Research

Main Research Lines

Our overall goal is to study how the brain encodes and processes information to give rise to our thoughts, perceptions, memories, feelings and even the awareness of ourselves. For this, we pursue an interdisciplinary research program based broadly around six research lines.

I - Human single cell recordings

AnistonCell_2.jpgIn epileptic patients implanted with intracranial electrodes for clinical reasons, we study multiple single-neurons and local field potentials while the patients do different tasks. With this clinical setup we found a new type of neurons, the so called “concept cells” (a.k.a. “Jennifer Aniston neurons”), that respond to the identity of a given individual, disregarding visual details. For example, one neuron responded to different pictures of Jennifer Aniston, but not to other persons, objects, etc. These neurons also responded to the written or spoken name of the particular person and not to other names. We argue that these neurons represent concepts for creating and recalling declarative memories and we perform experiments to show how exactly this is done. 

Selected Publications

Brain Cells for Grandmother

R. Quian Quiroga, I. Fried, C. Koch

Scientific American 308(2):30-35, 2013.

Concept cells: The building blocks of declarative memory functions

Quian Quiroga R

Nature Reviews Neuroscience. (2012) 13: 587-597.

Invariant visual representation by single-neurons in the human brain.
Quian Quiroga R, Reddy L, Kreiman G, Koch C and Fried I

Nature, 435: 1102-1107; 2005. 

Selected Media Impact

Opening up brain surgery – Nature.

A neuron's obsession hints at biology of thought - The Wall Street Journal

Brain cells ‘recognize’ famous people – New York Times (22.6.05)

 

II - Modeling and Analysis of Neural data

spike_sortingt.jpgKey neuroscience questions rely on the optimal analysis of neural data. For this, we develop and use advanced methods of signal processing, especially for the analysis of large-scale neurophysiological recordings. In particular, we developed an automatic “spike sorting” algorithm (Wave_clus) for identifying the activity of single neurons from extracellular recordings, which is currently used by several neurophysiology laboratories world-wide. We are also working on a low-power on-chip implementation of the algorithm for wireless transmission to external devices. Although we already got excellent results with the current algorithm, we are always trying further optimizations. Given that there is no ground truth with real recordings, we also work on realistic simulations of extracellular recordings (NeuroCube) to test algorithms and electrode designs. Another related line of research involves extracting information from neural populations. For this we use machine learning (decoding algorithms) and information theory. In general, our goal is to identify as many neurons as possible and extract as much information as possible from neural recordings. 

Selected Publications

Unsupervised spike sorting with wavelets and superparamagnetic clustering.

R. Quian Quiroga, Z. Nadasdy and Y. Ben-Shaul

Neural Computation, 16: 1661-1687; 2004.

A detailed and fast model of extracellular recordings
Luis Camunas-Mesa and Rodrigo Quian Quiroga

Neural Computation 25, 1191–1212, 2013.

Extracting information from neural populations: Information theory and decoding approaches
Quian Quiroga R and Panzeri S

Nature Reviews Neuroscience. 10: 173-185; 2009. 

Selected Media Impact

Brain chips could help paralyzed patients - Daily Telegraph

Daily Mail

The Engineer

  

III – EEG & Eye-Tracking

eegWe use EEG and Eye-Tracker recordings to study visual perception. In this respect, we have been pushing two paradigm shifts. First, whereas the standard approach is to average several presentations and then study ensemble averages, we developed a method based on the wavelet transform, EP_den, to study single-trial evoked responses (responses in the ongoing EEG to stimulation). The main advantage of single-trial analyses is that we can study trial-by-trial variations and correlate these to perception and learning processes. Second, whereas the classic approach is to flash stimuli at the centre of the screen (where subjects are required to fixate), we combine EEG and Eye-Tracking recordings to study visual responses while subjects move their eyes, freely exploring complex scenes. Using Eye-Tracking information we can analyze the timing of different fixations and study evoked response in much more natural conditions. 

