Comparative neuroanatomy of prefrontal cortex
23 important questions on Comparative neuroanatomy of prefrontal cortex
Two visual streams in the past and nowadays:
1. Dorsal to premotor -> "where pathway" -> spatial information
2. Ventral -> "What pathway" -> process object information
Nowadays:
1. Vision for action, primate specialisation
2. Vision for perception, apes and monkeys (in an environment where you really have to rely on integrating a lot of visual information to get to your preferred type of food
Dorsal PFC and working memory?
- classical lesion work showed big impairment after dorsal PFC lesions
- recording showed sustained activation, but also when the stimuli remained on screen
- various interpretations included working memory, overt attention, covert attention, and prospective memory or goal-related activity
Kind of information, that is coded in the two visual streams
coding of metrics, distance, size -> stuff that you need to code if you need to move
2. Vision for perception:
Coding of feature conjunctions. How do you determine if a type of fruit is ripe or how do you know that that tree is a good one?
-> code a lot of information together. Probabilistic process
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What makes a human brain special?
Ventral prefrontal cortex. Properties
- Strong connections to higher-order temporal areas representing conjunctions of stimulus features. This contrast with the lower-level connections of caudal PFC.
- Multi-model sensory information
- Inferior parietal connections involved in objects and grasping
- Connections to premotor areas involved in hand and mouth actions
- Information about current needs directly from amygdala or via orbital PFC
5 subdivisions of prefrontal cortex
- orbital
- ventral
- dorsal
- caudal
- medial
How to study prefrontal cortex organisation?
Medial prefrontal cortex. Properties:
- Few sensory inputs compared to other PFC areas
- Connections to medial premotor regions involved in controlling actions based on internal cues
- Connections to hippocampus and amygdala suggesting access to memories of past events and information about outcomes valued in terms of current biological needs.
Orbital PFC in macaque:
Caudal PFC in macaque:
Dorsal PFC in macaque
What happens when we lesion rat's medial prefrontal cortex in the decision making?
Maybe rat was forgotten. To test that we place another barrier, so that the effort is equally high
-> lesioned rats will start choosing the best option again
-> still sensitive for the more reward, but not so good at overcoming the extra cost associated with it
Ventral PFC in macaque
Orbital prefrontal cortex. Properties
- Connections with olfactory, gustatory, and visual cortex -> allowing a representation of sensory outcomes
- Extensive interconnections with medial PFC
- Extensive amygdala connections
- Strong inferior temporal and perirhinal connections providing information about objects
What is special about the human brain?
every region in the brain has a unique set of connections to other parts of the brain
Which region in the middle of a human brain doesn't have a match in a macaque brain? And why?
region is involved in a lot of behaviours that other primates are really bad at. E.g. Analogical reasoning, thinking a number of steps ahead.
Caudal prefrontal cortex
- connections with both dorsal and ventral visual streams allowing caudal PFC to search for and direct attention to places and objects of value
- orbital PFC connections provide values of viewed items
- connections to oculomotor nuclei allow the frontal field to direct overt attention through eye movements
Dorsal prefrontal cortex. Properties:
- strong connections to posterior parietal cortex regions encoding visuospatial, quantity and timing information
- access to multi-sensory data from superior temporal cortex
- direct connections to perirhinal cortex providing object information
- connections to premotor areas involved in manual actions as well as medial PFC connections.
- long-term memory access with retrosplenial cortex
Stimulating parietal cortex -> same pattern of movement patterns. Why?
Particular parts only find in primates and the brain areas
- grasping
- reaching
- manipulating
Brain areas:
- ventral premotor cortex
- posterior parietal cortex
Medial prefrontal cortex. Properties:
- Few sensory inputs compared to other PFC areas
- Connections to medial premotor regions involved in controlling actions based on internal cues
- Connections to hippocampus and amygdala suggesting access to memories of past events and information about outcomes valued in terms of current biological needs.
Orbital prefrontal cortex. Properties
- Connections with olfactory, gustatory, and visual cortex -> allowing a representation of sensory outcomes
- Extensive interconnections with medial PFC
- Extensive amygdala connections
- Strong inferior temporal and perirhinal connections providing information about objects
Ventral prefrontal cortex. Properties
- Strong connections to higher-order temporal areas representing conjunctions of stimulus features. This contrast with the lower-level connections of caudal PFC.
- Multi-model sensory information
- Inferior parietal connections involved in objects and grasping
- Connections to premotor areas involved in hand and mouth actions
- Information about current needs directly from amygdala or via orbital PFC
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