167 terms
Neurophys III Final
Which researchers found that electrically stimulating certain areas in the brain and brainstem produced cortical activation?
Moruzzi and Magoun
Arousal states appear to be determined by in interaction about the ___________, __________, _________ and ___________.
brainstem, hypothalamus, thalamus, basal forebrain
Dampening of arousal systems with concomitant active inhibition by ______________ systems produces sleep.
thalamo-cortical
Areas maintaining wakefulness include?
oral pontine reticular formation,
midbrain central tegmentum,
posterior hypothalamus
midbrain central tegmentum,
posterior hypothalamus
Where are sleep promoting areas located?
midline brainstem,
dorsolateral medullary reticular formation,
anterior hypothalamic preoptic region
dorsolateral medullary reticular formation,
anterior hypothalamic preoptic region
What is the "sleep modulating center", with both sleep and waking active sites?
Magnocellular nucleus basalis of Meynert located in the forebrain
The Magnocellular nucleus basalis of Meynert located in the forebrain has projections to ___________ and ______________.
neocortex, midbrain reticular formation
What type of projections are projections from the Magnocellular nucleus basalis of Meynert?
acetylcholine projections
Sleep is a behavioral state that differs from wakefulness by a readily reversible loss of ______________________.
reactivity to event's in one's environment
Sleep is divided into stages based on?
electroencephalography (EEG),
electro-occulogram (EOG),
electromyogram (EMG)
electro-occulogram (EOG),
electromyogram (EMG)
What are the two "light" stages of non REM sleep?
I and II
What are the two "deep" stages of non REM sleep?
III and IV
During Rapid Eye Movement sleep, the EEG resembles?
awake state or NREM stage I
During REM sleep, what happens to EMG activity?
dramatic decrease
Descriptive words for stage I NREM?
I-light, theta, delta (low amplitude) horizontal eye
Descriptive words for stage II NREM?
II-light, theta, delta, sleep spindles, K complexes
Descriptive words for stage III NREM?
III, deep, high amplitude delta (20-50%)
Descriptive words for stage IV NREM?
IV, deep, high amplitude delta (>50%)
Electrical stimulation of _____________________ produces slow wave sleep.
nucleus tractus solitarius (NTS)
Lesions in the nucleus tractus solitarius produces _________________.
cortical desynchronization (waking pattern of EEG)
NTS appears to inhibit more rostrally situated neurons in the ____________________ system.
ascending reticular activating
Direct connections between NTS and major areas of the ____________ system exist.
limbic (anterior thalamus, hypothalamus, amygdala)
Where might lesions produce insomnia?
seritonin rich raphe nucleus
What chemical can produce insomnia by blocking production of serotonin?
Parachlorophenylalanine (a trytophan hydroxylase inhibitor)
Slow wave sleep can be restored in PCPA induced insomnia by administration of _______________.
5 Hydroxytrytophan
How does serotonin appear to modulate sleep?
its effect on other hyponogenic factors in the anterior hypothalamus and suprachiasmatic nucleus
Serotonin is a precursor for what?
melatonin
Melatonin is synthesized and released by the ______ gland.
pineal
Melatonin is synthesized and released by the pineal gland through ___________ activation from the ______________ tract.
sympathetic,
retino-hypothalamic
retino-hypothalamic
What effect does prolonged bright light stimulation have on melatonin and sleep?
supresses
________________________ appears to inhibit waking areas in the rostral midbrain and mesopontine reticular core.
Preoptic nucleus of ant. Hypothalamus
Preoptic nucleus of ant. Hypothalamus appears to inhibit waking areas in the _______________ and ___________________________.
rostral midbrain, mesopontine reticular core
Where is prostaglandin D2 highly concentrated?
preoptic nucleus
Prostaglandin inhibition by _____________ can decrease diurnal sleep.
indomethacin
The __________________ may also promote sleep by inhibiting the waking area in the posterior hypothalamus.
anterior hypothalamus
What factors have hynogenic effects by acting on the anterior hypothalamus.
triazolam, 5HTP, muramyl peptides, PGD2
What type of neurons are involved in sleep spindles and delta waves?
