Emam 2-AB Flashcards
What is a sensory receptor?
ransduce physical signals (detect stimuli) into encoded neural signals, which transport information to nerve centers
what kind of neurons are afferent
sensory
What kind of neurons are efferent
motor neurons
What are interneurons
neurons that are exclusively in the CNS
what are gated channels activated by
a stimulus, such as a change of voltage across the membrane
What is a sodium potassium pump
transports Na+ and K + across the cell membrane. Sodium os actively removed from the cell via this
define synapse
decision and integration points in the nervous system
What do synaptic vesicles contain
neurotransmitters
What do action potentials open
voltage sensitive Ca2+ channels, that cause the vesicle to move the membrane of the terminal bouton
Define NT
endogenous chemicals that allow neurons to communicate with each other throughout the body
What is the synaptic cleft?
when synaptic vesicle fuses with the cell membrane, the NT it contains is released into the synaptic cleft where it binds to receptors on the dendrite of the post-synaptic nerve cell
What is an excitatory synapse
causes a slight depolarization of the second cell (receptor opens to let Na+ in), called an excitatory postsynaptic potential (EPSP)
What is an inhibitory synapse
causes a slight hyperpolarization of the second cell (the receptor opens a receptor that allows Cl- in), called an inhibitory postsynaptic potential (IPSP)
Spatial summation
number and type of synapses on its dendrites
Temporal Summation
rate at which the presynaptic neuron fires
What two factors depend of if a postsynaptic cell reaches the threshold
spatial and temporal summation
What is a neuromodulator?
something that alters the sensitivity of neurons
What is sensory perception
The ability to understand and interact with the environment using senses of sight, smell, hearing, taste, touch
What is a azimuth
the angular measurement between the sound source and a reference direction
What is the Nucleus magnocellularis
½ cochlear nuclei. Processes the timing of sound
Nucleus angularis function
processes sound intensity
Inferior colliculus function
region of the midbrain where the neurons create a map auditory space
what is the optic tectum
area of the brain responsible for visual localization and orientation of the head
What is long term potentiation
persistent strengthening of synapses that enables a long-lasting increase in synaptic transmission in a neuronal network.
What is long term depression
an activity-dependent reduction in the efficacy of neuronal synapses lasting hours or longer following a long patterned stimulus
What is synaptic remodeling
changes in the number of dendritic spines of the postsynaptic neuron, production of growth factors by glial cells (which modify the growth of dendrites and axons), and activation of CREB, which also produce structure changes of synapses
What is neurogenesis
process where new neurons are formed
what is deafferentation
when the sensory nerve is cliped or chemically blocked
Draw the stucture of a basic neuron and label
just do it
Why are neurons polarized
Nerve cells are polarized when unexpired
More negative inside the cell membrane
What is more concentrated inside the cell
K
is there net movement of K across the membrane?
nah
Describe an action potential
Local depolarization of membrane opens voltage-sensitive sodium gates at neighboring points
This causes an action potential to travel down the axon
action potential occurs when the membrane potential of a specific cell rapidly rises and falls
Can you describe, generally, how a barn owl localizes sound? The neural pathways involved in timing and intensity of sound?
arn owl can detect the position of a prey item in complete darkness
Sensory perception begins with organization of sensory structures
Limit (tuned to) detection of stimuli
Pattern of feathers on face of owl and organization of its ears that allow it to determine the spatial location of prey without visual inputs
Owl uses difference of arrival times of sound to its two ears and difference in sound intensity between the two ears to determine the horizontal & vertical position of a sound stimulus
Ex. A noisy mouse
Information about timing of sound & sound intensity between ears travels as impulses in the Auditory nerve to the central nervous system
Axons in auditory nerve on each side of the head send a branch to two cochlear nuclei – the nucleus magnocellaris, which processes the timing of sound & the nucleus angularis, which processes sound intensity
Information relayed to external nucleus of the inferior colliculus, a region in the mid brain, where the neurons literally create a map auditory space
Specific neuron in the inferior colliculus responds maximally to specific binaural difference in the arrival of sounds
Auditory map space then relayed to the optic tectum (area of brain responsible for visual localization and orientation of head)
Can you describe habituation and sensitization in Aplysia?
