Somatosensory Research Methods

Preface to the Series
Preface
Reference
Contents
Contributors
Part I: Discriminative Touch, Proprioception, and Kinaesthesis
Chapter 1: Detection, Discrimination & Localization: The Psychophysics of Touch
1 Introduction
1.1 Detection of Touches and Vibrations
1.2 Tactile Discrimination and Tactile Spatial Resolution
1.3 Summary
2 Materials
2.1 Presenting Pressure Stimuli (Vibrations) to the Fingertip
2.1.1 Loudspeakers
2.1.2 Bone-Conducting Hearing-Aid Vibrator
2.1.3 Solenoid
2.1.4 Piezoelectric Chips
2.1.5 Pneumatic (Air-Puff) Stimulation
2.1.6 Summary
2.2 Presenting Gratings to the Fingertip
2.2.1 Gratings
2.2.2 Presentation
2.3 Software
2.4 Calibration and Quality Control
2.4.1 Stimulus Timing and Amplitude
2.5 Environmental Conditions
3 Methods
3.1 Experimental Tasks
3.1.1 Detection
3.1.2 Discrimination
3.1.3 Localization
3.2 Experimental Design
3.2.1 One Interval or Two?
3.2.2 Yes/No, Magnitude, Forced-Choice, or Confidence?
3.2.3 Manual, Pedal, or Vocal Responses?
3.2.4 Constant or Varying Stimulus Magnitude?
3.2.5 Stimulus Waveform: Square-Wave, Sinusoidal, or Broadband?
3.2.6 Task Difficulty and Duration
3.3 Experimental Procedures
3.3.1 Vibrotactile Detection and Discrimination
3.3.2 Spatial Acuity
4 Notes
4.1 Tactile Hardware Is Not Uniform Over Time or Across Devices
4.2 3D Printing Tactile Stimuli
4.3 Participant-Specific Environmental Considerations
4.4 Task Comprehension and Training
4.5 Frequency and Intensity Interact
4.6 Adaptive Staircases and Experimenter Expertise
4.7 Attention
References
Chapter 2: Methods of Somatosensory Attenuation
1 Introduction
1.1 Behavioral Methods of Somatosensory Attenuation
1.2 Insights from Computational Motor Control
1.3 Clinical Applications
1.4 Beyond Human Somatosensation
2 Materials
3 Methods
3.1 Force-Matching Task
3.2 Force-Discrimination Task
3.3 Comparing the Tasks: Advantages and Disadvantages
4 Notes
4.1 Comfort
4.2 Instructions in the Force-Matching Task
4.3 Instructions in the Force-Discrimination Task
4.4 Intensity of the Active Tap
References
Chapter 3: Muscle Tendon Vibration: A Method for Estimating Kinesthetic Perception
1 Introduction
2 Materials
2.1 Mechanical Vibrators
2.2 Evaluation Tools
3 Methods
3.1 Experimental Design and Procedure
3.1.1 Vibration Parameters
3.1.2 Sensory Context
3.1.3 Instructions
3.1.4 Recording
3.1.5 Practice and Familiarization Trials
3.2 Quantification of Movement Illusions
3.3 Assessment of Discrimination Thresholds
3.4 Measurements of Motor Responses
3.4.1 Recording
3.4.2 Processing
