JD - Sensory Systems Flashcards
What is the amygdala associated with?
Changing mood
What are the multiple layers of sensory systems? (3)
Transduction
- Stimuli detected by specialised transmembrane receptor protein in sensory receptor cell
Encoding
- Action potential generated to sensory neuron
Processing
- Signals travel to the brain and are processed
What are the functional categories of receptors?
- Exteroceptors
- Proprioceptors
- Interoceptors
Describe the process of signal transduction
Signal transduction → Current → Generator potential → Action potentials
How can stimulus strength be encoded? (2)
Stimulus strength can be encoded by the:
- Amplitude of the generator potential
- Frequency of action potentials
Name two ways a signal can be transmitted in response to sensory stimuli
- Specialised sensory neuron (direct)
- Specialised epithelial receptor (requires exocytosis)
What is the adaptation of Tonic receptors vs Phasic receptors?
TONIC RECEPTOR
- Slowly adapting
PHASIC RECEPTOR
- Rapidly adapting
What are Trigeminal ganglia and Dermatomes?
Trigeminal ganglia- sensory receptors for the face
Dermatome: a region of skin innervated by the spinal nerve of a single DRG
What conveys fine touch information to central circuits?
Somatosensory afferents
What are receptive fields and what are they determined by?
Receptive fields: area of the skin surface over which stimulation results in a change in the rate of action potentials
The size of the receptive field is determined by the
- Number of sensory receptors
- Size of the branching of the sensory afferent within the skin
The greater the density of receptors the smaller the receptive fields of individual afferent fibres
How does 2-point discrimination work?
Two points of touch simultaneously
Perceived as one point of touch in areas of low spatial acuity (e.g back)
Perceived as two points of touch in areas of high spatial acuity (e.g finger)
How is tactile information transmitted from the body and face?
Dorsal Column-Medial Lemniscal System (body):
-> 1/2/3-order neurons transducing to somatosensory cortex
Trigeminothalamic System (face):
-> different, but also via thalamus
Name examples of superficial and deep receptors involved in mechanotransduction
SUPERFICIAL RECEPTORS (Small RF, High SA)
- Meissner’s Corpuscle (Phasic)
- Merkel Disk’s (Tonic)
DEEP RECEPTORS (Large RF, Low SA)
- Ruffimi’s Corpuscle (Tonic)
- Pacinian Corpuscle (Phasic)
How does transduction occur in a Pacinian Corpuscle?
Vibratory cues will be transduced and modulate shape of ion channels allowing the influx of sodium ions
→ Depolarisation of afferent neurone