Selected publications

Automatic denoising of single-trial evoked potentials
Maryam Ahmadi and Rodrigo Quian Quiroga

NeuroImage 66: 672-680, 2013.

Uncovering the Mechanisms of Conscious Face Perception: A Single-Trial Study of the N170 Responses
Joaquin Navajas, Maryam Ahmadi and Rodrigo Quian Quiroga

Journal of Neuroscience 33(4): 1337-1343, 2013.

Looking for a face in the crowd: fixation-related potentials in an eye-movement visual search task. 

Lisandro Kaunitz, Juan Kamienkowski, Alexander Varatharajah, Mariano Sigman, Rodrigo Quian Quiroga and Matias Ison.

Neuroimage 89: 297–305; 2014.

  

IV – Neuroprosthetics

Neuroprosthetics_robot_armParalyzed patients (or amputees) can have the will to, for example, reach to a particular object, but are not able to execute the movement. The idea of neuroprosthetics is to develop brain-machine-interfaces to drive external devices, such as a robot arm, directly from brain signals. With this application in mind, we study different strategies to reach at objects using real or simulated brain and eye-tracking signals. 

Selected publications

Real Time Decoding for Brain Machine Interface Applications
Jonathan Becedas and Rodrigo Quian Quiroga.

Journal of Bioinformatics and Biological Engineering 2: 20-32; 2014.

Neural Prostheses: linking brain signals to prosthetic devices

Pedreira C, Martinez J and Quian Quiroga R

Proceedings ICROS-SICE. Fukuoka, Japan. August 2009.

Movement intention is better predicted than attention in the posterior parietal cortex. 

Quian Quiroga R, Snyder L, Batista A, Cui H and Andersen, R

Journal of Neuroscience 26: 3615-3620; 2006. 

Selected Media Impact

BBC News

 

V – Art & Science

embrace arts

Historically, there has been very little interaction between arts and science, but clearly artists and neuroscientists have complementary knowledge and expertise about perception and behavior. Our goal is to create links between science and arts to study how we perceive, remember, attend, make decisions, etc. Our goal, on the one hand, is to bring scientific methodologies, like Eye-Tracking recordings, to museums and art galleries in order to study art perception in its natural environment. On the other hand, we seek interactions with painters, writers or magicians, among other artists, to get new insights into visual perception, decision making and memory processes. As a result of this interaction we have had an Art & Science exhibition at the Embrace Arts gallery in Leicester (“The art of visual perception”) and have organized a minisymposium about science and magic (“The Neuroscience of Magic”). 

Selected publications

How do we see art: an eye-tracker study.

Rodrigo Quian Quiroga, Carlos Pedreira

Frontiers in Human Neuroscience. 5:98, 2011.

Looking at Ophelia: A comparison of viewing art in the gallery and in the lab.

Binnie J, Dudley S, Quian Quiroga R.

Advances in Clinical Neuroscience and Rehabilitation. Vol 11. Number 3: 15-18, 2011.

In retrospect: Funes the Memorious
Quian Quiroga R.

Nature. 463: 611; 2010. 

Selected Media Impact

Neuro-magic: Magician uses magic tricks to study the brain’s powers of perception and memory (University of Leicester Press Office)

The Art of Visual Perception – Video coverage of “The Art of Visual Perception” exhibition at Embrace Arts.

What makes a masterpiece? – Channel 4

 

VI – Electrophysiology & 2-photon imaging recordings

We have recently started work on an animal model of concept cells to perform both electrophysiology and 2-photon imaging recordings in the mice hippocampus, while the animals navigate in a virtual reality environment. The goal is to compare concept representations in mice with those we found and study in humans and extend the studies in humans by having recordings of larger number of neurons, in different areas and at different stages of concept formation.

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Contact Us

Centre for Systems Neuroscience

Centre for Medicine,
Department of Neuroscience, Psychology and Behaviour
University of Leicester
15 Lancaster Rd,
Leicester LE1 7HA

UK

T +44 (0)116 252 3249

E csn@le.ac.uk

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