Biological Sciences, Lehigh University Lehigh University home page Department of Biological Sciences home page
Faculty, Biological Sciences, Lehigh University

Julie Haas, Ph.D.
Associate Professor

Research Interest:

Iacocca Hall
111 Research Drive, D226
Bethlehem, PA 18015


email Dr. Haas

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Brain & Behavior

Whitehall Foundation

Dr. Haas' research is funded by the National Science Foundation, Brain & Behavior Foundation and the Whitehall Foundation

Julie Haas, Ph.D.


Julie Haas, Ph.D.Our research is focused on electrical synapses.  Formed by pores that connect the cytoplasm of coupled cells, these synapses allow ions and information to flow directly between neurons.

We are interested in determining the relationships between electrical synaptic strength, synchrony in circuits of coupled neurons, and the more abstract process of attention.  These ideas coalesce within the thalamus, in a specific nucleus where electrical synapses are particularly dense; it is this nucleus that is thought to gate cortical attention to the sensory surround.  I hypothesize that the strength of electrical synapses within this nucleus is a crucial component for the control of human attention.

Using paired recordings, we investigate how electrical synapses change in strength in response to activity in the neurons they couple, and work to identify the molecular machinery involved in electrical synapse plasticity.  In addition, we use computational models to explore how electrical synapses, and changes in their strength, contribute to information processing in neuronal circuits of the thalamus.




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 and population activity of principal cells in response to transient inputs within canonical feedforward circuits. PLOS:  Computational Biology, doi: 10.1371/journal.pcbi.1006440.

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. J. Physiology. 595: 4417–4430

Highlighted in:
How do electrical synapses regulate their strength?  Debanne D and Russier M., J. Physiology (2017)

Haas JS, Greenwald C, and Pereda A (2016). Activity-dependent plasticity of electrical synapses: increasing evidence for its presence and functional roles in the mammalian brain. BMC Cell Biology. DOI: 10.1186/s12860-016-0090-z

Haas JS (2015). A new measure for the strength of electrical synapses. Front. Cell. Neurosci. 9:378. doi: 10.3389/fncel.2015.00378.

Sevetson J and Haas JS (2014). Asymmetry and modulation of spike timing in electrically coupled neurons. J. Neurophysiol. doi: 10.1152/jn.00843.2014.

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, special issue on Electrical Synapses. 1487:140-9

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

Haas JS and Landisman CE (2011) State-dependent modulation of gap junction signaling by the persistent sodium current. Frontiers in Cellular Neuroscience 5:31.

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.

Book Chapters:

Abarbanel HDI, Haas JS, Talathi SS (2007) Synapses and neurons: Basic properties and their use in the recognition of environmental signals. In Lecture Notes in Supercomputational Neuroscience, Springer-Verlag.

White JA and Haas JS (2001) Noise from voltage-gated ion channels: effects on dynamics and reliability in intrinsically oscillatory neurons. In Handbook of Biological Physics, Vol. 4,  F Moss and S Gielen (eds.), Elsevier Press, Amsterdam.

Lab Personnel

The Haas Lab - 2018

Haas Lab 2018

(l-r) Julie Haas, Ph.D., Tuan Pham ('18), Brandon Fricker, Huaixing Wang, Ph.D.
missing: Brigette Suerig, Taylor Dube


The Haas Lab - 2015

Julie Haas, Ph.D.
Undergraduate Researchers: Sarah Fittro, Emily Heckman, Bijal Desai;
Julie Haas, Ph.D. Principal Investigator



Lab Alumni

Bijal Desai
Bijal Desai
now a medical student at Case Western
Sarah Fittro
Sarah Fittro
now in physician assistant program at Yale University
Emily Heckman
Emily Heckman
now Ph.D. student at Univ. of Oregon
Tuan Pham
Tuan Pham
now a Ph.D. student at Univ. of Chicago
Jessica Sevetson
Jessica Sevetson
now a Ph.D. student at Brown Univ.

Positions Available
Please contact Dr. Julie Haas if you are interested in doing research in her lab.

Biological Sciences
111 Research Drive
Bethlehem, PA 18015
Phone: 610-758-3680
Fax: 610-758-4004