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Midterm Three
lectures 19 - lecture 24
Question | Answer |
---|---|
what are the four pieces of evidence discussed in lecture that supports that suprachiastic nucleus regulates the circadian rhythm or functions as the biological clock? | dyes were injected in the SCN of a brain of a rat and showed that the SCN were active during the day and not during the night | neurons from the extracted SCN showed a ~24 hour cycle of firing rate | mice w/ lesioned SCN had a disrupted circadian rhythm |
what is the average human circadian rhythm? | approximately 25 hours |
what is entrainment | use of external cues to regulate internal biological system, the recalibration of the circadian rhythm through light signals gained from light |
how does light regulate/entrain circadian rhythm? | light received from the eyes ... light hyperpolarizes cells.. Intrinsically Photosensitive retinal ganglion cells (RGC) will project towards the SCN -> retinohypothalamic tract (retina to the hypothalamus) |
is the SCN above or below the optic chiasm? | above |
will cutting the nerve/optic nerve after the optic chiasm disrupt entrainment? | vision will be impaired but entrainment is not disrupted, cutting the nerve before the retinohypothalamic tract reaches the optic chiasm will disrupt entrainment |
What molecule/receptor is responsible for RGCs unique ability? | melanopsin, an opsin - it's a g-protein when light hits RCG it causes the g-protein couple to activate, the g-protein opens the sodium channel .. AP occurs and reaches the SCN |
What is the role of the pineal gland in the circadian rhythm? | the pineal gland releases melatonin, a hormone released in the blood that helps regulate SCN rhythm, and other tissues |
Where is the pineal gland located? | posterior to the thalamus |
are melatonin levels active during the night or day? | Melatonin levels are high during the night and the are low during the day |
What is the role of the SCN in the pineal gland? | The SCN inhibits the pineal gland during the day |
What is the biological mechanism involved in sleep | Proteins are destroyed and produced takes 24 hr. Genes code for proteins that regulate gene and protein expression. This gene expression cycle also controls the activity in SCN neurons, so that is why the SCN neurons show patterns of act. that are 24 hrs. |
T/F: Melatonin helps regulate circadian rhythms in other tissue | True |
T/F: Melatonin is necessary to sleep | False |
T/F: Melatonin regulates circadian rhythm | True |
T/F: Taking melatonin can help adjust to jet lag | True |
What is sleep? | Is a reversible state of reduced responsiveness associated with immobility |
What are the features of stage 1 sleep? | Beta waves - alpha waves, stage 1 non-rem, low arousal threshold |
What are the features of stage 2 sleep? | light sleep, waves are slower in frquency, signals become more synchronized, sleep spindles are present |
What are the features of stage 3 sleep? | delta waves appear, slow wave sleep |
What are the features of stage 4 sleep? | more delta waves, slow wave sleep |
What happens as a person progress through the 4 sleeping stages? | Arousal threshold rises , breathing and heart rate decreases |
How does REM influence motor activity? | inhibitory descending motor pathways from the brain inhibit sensory pathways to the brain and inhibit movement |
How is REM achieved in sleep? | Stage 1-4, Stage 1 - REM, REM continues to become progressively longer |
What is REM? | REM sleep is characterized by fast and low- amplitude waves, which are similar to the beta waves of the awake state, arousal thresholds are high but spontaneous awakenings are more likely |
How is thalamus involved in sleep? | If it's inhibitory area is stimulated it leads to non-REM sleep state. It is low in activity during sleep state |
Areas in brainstem in sleep? | If activated it can in lead to an awake or REM state |
How is weak sensory stimulation achieved in sleep? | There is a lower and more synchronous frequency between the cortex and the thalamus. |
What disrupts more synchronous and lower frequency firing b/w the thalamus and the cortex? | The reticular activating system, it is active when an animal is awake or in REM sleep. Neurons for RAS ascend to the thalamus and the cortex. |
What are five key neurotransmitters used by the reticular activating system? | Acetylcholine, GABA, Norepinephrine, Dopamine, Serotonin |
What are the purpose of sleep? | restore's body's homeostasis, conserve energy and restore fuel stores, clean out toxins and metabolic byproduct through CSF, synaptic scaling to cut back new connections made while awake, memory consolidation |
what shows the importance of sleep? | - We sleep more after a bout of sleep deprivation - The sleep after being sleep deprived is more efficient (more stage 3 and 4) - There are cognitive impairments after sleep deprivation |
