Prefrontal Cortex and Information

what are some important parts of the brain relating to memory?

• prefrontal cortex

• anterior/medial portion of the temporal lobe

what is the prefrontal cortex?

also known as the “personality center” or “CEO of the Brain” the prefrontal cortex intelligently regulates our thoughts, actions and emotions through extensive connections with other brain regions

• responsible for executive functions of the brain

• has 4 subcategories: lateral prefrontal cortex, media prefrontal cortex, frontal pole & the ventromedial prefrontal cortex

• (it is located in the anterior portion of the frontal lobe)

where does the prefrontal cortex receive its projections from?

from the mediodorsal nucleus of the thalamus

where does the mediodorsal nucleus of the thalamus send direct input/information to?

instead of sending it to the sensory cortical regions, the mediodorsal nucleus sends information to the association cortex

what is the association cortex?

composed of cortical areas that are located between visual, auditory, and somatosensory cortices (located mostly on the cerebral surface) , the association cortex is largely responsible for the complex processing that goes on between the arrival of input in the primary sensory cortices and the generation of behavior

• it is far more complex than other primary motor and sensory cortical regions

how does information flow in the brain?

the brain is wired so that information flows forward from the parietal (sensory/mapping), temporal (auditory), and occipital (visual) lobes to the prefrontal cortex in the frontal lobe

• the information is then processed and acted on via executive functions

what is the role of perceptions in all this?

perceptions: information gathered by the sensory regions, then passed through the brain for processing

• perceptions help the prefrontal cortex make executive functions

what is an executive function?

decisions made by the prefrontal cortex based off of the provided information from parietal (sensory/mapping), temporal (auditory), and occipital (visual) lobes

what are executive functions involved in? give examples

• decision making

• planning

• reasoning

• creativity

• self-monitoring

• directed behavior (inhibition and activation)

what is special about executive functions and the prefrontal cortex?

they allow for the organism to bypass habitual responses (ie breaking or changing bad habits)

what are the four prefrontal control systems?

• lateral prefrontal cortex

• media prefrontal cortex

• frontal pole

• ventromedial prefrontal cortex

lateral prefrontal cortex

• located on the medial surface and down near the bottom of the prefrontal cortex

supports goal-oriented behavior, initiating (getting a response Started.), also involved in simulating consequences, also involved in working memory systems, forming abstract Concepts, rules and principles

medial prefrontal cortex

• located on the medial side of the brain (not visible)

supports guiding and monitoring behavior 

frontal pole cortex

• located on the most anterior region of the prefrontal cortex

because of technical difficulties in studying this area, its role in primate cognition had remained largely unknown beyond specifically human behavior and cognitive abilities, e.g. action selection

what is the ventromedial prefrontal cortex?

• located on the medial surface and down near the bottom of the prefrontal cortex

it is a set of interconnected regions that integrate information from affective sensory and social cues, long-term memory, and representations of the 'self'

what are the supplementary motor area and premotor area responsible for?

responsible for complex motor activities or coordinated motor activities

what is the premotor cortex

• located just anterior to the primary motor cortex

involved in planning and organizing movements and actions

explain this diagram of input & output pathways of the prefrontal cortex

• dotted lines on the diagram represent the prefrontal cortex

• the sensory regions (input)  that receive information from the visual and auditory information feed the information to the prefrontal cortex 

• information coming from sensory areas, auditory areas and multi models of the brain (some areas of the brain located primarily in the parietal temporal region that get sensory info are responsive to a variety of sensations) that they receive are fed to the prefrontal cortex to act on this information as well

what do all sensory regions have in common?

they all send information forward to the prefrontal cortex for the region to act on that information 

• sensory information arrives at different sensory cortices, but there is one area or the temporal parietal region that gets sensory input from multiple sensory modalities

why is the prefrontal cortex called the CEO of the brain?

because it receives sensory information, acts on the sensory information, makes decisions on the sensory information that it receives, 

• it’s constantly monitoring, constantly regulating behaviors in different parts of the body (some of which we aren't even aware of)

what is the frontal eye field (FEF)? how is this an example of the prefrontal cortex interacting with a sensory region?

the prefrontal cortex will direct the eyes to focus on certain parts of the stimulus field given a part of that field is interesting appropriate for the organisms to make some kind of decision or not. 

• FEF exchanges information with the prefrontal cortex

what is bottom-up processing?

visual stimuli enter through the retina, the message of the stimuli is transmitted into the visual cortex, and then it is processed and understanding and experience of the perception occur

what is top-down processing?

the thinking centers of the brain can activate cognitive controls adjusting the feeling centers of the brain

• the prefrontal cortex allows us to take all this information from different sources and weigh the best option, thus allowing us to break bad habits/routines

what is the Wisconsin card sorting test?

a measure of abstract thinking 

• participants were given a set of cards and are asked to arrange them based on some type of sorting rule that is never made explicit, using, only by feedback from each trial  

• the rules for sorting the cards are determined by the person running the experiment and the subject is only to receive positive or negative feedback

• the person running the experiment can decide that the stack of cards should be arranged by color and the subject begins to sort while the experimenter may say whether it is incorrect or correct, and the subject can figure out or aquire the knowledge that can affect future behavior 

***relies on how negative feedback prompts a change***

why is the Wisconsin card test important and what did it reveal?

patients who have problems with their dorsal lateral prefrontal cortex tend to not be able to integrate these changing signals that would guide appropriate behavior 

• if someone who has damage to their prefrontal cortex, was tested in the card task, you’ll find repeated behavior

• subjects with damage have difficulty suppressing inappropriate behavior because of the failure to integrate the cues that help to establish appreciation for the rules  

for success to occur on this type of task, its necessary to inhibit the formerly appropriate 

what are prepotic responses?

basically old habits that were created before new information or stimuli caused a shift in behavior

what is the Stroop test?

a measure of inhibitory functions 

• dominant signals come in the form of the written word 

• ie people who have damage to this part of the brain have difficulty reading the word “blue” in red typing

• the natural response is to read the word but we are asked to inhibit the word and say the color of the ink

this short conflict causes one to slow down (inhibit our natural response) and process the secondary information (the color of the ink) and give the appropriate answer

who was phineas gage and what happened to him?

his accident: a work explosion caused a 43in rod to tear through his left cheek, his brain, and exit his skull

• behaviors after the injury: initially wasn’t all that affected but it could have been a symptom of shock, an infection caused him to enter a semi-comatose state

• behaviors after his recovery: his personality had drastically changed (negatively), he began to drink, and traveled around doing jobs here and there—this was very different from the lively, stable person he had been before his accident

• what was retained: consciousness at time of accident, speech, walking ability, memory, time telling (he knew how much time had passed)

• what wasn't retained: after the infection he struggled with differentiating currency, lost vision an eye

• what functions did he lose: eye sight in one eye, possibly social inhibition due to damage on left (emotional processing) & right (decision making) prefrontal corticles

• he died after a series of epileptic seizures