3.5 Neural Basis of the Proprioceptive System
3.6 A Tool for Rehabilitation Perspectives
4 Notes
4.1 Establishing Illusion Presence
4.2 Avoiding After-Effects
4.3 Individual Differences
4.4 Participant´s Attentional State
References
Chapter 4: Creating Tactile Motion
1 Introduction
1.1 Chapter Aim
1.2 Sources of Information (Cues) About Tactile Motion
1.3 Tactile Motion Illusions and Distortions
1.4 Devices Used to Create Tactile Motion
1.5 Approaches to the Study of Tactile Motion
2 Materials and Methods for One Discrete and One Continuous Motion Study
2.1 Sensory Saltation (the Cutaneous Rabbit Illusion)
2.1.1 Materials
2.1.2 Methods
2.2 Filling-in of a Numb Spot with Continuous Motion
2.2.1 Materials
2.2.2 Methods
3 Notes
3.1 Haptic Terminology
3.2 Systematic Review of Tactile Motion
3.3 Random-dot Patterns
3.4 Controlling Tactile Stimuli
3.5 Amodal and Modal Completion
3.6 Number of Response Options
3.7 Definitions of ``Filling-in´´
3.8 Discrete Versus Continuous Stimuli
3.9 Direct Report Versus Forced-choice Responses
References
Chapter 5: Measuring Tactile Distance Perception
1 Introduction
2 Materials
3 Methods
3.1 Size Estimation Methods
3.1.1 In Magnitude Estimation
3.1.2 In Absolute Estimation
3.1.3 In Visual Comparison
3.1.4 In Kinesthetic Estimation
3.2 Size Estimation Analysis
3.2.1 Linear Regression
3.2.2 ANOVA
3.2.3 Multidimensional Scaling
3.2.4 Computational Models
3.3 Forced-Choice Methods
4 Notes
4.1 The Two-point Discrimination Task
4.2 Testing Different Parts of the Body
References
Part II: Affective Touch, Pain, Wetness, Itch, and Interoception
Chapter 6: Affective Touch: Psychophysics, Physiology and Vicarious Touch Perception
1 Introduction
1.1 The Periphery
1.2 The Cortex
2 Materials
2.1 Stimulus Delivery
2.1.1 Rotary Tactile Stimulator and Force Transducer
2.1.2 Manual Stroking Techniques
2.1.3 Videos for Vicarious Touch
2.2 Implicit Measures of Affective Touch
2.2.1 Facial Electromyography (EMG)
2.2.2 Microneurography
3 Methods
3.1 Control Conditions and Stimuli
3.2 Stimulus Velocity
3.3 Stimulus Evaluation
3.4 Manual and Robotic Stroking Procedures
3.5 Video-Based Induction
3.6 Facial EMG
4 Notes
4.1 Participant Movement
4.2 Training
4.3 Participant Blinding and Attention
4.4 Pleasantness Versus Intensity
4.5 Bare Hands Versus Gloves
4.6 Hairy Versus Glabrous Skin
4.7 Unusual Stimulus Velocities
4.8 Securing Electrodes
4.9 Confirming Electrode Placement
4.10 Condition Blinding
References
Chapter 7: Qualia, Brain Waves, and Spinal Reflexes: The Study of Pain Perception by Means of Subjective Reports, Electroencep...
