Complex functions of the brain Flashcards
Which three components show a rhythmic pattern of roughly 24 hours?
Body temperature
Growth Hormone
Cortisol
What is the name of the photopigment found in the photosensitive retinal ganglion cells
Melanopsin
What is considered the “master clock”
The suprachiasmatic nucleus of the hypothalamus
Which brain waves are characteristic in stage 1 NREM sleep?
Theta Waves
Descent into stage 2 NREM sleep is characterised by:
10-12Hz oscillations = sleep spindles
Brain waves characteristic of stage Stage 3&4 NREM sleep
Delta Waves
Brain waves characteristic in REM sleep
Alpha Waves
Brain oxygen use in REM vs awake
Brain oxygen use: REM > awake
What is narcolepsy
REM sleep attacks - people enter REM sleep from wakefulness during the day
What is a possible cause of narcolepsy?
Mutation in the orexin receptor gene (Orx2) – hyperexcitability of neurons that generate REM sleep
Define Memory
persistence of learning over time through the storage and retrieval of information
What are the 3 gross stages of memory:
1 - Encoding (orregistration): receiving, processing & combining information
2 - Storage /consolidation: creation of a permanent record of encoded information
3 - Retrieval (recall or recognition): calling back of stored information in response to some cue
Temporal Classifications of memory
1 - Immediate Memory: Ability of brain to hold onto ongoing experience
2 - Short Term memory: (working memory)
3 - Long term memory: storage of information over an extended period
Types of LTM
Declarative (explicit) Memory - info that is explicitly stored & involves conscious effort to be retrieved
Non-declarative (Implicit Memory/ procedural) - collection of non-conscious knowledge systems provide capacity of skill learning, habit formation, phenomenon of priming
Approaches led to us understanding structures involved in memory formation & maintenance
- Imaging studies (fMRI/PET scans)
- Lesion studies
- Karl Leshley
- Pathological & brain injury studies
- Patient HM
Brain region underlying declarative memory acquisition & storage
Hippocampus & adjacent medial temporal lobe structures
Brain areas underlying nondeclarative memory storage & acquisition
Basal ganglia, prefrontal cortex, amygdala, sensory association cortices & cerebellum
Role of the hippocampus in LTM:
- Encoding & consolidation of new declarative memories
- Key to navigation/spatial memory
- Project info to cortical areas for storage to give meaning & make connections w other memories: The catalyst for LTM
(but the memory engram is in various places in the cortex)
What is Huntington’s
Atrophy of caudate & putamen - perform poorly on motor skill learning tests
LTM storage a variety of cortcial sites:
a) site for meaning of words
b) site for memories of objects & faces
a) Wernicke’s area
b) Temporal cortex
Anterograde Amnesia
The inability to establish new memories following neurological insult
Retrograde Amnesia
Difficulty retrieving memories established prior to the precipitating neuropathology
Effect of age on memory
1) Decrease in brain mass (volume) - shrinkage of frontal lobe & hippocampus
2) Decrease in synaptic connections/cortical density - reduced synaptic connections in cortex & deterioration of memory engrams
3) Reduction in the production of chemical messengers - reduction in NTs (dopamine) & reduction in neuroprotective hormones (eostrogen)
4) Decreased blood flow to the brain - impair memory & lead to changes in cognitive skills
Dementia
A syndrome characterized by failure of recent memory & other intellectual functions
3 principle features of AD (Alzheimer’s Disease)
1) Neurofibrillary tangles: abnormal accumulations of protein (tau) collects inside of neurons
2) Amyloid plaques: aggregates of misfolded proteins that form in the spaces between nerve cells
3) Diffuse Neuronal loss: neural loss in brain regions such as hippocampus & prefrontal cortex (essential memory formation & executive functioning)
Types of AD:
1 - Early onset AD: due to mutation on chromosome 21; mutation of amyloid precursor protein (APP)
2 - Late onset AD: pathological deposition of amyloid beta peptide; found ApoE protein (molecule that chaperoned cholesterol in bloodstream) & association w chromosome 19 in the same region as the gene that encodes for isoform of ApoE is located
Mild Cognitive Impairment
Minor problems w cognitive function affecting mental abilities such as memory & thinking (not sever enough to classify as dementia)
Encephalopathy
Disease that affect the function/structure of the brain - may include infections, toxins, drugs.
Symptoms - progressive loss of memory & cognitive ability, subtle personality changes, inability to concentrate, lethargy, progressive loss of consciousness
Traumatic Brain Injury (TBI)
Disruption in normal function of the brain caused by blow, jolt to head or violently hitting an object
Symptoms - attention & concentration problems, trouble thinking clearly, problems with ST & LTM
Common in athletes - chronic TBI linked to increased suicide rates
