Neuronal Networks Laboratory University of Nottingham Medical School
Neuronal Networks Laboratory University of Nottingham Medical School Neuronal Networks Laboratory Using Plexon at Nottingham: Sensory Gating, Anxiety, Seizures, and Pain Dr Rob Mason School of Biomedical Sciences University of Nottingham Medical School
Neuronal Networks Laboratory Talk Format • Brief overview of what we have been studying using Plexon system(s) at Nottingham • Indicate on route some hardware developments & signal processing / analysis approaches we use Ø schizophrenia – sensory gating Ø epilepsy Ø anxiety Ø pain
Multiple Electrode Recordings in vivo simultaneous multichannel spike & field potential recording • 64 -channel MAP system • 32 -channel MAP system • 64 -channel Recorder system • 16 -channel Recorder system – with Cine. Plex for behavioural studies Ø used MAP & Recorder for in vitro MEA studies with brain slices & neuronal cultures
Neuronal Networks Laboratory LAB TEAM epilepsy Ben Coomber Clare Roe [Dr Mike O’Donoghue] schizophrenia Dr Jill Suckling Dr Dissanayake [Prof CA Marsden] anxiety Dr Carl Stevenson [Prof CA Marsden] pain Dr Steve Elmes [Dr V Chapman] rodent USVs Beth Tunstall [Dr S Beckett] data analysis Margarita Zachariou [Dr S Coombes / Dr M Owen] [Mathematics Dept] Dr David Halliday (University of York) Prof D Auer (f. MRI / ph. MRI)
LAB EXPERIMENTAL DIRECTIONS m. PFCx interconnectivity & functional context – in vivo studies - schizophrenia - drugs of abuse medial Pre-Frontal Cortex Contralateral m. PFC VTA PVt SCN circadian - affective states Hippocampus sensory gating - schizophrenia - epilepsy nucleus Accumbens USVs - affective states Amygdala maternal separation - depression
Neuronal Networks Laboratory • Dual site recordings VTA - m. PFC hippocampus - m. PFC amygdala - m. PFC • Systemic pharmacological manipulation • Local pharmacological manipulation “injec-trode” integrated microiontophoresis with recording array • Electrical stimulation • Independent electrode array microdrive • Anaesthetised & awake-behaving preparations
Neuronal Networks Laboratory University of Nottingham Medical School Neuronal Networks Laboratory Project #1: Schizophrenia • auditory-evoked sensory gating • effects of PCP / ketamine - model • effects of social isolation - model
Schizophrenia - VTA/m. PFCx dual-site recordings PFC VTA Prussian Blue reaction - locate recording site(s) - histology ventral tegmental area - VTA medial prefrontal cortex - m. PFC
Dual site recording: pre-frontal cortical / VTA recording multiple single-units & LFPs Neurone # 1 VTA cells 7 1 PFC cells 8 VTA LFP PFC LFP 1 m. V 5 s • Matlab scripts for off-line characterisation unit spike waveforms & LFPs
Local application of drugs – “injec-trode” Tubing attached to Hamilton syringe • Explore connectivity between PFC and VTA - Cannula tip e. g. local application of drug (e. g. glutamate) to VTA to drive m. PFC Electrode headstage Electrode tips Extra-VTA PFC Extra-VTA LFP PFC LFP 50 nl Glutamate (100 m. M) 10 s
Neuronal Networks Laboratory Sensory gating in hippocampus: A model for schizophrenia ? • Sensory gating: mechanism(s) by which irrelevant sensory information is filtered – enables efficient information processing • Auditory Conditioning-Test paradigm: measures reduction in auditory-evoked response produced by Test stimulus following a Conditioning stimulus • Stimuli: 3 k. Hz sine-wave / 10 ms duration / presented 500 ms apart / 80 -90 d. B • human P 50 wave = rat N 40 component • Gating absent in - schizophrenic patients (& near family members) - normal human volunteers given PCP / amphetamine - rats given PCP / amphetamine
Hippocampal CA 3 - auditory-evoked unit & LFP activity Units event tone LFPs 1 s LFP 2 averaged 128 trials -1 Trial # - 128 Averaged LFP m. V N 40 T/C ratio = 50% Cs Ts s
