Lecture 19 Flashcards
the extrapyramidal system pathway
basal ganglia gets information from cortex (except primary sensory) project to thalamus and back to cortex.
what is the extrapyramidal system modulated by
substantia nigra
the extrapyramidal system is used for
initiation, amplitude, and direction of learned movement
Cerebellum: input, output, and functions
input: sensory system
output: motor inhibition (perkinje cells)
makes programs for rapid skilled movements, including learning the precise timing
muscular distrophy
direct muscle impairment
myastheniagravis
auto immune attack on Ach-R
parkinson’s
loss of DA neurons in the substantia nigra, affecting DA used at excitatory synapses in basal ganglia
amyotrophic lateral sclerosis
motor neurons start dying, leading to muscle atrophy
Huntington’s disease
loss of normal inhibition in basal ganglia- extreme uncontrolled movements
damage to spinocerebellum
ataxia- degenerative disease of nervous system (coordination based on perception)
damage to cerebrocerebellum
decomposition of movement, impaired precision in motor learning
damage to vestibulocerebellum
affects posture, coordination of gaze with movement, and balance
motor skill learning in rats: reach training
in order to reach through window need to use non dominant hand. learn to do this. wrist and digit areas on non preferred hand expand and new synapses are formed
causes of stroke
either a break in the capillaries in the brain or a blood clot that clogs the capillaries. Both cases leads to a patch of brain that doesn’t have the nutrients it needs
hermaphrodite
male and female sex organs for both animals
appetitive behavior
interested in going further
copulation
each participating
steroid review
steroid hormones are small, lipophyllic molecules synthesized from cholesterol. easily move between cells and tissues. cannot be stored, released as soon as made, can easily pass from the circulation and into blood brain barrier.
testosterone can easily be changed into
DHT (androgen) or E2 (estrogen)
organizational effects of hormones
permanent or long lasting effects on behavior, have a critical period early in development, and establish substrate for future behavior
activation effects of hormone
temporary and diminish as hormone is metabolized, occur in adulthood, act on established substrate of receptors in tissues and brain
What is the development for male sex
Male mammals- male has a Y chromosome, SRV gene is on Y and becomes activated, early differentiation of testes from gonad, production of testosterone, masculinization of brain and body
what is the development for female sex
Females- lack of early testosterone leads to development of female gonads, genitalia, and brain circuits.
aromatization hypothesis
testicular androgens enter the brain and are converted there into estrogens to masculinize the developing nervous system, separate from effects on body
if there is a low amount of s a reductase
may cause baby born without penis
development of the body, brain, and behavior in absence of androgens
female (default) regression of wolffian ducts and growth of mullerian into fallopian tubes and uterus
development of the body, brain, and behavior in prescence of androgens
male, regression of mullerian ducts and growth of tubes for carrying sperm
during fetal development, how does a particular immune cell play a key role in determining male or female characteristics of the brain
fetal males have more mast cells in PoA than females. they release histamine, which induces local microglial to release prostaglandin molecules that in turn stimulate synapse development
androgen insensitivity syndrome
(not responsive to androgens) gene for androgen receptor is on the X chromosome. Act and appear female but have testes
congenital adrenal hypertrophy (CAH)
adrenal cortex too active, XX plus androgens, act and appear male, but have ovaries
XX and exposure to environmental androgens
appear male but also develop ovaries and uterus inside
guevedoces
5 alpha reductase deficiency, can’t convert testosterone intermediate, raised as girl then shifts in adolescence to male like
what hormones are linked to social attachment
oxytocin and vasopressin have been implicated in several forms of affiliative behavior including parental care, grooming, sexual behavior, and pair bonding
How are male rats responsive to pheromones/sexual stimulation?
Pheromones from receptive females are detected by the vomeronasal organ. Higher brain center axons converge on mPOH (medial preoptic area in males). Circulating testosterone is converted to estrogens and acts on these 2 sites (mPOA, and medial amygdala). Androgens act on spinal neurons to augment reflexes. Ventral midbrain neurons connect to those associated with ejaculation so those neurons become more likely to be active. From ventral midbrain to brainstem to spinal cord associated with posture of male (mounting)
How are female rats responsive to pheromones/ sexual stimulation?
Estrogens induce production of progesterone receptors to respond to that hormone. Estrogen affects neurons at these 2 sites (ventromedial hypothalamus, periaqueductal grey). Periaqueductal grey turns off sensations of pain and turns up sensations of pleasure. Communicates to medullary reticular formation, then goes to the spinal cord involved in lordosis- when the female arches her back to make herself more accessible to the male. Higher brain centers feed into the 2 sites as well and the male stimuli of touching her also stimulates lordosis
what structure is critical for female sexual behavior
the ventromedial hypothalamus (VMH)
what structure is critical for male sexual behavior
the medial preoptic area (mPOA)
phasic hormone shifts in females
causes times that pregnancy is possible and times that pregnancy is not. Can follow an endogenous rhythm like in humans and rats or an external one like day length in deer
female reciprocity to copulation may be linked to
tightly to hormone pattern in dogs and horses or loosely linked in great apes
what can help explain why autistic kids have difficulty forming a close relationship with someone else
their different oxytocin patterns
Difference between human sexual response cycles (orgasms) for males and females?
Males have sexual excitement, hit a minor plateau, then have an orgasm and then a refractory period before they can then be stimulated again for another orgasm.
Women can be sexually excited for a long period of time and never reach orgasm, they can be excited fast and reach orgasm fast, or it could be at a medium pace. They don’t have a refractory period before they can be stimulated again
what zone differs in between males who are straight and gay
INAH in anterior hippocampus is the same size in homosexual men as in women, but is smaller than straight males
Mr. Odonell
behavioral, hormonal, and molecular causes
drinking problem, neurons die in hippocampus, korsakoffs syndrome
Henry mokison (HM)
epilepsy, surgery removing front 2 inches of temporal lobe, severe anterograde amnesia for episodic material. Information not retained about where or what, but how could be learned
aplysia habituation (what happens, NT, short term v long term)
on being touched the gill and the siphon are withdrawn for some period of time, after repeated stimulation, the withdrawal reflex becomes much smaller. In habituation the axons don’t release as much neurotransmitters (glutamate) as a result of altered mobilization of NT vesicles. This is short term habituation that can last several minutes but after repeated habituation the sensory neuron retracts many of the collateral axon branches (can last up to 3 weeks)
aplysia sensitization
after shocking the tail, later touches to the siphon produce increased motor response.
