Cognition and Executive Functioning

Cognition and Executive Functioning

• The prefrontal cortex (PFC) is involved in high-order cognitive functions and is one of the last areas of the brain to develop, with the dorsolateral prefrontal cortex (DLPFC) showing the most differentiation.
• Damage to the PFC can cause apathy, lack of drive, inability to plan, maintain goals, or change plans, but does not typically affect IQ. It also affects creative thinking.
• Executive functioning includes working memory, divergent thinking, executive attention, and decision-making.

Dorsolateral Prefrontal Cortex (DLPFC)

• The DLPFC is involved in executive functioning, which includes working memory, divergent thinking, executive attention, and decision making.
• Damage to the DLPFC can result in apathy and lack of drive, as well as the inability to plan ahead and maintain goals or change plans, or plan for the future, doesn’t affect IQ though. It affects creative thinking as well

Orbitofrontal Cortex/ Ventromedial PFC (OFC/vmPFC)

• The OFC/vmPFC assesses stimulus reward or value, anticipates reward, performs self-based evaluations, and makes value-based decisions.
• It's a paralimbic cortex integrating motivational and emotional processes.
• Damage to OFC/vmPFC affects personality, causing lack of inhibition, self-indulgence, inappropriate behavior, quickness to anger, and pseudopsychopathy.

Baddeley’s Working Memory Model

• The central executive controls selective attention, manages memory processing, and integrates information.
• The visuospatial sketchpad manipulates and stores visual and spatial information temporarily.
• The phonological loop stores speech or sound-based information and uses articulatory subvocal rehearsal to retain information short term through repetition.

N-Back Test

• The N-back test requires participants to react to stimuli that were presented a certain number of items back.
• It engages working memory by involving storage, rehearsal, and retrieval of information.
• Increased spacing between stimuli (3-back) increases activity in the DLPFC, which is the central executive component.

Executive Functioning

• Executive functions enable response rather than reaction and include judgment, planning, anticipation, goal establishment, monitoring results and feedback, and working memory.
• Impairment can be assessed through tests, like the ABC test, abstraction, arithmetic, and the Stroop test.
• Poor executive functioning may manifest as perseveration and unrelated behaviors, not attributed to deficits in perception, memory, or language.

Stroop Test

• The Stroop test involves identifying the color of a word (that is a different color name) rather than reading the word itself.
• The Stroop effect results from the delay in processing due to conflicting information.

Poor Executive Functioning

• Characterized by perseveration and unrelated behaviors.
• Not attributed to deficits in perception, memory, or language capabilities.
• May include inability to switch attention, focus, or plan ahead

fMRI - How it Works and BOLD Effect

• fMRI measures blood flow in the brain during cognitive, emotional, and behavioral tasks.
• It is a non-invasive imaging technique that doesn't require injections.
• The BOLD (Blood Oxygen Level Dependent) effect is a naturally occurring contrast agent, reflecting changes in deoxyhemoglobin levels linked to neuronal activity.
• Increased neuronal activity leads to increased oxygenated blood and decreased deoxyhemoglobin, resulting in an increased magnetic signal that is quantified.

Advantages of fMRI

• fMRI can show functional differences even when behavioral differences are not observed.
• It has superior spatial resolution compared to other scans like ERP, PET, and SPECT.
• It is non-invasive, allows for repeated imaging, and can measure blood flow in near real-time.
• Open MRI options are available for claustrophobic individuals.

fMRI Uses

• fMRI is used for mapping brain function during motor, somatosensory, visual, and auditory processing, as well as higher integrative mental activity (executive functions, language, memory, learning, emotional processing, perception, and attention).
• It is utilized in clinical and neurological disorder research, including depression, schizophrenia, vegetative states, drug abuse, and Parkinson’s.
• fMRI is used for presurgical mapping to locate critical areas like the motor strip or language areas and for pharmacological assessments to quantify blood flow changes in response to drugs.
• It aids evaluation and treatment of head injuries and strokes, determining functional consequences of lesions and understanding brain reorganization.

fMRI Study Design

• Block designs involve alternating on and off periods, where the control condition ideally doesn't activate the part of the brain being monitored.
• Control and test conditions should be similar, differing only in the processing being studied.

fMRI Limitations

• fMRI is costly and not universally accessible.
• fMRI cannot be used for lie detection due to issues with participant compliance and the complexity of brain activity related to deception
• A baseline of rest is not a reliable control, as there is still brain activation.

fMRI - Neurolaw

• Neurolaw faces challenges due to limited understanding of the relationship between the brain, self, and agency.
• The technology may remove the human element, lack validity, and provide false positives.

Designing a Good fMRI Study

• A good study includes a well-defined research question, a defined population, a comparable control group, and a well-designed task.
• fMRI can lend credence to subjective complaints and identify changes in brain activity after treatment.

Emotion - James Lange Theory

• The brain creates a cognitive response to autonomic information.
• Emotions may share certain autonomic responses, and the intensity of emotions depends on the location of spinal cord injury.

Emotion - Damasio's Somatic Marker Theory

• Somatic markers are induced by internal or external stimuli.
• Frontal lobe injuries can cause rational thinking but poor decision-making.
• Awareness of emotion and empathy requires activation of the brainstem, amygdala, and frontal cortex.

Evolutionary Appreciation of Emotion

• Reptilian brainstem: avoiding harm
• Mammalian brain: approach rewards and acquire base necessities
• Human cortex: attach and connect with others

Brain Regions in Emotion

• Amygdala: Receives input from all sensory systems, connects to the hypothalamus, brainstem, and PFC.
• The amygdala regulates autonomic and hormonal responses, impacts conscious awareness, and its stimulation increases blood pressure, arousal, fear, anxiety, and dread.
• Hippocampus: Vital for memory, emotion, and spatial navigation, but vulnerable to stress.
• The hippocampus processes context; without it, people may experience generalized anxiety.
• PFC: Connected to limbic, autonomic, and endocrine systems. Facilitates conscious control over anxiety and planning of future emotional responses
• Damage can result in inability to express emotions, apathy, impaired planning, loss of inhibition, and poor decisions

Depression

• Monoamine hypothesis links depression to serotonin, dopamine, and noradrenaline imbalances.
• SSRI medications selectively inhibit serotonin reuptake.
• Lateralized PFC activity: Negative feelings flagged by the amygdala activate the right PFC while the left is not activated.
• Depression can be catalyzed by stressful life events, with early life stress potentially predisposing individuals.

Happiness

• Meditation:
• Meditation increases regional cerebral blood flow in the thalamus, cingulate inferior, orbital frontal cortex, and DLPFC.
• It can also increase activity in attention circuitry.
• Laughter:
• Decreases cortisol levels, enhances respiration, and increases endorphins and salivary immunoglobulin concentrations.
• Activates the mesolimbic dopaminergic system, anterior thalamus, ventral striatum/NAcc, ventral tegmental area (VTA), hypothalamus, and amygdala.
• Mindfulness Based Stress Reduction reduces activity in brain regions of the pain matrix involved in rumination, sensation, body representation, inhibitory control, self-regulation, and emotion.