Somatosensation: Mechanoreception and Proprioception

Somatosensation

Sense of touch and body position awareness.

Sensory modality

Type of sensory information processed by receptors.

Transduction

Conversion of physical stimulus to neural signal.

Mechanoreception

Detection of touch and pressure stimuli.

Proprioception

Awareness of body position in space.

Nociception

Detection of pain and tissue damage.

Adequate stimulus

Specific stimulus type for receptor activation.

Tuning curves

Graphs showing receptor specificity for stimuli.

Receptive fields

Area where a stimulus affects neuron activity.

Conduction velocity

Speed of neural signal transmission.

Adaptation

Decrease in response to constant stimulus.

Plasticity

Neural reorganization based on experience.

Serial processing

Sequential information processing through neural pathways.

Parallel processing

Simultaneous processing of different sensory modalities.

Dorsal root ganglia

Cluster of sensory neuron cell bodies.

Afferent fibers

Nerve fibers carrying signals to the CNS.

Two-point discrimination threshold

Minimum distance to distinguish two stimuli.

Receptive field properties

Characteristics determining sensory receptor response.

Ipsilateral

Same side of the body.

Contralateral

Opposite side of the body.

Conduction time calculation

Time taken for signal to reach CNS.

Conduction Velocity

Speed of signal transmission, 1m/s in example.

Temporal Fidelity

Rate of adaptation affects touch information quality.

Receptive Fields

Areas where sensory receptors respond to stimuli.

Two-Point Discrimination

Ability to distinguish two stimuli points on skin.

Dermatomes

Skin areas innervated by specific spinal nerves.

Shingles

Viral infection affecting specific dermatomes.

Somatoform Disorders

Physical symptoms without identifiable physical cause.

Dorsal Column-Medial Lemniscus (DCML)

Pathway for touch and proprioception signals to brain.

Ipsilateral

Same side of the body in neural pathways.

Contralateral

Opposite side of the body in neural pathways.

Primary Somatosensory Cortex

Brain area processing tactile information, areas 1-3b.

Somatotopic Map

Representation of body layout in the brain.

Receptive Field Size

Influences sensitivity and discrimination ability.

Evolutionary Benefit of Distorted Map

Enhanced sensitivity in critical body areas.

Mechanoreception

Detection of pressure and vibration on skin.

Slow-Adapting Receptors

Respond to constant pressure over time.

Fast-Adapting Receptors

Detect changes or movements in stimuli.

Plasticity in Mechanoreception

Adaptability of sensory representation in the brain.

Deafferentation

Loss of sensory input affecting cortical representation.

Tactile Sensitivity

Heightened sensitivity to touch stimuli.

Sensory Input Gain

Increased representation due to more sensory experience.

Background Noise Sensitivity

Overreaction to ambient sounds or stimuli.

Tactile Sensitivity

Sensitivity to touch, often requiring treatment.

Reorganization of Somatosensory Map

Brain's remapping after injury or sensory changes.

Phantom Limb Syndrome

Sensation of a missing limb post-amputation.

Case Study

Research method involving detailed individual examination.

Proprioceptors

Sensors in muscles and tendons for body position.

Dorsal Column-Medial Lemniscal Pathway

Pathway for proprioceptive and fine touch information.

Clarke's Nucleus

Nucleus involved in proprioceptive signal processing.

Somatosensory Map

Brain representation of body surface sensations.

Conduction Velocity

Speed of nerve signal transmission, 35-120 m/s.

Slow-Adapting Receptors

Detect constant pressure over time.

Fast-Adapting Receptors

Detect changes or movement in pressure.

Parallel Processing

Simultaneous processing of sensory information.

Somatotopic Organization

Spatial arrangement of sensory input in the brain.

Mechanoreception

Detection of mechanical pressure or distortion.

Vibration Sensation

Perception of oscillating pressure on skin.

Pressure Sensation

Perception of force applied to skin.

Receptive Fields

Area of skin where stimuli affect neuron response.

Tactile Objects

Items used for sensory stimulation, e.g., sandpaper.

Tight-Fitting Clothes

Clothing used to enhance tactile sensitivity treatment.

Remapping

Brain's adaptation to changes in sensory input.