University of Nottingham Medical School Neuronal Networks Laboratory Using Plexon at Nottingham:...

University of Nottingham Medical SchoolNeuronal 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

schizophrenia – sensory gating epilepsy

anxiety pain


Multiple Electrode Recordings in vivosimultaneous multichannel spike & field potential recording

• 64-channel MAP system• 32-channel MAP system – with CinePlex for behavioural studies • 64-channel Recorder system• 16-channel Recorder system used MAP & Recorder for in vitro MEA studies with brain slices & neuronal cultures

LAB TEAM

epilepsy Ben Coomber [Dr Mike O’Donoghue] Clare Roe schizophrenia Dr Jill Suckling [Prof CA Marsden]

Dr Dissanayake 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 (fMRI / phMRI)


LAB EXPERIMENTAL DIRECTIONS

mPFCx interconnectivity & functional context – in vivo studies

maternal separation - depression

circadian - affective states

sensory gating- schizophrenia- epilepsy

USVs- affective states

medial Pre-Frontal Cortex

Amygdalanucleus AccumbensHippocampusSCN

Contralateral

mPFC

VTA

- schizophrenia- drugs of abuse

PVt

• Dual site recordings

VTA - mPFC hippocampus - mPFCamygdala - mPFCmPFC - mPFC

• Systemic pharmacological manipulation

• Local pharmacological manipulation

“injec-trode” integrated microiontophoresis with recording array

• Electrical stimulation

• Independent electrode array microdrive

• Anaesthetised & awake-behaving preparations



Project #1: Schizophrenia

• auditory-evoked sensory gating

• effects of PCP / ketamine - model

• effects of social isolation - model


Schizophrenia - VTA/mPFCx dual-site recordings

medial prefrontal cortex - mPFCventral tegmental area - VTA

Prussian Blue reaction - locate recording site(s) - histology

PFC VTA

Dual site recording: pre-frontal cortical / VTA recording

multiple single-units & LFPs

1 mV5 s

VTA cells

PFC cells

VTA LFP

PFC LFP

1

8

1

7

Neurone #

• Matlab scripts for off-line characterisation unit spike waveforms & LFPs

• Explore connectivity between PFC and VTA -

e.g. local application of drug (e.g. glutamate)

to VTA to drive mPFC

Local application of drugs – “injec-trode”

10s

Extra-VTA

PFC

Extra-VTA LFP

PFC LFP

50 nl Glutamate (100 mM)

Electrode headstage

Tubing attached to Hamilton syringe

Electrode tips

Cannula tip

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: 3kHz sine-wave / 10ms duration / presented 500ms apart / 80-90dB

• human P50 wave = rat N40 component

• Gating absent in - schizophrenic patients (& near family members)

- normal human volunteers given PCP / amphetamine

- rats given PCP / amphetamine


1sLFP2 averaged 128 trials

Units

LFPs

Hippocampal CA3 - auditory-evoked unit & LFP activity

- 128

- 1

Trial #

sCs Ts

mV

N40N40

Averaged LFP

T/C ratio = 50%

eventtone

dentate gyrus CA3 region CA3 region

Single-unit PSTHs ‘ rasters histograms - gating rats

Unit 1

Unit 2

Unit 3

Unit 4

Spike raster

PSTH

LFP

LFP trial raster

Hippocampal CA3 auditory-evoked unit & LFP activity

Effects of PCP (1mg/kg i.p.) attenuates/abolishes sensory gating

Basal [128 trials]

T/C ratio = 32%

45mins after PCP

T/C ratio = 66%

1

Trail #

128


Project #2: Epilepsy

• kainate-induced epileptiform activity – TLE

• functional network interactions - hippocampus mPFC

• electrical stimulation – perforant pathway

• role of endocannibnoid system – CB1R pharmacology


hippocampus mPFC

PFC

Hipp

PFCHippL

HippM

Basal firing KA-induced firing (10mg kg-1, i.p.)

