Exam 3: Basic Motivations Flashcards
EEG
Reveals gross electrical activity of the brain, “brainwaves”
EOG
Records eye movements seen during REM sleep
EMG
Detects loss of activity in neck muscles during some sleep stages
4 Stages of Sleep
- Theta waves
- Spindles and K complexes
- Occasional delta waves (large and slow, 1-2 Hz)
- Predominantly delta waves
Awake characteristics
Asynchronous, low-voltage, high frequency (fast) waves
Pre-sleep characteristics
Intermittent alpha waves, bursts of low frequency (8-12 Hz) waves
Sleep characteristics
Synchronous, voltage increases and frequency decreases slows through stages 1-4
When are you paralyzed in your sleep?
During REM
When would a person sleepwalk?
During deep sleep
Recuperation
Sleep is needed to restore homeostatic balance lost during the day
Adaptation
Sleep is the result of an internal timing mechanism, evolved to conserve energy and to protect us from the dangers of the night
Zeitgebers
Environmental cues that entrain circadian cycles (ex: sun)
What direction are zeitgebers accelerated?
Flying east, trouble
What direction are zeitgebers decelerated?
Flying west, easy
What is the sleep-wake circadian clock?
Suprachiasmatic nucleus (SCN) in hypothalamus
4 Sleep-Wake areas
- Anterior hypothalamus (VLPO)-sleep
- Posterior hypothalamus-wakeful
- Rostral reticular formation-wakeful
- Caudal reticular REM nuclei-sleep
Homeostatic process
Sleep need, magnitude depends on amount of prior sleep and wakefulness
Circadian process
Sleep urge, governed by SCN clock
Hypnotic drugs
Enhance effect of GABA, increase sleep time, complications: tolerance, addiction, cessation=insomnia
Anti-hypnotic drugs
Increase activity of catecholamines, decrease sleep time, complications: lost appetite, addiction
Chronobiotic drugs
Alter circadian rhythm, knock out SCN, increase levels of melatonin
Insomnia
Latrogenic (pills), sleep apnea (obstructive, central), limb movement before or during sleep
Hypersomnia
Narcolepsy, cataplexy (loss of muscle tone), hypnagogic hallucinations
Set point
Point at which a variable physiological state (homeostasis) tends to stabilize, narrow range, same for everyone
Allostasis
Body’s set points can change from time to time
Negative feedbacks
Processes that reduce differences from set points
Dorsal parvocellular cells (PVN)
Project to medulla and spinal cord, controls parasympathetic system
Ventral parvocellular cells (PVN)
Project to medulla and spinal cord, controls sympathetic system
Medial parvocellular cells (PVN)
Releases hormones that affect release of other hormones from anterior pituitary
Magnocellular cells (PVN)
Release directly hormones from posterior pituitary
Anterior pituitary
Synthesizes and secretes hormones in response to hormones released by hypothalamus (medial parvo)-indirect
Posterior pituitary
Develops as an extension of hypothalamus, stores and secretes (but does not synthesize), magnocellular-direct
Ectoderms
Amphibians, reptiles, fish, cold-blooded, body temp matches environment
Endoderms
Mammals and birds, warm-blooded
Do you want more or less thyroxin when you are hot?
Less
Behavioral mechanisms for regulation of body temp
-Find cool or hot place
-Become more or less active
-Sleek/fluff fur-less/more clothes
-Stand alone/together
Controlled by LHA
Physiological mechanisms for regulation of body temp
-Sweat (pant of lick)/shiver
-Increase/decrease blood flow to skin
Controlled by PVN
Advantages of increased body temperature (2)
- Mobile all year long
2. Protection from fungal infections
What do physiological changes that maintain our body temp depend on?
Preoptic area and anterior hypothalamus
Osmotic thirst
Caused by eating salty foods, increases concentration of solutes in extracellular space
Hypovolemic thirst
Caused by losing fluid volume, such as bleeding or vomiting
Osmotic thirst receptors (2)
- OVLT- rostral to hypo
- SFO- superior to thalamus
Both detect their own water loss
What does the preoptic area do?
Generates the desire to drink
What do the supraoptic and paraventricular neurons do?
Conserve water
What is water conservation controlled by?
Release of ADH from posterior pituitary, it enables kidneys to reabsorb water and excrete concentrated urine
What is blood volume (BP) controlled by?
Baroreceptors, found in walls of arteries, veins, and heart, mechanoreceptor that is excited by stretch and inhibited by relaxation of blood vessel
Hypovolemia
Causes suppression of baroreceptor activity, stimulates vasomotor center to activate nuclei in hypo to generate desire to drink and conserve water (release of ADH)
Renin
Released by kidneys, leads to synthesis of angiotensin II (produces cravings for sodium tastes), causes constriction of blood vessels to increase blood pressure
How should hypovolemic thirst be quenched?
With a salty drink (not pure water)
Ghrelin
Hormone for hunger, in stomach
CCK
Hormone relating to satiety, in intestines, closes exit of stomach
Arcuate nucleus (AR)
“Master area” for control of appetite, regulates amount of sex hormones
What do hunger sensitive neurons in AR do?
Inhibit cells in PVN and turn off PVN inhibition of LH that promotes appetite
What do satiety sensitive cells in AR do?
