage |
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Term
| What is the Kindling Phenomenon? |
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Definition
Progressive intensification of convulsions seen with each subsequent electrode stimulation; used in Kindling model of epilepsy
Stimulated amygdala; no response at first, then gradually greater with progression |
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Term
| 2 interesting features of the Kindling Phenomenon? |
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Definition
Neuroplastic changes are PERMANENT - effects last even if simulations are stopped
Kindling produced by DISTRIBUTED simulations - need long intervals between stimulations |
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Term
| The Kindling Phenomenon is similar to _______________ in patients following some head injuries |
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Definition
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Term
| In what sense does the Kindling model NOT model epilepsy well? |
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Definition
| Does NOT model it well in the sense that Kindling seizures are exogenously induced, whereas epileptic seizures occur spontaneously |
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Term
| What are the problems seen with most mouse models of Alzheimer's? |
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Definition
| NO neurofibrillary tangles observed |
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Term
| What is currently the most similar animal model to human Parkinson's? |
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Definition
Rotenone model (type of pesticide) - injected into jugular, see PD-like symptoms
Best display of Lewy body inclusions of all animal models |
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Term
| What are caspases responsible for? |
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Definition
| Break down the cytoskeleton of the cell; activate DNAases which break down nucleus; involved in cell apoptosis |
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Term
| Differences between anterograde & retrograde degeneration of axons? |
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Definition
Anterograde - degeneration of distal segment, distal to transection; rapid
Retrograde - degeneration of proximal segment, from transection to soma; gradual |
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Term
| What is transneuronal degeneration? |
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Definition
| Spreads from damaged neuron to other nearby neurons with which it synapses on (anterograde) or those that synapse on it (retrograde) |
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Term
| Typical shape of cells undergoing apoptosis? |
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Definition
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Term
| How is PNS hospitable to neuronal regeneration? |
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Definition
Schwann cells produce neurotrophins and CAMs
Clear out debris to facilitate growth |
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Term
| Two different proposed mechanisms of neural reorganization? |
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Definition
Strengthening of existing connections by releasing lateral inhibition (explains fast recovery of function)
Establishment of new connections by lateral sprouting (explains magnitude of long-term changes) |
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Term
| How is cognitive reserve important following brain injury? |
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Definition
Study showed that in recoveries from head injuries to doctors, improvements due to cognitive reserve allowing them to complete tasks in other ways, NOT from recovery of lost function
Increasing neuronal pool allows different ways to get to the same end goal when one circuit is damaged |
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Term
| When stem cells were implanted into damaged brains of adult animals where did they migrate? |
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Definition
| Migrated to olfactory bulb and hippocampus (only sites of stem cell neurogenesis in adult mammals) |
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Term
| What area of the limbic system is particularly susceptible to damage from ischemia? |
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Definition
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Term
| When apoptosis inhibitor protein was expressed in rats prior to induced cerebral ischemia what were the results? |
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Definition
| Better retention of hippocampal neurons, better performance on Morris Water maze (better memory) |
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Term
| What is constraint induced therapy? |
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Definition
Used in stroke injuries - immobilize the good limb so the affected limb gets sufficient amount of rehab
Decreased amount of neural tissue lost - less transneuronal degeneration, induced BDNF elevation, needed CIMT + exercise to see benefits |
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Term
| Where is Broca's area located? |
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Definition
In the inferior prefrontal cortex of L hemisphere
Damage produces expressive aphasia |
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Term
| What are some tests of cerebral lateralization? |
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Definition
Sodium Amytal Test - tests language lateralization; anesthetize ipsilateral hemisphere with Na-amytal injection; assess capabilities of non-anesthetized hemisphere; showed L hemisphere dominance
Dichotic Listening Test - tests auditory lateralization; hear more digits on R side (L hemisphere lateralization) |
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Term
| What was the relation between hemisphere dominance and handedness? |
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Definition
Dextrals - L hemisphere dominant for language in almost all
Sinestrals - L hemisphere dominant for most; more variable than dextrals for hemisphere dominance for language |
