Autumn 2016

23rd September, Professor Penny Lewis (Cardiff University)

SM3, Maths

 
Exploring sleep’s impact on memory with targeted reactivation

Memories are neurally replayed during sleep, and this is important for their consolidation and integration with prior knowledge.  Targeted Memory Reactivation (TMR) is a technique which can be used to trigger the replay of specific memories on demand.  In this talk I will first describe a study which suggests that sleep plays a role the in integrating new information into pre-existing knowledge frameworks (or schemas).  I will next describe two studies which use TMR to examine a) the role memory replay in facilitating the emergence of explicit knowledge from implicitly learned material, and b) the role of memory replay in reducing emotional content of memories.  I will finish up by discussing a new method for identifying TMR cued replay in sleep using EEG classifiers.

http://psych.cf.ac.uk/contactsandpeople/academics/lewispenny.php

 


30th September, Professor Myra Conway (University of the West of England)

SM3, Maths

Prof. Conway’s talk concerns the role of glutamatergic neurotransmission in memory and learning, and how disruptions contribute to Alzheimer’s disease.

Glutamatergic neurotransmission is important for memory and learning and is severely disrupted in Alzheimer’s disease.  Recent studies by our group have demonstrated that a metabolic protein involved in regulating brain glutamate is significantly upregulated in AD brain relative to age-matched controls.  In this talk I will focus on how this protein forms metabolons that can be influenced by the redox state and how this will influence glutamate regulation.  I will also introduce one of our current research questions, which asks if these proteins can also act as novel chaperones and consider their role in protein folding.  This is important as misfolded proteins and aggregate accumulation contributes to disease pathogenesis.

http://people.uwe.ac.uk/Pages/person.aspx?accountname=campus%5Cme-conway


7th October, ‘Supervisor Snapshots’ session

SM3, Maths

This session is exclusively for first year students of the Neural Dynamics programme. Supervisors from the university will be discussing the rotation projects they are offering to the new students.


14th October, ‘Supervisor Snapshots’ session

Location TBC

This session is exclusively for first year students of the Neural Dynamics programme. Supervisors from the university will be discussing the rotation projects they are offering to the new students.

21st October, Dr Wessel Woldman (University of Exeter)

SM3

Analysis and modelling of epileptiform discharges

I will discuss how the epileptic activity of the brain is distributed over the course of a day using a large clinical data-set. We studied dynamic patterns of epileptiform discharges captured on recordings of scalp electroencephalogram (EEG) from 107 people with generalised epilepsies. I will show that discharges are distributed non-randomly over the course of 24 hours both in frequency and duration, after which I will show how a particularly simple phenomenological model can be used to reproduce the discharge distributions of individual subjects. In a broader setting, this work provides further support for the emergent concept that epileptic activity emerges from the interplay between a global network structure and the individual dynamics of specific brain regions.

http://www.exeter.ac.uk/cbma/team/mrcfellows/


4th November, Dr Alain Nogaret (University of Bath)
SM3
 
 

11th November, Dr Francesca Spiga
SM3
 
Origin and regulations of glucocorticoids ultradian rhythms: insights from experimental and mathematical data
 
 

18th November, Dr Konstantinos Kalafatakis

SM3

Different patterns of glucocorticoid rhythmicity change resting state networks and brain’s responses to emotional stimulation in healthy male individuals

Background: Glucocorticoids’ (GCs) rhythmicity is a dynamic biological factor for their regulatory effects, particularly important in the parts of the brain that show high sensitivity to GCs. Such brain regions, like the corticolimbic structures, are abundant in glucocorticoid- and mineralocorticoid receptors, through which GCs modulate various cognitive and behavioural phenotypes in humans.

Aim: To examine the effect of different temporal patterns of glucocorticoid presentation on the corticolimbic areas’ resting state networks and neural processing of emotional faces with the application of functional magnetic resonance imaging (fMRI).

Methods: 15 healthy, male, right-handed individuals participated in an interventional, double-blinded, placebo-controlled, crossover study. The three treatment schemes had a duration of 5 days. All participants received oral metyrapone loading (gradually increasing total daily dose from 1g to 2.5g) to suppress endogenous cortisol adrenal activity. A fixed total daily dose of hydrocortisone 20mg was exogenously replaced via 3 different methods (1 per treatment arm): (a) orally, (b) subcutaneously in a continuous manner and (c) subcutaneously in a pulsatile manner. Individuals participated in a functional neuroimaging study on day 5.

