Week 7 Flashcards
What type of bipolar cells are activated by light?
ON Bipolar Cells
These cells respond positively to light stimuli.
What is a neuron’s receptive field?
The area of the retina that a neuron responds to
It determines how the neuron reacts to light stimuli.
What happens when light falls on a neuron’s receptive field center?
The neuron fires at its maximal rate
This indicates the neuron has an ‘on-center’ receptive field.
What is the effect of light falling on the off-surround region of a receptive field?
The neuron becomes inhibited
This leads to a decrease in firing rate.
What is the function of the lateral geniculate nucleus (LGN)?
It is a subregion of the thalamus that processes visual information
LGN neurons have center-surround receptive fields.
How many layers does the lateral geniculate nucleus (LGN) have?
6 layers
Layers 1-2 are magnocellular and layers 3-6 are parvocellular.
What do magnocellular layers of the LGN primarily detect?
Motion and brightness
These layers have large cells.
What is the primary visual cortex (V1) responsible for?
It processes edges, orientations of lines, and movement direction
Located in the occipital lobe.
What are orientation columns in the visual cortex?
Columns of neurons that respond to lines of the same orientation
They help in detecting specific angles.
What are the two distinct visual processing streams in the brain?
Dorsal stream and ventral stream
Dorsal is for ‘where’ and ventral is for ‘what’.
What is the dorsal stream responsible for?
Processing the object’s location and spatial awareness
It is directed towards the parietal lobe.
What does the ventral stream process?
Details of an object’s color and shape
It is directed towards the temporal lobe.
What is the role of layer 6 in the visual cortex?
It sends feedback signals to the LGN
This informs the LGN about current visual attention needs.
What is visual agnosia?
An inability to recognize visual objects despite intact perception
It is modality specific.
What is associative agnosia?
Failure to recognize visually presented objects despite intact perception
The individual can perceive the object but cannot identify it.
What does the fusiform face area (FFA) specialize in?
Recognizing faces
Damage to this area can lead to prosopagnosia.
What is the significance of receptive fields in visual processing?
They determine how neurons respond to visual stimuli
Receptive fields change complexity as visual processing progresses.
Fill in the blank: The retina contains _______ cells that help us see in dim light.
rods
Rods are responsible for black and white vision.
True or False: The primary visual cortex is located in the frontal lobe.
False
It is located in the occipital lobe.
What is the relationship between the left visual field and the LGN?
It contacts the right half of the retina in each eye
This crossover ensures correct processing of visual information.
