About the lab

Lab for Dynamics of Cortical Circuits
Importance of top-down (corticocortical) and bottom-up (subcortical) pathways in regulating visual responsiveness are crucial, how these two pathways working independently and how interact during coincident engagement in vivo to optimize visual perception while maintaining network stability is unknown. Sensory-evoked responses in V1 neurons are highly dependent on subcortical neuromodulation pathways that regulate brain state. With cell-type-specific resolution using optogenetics and optopatcher in vivo, we are addressing how corticocortical and subcortical pathways (such as cholinergic and serotonergic systems) interact to regulate responsiveness of layer II/III neurons of V1. Our studies provide insight into the rules and conditions governing....

Featured projects (1)

Project
The cholinergic system is a potent neuromodulatory system that plays critical roles in cortical plasticity, attention and learning.In this project, we are examining how the cholinergic system modulate the activity of neurons of V1 in response to stimulus contrast.

Featured research (2)

Introduction: Sensory processing is profoundly regulated by brain neuromodulatory systems. One of the main neuromodulators is serotonin which influences higher cognitive functions such as different aspects of perceptual processing. So, malfunction in the serotonergic system may lead to visual illusion in psychiatric disorders such as autism and schizophrenia. In this work, we examined the serotonergic modulation of visual responses of neurons to stimulus orientation in the primary visual cortex. Methods: Eight-weeks old naive mice were anesthetized and craniotomy was done on the region of interest in primary visual cortex. Spontaneous and visual-evoked activities of neurons were recorded before and during the electrical stimulation of dorsal raphe nucleus using in vivo whole-cell patch-clamp recording. Square-wave grating of 12 orientations was presented. Data was analyzed and Wilcoxon signed-rank test, used in order to compare the data of two conditions that belong to the same neurons, with or without electrical stimulation. Results: The serotonergic system changed orientation tuning of about 60 % recorded neurons by decreasing the mean firing rate in two independent visual response components: gain and baseline response. It also increased mean firing rate in a small number of neurons (about 20%). Beyond that, it left the preferred orientation and sensitivity of neurons unchanged. Conclusion: However, serotonergic modulation showed a bi-directional effect; it seems to cause predominately divisive and subtractive decreases in the visual responses of the neurons in the primary visual cortex that can modify the balance between internal and external sensory signals and result in disorders.

Lab head

Mir-Shahram Safari
Department
  • Neuroscience Research Center
About Mir-Shahram Safari
  • http://on.fb.me/1s4Gv9n

Members (8)

Sajjad Farashi
  • Hamadan University of Medical Sciences
Parviz Ghaderi
  • École Polytechnique Fédérale de Lausanne
Sareh Rostami
  • Shahid Beheshti University of Medical Sciences
Somayyeh Golalizadeh
  • Alzahra University
Hamid Azimi
  • Université de Fribourg
Alireza Hooman Kia
  • Shahid Beheshti University of Medical Sciences
Fatemeh Bazelli Mahbob
  • Shahid Beheshti University
Tadaharu Tsumoto
Tadaharu Tsumoto
  • Not confirmed yet
Abdol-Hossein Vahabie
Abdol-Hossein Vahabie
  • Not confirmed yet
Vinícius Lima Cordeiro
Vinícius Lima Cordeiro
  • Not confirmed yet
Sareh Rostami
Sareh Rostami
  • Not confirmed yet
Mehdi Sohrabi Haghighat
Mehdi Sohrabi Haghighat
  • Not confirmed yet
Rie Kimura
Rie Kimura
  • Not confirmed yet
Parnaz Golnar Nik
Parnaz Golnar Nik
  • Not confirmed yet
Parviz Ghaderi
Parviz Ghaderi
  • Not confirmed yet