Exam 3 Flashcards
(42 cards)
What does an EEG electrode measure?
An EEG measures the summation of action potentials within a given area of the cortex over time.
• What do alpha waves look like? What states of consciousness is it associated with? *
moderate frequency, moderate amplitude
Associated with wakeful rest with eyes closed
• What do beta waves look like? What states of consciousness is it associated with? *
high frequency, low amplitude
associated with normal wakeful consciousness and concentration
• What do delta waves look like? What states of consciousness is it associated with? *
low frequency, high amplitude (hence – slow-wave sleep)
associated with deep often dreamless sleep, slowest brain waves
• Characteristics of REM sleep
- has an awake EEG pattern
- rapid eye movement during this period
- associated with narrative dreams
- no muscle tone during REM sleep
• Activity in the reticular activating system during arousal, sleep, and REM *
Reticular activating system (RAS) is active during arousal.
RAS is inactive during slow wave sleep.
RAS becomes active again in REM sleep
• Can dreams occur during non-REM sleep? How does dream content map onto brain anatomy?
- Nightmares with static images tend to occur in slow wave sleep not REM
- dreams can occur in non-REM sleep.
- perception of movement activates the superior temporal sulcus (what we dream about can activate the area of the brain associated with that action)
• Effects of ventral lateral preoptic area activity and damage on sleep *
The ventral lateral prep-tic area becomes active at night and inhibits activity in the RAS.
- it promotes sleep
- if damaged, leads to insomnia and death.
• Role of orexin in sleep
- Stimulant neurotransmitter
- Damage to these neurons results in narcolepsy.
- Contributes to “effortful wakefulness”.
- VLPA makes it inactive at night
• Role of histamine in sleep
- Stimulant Neurotransmitter
- Drugs that block histamine receptors cause drowsiness.
- VLPO makes it inactive at night
• Role of adenosine in sleep
- hypnotic neurotransmitter
- Builds up in the basal forebrain during day and inhibits neurons.
- Caffeine is an adenosine antagonist
• What is the role of sleep in learning and synapse size? *
Sleep is the time when we consolidate information gathered during the day.
-important information stored in large synapses.
-less important information being held in smaller synapses.
(Also if you smell something and smell it again during slow wave sleep you recall the information better)
• Brain activity in some cases of persistent vegetative states
Case study shows brain activity that suggests awareness of commands.
-awake but unaware of surroundings
• What are the changes in gene expression across daily circadian cycle
gene activity is increased during the day and decreased at night.
• Do circadian rhythms change in the absence of daily light/dark cycle?
- Light does impact our circadian rhythm
- However the blind still have circadian rhythms
- If one lives in constant light conditions for weeks, the cycles become prolonged
• Role of the suprachiasmatic nucleus in circadian rhythms.
- Circadian rhythms are dependent on SCN
- Removal of SCN leads to lack of circadian rhythm
- SCN receives direct input from the eye
• Organizational vs. activational effects of hormones *
Organizational: (developmental) permanent change in brain and sex organs due to hormonal exposure during development
Activational: temporary change (e.g. functional) in sexual behavior due to hormonal exposure during adulthood
• Development of primary sex organs and gender-specific brain *
Males XY Females XX
- Testes are the Determining Factor (or SRY) gene on Y chromosome causes testicular development in males
- Nature produces a female by default unless two hormones are released by testes: Mullerian-inhibiting hormone (prevents ovaries/defeminization), and Testosterone (stimulates male development, masculinization.)
• Hormonal cascade during puberty
- release of gonadotropin-releasing hormone (GnRH) from hypothalamus
- Stimulates release of follicle-stimulating hormone (FSH) and lutenizing hormone (LH) from pituitary.
- Stimulates estrogen (E) and progesterone (P) from ovaries or testosterone (T) from testes.
= secondary sex characteristics
• Activational effects of hormones on female and male sexual behavior
In human females, initiation of sexual activity is greater during ovulation (when Estrogen levels are high).
More testosterone in males = more sexual drive
• Evidence for specific brain regions in male and female sexual behavior *
Males have a larger olfactory bulb and medial amygdala.
(Lesions on medial amygdala decrease Male sex drive)
-When viewing porn, males have greater amygdala activation
-High amygdala activity predicts more sexual partners in women but fewer partners in men. Low amygdala activity predicts more sexual partners in men but fewer partners in women.
- The medial preoptic area (MPA) of hypothalamus is larger in males. (Lesions abolish sexual behavior in males)
-Ventromedial nucleus of hypothalamus is larger in females (Lesions reduce sexual receptivity.)
• Biological determinants of sexual orientation
- Activational effects
- Genetics
- Developmental effects
- Brain activation as a function of orientation
- T levels in lesbians are slightly higher than in straight women. (T levels in gay and straight human males do not differ.)
- Altering the function of specific genes in flies elicits change in orientation. (If sexual orientation in humans is genetic, it likely involves many genes.)
- Females with congenital adrenal hyperplasia (CAH) are overexposed to testosterone-like hormones in utero, 1/3 are gay. Individuals who are XY but have Androgen Insensitivity Syndrome (AIS) do not masculinize in utero and develop female appearance, most are interested in men. The greater the # of older biological brothers, the greater the likelihood of homosexuality in males (related to a mother’s antibodies against testosterone.)
- Smelling androstendione activates anterior hypothalamus in gay men and women. Estrogen smell activates anterior HT in gay males but posterior HT in straight males.
pair bonding, oxytocin, and vasopressin in voles and people. *
Monogamous Prairie voles have a high level of oxytocin, vasporessin compared to other non monogamous montane voles.
- an oxytocin antagonist administered to a female prairie vole and a vasopressin antagonist given to a male prairie vole decreased partner preference.
- there is a SNP “334” identified that shows nonmongamous pair-bonding behavior in some men
- Intranasal oxytocin increases positive behavior and decrease stress in marital fights
• Advantages to studying simpler organisms (Aplysia)
- Mammalian brains are too big.
- Most higher order forms of learning and memory are too complicated.
- Study the simplest forms of learning and memory in the simplest nervous systems