1 Introduction
1.1 Measuring Pain: A Methodological Conundrum
1.2 Methodological Developments
1.3 Experimental Versus Clinical Pain
1.4 Application to Different Populations
2 Materials
2.1 Psychophysics and Behavioral Responses During Pain Assessment
2.1.1 Stimulation Apparatus
2.1.2 Recording Apparatus and Consumables
2.1.3 Software
2.1.4 Ratings and Behavioral Responses to Pain
2.1.5 Questionnaires
2.1.6 Observational Measures
2.2 Example Material 1: Transcutaneous Electrical Stimulation
2.3 Example Material 2: Capsaicin Application
2.4 EEG and EMG Responses During Pain Assessment
3 Methods
3.1 Screening and Instructions
3.1.1 General Recommendations
3.1.2 Clinical Populations
3.2 Pain Assessment and Calibration
3.3 Nociceptive Stimulation and Pain Induction
3.4 Psychophysics and Behavioral Responses
3.5 EEG and EMG Recording
3.6 Data Processing
3.7 How to Conduct a Short-Lasting Acute Pain Study
3.8 How to Conduct a Prolonged Acute Pain Study
4 Notes
4.1 The Role of Cognitive Factors and Their Impact on Design and Interpretation
4.2 Design and Procedural Issues
4.3 Ethical Considerations
4.4 Children and Individuals Who May Lack Capacity (Including Cognitive Impairment)
4.5 Recruitment and Screening
4.6 Stimulus Material and Stimulation Methodology
4.7 Data Analysis and Interpretation
References
Chapter 8: The Many Challenges of Human Experimental Itch Research
1 Introduction
2 Materials
2.1 Chemically Evoked Itch
2.2 Electrical/Mechanically Evoked Itch
2.2.1 How to Create an Electrically Evoked Itch Stimulus
2.2.2 How to Create a Mechanically Evoked Itch Stimulus
2.3 Psychologically Evoked Itch
2.3.1 How to Create an Itch-Inducing Stimulus Set for Visually Evoked Itch (VEI)
2.3.2 How to Create an Itch-Inducing Stimulus Set for Auditory Evoked Itch (AEI)
2.4 How Can We Assess Itch?
2.4.1 Self-Report Measures
2.4.2 Behavioral Observation
2.4.3 Physiological Correlates
2.4.4 Central Nervous System Correlates
3 Methods
3.1 Chemically Evoked Itch
3.1.1 Histamine Prick Test
Preparation
Induction
Data Collection
Tips and Tricks for the Histamine Prick Test
3.1.2 Cowhage
Preparation
Induction
Data Collection
Tips and Tricks for the Cowhage Test
3.2 Electrical or Mechanically Evoked Itch
3.2.1 Basic Paradigms for Electrically Evoked Itch
3.2.2 Basic Paradigms for Mechanically Evoked Itch
3.3 Psychologically Evoked Itch
3.3.1 Basic Paradigms for VEI
Static Images
Moving Images
3.3.2 Basic Paradigms for AEI
Auditory Only
4 Notes
4.1 Slowness of Itch
4.2 When Itch Becomes Pain
4.3 Dose Variability of Cowhage
4.4 Technical Aspects of Producing Auditory and Visual Itch Stimuli
4.5 Controlling the Visual Stimulus
4.6 Prior Itch Experience and Choice of Rating Scales
4.7 Other Factors
4.7.1 External Environment
4.7.2 Demand Characteristics
References
Chapter 9: Experimental Framework and Methods for the Assessment of Skin Wetness Sensing in Humans
1 Introduction
1.1 History of Wetness Perception
1.2 Directions in Wetness Perception Research
2 Materials
2.1 Hardware
2.2 Consumables
2.3 Environmental Conditions
3 Methods
3.1 Participants
3.2 Experimental Protocol
3.2.1 Example 1: Wetness Detection-External Moisture and Active Touch
3.2.2 Example 2: Wetness Magnitude Estimation-External Moisture and Passive Touch
3.2.3 Example 3: Wetness Magnitude Estimation-Self-Produced Moisture and the Interaction Between Wetness and Tactile Cues
3.3 Analysis
3.3.1 Example 1: Wetness Detection-External Moisture and Active Touch
3.3.2 Example 2: Wetness Magnitude Estimation-External Moisture and Passive Touch