2s

Kainate-induced epileptiform activity – dual recording hippocampus & mPFC

mPFC

Hipp

mPFCHIPP

Hippocampal-mPFC – functional connectivity

Burst analysis – Synchrony index - Cross-correlation – coherence - PDC

-1 -0.5 0 0.5 10

2

4

6

8

10

12

14

sig001a

-1 -0.5 0 0.5 10

20

40

60

sig006a

-1 -0.5 0 0.5 1Time (sec)

0

5

10

15

sig008b

-1 -0.5 0 0.5 10

1

2

3

4

5

sig023c

-1 -0.5 0 0.5 10

2

4

6

sig023e

-1 -0.5 0 0.5 1Time (sec)

0

1

2

3

4

sig024a

Crosscorrelograms, reference = sig006a, bin = 1 ms

Co

un

ts/b

in

Ref unit

mPFC Hippocampus

unit 3H

unit 1H

unit 2H

PDC Analysis – Unit populations

Identify direction of activity between hippocampus and mPFC - PDC applied: technique with potential to reveal the neuronal ensemble drive direction.

Note: the magnitude of the classical coherence gives no information about directional connectivity, but its phase may do so.

KAKA

PDC Analysis – LFPs

Representative PDC plot between LFPs recorded from 3 electrodes in both• mPFC (AD01-08) • hippocampus (AD10 to AD16 = medial to lateral electrodes).

TIME FRAME #

HippocampusmPFC

mP

FC

Hip

po

ca

mp

us

Red boxes highlight PDC between brain regions – suggesting the predominant flow is from mPFC 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

• 45min post-KA - hippocampus

LFPanalyser suite 2006

% Power Distribution Basal

45min Post-KA



Project #3: Nociception & pain management

• dual spinal cord / supraspinal recording

Role of endocannabinoid system in normal physiology and pain (e.g. neuropathic) states


-2 0 2 4 6Time (sec)

10

20

30

40

sig004a

Perievent Rasters, reference = Event002, bin = 100 ms

Fre

quen

cy (

imp/

sec)

innocuous (7g) stimulation

-2 0 2 4 6Time (sec)

20

40

60

sig004a

Perievent Rasters, reference = Event002, bin = 100 ms

Fre

quen

cy (

imp/

sec)

noxious (65g) stimulation

Mechanically-evoked response in somatosensory thalamus (VPM)


Project #4: Affective stateCortico-limibic network interactions

• anxiety effects of maternal separation

pharmacologically-induced (e.g. FG-7142) anxiety

• behavioural sequalaerodent ultrasound vocalisations


• Role of nuc accumbens in USV-mediated Behaviours

• nucleus accumbens / basolateral amygdala - mPFCx functional connectivity

nucleus accumbens – mPFC

Rat ultrasound vocalisations (USVs) & affective stateNeuronal Networks Laboratory

50kHz

22kHz

Time (s)

Fre

quen

cy (

kHz)

~22 kHz calls - aversive stimuli (call Type G)

~50 kHz calls

- rewarding stimuli (Types A-F)

Combined unit / LFP with USV / behavioural recording

50 ms

25

50

75

100

125

kHz

1V

296:1

296

0.05 0.10 0.15 0.20 0.25 0.30 s

25

50

75

100

125

kHz

1V

295:1 295:2295:3 295:4 295:5 295:6

295

USV call start time

unit activity - nuc accumbens

USV Recorder input

Behavioural data

Local Field Potential (LFP)

Spectrogram of specific calls [AviSoft]

Multiple Electrode Recordings in vivo

simultaneous multichannel spike / field potential / behavioural recording

Video camera CinePlex system

Behavioural Electrophysiology II

Circular arena recording using CinePlex

Movie - rat HopScotch: 8-microwire array in nuc. accumbens - 6 weeks post implant


Recorded video

Neural data


Lab web site

www.nottingham.ac.uk/neuronal-networks


That’s all folks

University of Nottingham Medical School Neuronal Networks Laboratory Using Plexon at Nottingham:...

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