Schizophrenia and Dopamine Hypothesis Quiz

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Questions and Answers

What does the dopamine hypothesis for schizophrenia primarily explain?

The onset of the disorder in childhood

Cognitive deficits and impairments

Negative symptoms such as lack of motivation

Positive symptoms such as hallucinations (correct)

What is a significant side effect associated with the use of dopamine antagonists?

Enhanced cognitive functions

Tardive dyskinesia (correct)

Decreased muscle coordination

Increased dopamine production

How does hypofrontality relate to the symptoms of schizophrenia?

It contributes to cognitive symptoms and may be linked to dopamine imbalances (correct)

It leads to increased positive symptoms

It is a cause of increased dopamine levels

It results in higher activation of the fusiform face area

What makes indirect NMDA agonists potentially safer than direct NMDA agonists?

They reduce the risk of excitotoxicity Signup and view all the answers

What differentiates atypical antipsychotics from traditional antipsychotics?

They target both dopamine and serotonin while minimizing motor side effects Signup and view all the answers

What did Lashley's experiments suggest about where memories are stored in the brain?

Memories are distributed throughout the brain. Signup and view all the answers

Which brain area is associated with the engram for the classically conditioned eyeblink response?

Interpositus nucleus of the cerebellum Signup and view all the answers

In Baddeley’s model, which system is primarily responsible for handling visual and spatial information?

Visuospatial sketchpad Signup and view all the answers

What type of memory is primarily associated with the function of the basal ganglia?

Procedural memory Signup and view all the answers

What was the surgical outcome for Patient H.M. regarding his ability to form new memories?

He suffered from severe anterograde amnesia. Signup and view all the answers

What is required for long-term potentiation (LTP) to take place?

Persistent, strong synaptic stimulation Signup and view all the answers

How do AMPA and NMDA receptors contribute to long-term potentiation?

AMPA receptors allow sodium influx; NMDA receptors allow calcium influx. Signup and view all the answers

What role does calcium play in long-term potentiation?

Calcium triggers intracellular signaling cascades. Signup and view all the answers

What is the primary function of the hippocampus in spatial navigation?

It forms cognitive maps and supports spatial memory. Signup and view all the answers

What does reconsolidation refer to in the context of memory?

Reactivated memories become malleable and can be updated or altered. Signup and view all the answers

What is the main idea behind the Morris Water Maze experiment?

To demonstrate the role of the hippocampus in spatial learning and navigation. Signup and view all the answers

What is epigenetics primarily concerned with?

Changes in gene expression caused by environmental factors without altering the DNA sequence. Signup and view all the answers

Which statement best describes the process of natural selection?

Traits that enhance survival and reproduction increase in frequency over generations. Signup and view all the answers

What is the role of astrocytes in the central nervous system (CNS)?

Forming inhibitory glial scars that limit axon regrowth. Signup and view all the answers

What is the main function of Broca's area in the brain?

Producing speech and language. Signup and view all the answers

How does phonological dyslexia differ from surface dyslexia?

Phonological dyslexia involves difficulty with word recognition, surface dyslexia involves sounding out words. Signup and view all the answers

What is a key feature of seasonal affective disorder (SAD)?

It is linked to reduced light exposure during winter months. Signup and view all the answers

What is a main symptom of Wernicke's aphasia?

Difficulty comprehending language. Signup and view all the answers

What does neurogenesis refer to?

The formation of new neurons. Signup and view all the answers

What is a challenge associated with the monoamine hypothesis for depression?

It does not explain why antidepressants take weeks to show effects. Signup and view all the answers

What is the interpreter in the left hemisphere proposed to do?

Create coherent narratives from incoming information. Signup and view all the answers

What defines cognitive symptoms of schizophrenia?

Impaired memory, attention, and executive functioning. Signup and view all the answers

Study Notes

Memory Systems

Lashley's research on memory localization involved systematically removing parts of rats' cerebral cortex while training them in mazes. His finding: memory is distributed throughout the brain, not confined to a single area. Limitations: relied on behavioral observation; didn't focus on specific neural circuits.
The cerebellum's interpositus nucleus is a proposed site for the engram of the classically conditioned eyeblink response.
Baddeley's model focuses on working memory and its components: the phonological loop, visuo-spatial sketchpad, central executive, and episodic buffer.

Neural Correlates of Working Memory

Phonological loop: Left temporal and parietal lobes.
Visuo-spatial sketchpad: Occipital and parietal lobes.
Central executive: Prefrontal cortex.

Basal Ganglia in Memory

The basal ganglia are involved in procedural memory and habit learning.
Dopamine regulates basal ganglia circuits and reinforces learning by signaling reward prediction errors.

Patient H.M. Case Study

H.M. underwent surgical removal of portions of his medial temporal lobes, including the hippocampus.
This caused severe anterograde amnesia—inability to form new declarative memories.
His procedural memory and long-term memories from before the surgery remained intact.
This supports the idea that different brain systems handle different types of memories, and that the hippocampus is critical for forming new declarative memories, but not for procedural ones.

