Massihullah Hamidi

Email: mhamidi@wisc.edu

Research Project:

I am studying the structure and mechanism of working memory in humans. Specifically, I use repetitive transcranial magnetic stimulation (rTMS) and electroencephalography (EEG) as tools to investigate the contributions of various brain areas to working memory. rTMS temporarily alters activity in a focused region of the brain using a reversible electric disturbance induced by a strong magnetic field, thus allowing controlled studies in normal subjects. I have recently found that rTMS to the parietal lobe leads improvements in working memory of locations and with EEG have since determined that this improvement is due to rTMS-induced alterations in neuronal oscillations.

Abstracts and Publications:

• Hamidi, M., H.A. Slagter, and B.R. Postle. 2008. Delay-period neuronal oscillations are modulated by 10 Hz TMS: A simultaneous rTMS/EEG study. Cog. Neurosci. Soc. Abstr.
• Hamidi, M., H.A. Slagter, and B.R. Postle. 2007. The role of neuronal oscillations in retention of information in working memory. Soc. for Neurosci. Abstr.
• Hamidi, M. and B.R. Postle. 2007. Investigating retinotopic representations during attention and spatial working memory using phase-encoded fMRI. Human Brain Mapping Abstr.
• Hamidi, M., G. Tononi, and B.R. Postle. 2007. Evaluating the role of prefrontal and parietal cortices in memory-guided response with repetitive transcranial magnetic stimulation. Cog. Neurosci. Soc. Abstr.
• Postle, B.R. and M. Hamidi. 2007. Nonvisual codes and nonvisual brain areas support visual working memory. Cereb. Cortex. In press. [PDF]
• Hamidi, M., G. Tononi, and B.R. Postle. 2006. Role of frontal and parietal regions in retention of information in working memory: A repetitive transcranial magnetic stimulation study. Soc. Neurosci. Abstr.
• Postle, B.R., F. Ferrarrelli, M. Hamidi, E. Feredoes, M. Massimini, M. Peterson, A. Alexander, and G. Tononi. 2006. Repetitive transcranial magnetic stimulation dissociates working memory manipulation from retention functions in prefrontal, but not posterior parietal, cortex. J. Cog. Neurosci. 18: 1712-1722. [PDF]
• Hamidi, M., G. Tononi, and B.R. Postle. 2006. Effect on spatial working memory of repetitive transcranial magnetic stimulation of the dorsolateral prefrontal cortex and superior parietal cortex. Cog. Neurosci. Soc. meeting, San Francisco, CA.
• Postle, B.R., M. Hamidi, M. Masimini, F. Ferrarelli, M.J. Peterson, A. Alexander, and G. Tononi. 2004. Equipotentiality of prefrontal and superior parietal cortex contributions to executive control of working memory? Evidence from fMRI-guided rTMS. Soc. Neurosci. Abstr.