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Department of

Biological Sciences

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Julie Haas, Associate Professor of Biological Sciences at Lehigh University

Julie Haas

Associate Professor

610.758.6276
juh312@lehigh.edu
D226 - Iacocca Hall
Education:

Ph.D., Biomedical Engineering, Boston University;

Methods in Computational Neuroscience, Marine Biological Laboratory;

B.A., Music and Mathematics, Indiana University

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Research Areas

Research Statement

The ultimate goal of my research is to understand how the “searchlight” of neural attention upon the sensory surround, as hypothesized by Crick, is focused and carried out by the inhibitory neurons and circuitry of the thalamic reticular nucleus (TRN).  Because the TRN is the main source of inhibition within ascending sensory pathways in the brain, it is uniquely positioned to exert control over sensory selection and attention.

One main focus involves electrical synapses, a unique type of interneuronal connection that allows ions to pass directly between membranes of coupled neurons. These fast and powerful synapses are the dominant form of neuronal connection within the TRN. We work to describe the relationships between electrical synaptic strength, dynamics in circuits of coupled neurons, and the more abstract process of attention.  We also explore how input from other brain areas, such as the amygdala, modulates the activity of the TRN.

We use electrophysiology and optogenetics in brain slices to map coupled networks, to investigate how electrical synapses change in strength in response to activity in the neurons they couple, and to identify the molecular machinery involved in electrical synapse plasticity.  We use computational models to explore how electrical synapses, and changes in their strength, contribute to information processing in neuronal circuits of the thalamus.  
 

The Haas lab is grateful for past and present funding from The Whitehall Foundation, the Brain and Behavior Foundation, the National Science Foundation, and the National Institutes of Health.

Google Scholar profile

Vaughn MJ, Yellamelli N, Burger RM, Haas JS (2024). Dopamine receptors D1, D2, and D4 modulate electrical synapses and excitability in the thalamic reticular nucleus. J. Neurophysiol.

Vaughn MJ, Laswick Z, Wang H, and Haas JS (2023). Functionally distinct circuits are linked by heterocellular electrical synapses in the thalamic reticular nucleus. eNeuro 0269-23.2023

Vaughn MJ and Haas JS (2022). On the Diverse Functions of Electrical Synapses. Front. Cell. Neurosci. 16:910015.

Mendoza, A and Haas JS (2022). Intrinsic sources and functional impacts of asymmetry at electrical synapses. eNeuro, 0469-21.2022

Wang, H and Haas JS (2021). GABABR modulation of electrical synapses and plasticity in the thalamic reticular nucleus. International Journal of Molecular Sciences 22(22):12138. Special Issue: Chemical Regulation of Gap Junction Channels and Hemichannels 2.0.

Fricker B, Heckman E, Cunningham PC, Wang HW, and Haas JS (2021). Activity-dependent long-term potentiation of electrical synapses in the mammalian thalamus. Journal of Neurophysiology 125 (2), 476-488

Aizenberg M, Rolón-Martínez S, Pham T, Rao W, Haas JS and Geffen MN (2019). Projection from the amygdala to the thalamic reticular nucleus amplifies cortical sound responses. Cell Reports 28 (3), 605-615

Pham T and Haas JS (2019). Electrical synapses regulate both subthreshold integration and population activity of principal cells in response to transient inputs within canonical feedforward circuits. PLoS Computational Biology 15(2): e1006440

Pham T and Haas JS (2018). Electrical synapses between inhibitory neurons shape the responses of principal neurons to transient inputs in the thalamus. Scientific Reports 8:7763

Sevetson J, Fittro S, Heckman E and Haas JS (2017). A calcium-dependent pathway underlies activity-dependent plasticity of electrical synapses. Journal of Physiology 595: 4417–4430

Haas JS, Greenwald C and Pereda, AE (2016). Activity-dependent plasticity of electrical synapses: increasing evidence for its presence and functional roles in the mammalian brain. BMC Cell Biol. 2016 May 24;17 Suppl 1:14

Haas JS (2015). A new measure for the strength of electrical synapses. Frontiers in Cellular Neuroscience. 9:378

Sevetson J and Haas JS (2014). Asymmetry and modulation of spike timing in electrically coupled neurons. J. Neurophysiol. 113(6):1743-51

Vogels TP, Froemke R, Doyon N, Gilson M, Haas JS, Liu R, Maffei A, Miller P, Wierenga P, Woodin M, Zenke F and Sprekeler H (2013). Inhibitory synaptic plasticity: Spike-timing dependence and putative network function. Frontiers in Neural Circuits 7:119

Haas JS and Landisman CE (2012). Bursts modify electrical synaptic strength. Brain Research 1487:140-9

Haas JS and Landisman CE (2012). State-dependent modulation of gap junction signaling by the persistent sodium current. Frontiers in Cellular Neuroscience 5:31

Haas JS, Zavala B and Landisman CE (2011). Activity-dependent long-term depression of electrical synapses. Science 334(6054):389-393.  Highlighted in:

  • Neuroscience. The strength of electrical synapses.  Hestrin S., Science 334(6054):315-6 (2011)

  • Synaptic plasticity: tuning electrical synapses. Whalley K. Nature Reviews Neuroscience 12(12):705 (2011)

Haas JS, Kreuz T, Torcini A, Politi A, Abarbanel HDI (2010). Rate maintenance in spiking neurons driving with strong inputs of varying speeds. European Journal of Neuroscience 32(11):1930-9

Kreuz T, Chicharro D, Andrzejak RG, Haas JS, Abarbanel HDI, Politi A (2009). Measuring multiple spike train synchrony. J. Neurosci. Methods 182(2):287-299.

Kreuz T, Haas JS, Morelli A, Abarbanel HDI, Politi A (2007). Measuring spike train synchrony. J. Neurosci. Methods 165(1):151-61

Haas JS, Dorval AD, White JA (2007). Contributions of Ih to feature selectivity in layer II stellate cells of the entorhinal cortex. J. Computational Neuroscience 22(2):161-71

Haas JS, Nowotny TN, Abarbanel HDI (2006). Spike-timing-dependent plasticity at inhibitory synapses in the entorhinal cortex.  J. Neurophysiol 96: 3305-3313

Netoff TI, Banks MI, Dorval AD, Acker CD, Haas JS, Kopell N, White JA (2004). Synchronization in hybrid neuronal networks of the hippocampal formation. J. Neurophysiol. 93(3):1197-1208

Haas JS and White JA (2002). Frequency selectivity of layer II stellate cells in the medial entorhinal cortex. J. Neurophysiol. 88(5): 2422-2429
 

Teaching

Synapses, Plasticity and Learning (Bios 385 and 415)

Neurophysiology Laboratory (Bios 278)  

Professional Skills for Graduate Students (Bios 401)