Long-Term Potentiation (LTP)

LTP requires persistent, strong synaptic stimulation.
AMPA receptors allow sodium influx, and NMDA receptors allow calcium influx after depolarization removes the magnesium block.
Calcium triggers signaling cascades that strengthen synaptic connections, resulting in increased dendritic spines and AMPA receptors.

Memory Consolidation

The standard model of consolidation suggests that memories are initially stored in the hippocampus, then gradually transferred to the cortex.
Reconsolidation describes the process where reactivated memories become malleable and can be updated or altered.

The hippocampus plays a crucial role in forming cognitive maps and supporting spatial memory.
The Morris Water Maze is a test where rodents find a submerged platform to demonstrate the hippocampus's critical role in spatial learning and navigation.

Genetics and Evolution

A gene is a unit of hereditary information composed of DNA.
Epigenetics studies how environmental factors can cause changes in gene expression, without altering the DNA sequence itself.
Twin and adoption studies can help isolate genetic and environmental effects for predicting human behavior.
Natural selection favors traits that enhance survival and reproduction. Human evolution continues, but does not necessarily imply improvement.
Lamarckian evolution, where acquired traits are inherited, lacks scientific support.

Developmental and Plasticity

Newborn brains have more neurons than adult brains, but adults have more refined synaptic connections.
Axon growth during development is guided by chemical signals.
Studies on musicians' brains compared to non-musicians demonstrate cortical plasticity, where skill-related areas show increased representation.
Dendrites can increase their spines and strengthen synaptic connections as a result of learning.
Phantom limb pain results from cortical reorganization following limb loss.

Recovery, Hemispheric Differences & Language

Neurogenesis is the formation of new neurons, observed in the hippocampus and olfactory bulb.
Axon regrowth in the central nervous system is constrained due to astrocytes forming inhibitory glial scars.
The left hemisphere excels in language, logical reasoning, and analytical tasks; the right hemisphere is stronger in spatial abilities, facial recognition, and understanding emotions.
The interpreter is a left-hemisphere function that creates coherent narratives based on incoming information.
The left hemisphere processes language grammar and syntax, while the right interprets prosody and emotional tone.
Broca's area, located in the left frontal lobe, is crucial for speech production. Damage leads to Broca's aphasia, characterized by difficulties in speech production but relatively preserved comprehension. Wernicke's area, in the left temporal lobe, is essential for language comprehension. Damage causes Wernicke's aphasia, which results in fluent but nonsensical speech. The visual word form area, in the left occipitotemporal region, is vital for recognizing written words.
Phonological (dysphonetic) dyslexia involves difficulties sounding out words, while surface (dyseidetic) dyslexia involves difficulties recognizing words by sight.

Mood Disorders

Potential underactivity in both the prefrontal cortex and hippocampus is implicated in depression.
The monoamine hypothesis suggests depression correlates with reduced serotonin, dopamine, and norepinephrine—antidepressants work to increase these levels.
However, the monoamine hypothesis fails to explain why antidepressants take weeks to work, despite rapid monoamine increases.
Hippocampal neurogenesis may contribute to slower antidepressant effects. Ketamine promotes rapid synaptic strengthening and neurogenesis by increasing glutamate activity.
Electroconvulsive therapy (ECT) induces seizures to treat severe depression and has side effects like memory loss and confusion.
Seasonal affective disorder (SAD) is correlated with decreased light exposure during winter and addressed with light therapy, antidepressants, and cognitive-behavioral therapy.
Lithium is often used for mood stabilization in bipolar disorder.

Schizophrenia

Schizophrenia involves positive symptoms (hallucinations, delusions, disorganized thoughts), negative symptoms (apathy, lack of emotion, social withdrawal), and cognitive symptoms (impaired memory, attention, and executive functioning).
Epidemiological studies suggest prenatal viral exposure, particularly in the second trimester, as a potential risk factor for schizophrenia.
The dopamine hypothesis suggests overactive dopamine is involved in positive symptoms, but is incomplete as it doesn't fully explain negative and cognitive symptoms.
Dopamine antagonists, while treating symptoms, can cause side effects like tardive dyskinesia.
Reduced prefrontal cortex (PFC) activity (hypofrontality) is tied to cognitive symptoms and possibly dopamine imbalances in schizophrenia.
Indirect NMDA agonists are safer than direct NMDA agonists as treatments for schizophrenia due to a lower risk of excitotoxicity.
Atypical antipsychotics target both dopamine and serotonin to address positive and negative symptoms with reduced motor side effects compared to traditional antipsychotics.

Autism

Autism Spectrum Disorder (ASD) features impaired social communication, repetitive behaviors, and restricted interests.
Autistic children show early brain overgrowth, followed by a period of slowed or atypical development.
Reduced activity in the fusiform face area (FFA) and the temporal parietal junction (TPJ), during face recognition and perspective-taking processes, supports the notion of these brain regions being associated with ASD.

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Description

Test your knowledge on the dopamine hypothesis of schizophrenia, including its implications, side effects of dopamine antagonists, and the role of NMDA agonists. This quiz also covers the differences between atypical and traditional antipsychotics. Dive in to deepen your understanding of these essential concepts in psychology and psychiatry.