- A circuit for a looming responsive descending neuron, DNp03, in D.mel
- Haley Croke
- looming evoked flight maneuvers are driven by DNp03
- same looming stim can evoke many different behaviors all controlled by different DNs
- DNp03 responds to loom ipsilaterally and cares about fast looms
- wing motor neurons are downstream (depress wings to initiate turn)
- flies with no DNp03 activation do not turn during flight
- neck is also downstream perhaps for gaze stabilization
- A gut-brain circuit regulates sugar ingestion in Drosophila
- Xinyue Cui (Yapici lab)
- gut brain axis regulates sugar ingestion
- Ingestion neurons (IN1) regulate ingestion (12 neurons)
- activate when feeding, strongest activity in hungry flies
- receive input from sugar sensitive neurons that express Gr43a
- Gr43a is the only sugar taste receptor gene thats also expressed in the gut
- they imaged the gut neurons in vivo
- IN1 output to crop duct gating neurons which gate food going into the stomach
- so pathway is — Gr43a (gut) - IN1 (brain) - CDG (gut)
- Long term neuropeptide modulation of pC1 neurons and female sexual drive through pyrexia TRP channel
- Do-Hyoung Kim
- female sexual drive controlled by pC1
- the decision to mate is driven by motivation and internal state
- sexual maturation driven in part by changing levels of Juvenile Hormone
- decrease in motivation post mating driven by sex peptide
- SAG activity increases over time after mating (SP inhibits SAG)
- pC1 is a good readout for the internal state of the female and receives male courtship stimuli input
- the excitability changes during maturation and this might be driven by cAMP levels
- used CRE activity as an indicator of drive
- DH44 receptors required for pC1-CRE activity
- there is positive feedback in 2 neurons that express both DH44 receptor types in pC1 neurons
- looked for CRE downstream cation channels and found pyrexia and knockdown in mature virgins gets rid of drive
- The same neuron in different brains--Testing the effect of genetic background on the functionality of individual neurons
- Alexandre Leitao
- there is phenotypic variation within species which can be due to genes and environment
- there is a lot of variation in response to looming stimulus in flies
- they can freeze or flee and this is mediated by DNp09
- used the DGRP from bloomington which is a collection of inbred lines all originated from wild caught flies in the USA
- inhibiting DNp09 doesnt always reduce freezing in all fly lines tested due to different genetic background but they dont know the mechanisms of why yet
- Dynamic temporal coding in an olfactory circuit
- Kristyn Lizbinski
- lateral horn does odor processing
- interested in LHLN called AV4a1
- receive a ton of inputs from DM1
- AV4a1 is activated by acetic acid and not by apple cider vinegar
- however, DM1 strongly activated by apple cider vinegar. So theres a mismatch
- ACV and acetic acid have similar PN representation but the activity levels in those PNs are different
- blockade of inhibition reveals activation from other odors
- inhibition selectively tunes the odor responses
- AV4a1 integrates odors over time in a supralinear way
- Neural circuit mechanisms for halting in Drosophila
- Neha Sapkal (Salil Bidaye lab)
- there is a preprint on biorxiv for this talk
- how do halting circuits interact with walking circuits
- BPN, DNp09, and MDN all drive walking in a certain direction
- BRK neurons (halt neurons) override all walking neurons and the fly stops
- if activated mid stride, the fly will finish the step but no more.
- BRK has 2 output regions, the brain and the VNS
- Using decapitated flies, they drove walking then activated BRK and this still overrides the walking
- so its the VNS BRK that are important for the behavior
- BRK is also recruited during grooming
- there is a BRK neuron in each segment in the VNS for each leg.
- helps to determine which leg is used during walking
- silencing BRK causes the flies to tip over
- BRK is important for stability especially during grooming
- Higher order connectivity explains functional properties of visual circuitry
- Iris Titos
- studying substance use disorder in flies
- flies develop an amphetamine time dependent preference
- PAM cluster required for the time preference
- dietary protein activates gut secratory cells and extra protein diminishes amphetamine preference
- gut tachykinin mediates peptone protection agains amphetamine preference
- Dietary effect on PAM neurons
- high protein decreases PAM activity
- and tachykinin is required for this effect
- Mechanosensory and command contributions to the grooming sequence
- Shingo Yoshikawa
- there is a sequence of actions during grooming
- MGT activation (they named this neuron after back scratching in Japanese) drives thoracic grooming and overrides head grooming
- silencing reducing thoracic grooming
- has inputs from T1 and T2 and the output is T3
- have synapses with thoracic sensory neurons
- MGT is not involved with back leg rubbing even though it always follows thoracic grooming
- Revealing the brain-wide representation of the visuomotor transformation
- Tom Clandinin
- whole brain imaging using BIFROST to register the brain
- neural activity is spatially structured in relation to movement in the brain
- turning is an asymmetric signal in the brain
- there is an asymmetric signal that shows up 10 seconds before a turn happens that predicts which way the fly will turn