GABAergic
Sedatives and hypnotics stimulate __________ receptors and facilitate sleep.
GABA
Sleep spindles are rhythmic cortical waveforms generated by oscillatory activity in ______________ of the thalamus.
nucleus reticularis
Slow waves are generated in ________________ circuits arising in _______________.
neocortical, all cortical layers
An increase in GABAergic anterior hypothalamic preoptic and basal forebrain neurons is associated with _______ sleep.
slow wave
What is cortical EEG doing in REM sleep?
highly desynchronized (similar to waking)
What type of sleep is associated with pontine geniculate occipital spikes?
REM
What phasic events are associated with PGO spikes?
rapid eye movements, changes in respiration, heart rate, muscle twitches, and dreaming
Where do PGO spikes originate from?
REM-ON cells in medial pontine reticular formation and adjacent reticular tegmental nucleus
In animals, REM sleep has been eliminated by placing lesions where?
ventral to locus ceruleus
REM sleep can be induced by cholinergic stimulation of the __________.
pons
REM sleep can be induced by __________ stimulation of the pons.
cholinergic
REM-OFF cells are represented by what cells? (which become silent during REM)
noradrenergic cells of locus ceruleus
___________ is 30% greater in REM sleep.
Rheobase
What is the progressive decrease in muscle tone in REM sleep associated with?
hyperpolarization of moter neurons
What type of sleep does many antidepressants suppress?
REM
What happens in REM behavior disorder?
persistant muscular tone during REM, bursts of excessive limb and body movements,
There is a reduction in body and brain temperature at the onset of sleep. What change is this associated with?
vasodilation
At the onset of sleep, there is reduced thermosensitivity of ______________.
hypothalamic preoptic nucleus
What serves as an endogenous clock influencing both sleep and body temp in a closely coupled fashion?
suprachiasmatic nucleus
How much does brain metabolism decrease in slow-wave sleep?
20-35%
Is inhibition of TSH sleep promoting or sleep inhibiting?
promoting
Is inhibition of cortisol sleep promoting or sleep inhibiting?
promoting
Is stimulation of GH and prolactin sleep promoting or sleep inhibiting?
promoting
Is muramyl peptide sleep promoting or sleep inhibiting?
promoting
Is prolactin sleep promoting or sleep inhibiting?
promoting
Is stimulation of TSH sleep promoting or sleep inhibiting?
inhibiting
Is stimulation of cortisol sleep promoting or sleep inhibiting?
inhibiting
Who is more likely to be obese, those who sleep more than 9 hours or those who sleep less than 6 hours?
less than 6 hours
What are the causes of epilepsy?
trauma, oxygen deprivation, tumors, infections, toxic states
What are precipitating causes of seizure?
strong emotional stimuli, alkolosis (hyperventilation), drugs, fever, loud noises/flashing lights
What terminates a seizure?
neuronal fatique, active inhibition?
What is the incidence of epilepsy?
.5-1% of population (2nd most common neurological disease)
Which type of seizure is associated with Aura, Tonic Phase, Tonic-clonic phase and Post-ictal phase?
Grand Mal
Which type of seizure is associated with "zone-out"?
Petite Mal
What type of seizure is Focal- and symptoms depend on the area of the brain that is involved?
Psychomotor
Which type of seizure "migrates"?
Jacksonian
Which type of seizure is associated with brief muscle jerks and dementia?
myoclonic
Which type of seizure is a "drop" seizure?
atonic
Which type of seizure is a life-threatening and persistant state of seizure?
