Ch. 4: Touche

Body Senses:

• Somatosenses: Body senses

• Haptic perception: active exploration of the environment by touching and grasping objects with our hands

Sensing Touch

the transduction of skin sensations into neural signals

Touch receptors

• Tactile receptive field: pain, pressure, texture, pattern, or vibration to a receptor

• Thermoreceptors: cool, warmth, skin temperature changes

Neural Representation of body’s surface

• left half of body represented by right half of brain and vice versa

• Different locations on body that project sensory signals to different location in brain

• Distinctions between what and where pathways in touch

Sensing Pain

damage or potential damage to the body; tissue damage transducted by pain receptors:

• A-delta fibres: Quick, sharp pain

• C fibres: Long, dull pain

Two pain pathways

1. Were info to somatosensory complex

2. Motivational and Emotional info to hypothalamus, amygdala and frontal lobe

Referred pain

feeling of pain when sensory information from internal and external areas converges on the same nerve cells in the spinal chord

Gate-control theory

signals arriving from pain receptors in the body can be stopped, or gated by interneurons in the spinal cord vis feedback from two directions

Brain-Gated Pain

brain’s feedback to the spinal chord comes from the periaqueductal grey(PAG) in the midbrain

Body Position

seonsory receptors provide info needed to perceive the position, and movement of limbs, head and body

Proprioception

sense of bodily position