A5015107357- Neural dynamics and brain function
- Circadian rhythm and melatonin
- Zebrafish Biomedical Research Applications
- Muscle activation and electromyography studies
- Photoreceptor and optogenetics research
- Neuroscience and Neuropharmacology Research
- Neuroscience and Neural Engineering
- Primate Behavior and Ecology
- Memory and Neural Mechanisms
- Ion channel regulation and function
- Advanced Memory and Neural Computing
- Neuroendocrine regulation and behavior
- Neuroscience of respiration and sleep
- Neurobiology and Insect Physiology Research
- stochastic dynamics and bifurcation
- Cell Image Analysis Techniques
- Spinal Cord Injury Research
- Sleep and Wakefulness Research
- Biochemical Analysis and Sensing Techniques
- Regulation of Appetite and Obesity
- Receptor Mechanisms and Signaling
- Electrochemical Analysis and Applications
- Machine Learning and ELM
- Nicotinic Acetylcholine Receptors Study
- Animal Vocal Communication and Behavior
University College London
2010-2024
University of Cambridge
2003-2009
Spinal motoneurones (Mns) constitute the final output for execution of motor tasks. In addition to innervating muscles, Mns project excitatory collateral connections Renshaw cells (RCs) and other Mns, but latter have received little attention. We show that receive strong synaptic input from throughout development into maturity, with fast-type systematically receiving greater recurrent excitation than slow-type Mns. Optical recordings activation in one spinal segment can propagate adjacent...
Motoneurons (MNs) control muscle contractions, and their recruitment by premotor circuits is tuned to produce accurate motor behaviours. To understand how these coordinate movement across between joints, it necessary whether spinal neurons pre-synaptic pools have divergent projections more than one MN population. Here, we used modified rabies virus tracing in mice investigate interneurons projecting synergist flexor or extensor MNs, as well those antagonist pairs of muscles controlling the...
Elaborate behaviours are produced by tightly controlled flexor-extensor motor neuron activation patterns. Motor neurons regulated a network of interneurons within the spinal cord, but computational processes involved in control not fully understood. The neuroanatomical arrangement and premotor into topographic patterns related to their muscles is thought facilitate how information processed circuits. Rabies retrograde monosynaptic tracing has been used label innervating specific pools, with...
In many neurological conditions, early-stage neural circuit adaption can preserve relatively normal behaviour. some diseases, spinal motoneurons progressively degenerate yet movement is initially preserved. We therefore investigated whether these neurons and associated microcircuits adapt in a mouse model of progressive motoneuron degeneration. Using combination
The mammalian circadian pacemaker, the suprachiasmatic nucleus (SCN), contains receptors to adipose tissue hormone leptin. In present study, effects of leptin on electrophysiological activity SCN cells were characterised in vitro rat brain slices. During extracellular recording, application 20 n m (n = 36) decreased mean spike frequency (Wilcoxon signed rank test, z −3.390, P < 0.001) and increased irregularity firing measured by entropy log interspike interval distribution (Student’s...
Although Renshaw cells (RCs) were discovered over half a century ago, their precise role in recurrent inhibition and ability to modulate motoneuron excitability have yet be established. Indirect measurements of suggested only weak modulatory effect but are limited by the lack observed responses inputs from single RCs. Here we present dual recordings between connected RC–motoneuron pairs, performed on mouse spinal cord. Motoneuron demonstrated that synapses elicit large inhibitory...
Renshaw cells represent a fundamental component of one the first discovered neuronal circuits, but their function in motor control has not been established. They are only central neurons that receive collateral projections from outputs, yet efficacy excitatory synapses single and converging motoneurons remains unknown. Here we present results dual whole-cell recordings identified, synaptically connected cell-motoneuron pairs mouse lumbar spinal cord. The responses demonstrate motoneuron...
In neonatal mice motoneurons excite Renshaw cells by releasing both acetylcholine (ACh) and glutamate. These two neurotransmitters activate types of nicotinic receptors (nAChRs) (the homomeric α7 the heteromeric α*ß* receptors) as well glutamate (GluRs) (AMPARs NMDARs). Using paired recordings, we confirm that a single motoneuron can release transmitters on post-synaptic cell. We then show co-transmission is preserved in adult animals. Kinetic analysis miniature EPSCs revealed quantal mixed...
Communication between neurones in the central nervous system depends on synaptic transmission. The efficacy of synapses is determined by pre- and postsynaptic factors that can be characterized using quantal parameters such as probability neurotransmitter release, number release sites, size. Existing methods estimating based multiple fluctuation analysis (MPFA) are limited their requirement for long recordings to acquire substantial data sets. We therefore devised an algorithm, termed...
