Topic: somatosensory cortex

Traditionally, touch is associated with exteroception and is rarely considered a relevant sensory cue for controlling movements in space, unlike vision. We developed a technique to isolate and measure tactile involvement in controlling sliding finger movements over a surface. Young adults traced a 2D shape with their index finger under direct or mirror-reversed visual feedback to create a conflict between visual and somatosensory inputs. In this context, increased reliance on somatosensory input compromises movement accuracy. Based on the hypothesis that tactile cues contribute to guiding hand

GABAergic interneurons are chiefly responsible for controlling the activity of local circuits in the cortex. Chandelier cells (ChCs) are a type of GABAergic interneuron that control the output of hundreds of neighbouring pyramidal cells through axo-axonic synapses which target the axon initial segment (AIS). Despite their importance in modulating circuit activity, our knowledge of the development and function of axo-axonic synapses remains elusive. We have investigated the emergence and plasticity of axo-axonic synapses in layer 2/3 of the somatosensory cortex (S1) and found that ChCs follow w

The shapes of neuronal morphologies are essential for the dynamical properties of the brain, as their branching patterns govern different functional properties of cell types. However, disagreements on the definition of neuronal classes due to the subjective views of the experts have spawned several efforts to find an objective way of deriving a morphology classification. We combine machine learning with a variety of mathematical tools to group neuronal morphologies into stable classes. We show that different methods perform optimally on different use-cases. Thus, we propose a combination of tr

Sensory experience and perceptual learning changes receptive field properties of cortical pyramidal neurons possibly mediated by long-term potentiation (LTP) of synapses. We have previously shown in the mouse somatosensory cortex (S1) that sensory-driven LTP in layer (L) 2/3 pyramidal neurons is dependent on higher order thalamic feedback from the posteromedial nucleus (POm), which is thought to convey contextual information from various cortical regions integrated with sensory input. We have followed up on this work by dissecting the cortical microcircuitry that underlies this form of LTP

Sequential temporal ordering and patterning are key features of natural signals, used by the brain to decode stimuli and perceive them as sensory objects. Touch is one sensory modality where temporal patterning carries key information, and the rodent whisker system is a prominent model for understanding neuronal coding and plasticity underlying touch sensation. Neurons in this system are precise encoders of fluctuations in whisker dynamics down to a timescale of milliseconds, but it is not clear whether they can refine their encoding abilities as a result of learning patterned stimuli. For exa

Despite the consistency of symptoms at the cognitive level, we now know that brain disorders like Autism and Schizophrenia can each arise from mutations in >100 different genes. Presumably there is a convergence of “symptoms” at the level of neural circuits in diagnosed individuals. In this talk I will argue that redundancy in neural circuit parameters implies that we should take a circuit-function rather that circuit-component approach to understanding these disorders. Then I will present our recent empirical work testing a circuit-function theory for Autism: the idea that neural circuits sho

Different explanations have been put forward to account for gender-related differences in mental rotation (MR) tasks. This fMRI study focused on the two main strategies - allocentric and egocentric - for solving a MR task. The allocentric strategy has been shown to be faster and more effective than the egocentric strategy. Since men are better than women at solving this task, one would predict that men tend to use the object's frame, while women tend to use their own frame. 62 participant went through two experimental conditions, requiring them to use a specific method for solving a MR task. B

Neurostimulation employing photoactive organic semiconductors presents a promising alternative to conventional techniques, enabling targeted action and wireless control through light. This study investigates the efficacy of stimulation of the neuronal networks in vivo using organic electrolytic photocapacitors (OEPC) and explores the interactions between the device and neural tissue following a long-term implantation.OEPC implants were positioned subdurally on the somatosensory cortex of adult rats, with the craniectomy site sealed by a transparent window. Three weeks post-implantation, animal