3.3.3 Example 3: Wetness Magnitude Estimation-Self-Produced Moisture and Differences Between Loose and Tight Clothing
4 Notes
4.1 Instructing Participants
4.2 Experimental Duration
4.3 Experimental Design
4.4 Between-Participant Variation
4.5 The Psychophysical Task
4.6 Temperature Manipulation
References
Chapter 10: Skin-Mediated Interoception: The Perception of Affective Touch and Cutaneous Pain
1 Introduction
2 Materials
2.1 Affective Touch Task
2.2 Cutaneous Pain Task
2.2.1 Thermal Pain
2.2.2 Mechanical Pain
2.2.3 Electrical Pain
2.2.4 Experimental Design Factors
3 Methods
3.1 Methodological Considerations in Affective Touch Studies
3.1.1 Stimulus Properties
3.1.2 Rating Scales
3.1.3 Participant Inclusion and Exclusion Criteria
3.1.4 Experimental Design
3.1.5 Behavioral Data Analysis
3.1.6 Neuroimaging Methods
3.2 Methodological Considerations in Cutaneous Pain Studies
3.2.1 Stimulus Properties
3.2.2 Rating Scales
3.2.3 Participant Inclusion and Exclusion Criteria
3.2.4 Experimental Design
3.2.5 Behavioral Data Analysis
3.2.6 Neuroimaging Methods
3.3 Conclusion
4 Notes
4.1 Top-Down Factors and Self-Report Measures
4.2 The Role of Attachment Style
4.3 Monitoring Skin Temperature
4.4 Three Dimensions of Interoception
4.5 Handedness
References
Part III: Individual Differences, Development, and Illusions
Chapter 11: Atypical Development of Tactile Processing
1 Introduction
1.1 Background
1.2 The Neurodevelopment of Tactile Function Studied Using Multiple Methods
1.3 Summary
2 Materials
2.1 Questionnaires
2.2 Observation-Based Approaches
2.3 Quantitative Sensory Approaches
2.4 Psychophysical Approaches
2.5 Social and Affective Touch
2.6 Imaging Approaches
3 Methods
3.1 Questionnaires
3.1.1 Short Sensory Profile (SSP)
3.1.2 Adult/Adolescent Sensory Profile (AASP)
3.1.3 Sensory Perception Quotient (SPQ)
3.1.4 Sensory Experiences Questionnaire (SEQ3)
3.1.5 Sensory Processing Measure (SPM)
3.1.6 Glasgow Sensory Questionnaire (GSQ)
3.2 Observation-Based Approaches
3.2.1 Sensory Assessment for Neurodevelopmental Differences (SAND)
3.2.2 Sensory Over-Responsivity (SensOR) Scales
3.2.3 The Sensory Processing 3-Dimensions Scale (SP-3D)
3.3 Quantitative Sensory Approaches
3.3.1 NIH Toolbox
3.3.2 Sensory Integration and Praxis Test (SIPT)
3.3.3 Evaluation in Ayres Sensory Integration (EASI)
3.4 Psychophysical Approaches
3.5 Social and Affective Touch
3.6 Imaging Approaches
3.7 Interpretation of Altered Tactile Processing in Neurodevelopment
3.8 Future Work
4 Notes
4.1 Populations
4.2 Questionnaires
4.3 Observation-Based Approaches
4.4 Quantitative Sensory Approaches
4.5 Psychophysical Approaches
4.6 Facilitating Pediatric Testing
4.7 Social and Affective Touch
4.8 Imaging Approaches
References
Chapter 12: Measuring Touch Sensitivity in an Aging Population
1 Introduction
2 Materials
3 Methods
3.1 Participants
3.1.1 Age Ranges and Groups
3.1.2 Demographic & Participant Information
3.1.3 Socioeconomic Background and Life Experience
3.1.4 Medical Conditions
3.2 Preparation
4 Notes
4.1 Measuring Force and Movement
4.2 Duration of Experimental Sessions
References
Chapter 13: Somatosensory Illusions
1 Introduction
1.1 Why Study Illusions?
1.2 Variety of Somatosensory Illusions
1.3 Illusions and Measurement
1.3.1 Use of Indirect Measures
1.3.2 Knowing That the Percept Is Illusory
1.3.3 Dealing with Unique, Rare, or Conflicting Experiences
2 Materials and Methods for Two Example Illusions
2.1 Rubber Hand Illusion (RHI)
2.1.1 Materials
2.1.2 Methods
2.2 Whose Hand Illusion (WHI)
2.2.1 Materials
2.2.2 Methods
3 Notes
3.1 Illusory Perception of Different Stimuli as Equal
3.2 Keywords for Database Searches
