Term
| Why do reticular neurons have typically very long & straight dendrites? |
|
Definition
| so that they cover a large volume of tissue |
|
|
Term
| Does the reticular formation consist of several subdivisions? |
|
Definition
|
|
Term
| Do large or small cells make up the medial two-thirds of the reticular formation (the pons & the medulla)? |
|
Definition
| many large cells (giant cells) |
|
|
Term
| Do large or small cells make up the lateral 1/3 of the reticular formation? |
|
Definition
| almost exclusively small cells |
|
|
Term
| Why does the reticular formation appear to consist of numerous transversely oriented disks? |
|
Definition
| most dendrites of reticular cells have the same preferential orientation |
|
|
Term
|
Definition
| a narrow, sagittally oriented plane of neurons in the midline of the medulla, pons, & mesencephalon |
|
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Term
|
Definition
| a small group of only about 15,000 strongly pigmented neurons located under the floor of the fourth ventricle |
|
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Term
| What is the difference in the transmitter released by the raphe nuclei versus the locus coeruleus? |
|
Definition
raphe nuclei = serotonin
locus coeruleus = norepinephrine |
|
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Term
| Is the raphe nuclei important for homeostatic control? |
|
Definition
|
|
Term
| Are many raphe nuclei chemosensitive? |
|
Definition
| yes! they measure the CO2 level in the blood |
|
|
Term
| What is the overarching function of the locus coeruleus? |
|
Definition
| increasing arousal & attention in response to salient sensory information |
|
|
Term
| Where does the locus coeruleus get instruction to shift behavior from? |
|
Definition
|
|
Term
| 4 main regions the reticular formation sends fibers to |
|
Definition
1. thalamus
2. spinal cord
3. brain stem nuclei
4. cerebellum |
|
|
Term
| Where do descending fibers from the reticular formation run & what do they control? |
|
Definition
| they run in the ventral part of the lateral funicle & in the ventral funicle & are related to muscle control |
|
|
Term
| 3 main functions of the ventral reticulospinal tract |
|
Definition
1. postural control
2. orientation of the head & body
3. voluntary movements of the proximal body parts |
|
|
Term
| What are connections from the superior colliculus crucial for? |
|
Definition
| orienting movements toward novel stimuli |
|
|
Term
| What do dorsal reticulospinal fibers control? |
|
Definition
|
|
Term
| Where do ascending fibers from the reticular formation end? |
|
Definition
| in the intralaminar thalamic nuclei |
|
|
Term
| What is mediated by the spinothalamic tract? |
|
Definition
| nociceptive & thermoceptive signals to the reticular formation |
|
|
Term
| How do visceral sensory signals reach the reticular formation? |
|
Definition
| collaterals of ascending fibers from the solitary nucleus |
|
|
Term
| How can the reticular formation be influenced by visual signals? |
|
Definition
| the superior colliculus gets visual information directly from the retina & contacts the reticular formation |
|
|
Term
| Where do corticoreticular fibers arise? |
|
Definition
| in the cortical areas that give origin to the pyramidal tract |
|
|
Term
| What is the corticoreticulospinal pathway important for? |
|
Definition
| control of voluntary & autonomic movements |
|
|
Term
| What part of the reticular formation gets information from the basal ganglia? |
|
Definition
| the mesenscephalic reticular formation |
|
|
Term
| What do fibers from the hypothalamus ending in the reticular formation coordinate? |
|
Definition
| the activity of different peripheral parts of the autonomic nervous system |
|
|
Term
| Where is the facilitatory region located in comparison to the inhibitory one? |
|
Definition
|
|
Term
| Where are neurons with respiratory movement-related activity concentrated? |
|
Definition
| ventrolateral medullary reticular formation (ventral respiratory group) (VRG) |
|
|
Term
|
Definition
| a small neuronal network in the rostral part of the VRG that is the rhythm generator for respiratory muscles |
|
|
Term
| 3 places the VRG gets sensory information |
|
Definition
1. thoracic cage (degree of expansion)
2. lungs (degree of expansion)
3. chemoreceptors (blood pH & CO2 content) |
|
|
Term
| What part of the reticular formation is responsible for coordinating the necessary adjustments of vascular resistance & cardiac output? |
|
Definition
| rostral ventrolateral medulla (RVLM) |
|
|
Term
| Synchronization in which network is characteristic of a conscious state? |
|
Definition
|
|
Term
|
Definition
| direct recordings from the exposed cortex done during brain surgery |
|
|
Term
| desynchronization (activation of the EEG) |
|
Definition
| the change of wave pattern from alpha to beta waves |
|
|
Term
| What part of the brain determines the level of consciousness? |
|
Definition
|
|
Term
| Is arousal or relaxation associated with desynchronization of the EEG? |
|
Definition
|
|
Term
| What is the main task of the ascending activating system? |
|
Definition
| to focus our attention on certain stimuli or internal events, rather than to produce a diffuse awareness |
|
|
Term
| Are serotonergic raphe neurons & histaminergic neurons in the hypothalamus more active during wakefulness or during sleep? |
|
Definition
|
|
Term
| What are the different roles of ACh, norepinephrine, dopamine, & serotonin on performing tasks? |
|
Definition
ACh = increase precision of the performance
norepinephrine = reduce effects of distracting stimuli
dopamine = increase speed of execution
serotonin = limit the frequency of impulsive response errors |
|
|
Term
| What happens to alpha waves when a subject is falling into a deep, quiet sleep? |
|
Definition
| alpha waves disappear altogether & are replaced by irregular slow waves with greater amplitude (slow-wave sleep) |
|
|
Term
| Why is phase V sleep different than phases I - IV? |
|
Definition
| the EEG is desynchronized & there are conjugated movements of the eyes much like a person is looking at moving objects |
|
|
Term
| Is sleep necessary for plasticity? |
|
Definition
|
|
Term
| Is sleep important for learning & memory? |
|
Definition
|
|
Term
| What part of memory takes place predominantly in specific sleep phases? |
|
Definition
| consolidation of newly learned material |
|
|
Term
| Where are the neuronal groups most directly involved in sleep control located? |
|
Definition
| in the brain stem, esp. in the pons |
|
|
Term
| What neurons are crucial for induction of sleep? |
|
Definition
| activity in ACh neurons in the dorsolateral pons |
|
|
Term
| What type of receptors mediate the effects of ACh in the thalamus? |
|
Definition
|
|
Term
| When do the pontine ACh neurons fire in relation to the eye movements in REM sleep? |
|
Definition
| in bursts ahead of the eye movements |
|
|
Term
| What do monoamines do for sleep? |
|
Definition
| they inhibit the ACh neurons, thus increasing wakefulness |
|
|
Term
| What do drugs that enhance the synaptic effect of serotonin do for sleep? |
|
Definition
|
|
Term
| Are spinal motoneurons inhibited or excited during REM sleep? |
|
Definition
|
|
Term
| How much REM sleep do newborn infants need per day? |
|
Definition
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