Geoff Ghose, Ph.D.

Associate Professor, Department of Neuroscience

E-mail: geoff@cmrr.umn.edu

Lab Website: http://www.ghoselab.cmrr.umn.edu

 


Research Interests:

I am interested in how cognitive phenomena, such as learning and attention, affect the neuronal signals underlying visually guided behaviors. My laboratory studies striate and extrastriate areas of visual cortex in monkeys that have been trained to perform sophisticated visuo-motor tasks. Extracellular activity on single and multiple neurons is related to behavioral performance while the animals perform these tasks. These studies will be complemented by a direct study of neuronal populations using both intrinsic optical imaging techniques as well as functional magnetic resonance. One line of study involves studying the neuronal basis of perceptual learning in the cerebral cortex. Monkeys are trained for many months to perform a difficult visual discrimination task and the potential physiological correlates of the trained behavioral improvement are studied (Ghose et al, 2002).

The second area of research addresses how strategies acquired during the course of training affect neuronal signals and visual performance. Although animals are sensitive to task timing and form temporal representations automatically there has been very little study of how timing strategies affect visual processing. Although there is evidence that task timing directly affects visual responses (Ghose and Maunsell, 2002) it is unclear how universal these affects are. It is also possible that behavioral strategies alter the relationship between individual neuronal activity and the performance of the animal. Because such strategies are automatically formed during any repetitive task, characterizing the effects of such strategies is critical for understanding the neuronal basis of perception and decision making.

Current projects in this area involve simultaneous measurements of neuronal activity and behavior in a challenging task whose demands very over time in a consistent manner. As with the perceptual learning project, a key aspect of the strategy project is the modeling how the signals from individual neurons are integrated and interpreted to form a percept and ultimately guide behavior.


Selected Publications:

(For a comprehensive list of recent publications, refer to PubMed, a service provided by the National Library of Medicine.)

Ghose GM, Bearl DW. Attention directed by expectations enhances receptive fields in cortical area MT. Vision Res. 2010 Feb 22;50(4):441-51. Epub 2009 Oct 9.

Ghose GM. Attentional modulation of visual responses by flexible input gain. J Neurophysiol. 2009 Apr;101(4):2089-106. Epub 2009 Feb 4.

Ghose GM, Harrison IT. Temporal precision of neuronal information in a rapid perceptual judgment. J Neurophysiol. 2009 Mar;101(3):1480-93.

Yoshor D, Ghose GM, Bosking WH, Sun P, Maunsell JH. Spatial attention does not strongly modulate neuronal responses in early human visual cortex.
J Neurosci. 2007 Nov 28;27(48):13205-9.

Yoshor D, Bosking WH, Ghose GM, Maunsell JH. Receptive fields in human visual cortex mapped with surface electrodes. Cereb Cortex. 2007 Oct;17(10):2293-302.

Ghose GM. Strategies optimize the detection of motion transients. J Vis. 2006 May 10;6(4):429-40.

Ghose GM, Learning in mammalian sensory cortex. Curr Opin Neurobiol. 2004 Aug;14(4):513-8.

Ghose GM, Maunsell JH. Attentional modulation in visual cortex depends on task timing.Nature. 2002 Oct 10;419(6907):616-20.

Ghose GM, Yang T, Maunsell JH. Physiological correlates of perceptual learning in monkey V1 and V2.J Neurophysiol. 2002 Apr;87(4):1867-88.


Current Graduate Students:

Katherine Weiner (Neuroscience, University of Minnesota).

Scott Warren (Neuroscience, University of Minnesota).

Former Graduate Students:

Blaine Schneider (Ph.D. 2011, Neuroscience, University of Minnesota).