T/F: Language ability is inherent and encoded in our genes | True |
what is sodium amytal? | anesthetic that is injected in a carotid artery, an artey that brings blood to one hemisphere of the brain, |
which hemisphere of the brain is the brain lateralized? | the left side of the brain |
what is Broca’s aphasia? | slow production of speech, but normal grammar and comprehension of speech (also know as expressive aphasia) |
Which brain area is Broca's area close to? | facial area of the motor cortex |
What is Wernicke's aphasia | poor production of comprehensible speech but words can be produced easily (receptive aphasia) |
Which brain area is Wernicke's area close to? | it is posterior to the auditory cortex |
Which area of the left hemisphere is damaged in Broca's aphasia? | left PFC |
Which area in the left hemisphere is damaged in a stroke patient with Wernicke's aphasia | left temporal lobe |
What neuron does connect the Wernicke's area to the Broca's area? | arcuate fasciculus |
which area of the left hemisphere is dedicated to production? | anterior left |
which area of the left hemisphere is dedicated to comprehension? | posterior right |
how does W. area work with B. area to process language? | You hear language via the aud. cor. Comprehend the language in W. area If a response is needed, then W. area sends signals to Broca’s area, where an appropriate response is planned B. area stimulates the appropriate facial motor areas to create words |
What is stroke? | blocking of oxygen in the brain that causes neuronal damage, only affects specific functions but may cause multiple damage in the brain (stroke/lesion rarely does damage only a single are in the brain) |
why is the model of language simplistic? | stroke rarely cause discrete damages in the brain, when specific brain regions dedicated to speech are destroyed, disruption in speech is only temporary. There are many areas in the cortex that will disrupt speech when they are stimulated. fMRI studies |
how are meaning of words distributed in the brain? | The meaning of words is distributed throughout the brain, but organized by general categories. Words that are in similar categories activate similar areas of the brain. |
how is language localized and distributed in the brain? | Localized: Areas in the left cortex are necessary to comprehend and produce speech | Distributed: The entire cortex is used to understand the meanings of specific words |
how did fmri studies challenged how the simplistic model of language? | using at an fMri, fMRI studies have also shown that there are not small discrete areas associated with language processing |
what is nondeclarative memory? | it is an implicit form of memory: procedural, emotional response and habits |
what is declarative memory? | explicit memory, involves memories of facts (semantic memory) and memory of events (episodic memory) |
what happens when memories under go the process of being stable? | short-term memories occur and must be consolidated to form long-term memories |
what is retrogade amnesia? | losing memories that were before the incident of damage |
what is anterogade amnesia | inability to form new memories |
We have learned from amnesiac patients that all these different forms of memory can be separated from each other. | You can lose long-term explicit memories, but still have implicit and short-term memories intact |
recency effect | ability to remember the last sensory information received and can be retrieval from the short-term memory |
serial position effect | higher likelihood of remembering the first and last information received how it works? primacy effect - beginning cues rehearsed repeatedly to be consolidated into LM recency effect - later cues received thatare retirieval in short term memory |
what are the features of working memory | 7 words on average, multiple storage sites in the brain, including PFC and lateral intraparietal corte (LIP |
how is delay-response task used in testing working memory? | Damage to the PFC impairs the monkey’s ability to perform the task. Recordings from PFC during the D-R task reveal that some neurons respond strongest during the delay period – neural correlate of working memory |
T/F: Stimulation of the PFC during brain surgery does not disrupts patient’s ability to perform working memory tasks | False |
T/F: Wisconsin card sorting task involves holding information about rules for sorting cards in working memory. Patients with damage to PFC have a difficult time with this task, especially when the sorting rules change | True |
What kind of activity does PFC have during delay period in the delay-response tasks? | it's active during the delay |
how is the lateral intraparietal cortex involved in working memory? | active during delay period after receiving visual cues - indicating that they are likely holding theinformation about the target location in memory |