Sensation and Perception BB test II

six senses

-Vision

-Audition (hearing)

-Somatosensation (touch; also temperature, pain, joint position)

-Gustation (taste)

-Olfaction (smell)

-Equilibrium (balance)

What are the four levels of processing?

1.Stimulus detector units (SDU)

2.Initial receiving centers

3.Integrating centers

4.Perception (conscious awareness)

Sensory Detection Units (SDUs)

•specialized sensory receptor neurons (primary sensory receptors) that convert sensory events from absolute, physical form into cellular signals (Action Potentials)

-Level at which environment first affects nervous system

-Encode frequency, duration, number, intensity, and location of environmental signals

Initial receiving centers

CNS site where sensory information is initially sent

Integrating centers

- receive and interpret messages from many sensors regarding same and/or different conditions

- integrate information (sum total of signals leads to particular response) - communicate messages to effectors ONLY if response is necessary

Perception

level at which we infer the nature and meaning of what has just been sensed

- Sensory information is finally "perceived"

SDU Brain Areas

- Vision (part of CNS), retina

- everything else is PNS

Initial receiving centers brain areas

- retina, medulla

integration center brain areas

limbic cortex (olfaction sense) and thalamus (every other sense)

perception brain areas

- primary sensory cortex for all senses

What lobe is taste and olfaction?

temporal

Balance

-normally never really reaches "conscious perception" unless it is disrupted

•Cortical areas that are involved include an area of the parietal lobe just behind the somatosensory cortex

Sense + Location of SDU: VAS

Vision -> *Retina (Part of CNS!)

Audition -> Cochlea (inner ear) - PNS

Somatosensation -> Skin, muscle, joints - PNS

Sense + Location of SDU: GOE

Gustation -> Tongue, throat - PNS

Olfaction -> Nose, throat - PNS

Equilibrium -> Vestibular organ (inner ear) - PNS

What do all SDUs have in common?

• they are specialized to transduce different types of environmental stimuli

What is special about the retina?

•Cells in retina: (vision) only system where sensory signal is heavily processed locally before being transmitted to the brain

Sensory transduction

•sensory receptors convert energy of a stimulus (e.g., light, air-pressure waves) into neural activity

Receptive field

•a region of space in which the presence of a stimulus will alter the firing of that neuron

-Higher level sensory neurons have larger receptive fields

What senses have receptive fields?

•Each individual sensory receptor (SDU) for touch and vision has a receptive field

What types of sensory information are encoded?

-frequency, duration, number, intensity, and location of environmental signals

Time

•all forms of sensory receptors encode information about time

-Action potentials are caused by the stimulus, which opens ion channels in the sensory receptor neuron

Duration

-how long the stimulus lasts

Frequency

how often it occurs

Quantity

(intensity; all forms of sensing) - how strong the stimulus is

Location

•where the environmental signal is coming from

Orient towards that site (attention shifts towards the signal source)

What brain area is important for integration of sensory information?

thalamus, a key player in integrating all the "external world" senses (except olfaction; smell is integrated through limbic system)

What is important for actual perception of sensory information?

primary sensory cortex

- primary visual cortex occipital lobe vision

- primary auditory cortex temp lobe hearing

- primary somatosensory cortex parietal lobe touch & equil

- taste & olfaction limbic & gust cortex in temp lobe

What can change our perceptions?

•Association cortex areas are located near primary sensory areas for perception

-What you PERCEIVE can change, even though what you SEE remains constant

- Depends on the state of activity in the association cortex

Spinal Cord

Dorsal Horn versus Ventral Horn

Dorsal Horn: SENSORY input

-Cell bodies in periphery send axons into dorsal horn that synapse onto interneurons

Ventral Horn: MOTOR output

-Cell bodies in ventral horn send axons that synapse onto muscle fibers

- contains cell bodies of motor neurons

The sensory receptors of the visual system are

rods and cones

Level 1 sensory stimulus detector units (SDUs)

include hair cells in the cochlea

Sensory transduction takes place in all of the following EXCEPT

audioreceptors in the pinna

The site of the eye where light energy initiates neural activity (i.e,. the site of transduction) is the

retina

What are some common points between different senses?

idk receptors?