Neuroscience: Brain Damage and Function

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Questions and Answers

How can studying damaged brains provide insights into neurotypical brain function?

  • By stimulating damaged brain areas and observing resulting behavioral changes.
  • By identifying atypical brain structures that compensate for damage.
  • By directly comparing the physical size of damaged and neurotypical brain regions.
  • By observing the functional deficits resulting from damage to specific brain areas. (correct)

Which condition is a split-brain procedure primarily intended to treat?

  • Severe, intractable epilepsy. (correct)
  • Alzheimer's disease.
  • Schizophrenia.
  • Traumatic brain injury.

What is the primary function of the corpus callosum?

  • To regulate emotional responses.
  • To process visual information.
  • To control motor functions on the opposite side of the body.
  • To facilitate communication between the two cerebral hemispheres. (correct)

In split-brain patients, why does information presented to one hemisphere not reach the other?

<p>The corpus callosum, which allows inter-hemispheric communication, is severed. (A)</p> Signup and view all the answers

Why might a split-brain patient be able to verbally describe an object presented to their left hemisphere but be unable to pick it out with their left hand?

<p>The left hemisphere controls language, and the right hemisphere controls the left hand. (C)</p> Signup and view all the answers

A split-brain patient is briefly shown a chimeric face composed of half of Brad Pitt's face and half of Leonardo DiCaprio's face. The half of Leonardo DiCaprio's face is on the right side. If asked to verbally identify the person they saw, what would they likely say?

<p>Leonardo DiCaprio. (C)</p> Signup and view all the answers

How do split-brain studies contribute to our understanding of brain function?

<p>They reveal the specialized functions of each hemisphere and the importance of inter-hemispheric communication. (B)</p> Signup and view all the answers

What can be inferred about a person's ability to adapt to split-brain condition?

<p>Adaptation is possible using strategies such as moving the eyes to allow information to enter both hemispheres independently. (A)</p> Signup and view all the answers

What does an electroencephalograph (EEG) measure?

<p>Electrical activity in the brain. (B)</p> Signup and view all the answers

Which of the following is a key advantage of EEG recordings in studying brain activity?

<p>They are noninvasive and relatively inexpensive. (D)</p> Signup and view all the answers

How did Hubel and Wiesel discover the function of feature detectors in the visual cortex?

<p>By inserting electrodes into the occipital lobes of anesthetized cats and observing the responses of individual neurons to visual stimuli. (C)</p> Signup and view all the answers

What is the function of feature detectors in the visual cortex?

<p>To selectively respond to specific aspects of a visual image, such as lines or shapes. (C)</p> Signup and view all the answers

Which technique provides information about the structure of the brain, allowing clinicians to see changes or abnormalities?

<p>Structural brain imaging. (C)</p> Signup and view all the answers

How does a computerized axial tomography (CT) scan create an image of the brain?

<p>By rotating a device around the head and taking a series of X-ray photographs from different angles. (D)</p> Signup and view all the answers

What is diffusion tensor imaging (DTI) primarily used for?

<p>Visualizing white matter pathways and mapping brain connectivity. (B)</p> Signup and view all the answers

How do functional brain-imaging techniques work?

<p>By detecting changes in blood flow and energy consumption in active brain areas. (C)</p> Signup and view all the answers

What is positron emission tomography (PET)?

<p>A technique that involves injecting a radioactive substance into the bloodstream to measure brain activity. (C)</p> Signup and view all the answers

What is a key advantage of fMRI over PET?

<p>fMRI can measure brain activity over briefer periods of time. (D)</p> Signup and view all the answers

What does resting state functional connectivity measure?

<p>The extent to which spontaneous activity in different brain regions is correlated over time. (D)</p> Signup and view all the answers

Which of the following is an example of a network that can be identified using functional connectivity measures?

<p>The default network. (C)</p> Signup and view all the answers

Why should caution be exercised when interpreting fMRI results, particularly in media depictions?

<p>FMRI images often result from a comparison between tasks and do not show all brain activity during a specific task. (B)</p> Signup and view all the answers

What is the primary purpose of transcranial magnetic stimulation (TMS)?