Measuring spike coding objectively is essential to establish whether activity recorded under one set of conditions truly different from that another conditions. However, there no generally accepted method for making such comparisons. firing frequency alone only partially reflects patterning. In this paper, novel quantities based on the logarithmic interspike intervals are proposed as useful measures spontaneous activity. We illustrate methods by comparing extracellular recordings...
The suprachiasmatic nucleus is regarded as the main mammalian circadian pacemaker but evidence for rhythmic firing of single units in vivo has been obtained only recently. present study was undertaken to determine if rhythms could be seen using measures activity addition mean spike frequency. We investigated whether there were changes irregularity cell measured by disorder interspike interval distribution neurones recorded and vitro. By plotting entropy log histogram that quantifies coding...
Novel measures of coding based on interspike intervals were used to characterize the responses supraoptic cells osmotic stimulation. Infusion hypertonic NaCl in vivo increased firing rate continuous (putative oxytocin) (Wilcoxon z= 3.84, P= 0.001) and phasic vasopressin) (z= 2.14, 0.032). The irregularity activity, quantified by log interval entropy, was decreased for (Student's t= 3.06, 0.003) but not (t= 1.34, 0.181). For cells, increase frequency decrease entropy significantly greater...
The effects of the application melatonin in vitro on electrophysiological activity suprachiasmatic neurones were characterised using novel measures coding based analysis interspike intervals. Perfusion 1 nM (n = 53) had no consistent effect mean spike frequency (Wilcoxon's sign rank, z -0.01, P 0.989), but increased irregularity firing (Student's paired t-test, t -3.02, 0.004), as measured by log interval entropy, and patterning (z -3.43, < 0.001), mutual information between adjacent...
Novel measures of coding based on interspike intervals were used to characterise the rhythms single unit activity in supraoptic nucleus during day/night cycle urethane-anaesthetised rats vivo. Both continuously firing and phasic cells showed significant (P < 0.001) diurnal spike frequency irregularity firing, as quantified by log interval entropy (ENT). Comparison ENT that amplitude was greater for than = 0.002). Rhythms persisted after hypertonic stimulation or pinealectomy both treatments...
Neural information is conveyed by action potentials along axons to downstream synaptic targets. Synapses permit functionally relevant modulation of the transmitted converging inputs. Previous studies have measured amount associated with a given stimulus based either on spike counts or relative frequencies sequences represented as binary strings. Here we apply theory phase-interval histogram (PhISH) measure extent stimulus-evoked response using statistical relationship between each interspike...
Abstract Spinal motoneurones constitute the final output for execution of motor tasks. In addition to innervating muscles, project excitatory collateral connections Renshaw cells and other motoneurones, but latter have received little attention. We show that receive strong synaptic input from throughout development into maturity with fast type systematically receiving greater recurrent excitation than slow motoneurones. Optical recordings activation in one spinal segment can propagate...
Abstract Elaborate behaviours are produced by tightly controlled flexor-extensor motor neuron activation patterns. Motor neurons regulated a network of interneurons within the spinal cord, but computational processes involved in control not fully understood. The neuroanatomical arrangement and premotor into topographic patterns related to their muscles is thought facilitate how information processed circuits. Rabies retrograde monosynaptic tracing has been used label innervating specific...
In the published paper of Bhumbra et al. (2008), link to software used, which appeared in last paragraph Materials and methods section, was incorrect. We apologize for these errors, reproduce corrected sentence below. The used analysis can be downloaded from http://www.pdn.cam.ac.uk/staff/dyball/index.html.
`Biologically inspired' activation functions, such as the logistic sigmoid, have been instrumental in historical advancement of machine learning. However field deep learning, they largely displaced by rectified linear units (ReLU) or similar its exponential unit (ELU) variant, to mitigate effects vanishing gradients associated with error back-propagation. The sigmoid however does not represent true input-output relation neuronal cells under physiological conditions. Here, bionodal root (BRU)...
Abstract Motor neurons control muscle contractions, and their recruitment by premotor circuits is tuned to produce accurate motor behaviours. To understand how these coordinate movement across between joints, it necessary whether spinal pre-synaptic pools, project more than one neuron population. Here, we used modified rabies virus tracing in mice investigate INs projecting synergist flexor or extensor neurons, as well those antagonist pairs of muscles controlling the ankle joint. We show...