Status Epilepticus
What is an altered sensation prior to a grand mal seizure called?
aura
What is the tonic phase of a grand mal seizure?
rigid stiffening of body, loss of conciousness
What is the tonic-clonic phase of a grand mal seizure?
strong muscle contraction and convulsions, which are over within minutes
What is the Post-ictal phase of a grand mal seizure?
return to conciousness, may be associated with confusion, stupor, slurred speech, weakness
What drugs are used to treat epilepsy?
phenobarbitol, dilantin, tegratol, depeken (Valproic Acid)
What is a surgical treatment of epilepsy?
excision of epileptic foci
What is a vagal stimulator treatment for?
epilepsy
What is a sensory evoked potential?
change in EEG resulting from stimulation of a sensory pathway
To determine sensory ep, EEG is recorded during?
repetitive natural stimulation (tap on skin or flash of light)
Is schizophrenia characterized by positive or negative symptoms?
negative (loss of function)
What are some of the positive symptoms of schizophrenia?
delusions, hallucinations, disorganized speech, bizarre behavior
What are some of the negative symptoms of schizophrenia?
alogoria, flat affect, anhedonia, avolition, attentional impairment
The positive symptoms of schizophrenia are associated with what area?
mesolimbic- ventral tegmental area to many areas of limbic system (dopaminergic)
The negative symptoms of schizophrenia are associated with what area?
mesocortical- ventral tegmental area to neocortex
What are some anatomical abnormalities associated with schizophrenia?
enlargement of ventricles and prominent sulci due to abnormal brain development
What is the concordance of schizophrenia in monzygotic twins?
40%
What is the concordance of schizophrenia in dizygotic twins?
10%
What is a psychological symptom of L-Dopa?
schizophrenia
What is the definition of "mood"?
sustained emotional state
Melancholia means?
black bile
Who first described unipolar depression in writings in the 5th century BC?
Hippocrates
Untreated unipolar depression typically lasts how long?
4-12 months
What condition is characterized by pervasive unpleasant mood that is present most of the day, along with at least three other symptoms (such as decreased sex drive, guilt, thoughts about dying/suicide, etc)?
Unipolar Depression
What is the term for inability to experience pleasure?
anhedonia
When are symptoms of unipolar depression symptoms usually worse?
in the mornings
What are some subtypes of unipolar depression?
(endogenous)melacholic, reactive
What is the incidence of unipolar depression?
5% or 8 mil in US
Bipolar is similar to unipolar with the addition of?
mania
Which disorder has an elevated or irritable mood which lasts at least a week?
bipolar
Overactivity, reckless involvements, and social intrusiveness are all symptoms of?
mania- bipolar
What is the concordance of general depression among monozygotic twins?
50%
The incidence of suicide in biologic relatives of depressed adoptees is _________ than biologic relatives of normal adoptees.
6-10 times higher
What treatment for depression has an effectiveness rate of about 90%?
Electroconvulsive therapy
How effective are drugs at treating depression?
70%
What are some examples of drugs for the treatment of depression?
MAO inhibitors, tricyclic, specific serotonin, uptake blockers, lithium salts
What receptors are changed in ECT therapy?
aminergic
MAO inhibitors decrease breakdown of ______________.
biogenic amines (norepinephrine and serotonin)
MAO inhibitors have a lag time of __________, and it takes __________ for full effect.
lag- 1 to 3 weeks
full effect- 4-6 weeks
full effect- 4-6 weeks
Tricyclic compounds work how?
biogenic amine uptake blockers
What is the response rate for tricyclic compounds in the treatment of depression?
70% response rate
Trycyclic compounds have a lag time of __________, and it takes __________ for full effect.
lag- 1 to 3 weeks
full effect- 4-6 weeks
full effect- 4-6 weeks
How does fluoxetine (Prozac) work?
specifically block the re-uptake of serotonin
Lithium Salts are effective at terminating ______________.
manic episodes
How do Lithium salts work?
inhibit neuronal signal transduction systems
What has a similar effect of lithium salts?
omega 3 fatty acids
What is a "key feature" of anxiety disorders?
frequent occurance of symptoms of fear
Excessive anxiety is _______.
maladaptive
What are the subjective manifestations of anxiety?
heightened sense of awareness, deep fear of impending disaster and death
What is the average age of onset for panic attacks?
late 20s
Infusion of sodium lactate into blood and inhalation of CO2 can trigger?
panic attacks
What are the drug treatments for anxiety?
benzodiazepines (valium, librium)
How do drugs for the treatment of anxiety work?
enhance activity of GABA receptor (opens Cl- channel, increasing Cl- influx, hyperpolarizing cell)
In US ____% of population older than 65 show mild to severe mental impairment.