<p>To temporarily mimic brain damage by deactivating neurons in specific areas of the cortex. (D)</p> Signup and view all the answers

How can TMS be used to establish causal relationships between brain regions and cognitive functions?

<p>By temporarily deactivating specific brain regions and measuring changes in behavior or cognition. (C)</p> Signup and view all the answers

What is one potential application of combining TMS with fMRI?

<p>To localize precisely where in the brain TMS is having its effect. (C)</p> Signup and view all the answers

What is a key challenge in determining whether a bigger brain is a smarter brain?

<p>The issue of third variables that may influence both brain volume and intelligence. (A)</p> Signup and view all the answers

What is the primary advantage of using large-scale databases like the UK Biobank in studies of brain volume and intelligence?

<p>They allow researchers to control statistically for the possible influence of confounding variables. (C)</p> Signup and view all the answers

In the studies using the UK Biobank, what cognitive measure was most closely related to brain volume?

<p>Fluid intelligence. (B)</p> Signup and view all the answers

What is the significance of the correlation found between brain volume and intelligence in the UK Biobank studies?

<p>It provides strong evidence for a relationship between brain volume and intelligence that cannot be explained by other measured variables. (C)</p> Signup and view all the answers

What conclusion can be drawn from the research on brain volume and intelligence?

<p>Brain volume accounts for a small portion of the variation in intelligence, but the relationship is complex and not fully understood. (A)</p> Signup and view all the answers

What was the significance of Paul Broca's work in the field of neuroscience?

<p>He provided evidence that the brain locations for speech production and speech comprehension are separate. (E)</p> Signup and view all the answers

What insight did the case of Phineas Gage provide to the study of neuroscience?

<p>It allowed researchers to investigate the hypothesis that the frontal lobe is involved in emotion regulation, planning, and decision making. (A)</p> Signup and view all the answers

How does the concept of neurodiversity influence the study of the brain?

<p>It encourages recognizing natural variations in brain structure and function rather than labeling differences as disorders. (D)</p> Signup and view all the answers

What is the significance of identifying brain networks through functional connectivity measures?

<p>Advances in understanding brain connectivity can enhance our ability to predict and characterize the clinical course of brain disorders. (A)</p> Signup and view all the answers

What is fluid intelligence as per the discussions on brain volume and intelligence?

<p>The ability to solve novel problems that demand logic and reasoning ability (B)</p> Signup and view all the answers

How can transcranial magnetic stimulation (TMS) contribute to understanding the role of the default network in cognition?

<p>By causing changes in the state of the brain through TMS pulses. (C)</p> Signup and view all the answers

How does studying the impact of brain damage on cognitive functions contribute to our understanding of the neurotypical brain?

<p>It helps identify the specific brain areas responsible for certain functions by observing what functions are lost when those areas are damaged. (B)</p> Signup and view all the answers

What critical advancement in understanding brain function came from the separate studies of Broca and Wernicke?

<p>The realization that specific areas in the left hemisphere are dedicated to speech production and language comprehension. (D)</p> Signup and view all the answers

In what way did the case of Phineas Gage contribute to early understanding of the frontal lobes?

<p>It suggested that the frontal lobe plays a role in personality, emotion regulation, planning, and decision making. (C)</p> Signup and view all the answers

How does the split-brain procedure provide insights into the distinct functions of the brain's hemispheres?

<p>By isolating information to one hemisphere and observing the specific capabilities and limitations of that hemisphere without input from the other. (D)</p> Signup and view all the answers

A split-brain patient is shown the word 'sun' to their right hemisphere and the word 'flower' to their left hemisphere. If asked to verbally report what they saw, what would they most likely say?

<p>'Flower' (A)</p> Signup and view all the answers

In split-brain patients, what is the underlying reason for the observed differences in their ability to name or identify objects processed by different hemispheres?

<p>Information presented to one hemisphere cannot be transferred to the other due to the severed corpus callosum. (A)</p> Signup and view all the answers

Why might a person with a split brain be able to assemble a puzzle with their left hand, yet struggle to verbally explain how they solved it?

