Semester

Spring

Date of Graduation

2021

Document Type

Thesis

Degree Type

MS

College

Eberly College of Arts and Sciences

Department

Biology

Committee Chair

Andrew Dacks

Committee Member

Kevin Daly

Committee Member

Sadie Bergeron

Abstract

Corollary discharge (CD) circuits provide critical information about movement and behavior to provide context to sensory processing. However, to date, there has not been a comprehensive study of CD circuits at a single-cell level. In this thesis, I aimed to resolve the connectivity of ascending histaminergic neurons, consisting of two pairs, the mesothoracic pair (MsAHNs) and metathoracic pair (MtAHNs) at a single-cell level and characterize contexts of activation. Using transgenic techniques, connectomics and transcriptomics, we identify neural populations receiving input from the AHNs and neural populations with significant output to the AHNs. We explored where the AHNs predominantly receive synaptic input or send synaptic output. We show that the AHNs are the sole source of histamine to the AMMC and HisClB receptors are broadly expressed in Johnston Organ neurons (JONs). I show that in addition to fast inhibition on JONs, the MtAHNs express diuretic hormone 44 (DH44) neuropeptide and target second order mechanosensory neurons in the saddle and vest. In addition to transmitter expression, I show that the AHNs have differential receptor expression and are targeted by different population of neurons. Finally, I show that the AHNs during courtship and solitary states, have different baselines of activity among the two pairs.

Embargo Reason

Publication Pending

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