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Shervin Safavi

Address: Spemannstr. 38
72076 Tübingen
Room number: 232
Phone: +49 7071 601 1683
Fax: +49 7071 601 652
E-Mail: shervin.safavi

 

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Shervin Safavi

Position: Phd Student  Unit: Logothetis

Logothetis NK , Safavi S , Kapoor V , Panagiotaropoulos T and Dwarakanath A (November-23-2015) Abstract Talk: Temporal Regimes of State-Dependent Correlated Variability in the Macaque Ventrolateral Prefrontal Cortex, 16th Conference of Junior Neuroscientists of Tübingen (NeNa 2015), Schramberg, Germany18.
Repeated presentation of the same stimulus results in variability in the spiking of neurons, often being correlated across neuronal pairs. However, apart from common input, a number of factors like local circuitry or dominant global states are known to induce this correlated variability. For example, slow (0.5-2.5 Hz) state transitions arising during anesthesia drive correlations in the primary visual cortex (V1). To investigate if a mechanism operating on a similar temporal regime drives correlations in the final stages of the ventral visual stream we recorded from the ventro-lateral prefrontal cortex (vlPFC) of anesthetized macaques using 10*10 Utah Arrays during periods of repeated visual stimulation (10s movie clip) and silence (10s). A Gaussian Process based factorization algorithm, previously used to unravel the underlying temporal regime of correlations in V1. returned a timescale of 14-16ms as the width of the temporal kernel, which translated to a frequency between 13-17 Hz after using an appropriate attenuation value in the spectrum of the estimated latent variable. This result indicates that apart from slow, anesthesia-induced fluctuations, intrinsic activity on a faster scale could be the source of pairwise correlations. Indeed, previous analyses of the local field potentials (LFPs) in vlPFC revealed a dominant oscillation in the beta band (13-25Hz) in both anesthetized and alert animals. Moreover, spike{spike Coherence, spike{field Coherence and other measures of spike{spike/LFP coupling suggest a significant interaction between spikes and LFP in the beta band. Despite these findings the Gaussian Process algorithm did not capture a significant amount of variance in our data, and even after accounting for the latent variable, the residual covariances remain significantly different from zero. We are currently exploring other state-space models.
pdf html CiteID: DwarakanathSKLP2015

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Articles (2):

Mahmoodi A, Bang D, Olsen K, Zhao YA, Shi Z, Broberg K, Safavi S, Han S, Ahmadabadi MN, Frith CD, Roepstorff A, Rees G and Bahrami B (March-2015) Equality bias impairs collective decision-making across cultures Proceedings of the National Academy of Sciences of the United States of America 112(12) 3835–3840.
Safavi S, Kapoor V, Logothetis NK and Panagiotaropoulos TI (September-2014) Is the frontal lobe involved in conscious perception? Frontiers in Psychology 5(1063) 1-2.

Posters (5):

Antoniou R, Safavi S, Kapoor V, Logothetis NK and Panagiotaropoulos T (October-9-2015): Perceptual modulation of pupillary reflex in macaque monkeys, Federation of European Neuroscience Society Featured Regional Meeting (FFRM 2015), Thessaloniki, Greece.
Safavi S, Panagiotaropoulos T, Kapoor V, Logothetis NK and Besserve M (November-12-2013): Coupling between spiking activity and beta band spatio-temporal patterns in the macaque PFC, 43rd Annual Meeting of the Society for Neuroscience (Neuroscience 2013), San Diego, CA, USA.
Safavi S, Ravishankar G, Endres D and Giese M (October-2013): A neuro-computational approach to identity-independent encoding of facial expressions, 14th Conference of Junior Neuroscientists of Tübingen (NeNa 2013), Schramberg, Germany.
Safavi S, Panagiotaropoulos T, Kapoor V, Logothetis NK and Besserve M (September-2013): Analyzing locking of spikes to spatio-temporal patterns in the macaque prefrontal cortex, Bernstein Conference 2013, Tübingen, Germany.
Giese MA, Ravishankar G, Safavi S and Endres D (March-14-2013): Physiologically-Inspired neural model for the processing of dynamic facial expressions, 10th Göttingen Meeting of the German Neuroscience Society, 34th Göttingen Neurobiology Conference, Göttingen, Germany.
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Talks (1):

Dwarakanath A, Safavi S, Kapoor V, Logothetis NK and Panagiotaropoulos T (November-23-2015) Abstract Talk: Temporal Regimes of State-Dependent Correlated Variability in the Macaque Ventrolateral Prefrontal Cortex, 16th Conference of Junior Neuroscientists of Tübingen (NeNa 2015), Schramberg, Germany 18.
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Last updated: Tuesday, 18.11.2014