<p>The right hemisphere, controlling the left hand, excels in spatial tasks, while language is predominantly processed in the disconnected left hemisphere. (D)</p> Signup and view all the answers

If a split-brain patient is briefly shown a picture of a cup to their left visual field, and a spoon to their right visual field, which object would they be able to verbally identify?

<p>The spoon (B)</p> Signup and view all the answers

What is one of the main advantages of using EEG recordings to study brain activity?

<p>EEGs are non-invasive and can detect rapid changes in brain activity, making them useful for studying states of consciousness. (C)</p> Signup and view all the answers

What did Hubel and Wiesel's experiments on anesthetized cats reveal about the neurons in the visual cortex?

<p>Neurons in the visual cortex are feature detectors, responding selectively to basic elements of visual stimuli like lines and edges at specific orientations. (C)</p> Signup and view all the answers

What key principle underlies functional brain-imaging techniques like PET and fMRI?

<p>Increased neural activity in brain regions leads to higher energy demand and increased blood flow, which these techniques detect. (D)</p> Signup and view all the answers

What does the technique of diffusion tensor imaging (DTI) primarily measure?

<p>The rate and direction of water molecule movement to visualize white matter pathways. (B)</p> Signup and view all the answers

What is a key advantage offered by fMRI over PET scans in studying brain activity?

<p>fMRI can localize changes in brain activity across shorter periods and doesn't require radioactive substances. (A)</p> Signup and view all the answers

What do correlated patterns of spontaneous brain activity measured during resting state functional connectivity reveal?

<p>Brain regions that are functionally connected and likely to work together as a network. (D)</p> Signup and view all the answers

How can TMS mimic brain damage and allow researchers to establish causal relationships between brain regions and cognitive functions?

<p>TMS delivers a magnetic pulse that temporarily deactivates neurons in a targeted brain region, allowing researchers to observe the effect on behavior and cognition. (D)</p> Signup and view all the answers

Combining TMS with fMRI can potentially provide what kind of information?

<p>It can show precisely where in the brain TMS is having its effect on neural activity and connectivity. (B)</p> Signup and view all the answers

Based on the research discussed, what is the strongest conclusion that can be drawn about the relationship between brain volume and intelligence?

<p>Larger brain volume is related to higher fluid intelligence, but other factors are also important. (C)</p> Signup and view all the answers

Why is it important to exercise caution when interpreting fMRI results, especially in media portrayals?

<p>fMRI images typically result from comparing experimental and control tasks, and increased activation in an area doesn't mean it's the only area involved in the experimental task. (A)</p> Signup and view all the answers

What does it mean to say the cerebral hemispheres exert contralateral control over the body?

<p>Each hemisphere controls sensory and motor functions on the opposite side of the body. (A)</p> Signup and view all the answers

How do scientists use transcranial magnetic stimulation (TMS) to study the role of specific brain regions in cognitive processes?

<p>By delivering magnetic pulses that temporarily disrupt brain activity, allowing observation of resulting changes in cognition. (D)</p> Signup and view all the answers

In studies using the UK Biobank database, what was the focus of the cognitive measures used to investigate the relationship between brain volume and intelligence?

<p>Fluid intelligence, particularly the ability to solve novel problems using logic and reasoning (C)</p> Signup and view all the answers

Why is the Human Connectome Project significant for neuroscience?

<p>It aims to provide a complete map of neural pathway connectivity in the human brain. (D)</p> Signup and view all the answers

What is the primary goal of structural brain imaging techniques?

<p>To provide information about basic brain structure. (C)</p> Signup and view all the answers

What is meant by the term 'neurodiversity'?

<p>The concept that variations in brain structure and function are natural and can lead to cognitive, social, and emotional differences. (D)</p> Signup and view all the answers

How might neuroimaging techniques be used to study memory distortions?

<p>By examining brain activity differences. (A)</p> Signup and view all the answers

Why it is difficult to definitively claim that having a bigger brain equates to being more intelligent?

<p>Correlational data prevent determining a causal relationship. (B)</p> Signup and view all the answers

How did Paul Broca's work contribute to our understanding of language processing in the brain?