3.3 Role of Knowledge in Perception
3.4 Variants of the Whose Hand Illusion
3.5 Whose Hand and Hand Postural Illusions
3.6 Switching Between Bistable Percepts as a Tool to Study Consciousness
3.7 Using Color Aftereffect to Encourage Open-Mindedness
3.8 Processing of Clockface Responses
References
Chapter 14: Sensory Substitution: Visual Information via Haptics
1 Introduction
1.1 Tactile Visual Devices
1.2 Design Considerations for a Tactile Visual SSD
1.2.1 Selecting and Encoding Task-Relevant Visual Information
1.2.2 Remapping from Optical Sensors to Skin
1.2.3 Tactor Selection and Arrangement
2 Materials: The Sound of Vision Device
2.1 Cameras
2.2 Tactile Stimulation Device
2.3 Acoustic Stimuli
3 Methods
3.1 Encoding Optical Information
3.2 Auditory and Tactile Stimulation
3.3 Training and Testing
3.4 User Feedback
4 Notes
4.1 Externalization of Touch
4.2 Sensory and Cognitive Load
4.3 Portability
4.4 Surface Texture
4.5 Moving Obstacles
4.6 Object Identification
References
Part IV: The Somatosensory Nervous System
Chapter 15: Microneurography: Recordings from Single Neurons in Human Peripheral Nerves
1 Introduction
2 Materials
2.1 Experimental Setup
2.2 Experimental Equipment
2.2.1 Electrodes
2.2.2 Microneurography System
2.2.3 Equipment for Finding the Nerve
2.2.4 In-Experiment Tools
2.2.5 Mechanical Skin Stimulation Equipment
2.2.6 Issues with External Interference
3 Methods
3.1 Experimental Setup: Accessing the Nerve
3.1.1 Welcome the Participant
3.1.2 Installation of the Participant
3.1.3 Instructions for the Participant
3.1.4 Electrode Location
3.1.5 Electrode Implantation
3.1.6 Experiments
3.1.7 Participant Management
3.1.8 Finding the Nerve
3.2 Single-Unit Recordings
3.2.1 Checking Electrode Quality
3.2.2 Knowing Your Way Around a Nerve
3.2.3 Searching for Individual Afferents
3.2.4 Identifying Afferents During Recording
3.2.5 Verifying Recording Quality
3.2.6 Begin the Protocol and Monitor
3.3 After the Experiment
4 Notes
4.1 Conduct with the Participant
4.2 Fiber Diameter
4.3 Participant Comfort and Movement
4.4 Participant Variation: Skin
4.5 Participant Discomfort
4.6 Fainting, Syncope, and Vagal Reactions
4.7 Unsuccessful Recordings
4.8 Electrode Insertion
4.9 Participant Variation: Nerves
4.10 The Median Nerve
4.11 Nerve Depths
4.12 Auditory Noise and Latency
4.13 Gripping the Electrodes
4.14 External Interference
4.15 Experiment Duration
4.16 Electrode Location and Depth
4.17 Single-Unit Receptive Fields
4.18 Sample Size
4.19 Spike Shapes
References
Chapter 16: Electrophysiological Techniques for Studying Tactile Perception in Rats
1 Introduction
2 Materials
2.1 Instrumentation for Generating Mechanical Stimuli
2.2 Peripheral Recording
2.3 Recording from Central Nervous System
2.3.1 Surface Electrodes for Summated Potentials
2.3.2 Penetrating Electrodes
2.3.3 Headstages, Amplifiers, and Other Equipment
2.4 Electrical Stimulation
2.5 Microinjection
3 Methods
3.1 Anesthesia
3.2 Basic Recording Techniques in the Periphery
3.3 Recording Techniques in the Somatosensory Cortex
3.3.1 Surgery
3.3.2 Recording Summated Potentials
3.3.3 Spike Recording from the Somatosensory Cortex
Recording
Spike Sorting
Psychophysical Task
3.4 Electrical Microstimulation of Neural Tissue
3.5 Microinjection of Drugs into the Somatosensory Cortex
4 Notes
4.1 Placement of Mechanical Stimulators on the Target Organ
4.2 Penetration of the Recording Electrodes
4.3 Stimulation Intensity
4.4 Recording During Microinjection
References
Chapter 17: Imaging Somatosensory Cortex in Rodents
1 Introduction
1.1 The Rodent Barrel Cortex as an Experimental Model for In Vivo Imaging
