Applied Cognitive Psychology food and drugs Flashcards
Detour: (In)Activation of Neurotransmitters
- Blocking release of Neurotransmitter
- Botulinium toxin (ACh) - > muscle paralysis
- Clozapine in Schizophrenia ( ↓ DA) - Reuptake by axon terminals or glial cells for reuse
- Cocaine and Speed delay reuptake of Norepinephrine (↑ pleasure)
- Anti-depressants (Prozac) block reuptake of Serotonin
- Lithium speeds reuptake ( ↓ DA) - Deactivated by enzymes
- COMT –gene encodes an enzyme that modulates DA in the PFC
- Nerve gas (VX) destroys AChE - Diffusion via blood
Dopamine
- “Pleasure” substance
Dopamine Associated with:
- Reward (ice-cream, promotions, ‘schadenfreude’, love :)
- Goal Proximity (to-do lists, video games)
- Motivation (trouble in Parkinson’s)
Dopamine and ADHD=
High Dopamine Transporter Density
- Impulsive, Increased cravings
- Reduced inhibition
Dopamine and Schizophrenia
: Overactive Dopamine
- DA-antagonists (blockers) reduce Hallucinations
Executive Functions
- Working memory = Updating/Monitoring
- Shifting= Switching/Shifting
- Inhibition
Wisconsin Card Sorting Task
- Working memory = Updating/Monitoring
The Wisconsin Card Sorting Task (WCST) is a neuropsychological test used to assess cognitive abilities, particularly abstract reasoning, cognitive flexibility, and executive functions. Participants are asked to sort cards based on different criteria, such as color, shape, or number, with the criteria changing throughout the test. The ability to adapt to these changes and learn new rules is evaluated. The WCST is valuable in diagnosing various neurological conditions and tracking changes in cognitive flexibility over time.
n-Back task
- Working memory = Updating/Monitoring
The n-Back task is a cognitive test used in psychology and neuroscience to assess working memory and attention. During the task, participants are presented with a series of stimuli, such as letters, numbers, or shapes, one at a time. They are then asked to indicate whether the current stimulus matches the one presented “n” steps earlier in the sequence. The value of “n” can vary, typically ranging from 1 to 3, with higher values indicating greater working memory demand. The task requires individuals to continuously update and maintain information in their working memory while simultaneously processing new stimuli, providing insight into their ability to sustain attention and manipulate information in real-time.
Executive Function: 1. Working memory = Updating/Monitoring Updating/Monitoring
- Primarily -> Working Memory
- Encode relevant incoming information
- Update/revise existing representations
- Manipulate representations
- Monitor for changes
Task Switching Paradigm (Alternate Runs)
- Shifting= Switching/Shifting
Executive Function: Switching/Shifting
- Engagement of a new/relevant task
- Disengagement from an old/irrelevant task
- Suppress proactive interference
Stop Signal Task
- Inhibition
The Stop Signal Task is a cognitive task designed to measure response inhibition, a component of executive function. In this task, participants are typically presented with a series of stimuli and instructed to respond to one type of stimulus as quickly as possible. However, occasionally, a “stop signal” is presented shortly after the initial stimulus, indicating that the participant should inhibit their planned response.
The main measure of interest in the Stop Signal Task is the “stop signal reaction time” (SSRT), which is the average time it takes for a participant to inhibit a response after the stop signal is presented. A longer SSRT indicates poorer response inhibition.
The Stop Signal Task is used in psychological research to assess inhibitory control and impulse control, and it has applications in studying disorders such as attention-deficit/hyperactivity disorder (ADHD), substance abuse disorders, and impulse control disorders.
Executive Function: Inhibition
- Suppress irrelevant but dominant actions
- Dominant actions can be:
Learned habits
Personality traits or tendencies
Practiced actions or overlearned skills
Cognitive Control Dilemma
Individual differences!
Dopamine & Cognitive Control
Flexibility vs Stability
Nigrostriatal Pathway:
The Nigrostriatal Pathway, primarily associated with motor control, indirectly influences cognitive functions such as working memory in the prefrontal cortex. While it doesn’t directly project to the prefrontal cortex, its connections with other brain regions, like the basal ganglia, suggest a role in cognitive processes. Dopamine, the neurotransmitter in this pathway, may modulate prefrontal cortical activity, impacting functions like working memory.
Nigrostriatal Pathway provides a signal to update
or maintain WM in the PFC
Tuberoinfundibular Pathway:
This pathway regulates the secretion of hormones from the pituitary gland, specifically the regulation of prolactin.
It connects the hypothalamus to the pituitary gland.
Dopamine released from neurons in the hypothalamus inhibits the release of prolactin from the anterior pituitary. This inhibition helps regulate the levels of prolactin in the bloodstream.
Dysfunction in this pathway can lead to hyperprolactinemia, a condition characterized by elevated levels of prolactin in the blood, which can result in symptoms such as menstrual irregularities, infertility, and lactation outside of pregnancy.
Mesolimbic Pathway:
This pathway is associated with the brain’s reward system and plays a role in motivation, reinforcement, and addiction.
It originates in the ventral tegmental area (VTA), located in the midbrain, and projects to various areas of the limbic system, including the nucleus accumbens, amygdala, and prefrontal cortex.
Dopamine released from neurons in the VTA is involved in mediating the pleasurable effects of rewarding stimuli, such as food, sex, and drugs. It reinforces behaviors that lead to the activation of this pathway.
Dysfunction in the mesolimbic pathway has been implicated in addiction and various psychiatric disorders, including depression and schizophrenia. Dysfunction can lead to abnormalities in reward processing, motivation, and emotional regulation.
High Prefrontal DA ->
Cognitive Stability
(goal maintenance, focusing, suppressing distraction, but inflexible/insensitive)
Low Prefrontal DA->
Cognitive Flexibility
(flexibility - inhibition and switching), but prone to distraction, interference)
U-shaped curve & Dopamine Level
- Both high and low levels of DA are associated with
low cognitive performance. - We all inherently tend to optimise our baseline DA
levels by using CNS stimulants or depressants or
both, sometimes together
schizophenia overdosing
