Mammalian brain

Question 1

optic chiasma

Answer 1

• cross structure on ventral side of brain where the two optic nerves cross over and enter occipital lobe
• nerve from left eye enters right hemisphere, nerve from right eye enters left hemisphere

Question 2

primary visual cortex (V1)

Answer 2

• simple cells process edges
• orientation selectivity = different cells are receptive to lines and edges of different orientation, specific neurons fire more when an edge is at a specific orientation
• complex cells process edges and motion
• end stopped cells process edges and form

Question 3

visual cortex, dorsal stream of visual information

Answer 3

• ‘where pathway’, motion, representation of object locations, control of eyes and arms, especially when visual information is used to guide saccades or reaching
• V1 to V2 to V6 (dorsomedial area), to posterior parietal complex (PCC) in parietal lobe
• PCC is responsible for mapping

Question 4

visual cortex, damage to dorsal stream

Answer 4

• optic ataxia = inability to use visuospatial information to guide arm movements
• akinetopsia = inability to perceive motion

Question 5

visual cortex, ventral stream of visual information

Answer 5

• ‘what’ pathway, inferioir temple lobe responsible for form recognition and object representation
• V1 to V2 to V4 to inferior temporal cortex in the temporal lobe

Question 6

visual cortex, damage to ventral stream

Answer 6

• agnosia = inability to recognise objects and faces and interpret facial expressions

Question 7

saccades

Answer 7

the involuntary action of your eyes moving to something new in your visual stream

Question 8

superior colliculus

Answer 8

• responsible for eye movements, applies movement vector to object
• visual information hits superficial layerm spreads to deep layer and generates a saccade

Question 9

superior colliculus, promotion and inhibition

Answer 9

• by the PPC (higher level of processing)
• volitional promotion = controls where attention is directed, allows for searching etc
• spontaneous inhibition allows saccade to be interrupted, eyes don’t follow change in visual scenery

Question 10

parietal lobe

Answer 10

• point of integration, bringing all information together to create a full sensory map of the 3D world
• responsible for identifying salient objects and the position of objects in relationship to you and your hand (saccade and reach)

Question 11

hippocampus in conjunction with parietal cortex

Answer 11

• creates egocentric 3D internal map
• informed by visual information, but once formed does not rely on visual information
• hippocampus forms memory/record of spaces through storing different neural signatures as different places
• allocentric and egocentric visual coding
• proximal and distal cues allowing for orientation in 3D space

Question 12

hippocampus in conjunction with medial temporal lobe

Answer 12

• responsible for episodic memory
• past events and places in relation to self, emotional state/response linked to recollection
• pattern completion, linking similar places to memory, hippocampus fills in gaps in context of memory
• pattern separation, noticing differences between similar places

Question 13

corpus callosum

Answer 13

information bridge between left and right hemisphere

Question 14

limbic system

Answer 14

responsible for emotional state involved in fight or flight response
- amygdala, hypothalamus, limbic lobe, olfactory bulb, septal area