Catalogue Search | MBRL
Are you sure you want to remove the book from the shelf?
{{itemTitle}}
1,753
result(s) for
"Wilson, Rachel"
Sort by:
Dopamine promotes head direction plasticity during orienting movements
In neural networks that store information in their connection weights, there is a tradeoff between sensitivity and stability
1
,
2
. Connections must be plastic to incorporate new information, but if they are too plastic, stored information can be corrupted. A potential solution is to allow plasticity only during epochs when task-specific information is rich, on the basis of a ‘when-to-learn’ signal
3
. We reasoned that dopamine provides a when-to-learn signal that allows the brain’s spatial maps to update when new spatial information is available—that is, when an animal is moving. Here we show that the dopamine neurons innervating the
Drosophila
head direction network are specifically active when the fly turns to change its head direction. Moreover, their activity scales with moment-to-moment fluctuations in rotational speed. Pairing dopamine release with a visual cue persistently strengthens the cue’s influence on head direction cells. Conversely, inhibiting these dopamine neurons decreases the influence of the cue. This mechanism should accelerate learning during moments when orienting movements are providing a rich stream of head direction information, allowing learning rates to be low at other times to protect stored information. Our results show how spatial learning in the brain can be compressed into discrete epochs in which high learning rates are matched to high rates of information intake.
A study demonstrates that plasticity in the head direction system in
Drosophila
is modulated by dopamine, which increases learning when reorienting movements are bringing in new spatial information.
Journal Article
How to pee your pants : the right way
Well, it happened. You peed your pants. You probably regret that second (okay, third) lemonade. We've all been there. This book has some tips to get you through it (including but not limited to traffic cone pants, extraterrestrial negotiations, food fights, and other very practical techniques). With her playful retro palette, debut author-illustrator Rachel Michelle Wilson offers a space to laugh with yourself through one of life's most embarrassing moments and remember that you're never as alone as you think.
BOOK
The Effect of Film Thickness on the Gas Sensing Properties of Ultra-Thin TiO2 Films Deposited by Atomic Layer Deposition
Analyte sensitivity for gas sensors based on semiconducting metal oxides should be highly dependent on the film thickness, particularly when that thickness is on the order of the Debye length. This thickness dependence has previously been demonstrated for SnO2 and inferred for TiO2. In this paper, TiO2 thin films have been prepared by Atomic Layer Deposition (ALD) using titanium isopropoxide and water as precursors. The deposition process was performed on standard alumina gas sensor platforms and microscope slides (for analysis purposes), at a temperature of 200 °C. The TiO2 films were exposed to different concentrations of CO, CH4, NO2, NH3 and SO2 to evaluate their gas sensitivities. These experiments showed that the TiO2 film thickness played a dominant role within the conduction mechanism and the pattern of response for the electrical resistance towards CH4 and NH3 exposure indicated typical n-type semiconducting behavior. The effect of relative humidity on the gas sensitivity has also been demonstrated.
Journal Article
Your future as a carpenter
\"Learn about opportunities in the carpentry field, and find out which skills you can acquire now to get there\"-- Provided by publisher.
Book
Glutamate is an inhibitory neurotransmitter in the Drosophila olfactory system
Glutamatergic neurons are abundant in the Drosophila central nervous system, but their physiological effects are largely unknown. In this study, we investigated the effects of glutamate in the Drosophila antennal lobe, the first relay in the olfactory system and a model circuit for understanding olfactory processing. In the antennal lobe, one-third of local neurons are glutamatergic. Using in vivo whole-cell patch clamp recordings, we found that many glutamatergic local neurons are broadly tuned to odors. Iontophoresed glutamate hyperpolarizes all major cell types in the antennal lobe, and this effect is blocked by picrotoxin or by transgenic RNAi-mediated knockdown of the GluC l α gene, which encodes a glutamate-gated chloride channel. Moreover, antennal lobe neurons are inhibited by selective activation of glutamatergic local neurons using a nonnative genetically encoded cation channel. Finally, transgenic knockdown of GluCl α in principal neurons disinhibits the odor responses of these neurons. Thus, glutamate acts as an inhibitory neurotransmitter in the antennal lobe, broadly similar to the role of GABA in this circuit. However, because glutamate release is concentrated between glomeruli, whereas GABA release is concentrated within glomeruli, these neurotransmitters may act on different spatial and temporal scales. Thus, the existence of two parallel inhibitory transmitter systems may increase the range and flexibility of synaptic inhibition.