Excite PVN cells that turn off LN cells thus ending meals
Organizational effect of hormones
Body development
Activation effect of hormones
Triggering reproduction-relating behaviors in mature adults
Primary organs that release sex hormones
Gonads: male-testes, female-ovaries; (adrenal glands also release small amounts of sex hormones)
3 kinds of steroid hormones
- Androgens
- Estrogens
- Progestins
Anterior pituitary sex hormone releasing strategy
Released from hypothalamic neurons into hypothalamopituitary portal system
Posterior pituitary sex hormones
Oxytocin and vasopressin synthesized in PVN and supraoptic nuclei of hypothalamus
Gonadotropins
Released by anterior pituitary, called FSH and LH,
PERIVENTRICULAR (different from PVN)
Regulation of sex hormone levels (2)
- Nervous system signals
2. Circulating hormones
Kisspeptin
From AR tells periventricular nucleus to release sex hormones
Primordial glands
Pair of gonadal structures that all fetuses have, regardless of genetic sex
Cortex has potential to be….
an ovary
Medulla has potential to be…
a testis
Sry protein
7th week after conception, Sry gene on Y chromosome, causes medulla to grow into a testis
No Sry protein
Cortex develops into ovary
Reproductive ducts (2)
- Wolffian system: male, seminal vesicles, vas deferens
2. Müllerian system: female; uterus, vagina, fallopian tubes
When does differentiation of ducts begin?
Third prenatal month
Bipotential precursor parts (4)
- Glans
- Urethral folds
- Lateral bodies
- Labioscrotal swellings
When does differentiation of external genitalia occur?
Second month of fetal development
Puberty
Increase in release of hormones (growth and sex tropic) by anterior pituitary
Infertility genotypes (2)
XO and XXY
Where are differences in the brain found between males and females?
Hypothalamus and amygdala
4 areas for brain mechanisms of sexual behavior
- Cortex
- Ventral striatum
- Hypothalamus
- Amygdala
Sexual orientation
Enduring pattern of romantic or sexual attraction to persons of same or opposite gender (or both)
Sexual identity
Sex, male or female (or combo), a person believes themselves to be
Theories of how we evolved ability to learn language (2)
- By-product of overall intelligence
2. Specialized brain modules
Problems with overall intelligence theory
- Normal intelligence, but genetic condition impairs language
- Williams syndrome: cognitive impairment but good language
Specialized Brain Module Theory
Built in mechanisms for language acquisition
7 main areas of cortex for language
- Primary visual cortex
- Primary auditory cortex
- Angular gyrus
- Wernicke’s area
- Arcuate fasciculus
- Broca’s area
- Primary motor cortex
Broca’s Aphasia
AKA nonfluent, expressive, and production aphasia, normal comprehension but slow and labored speech and writing difficulties
Wernicke’s Aphasia
AKA fluent, receptive, comprehension aphasia, poor comprehension, articulate speech but meaningless and writing difficulties
Dejerine
Reading aphasia, damage to left angular gyrus, damage in pathway from visual cortex to angular gyrus
Alexia
Inability to read
Agraphia
Inability to write
Conductive Aphasia
Selective damage to arcuate fasciculus, error awareness with attempts to correct them, poor repetition of unfamiliar words
Anterior lesions cause…
Expressive aphasia
Posterior lesions cause…
Receptive aphasia
Damage to frontal cortex for sign language
Impair making of gestures
Damage to temporal cortex for sign language
Impair understanding of gestures
What parts of the brains grow stronger when shifting languages?
Frontal cortex, temporal cortex, and basal ganglia (caudate)
2 types of dyslexia
- Developmental
2. Aquired
Magnosystem hypothesis
For dyslexia, processing in dorsal stream of visual system is impaired resulting in decreased activation of angular gyrus
Declarative Memory
Explicit, knowing what, broken up into: semantic and episodic
Procedural Memory
Implicit, knowing how, motor skills and conditioning
Retrograde amnesia
Memory loss for events before the trauma
Anterograde amnesia
Inability to form new memories after the trauma
What are medial temporal lobes involved in?
Explicit memory
Damage to anterior pole of medial temporal lobe
Deficit in semantic memory
Damage to caudal medial temporal lobe
Difficulties with episodic memory
3 major structures of caudal medial temporal lobe
- Rhinal cortex
- Hippocampus
- Amygdala
What does the hippocampus play a role in?
Memory for spatial navigation
Papez circuit
Part of limbic system, begins and ends with hippocampus
Brain structures involved in skill learning (2)
- Basal ganglia- patterns
2. Cerebellum- how to do things
Where is short-term memory stored?
Locations in the telecephalon, including the prefrontal cortex
Where is spatial memory stored?
DLPFC
Where are object identifiers stored?
VLPFC
What part of memory is degraded first from Alzheimer’s?
Episodic, followed by ST and semantic, then procedural
Contributing factor to memory loss in AD
Depletion of Ach in brain due to degeneration of basal forebrain
Cell assembly
Internal representation of an object consists of all of the cortical cells activated by the external stimulus
Basis of LTM according to Hebb
Changes in synaptic efficiency
LTP
Elicited by high frequency electrical stimulation of presynaptic neuron
3 part process for LTP
- Induction (learning)
- Maintenance (memory)
- Expression (recall)
Induction of LTP
NMDA receptors do not respond maximally unless glutamate binds and neuron is already partially depolarized, Ca+2 entry triggers events that lead to LTP
Maintenance and Expression of LTP
Occurs at specific synapses on a postsynaptic neuron, maintenance involves structural changes