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Term
| What are two pathways incoming visual information can take to reach the contralateral hemisphere? |
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Definition
Can cross via corpus callosum
Can cross via optic chiasm
**Nasal hemiretina crosses, temporal stays ipsilateral |
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Term
| Sperry & Myers cat experiments about CC..... |
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Definition
Transected optic chiasm & CC, put patch on one eye - info going in good eye remained ipsilateral
Cats in experimental group w/ lesions learned task as fast as controls (one hemisphere can learn as quickly as two combined)
Experimental cats could NOT retain learning when patch was switched to other eye; control cats & cats w/ either CC or OC lesioned could |
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Term
| What is the main difference between performance in animals vs. human split brain experiments? |
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Definition
Animals - hemispheres can perform equally
Humans - have one dominant and one minor hemisphere |
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Term
| What is "cross-cuing" and when is it observed? |
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Definition
| Seen in split brain patients - even though L hemisphere controls language, R hemisphere can cue L hemisphere by creating cues to tell it what to do |
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Term
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Definition
| Make sure all visual input stays on ipsilateral hemisphere - projects all of visual field onto temporal hemiretina to keep it ipsilateral |
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Term
| Which hemisphere is best at controlling ipsilateral movement? |
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Definition
| L hemisphere (L hemisphere lesions more likely to produce ipsilateral motor problems) |
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Term
| Which hemisphere appears to dominate for spatial ability? |
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Definition
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Term
| Which hemisphere is better at identifying facial expressions of emotion? |
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Definition
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Term
| Difference in performance of L and R hemisphere on dichotic listening test of digits vs. melodies |
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Definition
L hemisphere - R ear - performed better for digits
R hemisphere - L ear - performed better for melodies |
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Term
| What is the cognitive approach of the L hemisphere? |
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Definition
| It is the INTERPRETER - neuronal mechanisms trying to assess patterns of events continuously |
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Term
| 3 regions in hemisphere with anatomic asmmetry |
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Definition
Frontal Operculum - frontal lobe L hemisphere (Broca's)
Planum Temporale - lateral fissure temporal lobe in L hemisphere (Wernicke's)
Heschl's Gyrus - have 2 present in R hemisphere, only 1 in left; primary auditory cortex |
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Term
| What does the Analytic-Synthetic Theory state? |
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Definition
| Two basic modes of thinking; L hemisphere is analytic; R hemisphere is synthetic |
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Term
| Two fundamental survival advantages for lateralization? |
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Definition
- More efficient for group of neurons with common function to be spatially close
- Two different cognitive processes can be performed simultaneously in opposite hemispheres |
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Term
| What ability do humans have that allows us to produce language? |
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Definition
| Can exert fine motor control in voice |
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Term
| What causes conduction aphasia? |
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Definition
| Damage to arcuate fasciculus - pathway between Broca's & Wernicke's areas (cannot repeat words they just heard) |
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Term
| Damage to the arcuate fasciculus causes.... |
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Definition
| Conductive aphasia (can't repeat words they just heard) |
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Term
| Damage to L angular gyrus causes.... |
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Definition
alexia (can't read)
agraphia (can't write)
NO aphasias |
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Term
| What are the 7 components of the Wernicke-Geschwind model? |
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Definition
Primary visual, primary auditory, primary motor cortices
Angular gyrus
Broca's area
Wernicke's area
Arcuate fasciculus |
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Term
| Differences between phonological, grammatical, semantic analyses of language? |
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Definition
Phonological = how it sounds
Grammatical = how it is structured
Semantic = what it means |
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Term
| Two different ways in which reading can be done... |
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Definition
1) Lexical procedure - specific stored information about written words (good for familiar words)
2) Phonetic procedure - recognize letters & sound out word (good for unfamiliar words) |
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Term
| What are 2 different kinds of dyslexia which can develop from brain damage? Which reading procedure is mainly affected in each? |
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Definition
Surface dyslexia - cannot pronounce words based on memories (lose lexical procedure)
Deep dyslexia - lose phonetic procedure (usually due to L hemisphere damage) |
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