PSY247 Lecture 1: Introduction
4 Jun 2018
School
Department
Course
Professor
Introduction, principles and
methods
Perception is the body’s link to reality
- Physical stimuli and transduced into nerve impulses by
our sense organs.
- What we experience is only a reconstruction; we don’t
perceive everything that is in the environment.
- Perception is also called psychophysics (link between
physics and psychology).
The senses
- Vision. o
o
o o
We tend to focus on vision because of its high spatial and temporal
resolution.50% of the cortex is involved in processing visual
information.
When senses conflict, vision is trusted.Prosopagnosia is the inability to
recognise familiar faces.
- Audition.- Chemical senses:
o Gustation (taste).
o Olfaction (smell). - Body senses:
o Somatosensation:▪ Haptics/taction.
▪ Proprioception: o Equilibrioception.
Sense Stimulus Receptor Sensory Cortex structure
Vision
Electromagnetic energy
Photoreceptors
Eye
Primary visual
Hearing
Air pressure waves
Mechanoreceptors
Ear
Auditory
Touch
Tissue distortion
Mechanoreceptors and
thermoceptors
Skin, muscle, etc.
Balance
Gravity and acceleration
Mechanoreceptors
V estibular organs
Temporal
Olfaction
/gustation
Chemical compositions
Chemoreceptors
Nose and mouth
Primary taste or olfactory
NB: the notion that neurons relating to a specific sensory area are
located in a certain part of the cortex is called localisation of function.
7 physiological principles
Transduction
- Here, environmental energy is converted into electrical
impulses.
- Receptors turn physical energy into neural signals.
- Impulses travel along axons to terminals, releasing
neurotransmitters across synapses.
- The process of transduction: environmental energy
receptor cells neural signals. Hierarchical processing
- Neural impulses travel up the system to the cortex.
- Most senses (except olfaction) transport signals via the
thalamus, or the relay station. Until the thalamus, pathways are
unidirectional.
- Higher cortical areas also involve lateral (same level) and
feedback (top-down) connections.
- The process from neural signals thalamus receiving cortex
association areas.
6
Bottom-up vs. top-down processing
- Bottom-up processing is the flow of information from
sensory receptors to higher cortical areas, continually increasing
the level of complexity.
- Top-down processing is the influence prior knowledge has
on what is perceived.
- These types of processing are not a dichotomy, with
forward, lateral and backward connections in the visual pathway
demonstrating that information can flow in all directions.
Selectivity
- Within each sense, the stimuli may vary across different
dimensions. o For example, orientation may vary based on
degrees.
- The characteristic frequency refers to the idea that some
cells are selective for stimuli with certain characteristics.
- Tuning refers to the idea that although the cells might still
be triggered, the more stimuli differ from a cell’s preferred
stimulus, the smaller the reaction.
Document Summary
Physical stimuli and transduced into nerve impulses by our sense organs. What we experience is only a reconstruction; we don"t perceive everything that is in the environment. Perception is also called psychophysics (link between physics and psychology). We tend to focus on vision because of its high spatial and temporal resolution. 50% of the cortex is involved in processing visual information. Prosopagnosia is the inability to recognise familiar faces. Chemical senses: gustation (taste), olfaction (smell). Body senses: somatosensation: haptics/taction, proprioception: o equilibrioception. Nb: the notion that neurons relating to a specific sensory area are located in a certain part of the cortex is called localisation of function. Here, environmental energy is converted into electrical impulses. Receptors turn physical energy into neural signals. Impulses travel along axons to terminals, releasing neurotransmitters across synapses. The process of transduction: environmental energy receptor cells neural signals. Neural impulses travel up the system to the cortex.