Single-unit PSTHs ‘ rasters histograms - gating rats dentate gyrus CA 3 region Spike raster Unit 1 PSTH Unit 2 Unit 3 Unit 4 LFP trial raster LFP
Hippocampal CA 3 auditory-evoked unit & LFP activity Effects of PCP (1 mg/kg i. p. ) attenuates/abolishes sensory gating 1 Basal [128 trials] Trail # T/C ratio = 32% 128 45 mins after PCP T/C ratio = 66%
Neuronal Networks Laboratory University of Nottingham Medical School Neuronal Networks Laboratory Project #2: Epilepsy • kainate-induced epileptiform activity – TLE • functional network interactions - hippocampus m. PFC • electrical stimulation – perforant pathway • role of endocannibnoid system – CB 1 R pharmacology
Kainate-induced epileptiform activity – dual recording hippocampus & m. PFC Basal firing KA-induced firing (10 mg kg-1, i. p. ) PFC Hipp. L Hipp. M 2 s hippocampus m. PFC
Hippocampal-m. PFC – functional connectivity Burst analysis – Synchrony index - Cross-correlation – coherence - PDC m. PFC Hipp m. PFC HIPP m. PFC Hippocampus unit 1 H Ref unit 2 H unit 3 H
PDC Analysis – Unit populations Identify direction of activity between hippocampus and m. PFC - PDC applied: technique with potential to reveal the neuronal ensemble drive direction. KA KA Note: the magnitude of the classical coherence gives no information about directional connectivity, but its phase may do so.
PDC Analysis – LFPs Representative PDC plot between LFPs recorded from 3 electrodes in both • m. PFC (AD 01 -08) • hippocampus (AD 10 to AD 16 = medial to lateral electrodes). Hippocampus m. PFC TIME FRAME # Red boxes highlight PDC between brain regions – suggesting the predominant flow is from m. PFC to hippocampus Green boxes highlight that the predominant flow within hippocampus is from lateral to medial.
LFPanalyser suite 2006 – custom Matlab script • Basal (pre-KA challenge) - hippocampus
LFPanalyser suite 2006 • 45 min post-KA - hippocampus
LFPanalyser suite 2006
LFPanalyser suite 2006 % Power Distribution Basal 45 min Post-KA
Neuronal Networks Laboratory University of Nottingham Medical School Neuronal Networks Laboratory Project #3: Nociception & pain management • dual spinal cord / supraspinal recording Role of endocannabinoid system in normal physiology and pain (e. g. neuropathic) states
Mechanically-evoked response in somatosensory thalamus (VPM) innocuous (7 g) stimulation noxious (65 g) stimulation
Neuronal Networks Laboratory University of Nottingham Medical School Neuronal Networks Laboratory Project #4: Affective state Cortico-limibic network interactions • anxiety effects of maternal separation pharmacologically-induced (e. g. FG-7142) anxiety • behavioural sequalae rodent ultrasound vocalisations
nucleus accumbens – m. PFC Neuronal Networks Laboratory Rat ultrasound vocalisations (USVs) & affective state • Role of nuc accumbens in USV-mediated Behaviours • nucleus accumbens / basolateral amygdala - m. PFCx functional connectivity ~50 k. Hz calls - rewarding stimuli (Types A-F) Frequency (k. Hz) 50 k. H z ~22 k. Hz calls - aversive stimuli (call Type G) 22 k. Hz Time (s)
Combined unit / LFP with USV / behavioural recording unit activity - nuc accumbens USV call start time Behavioural data Local Field Potential (LFP) USV Recorder input Spectrogram of specific calls [Avi. Soft]
Multiple Electrode Recordings in vivo simultaneous multichannel spike / field potential / behavioural recording Video camera Cine. Plex system
Behavioural Electrophysiology II Neuronal Networks Laboratory Circular arena recording using Cine. Plex Movie - rat Hop. Scotch: 8 -microwire array in nuc. accumbens - 6 weeks post implant Recorded video Neural data
Neuronal Networks Laboratory University of Nottingham Medical School Neuronal Networks Laboratory That’s all folks Lab web site www. nottingham. ac. uk/neuronal-networks
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