Neuroscience Graduate Program

Office: (951) 827-5060
Fax:
PSYCHOLOGY BLDG 2123
Office Hours: M,W, 9am - 10am
Email: khaleel@ucr.edu

Khaleel Razak

Biography

Research Summary

I am interested in sensory processing, development and aging.

Current projects in the lab:

1.  Sound localization and echolocation behaviors in the pallid bat

The pallid bat belongs to a small group of bats called gleaners. While hunting, it uses echolocation to avoid obstacles and passive sound localization to locate terrestrial prey. Using single and multi-electrode recordings, tract tracing, neuropharmacology and behavioral analyses, I seek to understand the neural mechanisms underlying echolocation and passive sound localization.

2.  Aging, hearing loss and sound processing in mouse auditory cortex

We are interested in how processing of frequecny modulated sweeps are affected by aging and hearing loss. The long-term objective of this project is to identify the mechanisms underlying degraded sound processing with age and hearing loss and discover ways to delay or prevent such changes.

3. Auditory processing and vocalizations in a mouse model of Fragile X Syndrome (FXS)

A  transgenic mouse model is available to study FXS.  We are interested in determining FM sweep processing in the auditory cortex and the vocalizations produced by these mice.  The expected outcome is a model system to study communication deficits in FXS and autism

Students interested in taking an integrative approach to sensory processing and neural development are welcome to join my lab either through the Department of Psychology or through the Graduate Neuroscience Program. I also strongly encourage undergraduate student research in my lab.

Publications

• Rotschafer SE, Trujillo M, Dansie LE, Ethell, IM and Razak KA. Minocycline treatment reverses ultrasonic vocalization production deficit in a mouse model of Fragile X Syndrome. Brain Research. In Press.
• Trujillo M, Measor K, Carrasco MM and Razak KA. Selectivity for the rate of frequency modulated sweeps in the mouse auditory cortex.J. Neurophysiol. 106:2825-2837, 2011.
• Razak KA. Systematic representation of sound locations in the primary auditory cortex. J. Neurosci. 31:13848-13859, 2011.
• Fuzessery ZM, Razak KA and Williams AJ. Multiple mechanisms shape selectivity for  FM sweep rate and direction in the pallid bat inferior colliculus and AC. J. Comp. Physiol. [A]. 197:615-623, 2011.
• Razak KA and Fuzessery ZM. Development of parallel auditory thalamocortical pathways for two different behaviors. Front. Neuroanat. 21;4. pii: 134, 2010.
• Razak KA and Fuzessery ZM. Experience-dependent development of vocalization selectivity in the auditory cortex.  J. Acoust. Soc. Am. 128(3):1446-1451, 2010.
• Razak KA and Fuzessery ZM. GABA shapes a systematic map of binaural sensitivity in the auditory cortex.  J. Neurophysiol. 104: 517 – 528, 2010.
• Razak KA and Fuzessery ZM.  GABA shapes selectivity for the rate and direction of frequency modulated sweeps in the auditory cortex.  J Neurophysiol 102:1366-1378, 2009.
• Razak KA, Zumsteg, T and Fuzessery, ZM. Development of auditory thalamocortical connections in the pallid bat, Antrozous pallidus.  J. Comp. Neurol. 515:231-242, 2009.
• Razak KA and Fuzessery ZM. Facilitatory mechanisms underlying selectivity for frequency modulated sweeps in the auditory cortex. J. Neurosci. 28:9806-9816, 2008.
• Razak KA, Richardson, MD and Fuzessery, ZM. Experience is required for the maintenance and refinement of FM sweep selectivity in the developing auditory cortex. Proc. Natl. Acad. Sci. (USA) 105:4465-4470, 2008.
• Razak KA and Pallas SL. Inhibitory plasticity facilitates recovery of stimulus velocity tuning in the superior colliculus after chronic NMDA receptor blockade. J. Neurosci. 27:7275-7283, 2007.
• Razak KA and Fuzessery ZM. Development of inhibitory mechanisms underlying selectivity for the rate and direction of frequency-modulated sweeps in the auditory cortex. J. Neurosci. 27:1769-1781, 2007.
• Razak KA and Fuzessery ZM. Development of functional organization of the pallid bat auditory cortex. Hearing Res. 228:69-81, 2007.
• Razak KA, Shen W, Zumsteg, T and Fuzessery, ZM. Parallel thalamocortical pathways for echolocation and passive sound localization in a gleaning bat, Antrozous pallidus. J. Comp. Neurol. 500:322-338, 2006.
• Pallas SL, Wenner P, Gonzales-Islas C, Fagiolini M, Razak KA, Kim G, Sanes D and Birgit, R. Developmental plasticity of inhibitory circuitry. J. Neurosci. 26:10358-10361, 2006.
• Razak KA and Pallas SL. Dark rearing reveals the mechanism underlying stimulus size tuning of superior colliculus neurons. Vis. Neurosci. 23:741-748, 2006.
• Razak KA and Fuzessery ZM. Neural mechanisms underlying selectivity for the rate and direction of frequency-modulated sweeps in the auditory cortex of the pallid bat. J. Neurophysiol. 96:1303-1319, 2006.
• Razak, KA and Pallas SL. Neural mechanisms of stimulus velocity tuning in the superior colliculus. J. Neurophysiol. 94:3573-3589, 2005.
• Carrasco MM, Razak KA and Pallas SL. Visual experience is necessary for maintenance but not development of refined retinotopic maps in superior colliculus. J. Neurophysiol. 94: 1962-1970, 2005.
• Razak KA, Huang L and Pallas SL. Chronic NMDA receptor blockade increases receptive field size without affecting stimulus velocity or size tuning of superior colliculus neurons. J. Neurophysiol. 90(1): 110-119, 2003.
• Barber JR, Razak KA and Fuzessery ZM. Can two streams of auditory information be processed simultaneously? Evidence from the gleaning bat Antrozous pallidus. J. Comp. Physiol. A 189: 843-855, 2003.
• Razak KA and Fuzessery ZM. Functional organization of the pallid bat auditory cortex: emphasis on binaural organization. J. Neurophysiol. 87(1): 72-86, 2002.
• Razak KA and Fuzessery ZM. A systematic representation of interaural intensity differences in the auditory cortex of the pallid bat. NeuroReport 11(13): 2919-2924, 2000.
• Razak KA, Fuzessery ZM and Lohuis T. Single neurons respond to both active and passive sounds in the pallid bat auditory cortex. J. Neurophysiol. 81(3): 1438-1442, 1999.

Book Chapters

• Razak KA, Fuzessery, ZM, Carrasco MM and Pallas, SL. Developmental plasticity of inhibitory receptive field properties in the auditory and visual systems. In: Pallas, SL and Wenner, P (eds). Developmental plasticity of inhibitory circuits. Springer (In review).
• Pallas SL, Xu M and Razak KA. Influence of thalamocortical activity on sensory cortical development and plasticity. In: R. Erzurumlu, W. Guido, Z. Molnar, (eds.) Development and Plasticity in Sensory Thalamus and Cortex. Kluwer Academic/ Plenum Publishers, New York. 2005.