Can affect presynaptic neurons neurotransmitter release Or can

• Can affect presynaptic neuron’s neurotransmitter release • Or can affect postsynaptic neuron’s sensitivity • Or change action potential duration, etc

neuromodulation I: alteration of ion channel kinetics through changes in phosphorylation state Desai and Walcott, 2006: ACh decrements the responses of Ca++-dependent K+ channels thereby enabling greater initial responses as well as persistent responses to current injection (note…current injection mimics excitatory ionotropic input) ACh agonist application (i. e. , activation of ACh receptors change in membrane potential in response to neuromodulatory inputs is sometimes minimal current injection ACh agonist application (i. e. , activation of ACh receptors persistent firing rate response to shortterm excitatory input K+ efflux in response to depolarizing current step increasing current injection steps persistent firing response may, in turn, be modulated by number of excitatory inputs time ACh alters K+ outflow caused by Ca++ influx (as seen when excitatory ionotropic receptors are activated)

neuromodulation II: uneven distribution, across dendrites, of ion channel responses to neuromodulators leads to alteration of neuronal responses to intrinsic, but not extrinsic inputs in pyriform cortex (note…pyriform cortex has only 3 layers) Hasselmo et al. , 1997: both norepinephrine and acetylcholine depress synaptic responses to excitatory inputs in layer Ib (intrinsic connections) much more so than to excitatory inputs to layer Ia (extrinsic connections) – that is, each change the degree to which pyriform cortex listens to the outside world (extrinsic inputs) versus the inner world (cortex or ‘intrinsic’ inputs) layer Ia inputs to dendrites of layer II neurons arise from olfactory bulb layer Ib inputs to dendrites of layer II neurons arise in this case, both from other acetylcholine regions of cortex (mimicked by carbachol) and norepinephrine excitatory have the same responses to action on Ib layer Ia or Ib inputs stimulation under different conditions

Allostatic model • With repeated drug challenges: • The mesolimbic dopamine “reward” system develops tolerance • The extended amygdala “antireward” system sensitizes • Eventually, this leads to a new, depressed set point called allostasis

Aberrant learning model • With repeated drug challenges: • Hyperaccelerates the transition between action-outcome learning to stimulus-response learning • At the same time, damage to inhibitory inputs coming from prefrontal areas leads to gradual progression from habit to compulsion

Incentive sensitization model • With repeated drug challenges: • The motivational aspect of mesolimbic dopamine system sensitizes • The hedonic aspect develops tolerance, leading to “wanting” without “liking”

True or false? Metabotropic receptors are ion channels.

Multiple choice: Main nucleus of the norepinephrine system is the A. B. C. D. E. Posterior hypothalamus Ventral tegmental area Basal forebrain Raphe nuclei None of the above

Short answer: Activation of metabotropic receptors typically results in ___ of ion channels.

True or false? Deinactivated ion channels are closed.

Short answer: Part 1: If oxotremorine (a muscarinic receptor agonist) decreases K+ efflux, describe what happens to the neuron when it’s injected with the same current compared to a control neuron.

Short answer: Part 2: What happens when you increase the current?

True or false? Neuromodulators may allow a structure to become biased towards one type of input over another.

Multiple choice If you were forced to do drugs, you should pick: A. B. C. D. E. F. LSD Ecstasy Heroin Amphetamine Cocaine All of the above

True or false? The hippocampus proper is composed of the entorhinal cortex, dentate gyrus, CA 3, and CA 1.

Multiple choice: Which of the following is an autoassociative structure, as discussed in the lecture? A. B. C. D. E. Entorhinal cortex Dentate gyrus Subiculum CA 1 None of the above

True or false All of the inputs into CA 1 comes from CA 3, because the trisynaptic pathway progresses from dentate gyrus to CA 3 to CA 1.

True or false? Head direction cells code allocentric information.

True or false? If the environment is rotated, a rat’s place cell will rotate with it but its grid cells will not.

Short answer: The ___ cell is thought to be the bridge between orientation and place specificity.

Short answer: The geometric shape of grid cell activity is the ___.