Journal Article
Your future as an auto mechanic
\"Find out how to prepare for a job as an auto mechanic, and which different types of vehicles you can work on\"-- Provided by publisher.
Book
Transforming representations of movement from body- to world-centric space
When an animal moves through the world, its brain receives a stream of information about the body’s translational velocity from motor commands and sensory feedback signals. These incoming signals are referenced to the body, but ultimately, they must be transformed into world-centric coordinates for navigation
1
,
2
. Here we show that this computation occurs in the fan-shaped body in the brain of
Drosophila melanogaster
. We identify two cell types, PFNd and PFNv
3
–
5
, that conjunctively encode translational velocity and heading as a fly walks. In these cells, velocity signals are acquired from locomotor brain regions
6
and are multiplied with heading signals from the compass system. PFNd neurons prefer forward–ipsilateral movement, whereas PFNv neurons prefer backward–contralateral movement, and perturbing PFNd neurons disrupts idiothetic path integration in walking flies
7
. Downstream, PFNd and PFNv neurons converge onto hΔB neurons, with a connectivity pattern that pools together heading and translation direction combinations corresponding to the same movement in world-centric space. This network motif effectively performs a rotation of the brain’s representation of body-centric translational velocity according to the current heading direction. Consistent with our predictions, we observe that hΔB neurons form a representation of translational velocity in world-centric coordinates. By integrating this representation over time, it should be possible for the brain to form a working memory of the path travelled through the environment
8
–
10
.
Specific neurons in the fan-shaped body of the
Drosophila
brain convert translational information in relation to the fly’s body to externally referenced coordinates for navigation.
Journal Article
Your future as a plumber
Provides a detailed look at the day-to-day work of professionals in the plumbing industry, including opportunities for specialization and advancement--with profiles of real-life plumbers offering insight into the challenging and rewarding aspects of the career.
Book
Sensorimotor experience remaps visual input to a heading-direction network
In the
Drosophila
brain, ‘compass’ neurons track the orientation of the body and head (the fly’s heading) during navigation
1
,
2
. In the absence of visual cues, the compass neuron network estimates heading by integrating self-movement signals over time
3
,
4
. When a visual cue is present, the estimate of the network is more accurate
1
,
3
. Visual inputs to compass neurons are thought to originate from inhibitory neurons called R neurons (also known as ring neurons); the receptive fields of R neurons tile visual space
5
. The axon of each R neuron overlaps with the dendrites of every compass neuron
6
, raising the question of how visual cues are integrated into the compass. Here, using in vivo whole-cell recordings, we show that a visual cue can evoke synaptic inhibition in compass neurons and that R neurons mediate this inhibition. Each compass neuron is inhibited only by specific visual cue positions, indicating that many potential connections from R neurons onto compass neurons are actually weak or silent. We also show that the pattern of visually evoked inhibition can reorganize over minutes as the fly explores an altered virtual-reality environment. Using ensemble calcium imaging, we demonstrate that this reorganization causes persistent changes in the compass coordinate frame. Taken together, our data suggest a model in which correlated pre- and postsynaptic activity triggers associative long-term synaptic depression of visually evoked inhibition in compass neurons. Our findings provide evidence for the theoretical proposal that associative plasticity of sensory inputs, when combined with attractor dynamics, can reconcile self-movement information with changing external cues to generate a coherent sense of direction
7
–
12
.
Visual inputs to compass neurons can reorganize over minutes as a fly explores an altered virtual-reality environment.
Journal Article