Results: Under resting state conditions, the functional connectivity of various corticolimbic regions (like amygdala, orbitofrontal cortex, dorsal striatum, insula or cingulate) with regions implicated in the processing of visual and somatosensory stimuli and core components of the default mode and the salience network changes significantly between the 3 study groups. Moreover, across groups, these corticolimbic regions showed significantly different responses to emotional faces.

Conclusion: These data support the capability of altered GCs temporal dynamics to differentially modulate the level or mode of activation of susceptible brain areas under emotional stimulation and resting state condition. Implications about the role of GCs in the emotional control of cognition and development of psychopathology are discussed.

http://www.bristol.ac.uk/clinical-sciences/people/konstantinos-kalafatakis/index.html


25th November, Dr Nadia Cerminara

SM3

An action based map of C3 cerebellar microzones

A fundamental principle of cerebellar functional organization is its division into a series of longitudinally oriented modules. Each module is defined by its climbing fibre input from a specific subdivision of the contralateral inferior olive, which targets one or more longitudinal zones of Purkinje cells within the cerebellar cortex. In turn, Purkinje cells within each zone project to specific regions of the cerebellar or vestibular nuclei. Within several zones, smaller units known as ‘microzones’ have been identified electrophysiologically in anaesthetized animals. Within a given microzone, all Purkinje cells have climbing fibre-mediated input with similar receptive fields. Microzones and their associated input–output connections are thought to represent the basic operational units of the cerebellum. However, little is known about their function in awake, behaving animals. Experiments in the lab are investigating cerebellar microzones ‘in action’  by recording from single cerebellar neurones located in different microzones during performance of a visually guided forelimb reach/retrieval task in cats.

http://www.bristol.ac.uk/phys-pharm/people/nadia-l-cerminara/index.html


2nd December, Dr Gihan Weerasinghe (University of Oxford)

SM3
 
Deep brain stimulation (DBS) is a proven therapy for a variety of neurological disorders, including Parkinson’s disease and essential tremor. The current generation of technology operates on an open loop basis, where stimulation is delivered irrespective of a patient’s symptoms. In contrast, the closed loop approach, where the patient’s symptoms are continuously monitored and the stimulation delivered accordingly, has the potential to be both more effective and efficient than existing solutions. This talk will focus on the processing of measurement data in relation to closed loop DBS, in particular, the tremor data obtained from patients with essential tremor.
 
 

9th December, Associate Professor Yulia Timofeeva (University of Warwick)

SM3
Quantification of fast presynaptic Ca2+ kinetics using non-stationary single compartment model
 
Fluorescence imaging is an important tool in examining Ca2+-dependent machinery of synaptic transmission. Classically, deriving the kinetics of free Ca2+ from the fluorescence recorded inside small cellular structures has relied on singe-compartment models of Ca2+ entry, buffering and removal. In many cases, steady-state approximation of Ca2+ binding reactions in such a model allows elegant analytical solutions for the Ca2+ kinetics in question. However, the fast rate of action potential (AP)-driven Ca2+ influx can be comparable with the rate of Ca2+ buffering inside the synaptic terminal. In this case, computations that reflect non-stationary changes in the system might be required for obtaining essential information about rapid transients of intracellular free Ca2+. Based on the experimental data we propose an improved procedure to evaluate the underlying presynaptic Ca2+ kinetics. We show that in most cases the non-stationary single compartment model provides accurate estimates of action-potential evoked presynaptic Ca2+ concentration transients, similar to that obtained with the full 3D diffusion model. Based on this we develop a computational tool aimed at stochastic optimisation and cross-validation of the kinetic parameters based on a single set of experimental conditions. The proposed methodology provides robust estimation of Ca2+ kinetics even when a priori information about endogenous Ca2+ buffering is limited.
 
 

16th December, Dr Janine Bijsterbosch
SM3
 
The three slides of Christmas: Variability, Amplitude and Connectivity
 
The amplitudes of spontaneous fluctuations in brain activity are investigated rarely and are relatively poorly understood, despite their direct relevance to measures of functional connectivity (FC). However, resting state signal amplitudes may be a significant source of within-subject and between-subject variability, and this variability is likely to be carried through into FC estimates. In this talk I will describe both cross-subject and within-subject variability in the Human Connectome Project, and I will discuss the relationship between signal amplitude and estimated functional connectivity.
 

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