When sea slug moves across the ocean bottom, its gills are spread and its siphon (used for exertion) is extended If siphon is touched by predator
1)stimulus to skin stimulates sensory neurons on the skin
2) facilitiating interneurons is stimulated that synapses on the azon terminal of the sensory neuron from the siphon skin
3) Serotonin realsease from facilitating neuron
4) increase cAMP
5) cAMP causes closing of K channels which prolongs depolarization
6) more Ca enters the axon terminal as usual
7) increased release of NT by sensory neuron
8) increased firing rate of gill motor neuron
How are memories stored?
Brain regions operate in networks – organization of these changes when an animal learns (memories are formed)
Synapse number and strength correspond to strength of mem
What is the duration of a short term memory
minutes or hours
What is the duration of an intermediate - term memory
weeks, months or years
How long do long term memories last
weeks, months, years, decades
Why do we have different kinds of memories?
Memories correspond to synaptic modifications – changes in the strength or number of synapses
What NT is associated with long term potentiation
glutamate; With repeated stimulation the postsynaptic neuron becomes more and more sensitive to glutamate due to enhanced sensitivity of glutamate receptors on the postsynaptic membrane & recruitment of additional glutamate receptors
What factors aid the formation of long term memories
Long-term Depression: synaptic strength – sensitivity to glutamate – is decreased
This occurs when postsynaptic neurons are not regularly stimulated
Synaptic remodeling: changes in the number of dendritic spines of the postsynaptic neuron, production of growth factors by glial cells (which modify the growth of dendrites and axons), and activation of CREB, which also produce structure changes of synapses
Neurogenesis: growth of new neurons. At the foundation of learned behavior
Give an example of neurogenesis
Birds that store food have a larger hippocampus than birds that do not store food
Growth of new neurons varies seasonally – with need to store food
What is a central pattern generator
Related to motor neurons which control muscle movements
Motor patterns that are repeated over and over are often controlled by a central pattern generator
Network of neurons that generates patterned activity even when sensory input is removed from the system
What does an endocrine gland do
produce hormones
What are hormones
chemicals secreted in one part of the body that cause changes in other parts of the body
What is a target cell
hormones often remain in the blood stream for long periods and affect only these certain cells (target cells)
What is a peptide hormone?
amino acid chains (3-300 amino acids). Create relatively short-term changes of cell membrane properties
they are water soluble
bind to receptors on the membrane of the cel;
induce complex molecular interactions inside the target cell that often involve second messengers
What are steroid hormones?
group of closely related hormones secreted primarily by the gonads and adrenal glands in vertebrates
What are neurosteroids
steroid hormones produced by neurons
Rapidly modulate excitability and are involved in cell divsion and neurogenesis
What is an antihormone
similar to knock out strains. Young virgin males treated with progesterone show increased aggression, but those treated with the antihormone that blocks progesterone receptors, reduced aggression)
What does the challenge hypothesis state
the idea that temporal patterns of Testosterone are determined by a trade-off between the degree of male- male competition and the expression of parental care
What is alpha- fetoprotein
an estrogen binding protein produced in the liver of male and female fetuses, and binds to estradiol so it does not reach target brain neurons
What are the major classes of steroid hormones and where are they (generally) produced?
Androgens, progestogens, corticosteroids
Secreted by the gonads and adrenal glands in vertebrates
Derived from cholesterol
what does anadromous mean?