11
After the age of 75, there is a __% increase in dementia per year.
2
What is the most common form of dementia?
alzheimers
What are some general changes on CT or MRI associated with Alzheimer's Disease?
thining of cortical gyri, enlarged ventricles
What genes may be involved in Alzheimers?
primarily C21, can be C1, C14, C19
What are the neuronal features of Alzheimers?
extracellular plaques containing amyloid, neurofibrillary tangles
Where are amyloid plaques concentrated in Alzheimers?
neocortex, hippocampus
Neuronal cell loss in the hippocampus and nucleus basalis of Meynert indicates?
Alzheimer's
Decreased neuropeptides in alzheimers include?
somastatin, NPY, corticotrophin RF, Substance P, VIP
What is the normal cerebral blood flow?
50-65 ml/100 gms/min
Cerebral blood flow represents about ____% of resting cardiac output.
15
Most strokes (75%) are what type?
occlusive
What percent of strokes are hemorrhagic?
25%
Most substances that must cross the BBB are not _______ soluble and use specific carrier mediated transport systems.
lipid
What does the brain use for energy?
glucose
How does glucose gain entrance across the BBB?
GLUT 1
Is glut 1 energy dependent?
no
Where in the brain is there no BBB?
posterior pituitary and circumventricular organs (secretory areas)
Leaky areas of the brain (with no BBB) are isolated from the rest of the brain by ___________________ which prevent free exchange with CSF.
specialized ependymal cells (tancytes)
How is leucine and valine transported across the BBB?
energy and Na dependent L system (for large neutral AA with branched or ring side chains)
How is alanine and serine transported across the BBB?
Energy and Na dependent A system (for neutral AA with short linear or polar sidechains) OR ACS system
How is cysteine transported across the BBB?
ACS system (also transports alanine and serine along with A system)
Which system of transporting amino acids across the BBB may limit accumulation of -NT glycine in cord and +NT glutamate in the brain?
A system
What changes L-Dopa into dihydroxyphenylacetic acid?
DOPA Decarboxylase and monoamine oxidase
What enzyme detoxifies glutathione-bound compounds and vasoactive leukotrienes?
delta-glutamyl transpeptidase
Cerebral Spinal Fluid is secreted by?
Choroid Plexus
How much CSF is secreted by the Choroid Plexus each day?
500ml
What is the total volume of CSF?
150 ml
How often is CSF turned over?
3 times per day
CSF has less __________________________ (secretory products) than plasma.
less protein, glucose, K+, Ca++, Mg++, pH
CSF has more ___________________ (secretory products) than plasma.
Cl-, osmolarity, Na+
How is the constant external environment for neurons and glia maintained?
CSF communicates with brain ISF
What are the functions of CSF?
Communicates with brain ISF, removal of potentially harmful brain metabolites, mechanical cushion, reduces weight of brain, transport of peptides to distant sites, pH affects both ventilation and blood flow
What serves as the one-way valve to allow CSF to flow into the blood and not allow blood to flow into the CSF?
arachnoidal villi
Obstruction of flow of the CSF causes?
hydrocephalus
What is the normal CSF pressure?
10 mmHg
What usually causes noncommunicating hydrocephalus?
blockage of the aqueduct of Sylvius from a congenital defect or tumor
What usually causes communicating hydrocephalus?
blockage of fluid flow into subarachnoid space around basal regions of the brain or blockage of arcachnoidal villi
How can brain edema be treated?
IV mannitol, ventricular puncture