1.2 The Cortex at High Resolution: Principles of In Vivo Two-Photon Imaging
1.3 Fluorescent Molecules for Probing Intracellular Calcium Concentrations
2 Materials
2.1 Surgical Procedures: Equipment
2.2 Surgical Procedures: Consumables
2.3 Pharmacological Agents
2.4 Two-Photon Imaging: Hardware
2.5 Two-Photon Imaging and Analysis: Software
2.6 Monitoring Mouse Behavior: Hardware
3 Methods
3.1 Surgical Procedures in Adult Mice: Cranial Window and Viral Vector Injection
3.2 Imaging of the Intrinsic Optical Signal in Barrel Cortex
3.3 Habituation to Head-Fixation
3.4 Chronic Two-Photon Calcium Imaging in Barrel Cortex
3.5 Monitoring Mouse Behavior
3.6 Analysis
3.6.1 Image Processing
3.6.2 Whisker Tracking Analysis
4 Notes
4.1 Obtaining a Perfectly-Sized Craniotomy
4.2 Performing a Durotomy to Improve Visibility
4.3 Designing a Headbar for 2p Imaging of vS1
References
Chapter 18: Imaging Somatosensory Cortex: Human Functional Magnetic Resonance Imaging (fMRI)
1 Introduction
2 Materials
3 Methods
3.1 Data Collection
3.2 Preprocessing
3.2.1 Motion Correction
3.2.2 Distortion Correction
3.2.3 Aligning Anatomical and Functional Data
3.2.4 Transforming Data to the Surface Domain
3.2.5 Spatial Smoothing
3.3 Somatosensory fMRI Paradigms and Analyses
3.3.1 Imaging Somatotopic Maps
3.3.2 Imaging Somatosensory Function
4 Notes
4.1 How Many Participants Are Needed?
4.2 What MR Sequences and Parameters Should be Used?
4.3 Any Additional Advice on Which Software to Use?
4.4 What Makes a Good Participant?
4.4.1 Expertise
4.4.2 Comfort
4.4.3 Alertness
4.5 Are There Any Other Ways to Deal with Distortions?
4.6 How Long Should the Scan Session Last?
4.7 What About the Motor System?
4.8 Any Last Words of Advice?
References
Chapter 19: Electroencephalography of Touch
1 Introduction
1.1 Attention and SEPs
1.2 Multisensory Attention and SEPs
1.3 Affective Touch
1.4 Emotions and SEPs
1.5 Self-Other Processing and SEPs
2 Materials
2.1 Tactile Stimulators
2.2 EEG Acquisition Systems
3 Methods
3.1 Timing of SEPs
3.2 Vision of the Body and SEPs
3.3 Multisensory Temporal and Spatial Proximity
3.4 Body Posture, Spatial Congruency, and SEPs
3.5 Temporal Window of Emotion SEPs
3.6 Emotion and Self-Other SEPs
3.7 Vicarious Touch Parameters
3.8 Affective Touch Parameters
4 Notes
4.1 Tactile Interference in EEG Recording
4.2 Acoustic Interference
4.3 Peripheral Conduction Velocity
References
Chapter 20: Neurostimulation in Tactile Perception
1 Introduction
1.1 A Brief Outline and History of Brain Stimulation
1.2 Stimulating the Somatosensory System
2 Materials
2.1 TES and TMS Hardware
2.2 Neuronavigation Systems
2.3 Vibrotactile Devices and Environmental Conditions
3 Methods
3.1 Experimental Design
3.1.1 Single-Interval Designs
3.1.2 Multiple Interval Designs
3.1.3 Detection and Discrimination Tasks
3.1.4 Responses and Measures
3.1.5 Output from Motor Cortex Stimulation
3.1.6 Participant Debriefing
3.2 Neurostimulation Type
3.2.1 Transcranial Electrical Stimulation (TES)
3.2.2 Transcranial Magnetic Stimulation (TMS)
3.2.3 TES/TMS Combined with Other Neuroimaging Techniques
3.2.4 Peripheral Nerve Magnetic Stimulation
3.3 Scalp Test and Control Site Localization
4 Notes
4.1 Interactions Between Neurostimulators and Tactile Stimulators
4.2 Choosing a Tactile Task
4.3 Neurostimulation Likely Changes Participants´ Decision Criterion
4.4 Neurostimulation in Relation with Motor Evoked Responses
4.5 Neurostimulation and the Participant Sample Size
4.6 Neurostimulation Control Locations for Somatosensory Stimulation
4.7 Neurostimulation as a Somatosensory Stimulus
References
Index