Contact

Dr. David Omer

Address: Spemannstr. 38
72076 Tübingen
Room number: 134
Phone: +49 7071 601 1692
Fax: +49 7071 601 1678
E-Mail: david.omer

 

Picture of Omer, David, Dr.

David Omer

Position: Research Scientist  Unit: Alumni Logothetis

Probing the dynamics of cortical microcircuits

 

For many years cortical columns have been thought of as feedforward multilayer elementary operational units (OPUN) of cortex. Yet, both anatomical and physiological evidence contradict this concept. Specifically, each pyramidal cell receives approximately 10,000 synaptic inputs, of which about 75% are excitatory; the vast majority of these excitatory inputs arise from other cortical neurons which result in a strong intra-cortical recurrent connectivity with a relatively weak input from subcortical structures. Interposed between this recurrent excitatory-network of pyramidal cells are a large variety of GABAergic inhibitory interneurons strongly interconnected with projection neurons. Accumulating evidence suggests that OPUN may actually be instantiated in such recurrent Excitation-Inhibition (E-I) circuits, in which information related to sensors or effectors is processed in a highly non-linear (e.g. strong feedback) fashion and is shaped by the strong neuromodulatory activity of the ascending diffuse systems. This microcircuit architecture is not specific to any specific sensory area, but it has instead been evident anywhere it has been sought after, including the primary motor and premotor cortices in all studied mammals.

 

My group research goal is to probe into the functional principles of such microcircuits by studying both feedforward activity induced by sensory or electrical stimulation and neuromodulatory activity that appears to change proportionally both the excitatory and inhibitory conductances.

 

We are using VSDi which permits recording of activity of whole neuronal populations with high spatio-temporal resolution. We augment our observations with a battery of methods including electrophysiological recordings, MR imaging, histology and electrical stimulation of thalamus and/or modulatory subcortical nuclei, such as the locus Coeruleus and Nucleus basalis.

 

 

V1 response to an oriented grating visual stimulus, imaged with VSD @200Hz.

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Articles (6):

Omer DB, Hildesheim R and Grinvald A (November-2013) Temporally-structured acquisition of multidimensional optical imaging data facilitates visualization of elusive cortical representations in the behaving monkey NeuroImage 82 237–251.
Muir DR, Da Costa NMA, Girardin CC, Naaman S, Omer DB, Ruesch E, Grinvald A and Douglas RJ (October-2011) Embedding of Cortical Representations by the Superficial Patch System Cerebral Cortex 21(10) 2244-2260.
Fekete T, Pitowsky I, Grinvald A and Omer DB (October-2009) Arousal increases the representational capacity of cortical tissue Journal of Computational Neuroscience 27(2) 211-227.
Fekete T, Omer DB, Naaman S and Grinvald A (March-2009) Removal of spatial biological artifacts in functional maps by local similarity minimization Journal of Neuroscience Methods 178(1) 31-39.
Reidl J, Starke J, Omer DB, Grinvald A and Spors H (January-2007) Independent component analysis of high-resolution imaging data identifies distinct functional domains NeuroImage 34(1) 94-108.
Vanzetta I, Slovin H, Omer DB and Grinvald A (June-2004) Columnar Resolution of Blood Volume and Oximetry Functional Maps in the Behaving Monkey: Implications for fMRI Neuron 42(5) 843-854.

Contributions to books (4):

Grinvald A, Sharon D, Omer DB and Vanzetta I: Imaging the Neocortex Functional Architecture Using Multiple Intrinsic Signals: Implications for Hemodynamic–Based Functional Imaging, 907-926. In: Imaging in Neuroscience: A Laboratory Manual, (Ed) F. Helmchen, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY, USA, (May-2011).
Grinvald A, Omer DB, Sharon D, Vanzetta I and Hildesheim R: Voltage-sensitive dyes imaging in the neocortical activity, 799-816. In: Imaging in Neuroscience: A Laboratory Manual, (Ed) F. Helmchen, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY, USA, (May-2011).
Grinvald A, Omer DB, Naaman S and Sharon D: Imaging the dynamics of mammalian neocortical population activity in-vivo, 97-111. In: Membrane potential imaging in the nervous system: methods and applications, (Ed) M. Canepari, Springer, New York, NY, USA, (September-2010).
Grinvald A, Omer DB, Sharon D, Vanzetta I and Hildesheim R: Voltage-sensitive dyes imaging of neocortical activity, 673-688. In: Imaging in neuroscience and development: a laboratory manual, (Ed) R. Yuste, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY, USA, (2005).

Posters (7):

Omer DB and Grinvald A (October-2009): Dynamics of ongoing activity in the anesthetized and awake monkey, 39th Annual Meeting of the Society for Neuroscience (Neuroscience 2009), Chicago, IL, USA.
Omer DB, Rom L, Ultchin Y and Grinvald A (November-2008): The dynamics of ongoing activity in awake and anesthetized monkey are significantly different, 38th Annual Meeting of the Society for Neuroscience (Neuroscience 2008), Washington, DC, USA.
Omer DB, Rom L and Grinvald A (November-2007): Comparing the dynamics of ongoing activity in awake and anesthetized monkey, 16th Annual Meeting of The Israel Society for Neuroscience (ISFN 2007), Eilat, Israel, Neural Plasticity, 2007(Abstracts) 83.
Fekete T, Omer DB and Grinvald A (October-2006): Representational capacity of cortical tissue measured by topological analysis of its activity set, 36th Annual Meeting of the Society for Neuroscience (Neuroscience 2006), Atlanta, GA, USA.
Omer DB, Rom L and Grinvald A (October-2006): The dynamics of ongoing activity in the primary visual cortex of the awake monkey, 36th Annual Meeting of the Society for Neuroscience (Neuroscience 2006), Atlanta, GA, USA.
Omer DB and Grinvald A (December-2005): The dynamics of ongoing activity in the primary visual cortex of the awake monkey, 14th Annual Meeting of The Israel Society for Neuroscience (ISFN 2005), Eilat, Israel, Reviews in the Neurosciences, 16(Supplement) S50.
Omer DB, Slovin H and Grinvald A (October-2004): The dynamics of evoked and ongoing activity in the behaving monkey, 34th Annual Meeting of the Society for Neuroscience (Neuroscience 2004), San Diego, CA, USA.

Talks (3):

Omer DB and Logothetis NK (October-15-2012) Abstract Talk: Spiral waves dynamics in primary visual cortex of the anesthetized primate, 42nd Annual Meeting of the Society for Neuroscience (Neuroscience 2012), New Orleans, LA, USA(413.02).
Omer DB and Grinvald A (April-2007) Invited Lecture: The dynamics of evoked and ongoing activity in the behaving monkey, Mathematical Biosciences Institute Workshop 6: Information Processing in the Visual System, Columbus, OH, USA.
pdf
Grinvald A and Omer DB (April-2007) Abstract Talk: The dynamics of evoked and ongoing activity in the behaving monkey, 7th Meeting of the German Neuroscience Society, 31st Göttingen Neurobiology Conference, Göttingen, Germany, Neuroforum, 13(Supplement) 330.

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Last updated: Monday, 22.05.2017