<p>He discovered the area of the brain responsible for language production. (A)</p> Signup and view all the answers

What benefit did psychology gain as a result of the unfortunate change in Phineas Gage's personality?

<p>It helped start the hypothesis on the role of the frontal lobe in emotional control. (B)</p> Signup and view all the answers

In split-brain research using chimeric faces, how does a patient's response differ when asked to name the person they saw versus pointing to the face they recognized?

<p>They will name the person presented to the right hemisphere and point to the face presented to the left hemisphere. (D)</p> Signup and view all the answers

Neurons in the primary visual cortex that respond to specific orientations of lines or edges are called:

<p>Feature detectors (B)</p> Signup and view all the answers

What is the main purpose of the 'resting state functional connectivity' technique in fMRI studies?

<p>To assess how different brain regions are functionally connected to each other when no specific task is being performed. (C)</p> Signup and view all the answers

What considerations are necessary before using fMRI to detect if a recollection is accurate or not?

<p>If it is a complex real-world event. (C)</p> Signup and view all the answers

What did transcranial magnetic stimulation (TMS) reveal about the angular gyrus in the parietal lobe in relation to memory and imagination?

<p>That it plays a causal role as it decreases recalling past events. (A)</p> Signup and view all the answers

How does fMRI technology work to measure brain activity?

<p>By tracking blood oxygen levels to detect differences between oxygenated and deoxygenated hemoglobin. (B)</p> Signup and view all the answers

What is one limitation in using head volume to estimate intelligence?

<p>Early studies used imprecise/inadequate methods to estimate brain volume. (C)</p> Signup and view all the answers

Why is a large sample size beneficial in studies examining the relationship between brain volume and cognitive measures?

<p>It makes the data more stable when correlating volume with measures of intelligence. (A)</p> Signup and view all the answers

What did Nave et al.'s (2019) research using data from the UK Biobank reveal about the correlation between brain volume and fluid intelligence?

<p>A correlation of +19. (B)</p> Signup and view all the answers

Researchers use transcranial magnetic stimulation (TMS) to study the brain. What is the crucial advantage of using TMS?

<p>It allows researchers to establish causal relationships between specific brain regions and behavior. (D)</p> Signup and view all the answers

What is the significance of the Human Connectome Project?

<p>Mapping the complete network of neural connections in the human brain. (B)</p> Signup and view all the answers

How do functional connectivity measures derived from fMRI contribute to cognitive neuroscience?

<p>By assessing the degree to which activity in different brain regions is correlated over time during rest. (C)</p> Signup and view all the answers

Why is caution warranted when interpreting media depictions of fMRI results?

<p>Because media reports often oversimplify complex data and imply direct causal links that may not exist. (C)</p> Signup and view all the answers

What key finding emerged from studies using the UK Biobank data regarding brain volume and intelligence?

<p>A significant correlation was found between brain volume and fluid intelligence, even after controlling for other variables. (C)</p> Signup and view all the answers

Flashcards

Neurodiversity

Variations in brain structure and function that lead to differences in cognitive, social, and emotional functions. These should be differentiated from disorders or brain damage.

Broca's Aphasia

Loss of the ability to produce spoken language due to damage in the left frontal lobe.

Wernicke's Aphasia

Impairment in language comprehension but not speech production, associated with damage to an area in the upper-left temporal lobe.

Frontal Lobe's Role in Emotion

The hypothesis that the frontal lobe is involved in emotion regulation, planning, and decision-making which stems from damage to this area.

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Epileptic Seizure Spread

The process where seizures that begin in one hemisphere cross the corpus callosum to the opposite hemisphere, creating a feedback loop.

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Split-Brain Procedure

A surgical procedure where the corpus callosum is severed to alleviate the severity of seizures.

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Contralateral Control

The hemispheres exert control over the body, where the left hand is controlled by the right hemisphere and vice versa.

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Chimeric Face

A face assembled from half-face components, used to study hemispheric specialization in split-brain patients.

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Electroencephalograph (EEG)

A device used to record electrical activity in the brain through electrodes placed on the scalp.

