Module 3 (Sensation and Perception): Sensation and the Brain, Vision and the Visual Cortex

Question 1

Visual Brain

Answer 1

We do not have veridical experiences of sensory input - our experiences are a product of activity in our brains that are a result of sensory organs transducing environmental energy in electrochemical signals for the brain.

Question 2

Visual Transduction

Answer 2

Photoreceptors contain light sensitive chemicals (pigments) which absorb photons of light. This changes membrane conductance of photoreceptor and trigger depolarisation. Ganglia cells gather signals from back of photo receptors and converge to for the optic nerve which carries visual information to brain.

Question 3

Physiological Blind Spot

Answer 3

Cause due to a lack of photoreceptors on the retina directly infront of the optic nerve (where the optic nerve passes through the retina)

Question 4

Filling-In

Answer 4

The brain assumes that what is seen either side of the blindspot is also within the blindspot and “fills in” the blindspot with the assumed stimulus.