5. Prefrontal Cortex

Electrical stimulations of the frontal lobes

Introduced the term “prefrontal” to denote the silent cortex at the anterior end of the lobe, rostral to the electrically excitable motor region

Connections to the mediodorsal thalamus

Cortical Cytoarchitecture, granular frontal brain regions

Mediodorsal thalamic projections define prefrontal cortex

parcellation of mouse preforntal cortex

• no - exclude

• situated at the apex of cortical processing hierarchy

• organization of actions in the temporal domain

• executive memory

• goals and means to achieve them

• Syntax of action

• Executive control

• inhibitory control

• attention

• decsion makine

• continuous loop where sensory input is perceived, processed, and used to guide actions, which then produce new sensory input, allowing adaptive behavior.

• all prefrontal functions and areas are interdependetn & functions share areas and networks

• increases in size with phyl. devel.

• most prominent in primate

• viewed as diversification rather differentiation

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• last to myelinate

• Lateral PFC matures later that the medial and inferior PFC

• Modeling and differentation in superficial layers continue until puberty

• Volumetric reduction of gray matter and increase in white matter are completed only in adulthood

• PFC is among the most likely brain regions to show age-related cell loss and degeneration

6

1. Molecular layer

2. External granule cell layer

3. External pyramidal cell layer

4. Internal granule cell layer

5. Internal pyramidal cell layer

6. Multiform layer

• medial PFC

• areas in PFC are argranular

• rodent medial PFC resembles primate premotor and cingulate cortex

It means that the nerve fibers from the mediodorsal thalamus to the PFC are arranged in a structured, spatially organized way, with specific MD regions connecting systematically to distinct PFC areas. This ordered topography supports precise information integration crucial for cognitive functions like working memory, attention, and decision-making.

Mediodorsal thalamic projections are nerve pathways from the mediodorsal thalamus to the prefrontal cortex, crucial for memory, attention, and executive functions

emotion & motor

• Many little dense neurons in layer IV

• typical for sensoric

• typical for motoric or prefrontal areale

• less and little granular

Afferents are incoming signals to the PFC from other brain regions, while efferents are outgoing signals from the PFC to motor and other areas to guide behavior and cognitive control.

Cerebral means “relating to the brain” or “belonging to the brain.”

• a unique evolutionary diversification of the frontal lobe:

  • agranular areas next to allocortex

  • granular cortex next to agranular cortex

  • granular cortex projects to dorsal striatum, agranular cortex does not

  • granular prefrontal cortex is the most specialized and advanced

• has a different cytoarchitecture

• has different thalamic connections

• has different gene expression profiles

• is a functional analogue of the mammalian PFC

Because evolution selects for behavior, not specific brain regions, the better question is “How do rodents solve complex cognitive tasks?” focusing on function rather than anatomy.

A test assessing executive functions like cognitive flexibility and problem-solving by requiring participants to sort cards by changing rules without being told, measuring prefrontal cortex function.

Bi-stable vision is when a constant ambiguous image is perceived alternately in two different ways, showing how perception can switch despite unchanged visual input.

1. Rostral (anterior) LPFC manages abstract, long-term goals and episodic context.

2. Caudal (posterior) LPFC processes contextual signals like current rules.

3. Premotor Cortex handles immediate stimuli and translates them into motor plans.

A neuron—typically in the prefrontal cortex—that selectively fires based on the abstract rule being applied (e.g., "match" vs. "non-match"), regardless of the specific stimulus or response.

• Experiment by Freedman & Miller (2001): Monkeys categorized morphed images (between cats and dogs).

• PFC neurons responded selectively to abstract categories ("cat" or "dog").

• Neuronal firing was independent of specific sensory features—not just the look of the image.

• Indicates that the PFC encodes conceptual rules and abstract categories, not raw perception.

• Supports the role of the PFC in flexible, goal-directed cognition.

1. medio-lateral axis

2. ventro-dorsal axis

3. rostro-caudal axis