(involves fish such as salmon) that migrate up rivers from the sea to spawn
What is smoltification
the process of a young salmon becoming ready for entry into marine waters. This entails the change of color, change in osmoregulatory structure, and increased growth rate
How do peptide hormones function
create short term changes of the cell membrane properties
What is rheotaxis?
a form of taxis in many aquatic organisms, where they turn to face oncoming currents
How to steriod hormones function
they are fat soluble and enter target cells directly, and then bind to a receptor, enter the nucleus, and trigger gene transcription
How do neurosteroids function
May inhibit or enhance neurotransmission through modulation of GABAA or NMDA receptors
GABA is the major inhibitory neurotransmitter
What are the consequences of cellular responses to hormones?
Alter behavior through pathways:
Sensory and perceptual mechanisms
Development or activity of the central nervous system
Muscles used to execute behavior
How do hormones affect brain tissue?
They alter volume of brain tissue, number of cells in the brain tissue, the size of the neuron cell bodies, the extent of dendrite branching, the neuron sensitivity to a particular hormone, and the survival of neurons
What kinds of approaches are used to study hormone influences on behavior
Correlations between behavior and hormone levels are used to identify putative causal relations
Challenge hypothesis: the idea that temporal patterns of testosterone are determined by a trade-off between the degree of male-male competition (increased testosterone good) and the expression of paternal care (decrease in testosterone good)
What are the two major effects of hormones?
1) Organizational effects- effects that occur early in life; permanent effects that alter responsiveness of neurons to steroid hormones and organize development along separate pathways. Ex) Testosterone on adult reproductive behavior in rats or position of a female rat in the uterus
2) Activation Effects: occur in adulthood; alter previously established neuronal connections (small changes in neurotransmitter production or release) no major reorganization of established neural pathways
Estradiol in fetus male rats induces male-like behavior when they are adults. Female fetus rats produce estradiol, so why do adult females not exhibit male-like behavior?
Due to the alpha-fetoprotein (an estrogen binding protein produced in the liver of male and female fetuses, and binds to estradiol so it does not reach target brain neurons)
Do hormones cause behavior or does behavior alter levels of hormones?
Hormones alter behavior but the reciprocal is true too
Why are hormone levels controlled by the environment?
the production of hormones is typically timed to environmental conditions that predict events important for survival and reproduction
What are some environmental conditions that alter hormone production?
Photoperiod and social environment
Can you describe the life cycle of anadromous salmon and how hormones influence smoltificaion and behavior?
Environmental cues & hormones associated with behavioral, physiological and morphological changes over the life cycle
Higher water flow, longer photoperiod, and warmer temperatures prompt smoltification
Prolactin (promotes osmoregulation in fresh water) production declines
Prolactin and fish growth hormone are peptide hormones produced by the pituitary
Growth hormone increases and in combination with cortisol enhances tolerance for salt water
Thyroid Hormone induces the loss of stripes (parr marks) in parr (replaced by silver coloration)
Behavioral changes accompany smoltification:
There is a shift in orientation from upstream (positive rheotaxis) toward downstream (negative rheotaxis); reduced aggression; and the formation of schools
Transition back to freshwater to spawn is equally complex
Male pink salmon transition from ocean stage to spawning male
Then after they breed they basically fall apart and die L
define metamorphosis
process in which the NS is repeatedly dismantled and rebuilt.
Define ecdysteriod
coordinate the loss and reorganization of neurons
Describe play behavior
natural part of development for many species that is characterized by exaggerated movement, repetition of behavior, and juxtaposition of functionally different behavior patterns. Play appears to have a lack of purpose but influences Physical, social, and cognitive development
What is a sensitive period
the expression of behavior depends on the exposure to a stimulus over this time period. The onsets of these periods is caused by endogenous factors and exogeneous factors.
what is pragung
stamping (konrad lorenz)
Describe flial imprinting
Goslings learn characteristics of their mother and exhibit a preference. Young show an unlearned predisposition to follow the calls of a female if the appropriate species.
