Prelim 2 Questions 21-32 Flashcards
How are males responsive to pheromones/sexual stimulation?
Pheromones from receptive females are detected by the vomeronasal organ. Circulating testosterone is converted to estrogens and acts on mPOA and medial amygdala. 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 females 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 are the aspects to the women’s sexual/ emotional pattern cycle?
Willingness to become responsive, sexual stimuli with appropriate context, psychological and biological processing, spontaneous innate desire, subjective arousal, arousal and responsive sexual desire, nonsexual rewards (emotional intimacy, well being, lack of negative effects from sexual avoidance), sexual satisfaction with or without orgasm, multiple reasons and incentives for initiating/agreeing to sex, motivation, back to willingness to become responsive
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
Explain aplysia’s non associative learning (habituation) and the long term and short term versions.
Habituation- on being touched the gill and the siphon are withdrawn for some period of time, after repeated stimulation, the withdrawal reflex becomes much smaller.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)
Explain aplysia’s non associative learning (sensitization) and the long term and short term versions.
Sensitization- after shocking the tail, later touches to the siphon produce increased motor response. For sensitization, the pain signal comes in on presynapse, causes serotonin to be released, serotonin acts on the presynaptic side of sensory motor synapses, serotonin binds on metabotropic receptor, changes shape, activates cAMP on second messengers, kinases phosphorylate k+ channels causing them to stay open longer, continued depolarization, continued Ca2+, continued transmitter release (short term sensitization). Long term sensitization increases number of synapses between sensory and motor neurons
Explain long term potentiation
LTP is a long lasting increase in synaptic efficacy that results from plastic change at the synapse. Stimulation causes bursts of electrical stimulation, 1000 APs. After tetanus, the same stimulation evokes much larger (potentiated) responses.
Explain the mechanisms involved in long term potentiation (before tetnus)
Mechanisms- normal transmission (before tetanus) activates the AMPA receptors, causing a moderate response (small EPSP before tetanus) there are latent AMPA receptors ready to be moved into the postsynaptic membrane.
Explain the mechanisms involved in long term potentiation (during tetanus)
During tetanus the strong repeated stimulation causes postsynaptic neurons to depolarize enough to remove Mg2+ block from NMDA receptors. Once Mg2+ block is gone, Ca2+ enters the cell and causes a cascade that causes latent AMPA receptors to move to postsynaptic membranes. Tetanus results in an increase in the number of receptors on the postsynaptic membrane.
Explain the mechanisms involved in long term potentiation (after tetanus)
After tetanus, mg2+ block is back in place, more AMPA receptors and the postsynaptic neuron is more responsive than before (enhanced EPSP).
What is the pavilion eyeblink conditioning? What are the mechanisms? (US reflex pathway)
US reflex pathway- US (air puff) -> trigeminal nucleus -> cranial motor nuclei -> UR (blink)
Pavlovian eyeblink pathway involves modulation of the existing reflex pathway. Information about the US (air puff) is sent to the cerebellum. Information about the CS (tone) enters through the brainstem auditory pathway and converges with the US in the cerebellum. The critical plasticity that supports eyeblink conditioning takes place in the interpositus nucleus of the cerebellum. Lesions downstream from the interpositus nucleus block the expression of the learned behavior but do not block the acquisitions (savings). Lesions upstream from the interpositus nucleus prevents the acquisition of the learned behavior
The mechanism in interpositus nucleus is LTP using NMDA receptors, leading first to strengthening existing synapses and then later to addition of synapses
What is muscle memory?
PMC and SMA plan sequence and timing of muscle stimulation motor cortex will do. As learning precedes, control Shifts from Premotor cortex (PMC)- using current visual information to supplementary motor areas (SMA) and BG which carry out well learned movement sequences
How is the mind different from a computer?
Learning consists of modifying existing pathways. Learning does not consist of writing down and accessing something that is in some other part of the brain like a memory brain or a memory circuit like in a computer. Memory for a computer is static, there is only a limited amount of storage and memory on a computer. Whereas memory in the brain can grow and change with adding, subtracting, growing, or reducing synapses and synaptic connections.
Why are people interested in studying neuroscience bother studying animals? Use evidence from the semester
Human brains and other animal brains are formatted and developed nearly the same. They have the same structures just in rather different sizes
Does animal cognition perform sophisticated learning? Use evidence from the semester
Can see evidence of “theory of mind” in blue jay experiment. When the male blue jay watches the female blue jay eat, he then gives her food he has not seen her have before. They are able to make an inference about what some other bird is thinking, what food can they feed her to impress her