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Feature Detectors

Neurons in the visual cortex that selectively respond to certain aspects of a visual image, such as contrast, shape, and color.

Signup and view all the flashcards

Structural Brain Imaging

Neuroimaging techniques that provide information about the basic structure of the brain.

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Functional Brain Imaging

Neuroimaging techniques that provide information about the activity of the brain while people perform tasks.

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CT Scan (Computerized Axial Tomography)

A scanning technique that uses X-ray photographs from different angles, combined by computer programs, to show different tissue densities in the brain.

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MRI (Magnetic Resonance Imaging)

A technique that uses a strong magnetic field and radio waves to produce high-resolution pictures of soft tissue in the brain.

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DTI (Diffusion Tensor Imaging)

A type of MRI that visualizes white matter pathways by measuring the rate and direction of water molecule diffusion.

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Human Connectome Project

An international project aiming to provide a complete map of the connectivity of neural pathways in the human brain.

Signup and view all the flashcards

PET (Positron Emission Tomography)

A functional imaging technique where a radioactive substance is injected into the bloodstream to measure brain activity during tasks.

Signup and view all the flashcards

fMRI (Functional Magnetic Resonance Imaging)

A functional brain-imaging technique that detects the difference between oxygenated and deoxygenated hemoglobin to measure brain activity.

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Resting State Functional Connectivity

A technique using fMRI where participants rest quietly while measuring spontaneous activity in different brain regions to identify functionally connected networks.

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Default Network

A group of interconnected brain regions involved in internally focused cognitive activities, such as remembering, imagining, and mind-wandering.

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Transcranial Magnetic Stimulation (TMS)

A technique that delivers a magnetic pulse to deactivate neurons in the cerebral cortex for a short period, mimicking brain damage.

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Fluid Intelligence

The ability to solve novel problems that demand logic and reasoning ability.

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Study Notes

Studying the Damaged Brain

  • Neuroscience research links loss of perceptual, motor, emotional, or cognitive functions to specific brain areas to understand normal brain functions.
  • Neurodiversity acknowledges natural variations in brain structure and function, distinguishing them from disorders or damage; neurotypical brain is a more appropriate term than "normal" brain.
  • Paul Broca in 1861 identified Broca's area in the left frontal lobe as crucial for speech production; damage leads to inability to produce spoken language.
  • Carl Wernicke in 1874 discovered Wernicke's area in the upper-left temporal lobe, vital for language comprehension; damage results in impairment in understanding language.
  • Broca's and Wernicke's areas provided early evidence for separate brain locations for speech production and comprehension, and the left hemisphere's importance for language.

The Emotional Functions of the Frontal Lobes

  • The case of Phineas Gage, who had a 3-foot iron rod pass through his head in 1848, marked the beginning of frontal lobe function discoveries.
  • Post-accident, Gage's personality shifted to irritable, irresponsible, and indecisive, suggesting the frontal lobe's role in emotion regulation, planning, and decision-making.
  • Gage's study allowed researchers to understand the interactions between the frontal lobe, limbic system structures, amygdala, and hippocampus

The Distinct Roles of the Left and Right Hemispheres

  • Severe epilepsy treatment sometimes involves a split-brain procedure, severing the corpus callosum to prevent seizures from spreading between hemispheres.
  • Split-brain patients have information isolated to one hemisphere due to the severed corpus callosum.
  • Roger Sperry's experiments on split-brain patients revealed hemisphere specialization.
  • Language processing is largely a left-hemisphere activity, which was originally revealed in the discovery of Broca's and Wernicke's areas,
  • Contralateral control means the left hand is controlled by the right hemisphere, and vice versa.
  • Split-brain patients can verbally describe an object presented to the left hemisphere but cannot pick it up with the left hand.
  • Objects presented to the right hemisphere can be identified by touch with the left hand but cannot be verbally described.
  • Chimeric face experiments show split-brain patients identify faces based on the hemisphere receiving the information (left for naming, right for pointing).
  • Split-brain studies demonstrate distinct hemisphere functions and seamless cooperation when the corpus callosum is intact.

