A5081505918- Neural dynamics and brain function
- Visual perception and processing mechanisms
- Functional Brain Connectivity Studies
- EEG and Brain-Computer Interfaces
- Neural and Behavioral Psychology Studies
- Neurobiology and Insect Physiology Research
- Advanced Neuroimaging Techniques and Applications
- Retinal Development and Disorders
- Transcranial Magnetic Stimulation Studies
- Stress Responses and Cortisol
- Advanced MRI Techniques and Applications
- Intensive Care Unit Cognitive Disorders
- Ophthalmology and Visual Impairment Studies
- Neurogenesis and neuroplasticity mechanisms
- Primate Behavior and Ecology
- Treatment of Major Depression
- Neuroscience and Neuropharmacology Research
University of Oxford
2014-2024
Ernst Strüngmann Institute for Neuroscience
2021
Warneford Hospital
2017
Google (United States)
2016
McGill University
2009-2015
It is widely reported that the activity of single neurons in visual cortex correlated with perceptual decision subject. The strength this correlation has implications for neuronal populations generating percepts. Here we asked whether microsaccades, which are small, involuntary eye movements, contribute to between neural and behavior. We analyzed data from three different detection experiments, recordings middle temporal (MT), lateral intraparietal (LIP), ventral (VIP) areas. All experiments...
Cognitive dysfunction is common in depression during both acute episodes and remission. Vortioxetine a novel multimodal antidepressant that has improved cognitive function including executive depressed patients randomised placebo-controlled clinical trials. However, it unclear whether vortioxetine able to target directly the neural circuitry implicated deficits depression. Remitted (n=48) healthy volunteers were receive 14 days treatment with 20 mg or placebo double-blind design. The effects...
Extrastriate visual area V5/MT in primates is defined both structurally by myeloarchitecture and functionally distinct responses to motion. Myelination directly identifiable from postmortem histology but also indirectly image contrast with structural magnetic resonance imaging (sMRI). First, we compared the identification of using sMRI Rhesus macaques. A section-by-section comparison histological slices vivo for same block cortical tissue showed precise correspondence localizing heavy...
One of the most influential accounts central orbitofrontal cortex—that it mediates behavioral flexibility—has been challenged by finding that discrimination reversal in macaques, classic test flexibility, is unaffected when lesions are made excitotoxin injection rather than aspiration. This suggests critical brain circuit mediating flexibility tasks lies beyond cortex. To determine its identity, a group nine macaques were taught learning tasks, and impact on gray matter was measured....
Fluctuations of neural firing rates in visual cortex are known to be correlated with variations perceptual performance. It is important know whether these fluctuations functionally linked perception a causal manner or instead reflect non-causal processes that arise after the decision made. We recorded from middle temporal (MT) neurons monkey subjects while they detected random occurrence brief 50 ms motion pulse occurred either two (or simultaneously both) dot patches located same...
The evolution of a visually guided perceptual decision results from multiple neural processes, and recent work suggests that signals with different origins are reflected in separate frequency bands the cortical local field potential (LFP). Spike activity LFPs middle temporal area (MT) have functional link perception motion stimuli (referred to as neural-behavioral correlation). To cast light on underlie this link, we compared dynamics correlations MT spikes LFPs. Wide-band was simultaneously...
Variability in cortical neural activity potentially limits sensory discriminations. Theoretical work shows that information required to discriminate two similar stimuli is limited by the correlation structure of variability. We investigated these information-limiting correlations recording simultaneously from visual areas primary cortex (V1) and extrastriate area V4 macaque monkeys performing a binocular, stereo depth discrimination task. Within both areas, noise on rapid temporal scale...
Spike-time correlations capture the short timescale covariance between activity of neurons on a single trial. These can significantly vary in magnitude and sign from trial to trial, have been proposed contribute information encoding visual cortex. While monkeys performed motion-pulse detection task, we examined behavioral impact both single-trial spike-time two nonoverlapping pools middle temporal (MT) neurons. We applied three measures correlation our multiunit MT spike trains (Pearson's,...
Abstract Primate lateral intraparietal area (LIP) is critical for cognitive processing. Its contribution to categorization and decision-making has been causally linked neurons’ spatial sensorimotor selectivity. We reveal the intrinsic anatomical circuits neuronal responses within LIP that provide substrate this flexible generation of motor sensory targets. Retrograde tracers delineate a loop between two distinct operational compartments, with sensory-like, point-to-point projection from...
Correlations between responses in visual cortex and perceptual performance help draw a functional link neural activity visually guided behavior. These correlations are commonly derived with ROC-based neural-behavioral covariances (referred to as choice or detect probability) using boxcar analysis windows. Although windows capture the covariation behavior during steady-state stimulus presentations, they not optimized these short time-varying inputs. In this study, we implemented...
Noninvasive diffusion-weighted magnetic resonance imaging (dMRI) can be used to map the neural connectivity between distinct areas in intact brain, but standard resolution achieved fundamentally limits sensitivity of such maps. We investigated and specificity high-resolution postmortem dMRI probabilistic tractography rhesus macaque brains produce retinotopic maps lateral geniculate nucleus (LGN) extrastriate cortical visual area V5/MT based on their topographic connections with previously...
Abstract One of the most influential accounts central orbitofrontal cortex– that it mediates behavioral flexibility – has been challenged by finding discrimination reversal in macaques –the classic test –is unaffected when lesions are made excitotoxin injection rather than aspiration. This suggests critical brain circuit mediating tasks lies beyond cortex. To determine its identity a group nine were taught learning and impact on grey matter was measured. Magnetic resonance imaging scans...
ABSTRACT Variability in cortical neural activity potentially limits sensory discriminations. Theoretical work shows that information required to discriminate two similar stimuli is limited by the correlation structure of variability. We investigated these information-limiting correlations recording simultaneously from visual areas V1 and V4 macaque monkeys, performing a binocular, stereo-depth discrimination task. Within both areas, noise on rapid temporal scale (20-30ms) were stronger for...