Describe sexual impriting? What are the 2 phases?
involves early experiences with partners or siblings, which influences sexual preferences.
Acquisition phase(bonds with parents influence the young to socialize with individuals of the same species)
the Consolidation phase (social preferences direct individuals to court members of their own species when they become adults). The degree for which the courter is sexually motivated at the time of the first courtship attempt impacts the extent to when sexual preferences are fixed.
Who is Patrick Bateson
looked at sexual imprinting costs associated with inbreeding and outbreeding between goats and sheep, and Japanese quail. Found that males prefer the foster parent type and female preference was less impactful and more reversible
Who is Peter Maler
looked at the importance of learning in the development of song in birds
What is a subsong
in the first summer of life, males produce subsongs which are different songs of adult males
What is a plastic song
by the time of the first breeding season males produce their plastic song which is the typical adult male song
What is song crystallization
When the first breeding season begins the song of young males becomes crystalized to resemble his father and other males and remains unchanged after that.
Describe the brood parasite, and how they learn song
in the cowbird, male song of the parasite is delayed until their second summer when they hear conspecifics, showing that young males show and inherent own species bias to learn the song of the cowbird. However, in the white crowned sparrow, they learnt the song of their tutor species.
How do birds control exposure of chicks to androgens like testosterone and how do these levels
prenatal exposure to androgens in the yolk of eggs influences behavior. Black headed gulls lay several eggs and females can control the level of testosterone and other androgen deposited in the yolk (eggs that are laid later have more androgens). Higher androgen levels enhance 1) rate of development 2) Growth 3) Begging behavior
What animals show temperature-dependent sex determination?
Several lizard species, many turtles, and all crocodilians
Who is Arthur Hasler
looked at olfactory imprinting in salmon, and said that migration in some fish involves a sun compass
When do salmon learn the odor of their natal stream?
Around the time of smoltification (the transition from parr to smolt that occurs before the migration to the ocean)
What auditory experiences influence imprinting in ducks? Describe some experiments related to these experiences.
he auditory experience before they hatch is important to the preference that they form. A few days before hatching (the sensitive period) the duckling moves its head into the airspace in the egg and makes a “contentment call”. Preference for a mallard call is not seen in ducks made mute or isolated.
How is movement related to imprinting
Movement by the mother is necessary for the development of a visual preference. Duckings that were exposed to a stationary stuffed mallard hen do not preferentially follow a mallard hen
Can you describe the process of sexual imprinting in some birds
Both male and female Japanese quail prefer to spend time with first cousin over siblings, second or third cousins or unrelated relatives
What are the causes of maternal attachment?
1) activation of maternal responses (occurs right after parturition) and 2) Establishment of maternal selectivity (occurs 1-2 hours postpartum)
What are song nuclei? Anterior and posterior pathways?
song nuclei are the regions of the brain that are connected via the neural pathways that are involved in the production and acquisition of song. The Posterior pathway involves song production while the anterior pathway involves song acquisition
How are song nuclei related to song repertoire?
here is a positive correlation between the size of the song nuclei and song repertoire. The bigger the SN the greater the number of songs known
Who is Mark Hauber
showed that a vocal password is involved and serves as a trigger to learn song and physical attributes of the signaler
What hormone masculinizes the song system in zebra finches?
estrogen
What hormone is needed to activate the song system in zebra finches?
testosterone
How is auditory feedback involved in the development of song in white crowned sparrows?
Young males can listen to themselves and match their vocal output to memorize the songs heard during their sensitive period. Deaf young males fail to produce a normal song.
How does social experience influence song development in cowbirds
females adopt a copulatory posture when they hear a male’s song they like. The young males then learn what calls are attractive to the females. Because of this, dominant males in mixed sex flocks attack young subordinate males when they sing. This causes the young males to learn songs that don’t get they beat up, and therefore are song that are no attractive to the females.
What is a p value
A p value is the probability of an outcome that is crazier than if the null is true.