Studying the Brain's Electrical Activity

  • Electroencephalography (EEG) records the brain's electrical activity using electrodes on the scalp.
  • EEG can identify different states of consciousness and abnormal brain activity.
  • EEG is used to study brain activity during various psychological functions and is noninvasive and inexpensive.
  • David Hubel and Torsten Wiesel discovered feature detectors in the primary visual cortex by recording action potentials of individual neurons in cats.
  • Feature detectors are neurons that selectively respond to specific aspects of a visual image, like contrast, shape, and color.
  • Neurons in the temporal lobe are specialized for face processing; damage causes inability to perceive faces.
  • The correlation between lost function due to brain damage and the information processed by neurons in that area is compelling evidence linking brain to behavior.

Using Brain Imaging to Study Structure and to Watch the Brain in Action

  • Neuroimaging creates images of the living brain to study its structure and activity.
  • Structural brain imaging shows brain structure, revealing changes or abnormalities.
  • Functional brain imaging shows brain activity during cognitive or motor tasks.
  • Computerized axial tomography (CT) scans use X-rays to show brain tissue density and can locate lesions or tumors.
  • Magnetic resonance imaging (MRI) uses magnetic fields and radio waves to produce higher resolution images of soft tissue.
  • Diffusion tensor imaging (DTI) visualizes white matter pathways by measuring water molecule movement.
  • The Human Connectome Project aims to map all neural pathways in the brain.
  • Functional brain-imaging techniques detect changes in blood flow to identify active brain areas.
  • Positron emission tomography (PET) uses a radioactive substance to measure blood flow and identify active regions during tasks.
  • Functional magnetic resonance imaging (fMRI) detects differences between oxygenated and deoxygenated hemoglobin to measure brain activity.
  • Functional connectivity measures spontaneous activity correlations between brain regions using fMRI at rest.
  • Brain networks are sets of closely connected brain regions identified through functional connectivity.
  • The default network, identified via functional connectivity, involves regions in the frontal, temporal, and parietal lobes and is associated with internal cognitive activities.
  • Functional connectivity and DTI contribute to mapping the human connectome and have potential applications in understanding and predicting brain disorders.

Caution Is Needed Before Jumping to Conclusions

  • Functional neuroimaging (fMRI and PET) typically results from comparison between task and control task
  • FMRI/PET images do not mean we are only using that small part of our brain to perform the experimental task.
  • FMRI studies have shown greater brain activity during retrieval of accurate memories as opposed to inaccurate memories
  • However, it is not possible to tell whether a witness is recounting an accurate vs inaccurate memory based on fMRI results
  • It is important to think carefully before using fMRI evidence in everyday life because we do not know if lab results can be generalized to everyday complex events, and data is usually averaged across participants, where it is more difficult to measure individual differences.

Transcranial Magnetic Stimulation

  • Transcranial magnetic stimulation (TMS) temporarily deactivates neurons in the cerebral cortex using magnetic pulses.
  • TMS allows researchers to study causal relationships by observing changes in behavior when specific brain regions are temporarily "turned off."
  • Studies using TMS disrupting the angular gyrus in the parietal lobe reduced the amount of details that individuals remembered in past experiences and imagined in future experiences,
  • Researchers are combining TMS with fMRI to precisely locate the effects of TMS in the brain.

Hot Science: Big Brain, Smart Brain?

  • Sir Francis Galton studied head volume in high achieving Cambridge undergrads, concluding they had larger brains
  • But the correlation between brain volume and intelligence is complex and debated.
  • Early studies used imprecise head circumference measurements.
  • MRI studies generally show a positive correlation between brain volume and intelligence, though the strength varies (from almost 0 to 1).
  • Third variables such as age, socioeconomic status, height, or sex can influence the correlation.
  • Large-scale studies using the UK Biobank (UKB) have analyzed MRI-measured brain volume and cognitive measures in thousands of participants.
  • Fluid intelligence, which is the ability to solve novel problems, has a correlation of +.19 with brain volume after controlling for other variables.
  • A related study reported a slightly larger correlation of +.27
  • Brain volume accounts for only a small portion of the variation in intelligence.
  • The direction of causation between brain volume and intelligence remains unknown.

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