Neuropsychology of Handedness and Lateralization

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is a potential advantage of left-handedness in society?

Reduced stress levels

Increased interhemispheric connectivity (correct)

More opportunities for athletic success

Greater acceptance of diversity

Which of the following functions is NOT associated with lateralization?

Footedness

Vision

Height (correct)

Handedness

In emotional processing, which hemisphere is positively correlated with positive emotions?

Left hemisphere (correct)

Right hemisphere

Both hemispheres equally

None of the hemispheres

What does the term 'continuous polymorphism' indicate in the context of handedness?

The existence of diverse traits within a population (C) Signup and view all the answers

Which animal is cited as an example of having cerebral lateralization?

Chimpanzees (D) Signup and view all the answers

What happens to the sodium channels when the neuron is stimulated beyond the threshold?

Sodium ions flow into the cell. (B) Signup and view all the answers

What is the purpose of the resting potential in a neuron?

To prepare the neuron to respond rapidly. (A) Signup and view all the answers

What occurs during hyperpolarization of the neuron?

The membrane potential becomes more negative. (C) Signup and view all the answers

What is true about the action potential's peak in different axons?

The peak remains consistent within a specific axon. (B) Signup and view all the answers

What is a characteristic of subthreshold stimulation in neurons?

It causes a small response that quickly decays. (D) Signup and view all the answers

What percentage of left-handed individuals experienced aphasia due to right hemisphere lesions?

24% (D) Signup and view all the answers

What was the percentage of left-handers and ambidextrous patients with left hemisphere speech specialization without early damage?

69% (D) Signup and view all the answers

Which hypothesis proposed that male brains are more lateralized than female brains?

Levy Hypothesis (C) Signup and view all the answers

What did the groundbreaking experiment of Myers and Sperry (1953) demonstrate about the corpus callosum?

It enables independent functioning of hemispheres. (A) Signup and view all the answers

What component is primarily involved in the analgesic effects of opioid drugs?

Periaqueductal gray (B) Signup and view all the answers

After cutting the corpus callosum in cats, what was observed when the eye patch was switched?

Performance dropped to chance level. (A) Signup and view all the answers

What has recent research indicated about sex-based differences in brain lateralization?

There are no significant sex-based differences. (C) Signup and view all the answers

Which structure is part of the diencephalon?

Hypothalamus (D) Signup and view all the answers

What was the primary function associated with the corpus callosum identified in studies from the 1950s?

Information transfer between hemispheres. (C) Signup and view all the answers

What is the function of the thalamus?

Relays sensory information to the cortex (C) Signup and view all the answers

Which structure is known as the 'black substance' and is essential for the sensorimotor system?

Substantia nigra (D) Signup and view all the answers

What effect did early left hemisphere damage have on left-handed or ambidextrous patients' speech specialization?

Reduced left hemisphere specialization to 30%. (C) Signup and view all the answers

Where do the optic nerves cross each other in the brain?

Optic chiasm (A) Signup and view all the answers

The massa intermedia connects which part of the brain?

The two lobes of the thalamus (D) Signup and view all the answers

What role does the hypothalamus play in the body?

Regulates hormone release and motivated behaviors (A) Signup and view all the answers

Which structure is NOT located on the inferior surface of the diencephalon?

Thalamus (A) Signup and view all the answers

What is handedness believed to have contributed to in human evolution?

The development of language and fine motor function (D) Signup and view all the answers

Which statement accurately describes left-handedness?

Can be a normal variant in handedness (C) Signup and view all the answers

What characterizes the resting potential of a neuron?

There is a difference in electrical charge between the inside and outside (D) Signup and view all the answers

What is the primary component of a neuron's membrane?

Two layers of phospholipid molecules (C) Signup and view all the answers

Why do researchers use a microelectrode to measure resting potential?

To complete the electrical circuit inside the neuron (B) Signup and view all the answers

What could left-handedness indicate in rare cases?

Disturbances of cerebral development (A) Signup and view all the answers

What effect does the polarization of a neuron's membrane have?

It contributes to the resting potential (C) Signup and view all the answers

Which of these functions also demonstrates lateralizing tendencies, similar to handedness?

Language and emotion (D) Signup and view all the answers

Which hemisphere is better suited for encoding verbal memory materials?

Left hemisphere (B) Signup and view all the answers

What is a distinguishing factor between the memory functions of the left and right hemispheres?

The left hemisphere excels in episodic memory (B) Signup and view all the answers

Which approach connects specific memories to particular hemispheres?

Linking particular memory processes with particular hemispheres (B) Signup and view all the answers

What does the research suggest about the lateralization of memory for nonverbal material?

It is primarily managed by the right hemisphere (B) Signup and view all the answers

What aspect of cognitive abilities is considered the most lateralized?

Language abilities (D) Signup and view all the answers

What three areas of cortex are often focused on when identifying interhemispheric differences in brain anatomy related to language?

Planum temporale, frontal operculum, Heschl’s gyrus (A) Signup and view all the answers

Why is it important to break down complex cognitive tasks into individual cognitive processes?

To predict laterality of cognitive tasks (D) Signup and view all the answers

What is the primary focus of researchers studying cerebral lateralization?

Analyzing individual cognitive activities based on broader categories (D) Signup and view all the answers

Study Notes

Nervous System

The nervous system is composed of two primary divisions: the Central Nervous System (CNS) and the Peripheral Nervous System (PNS).
The CNS is composed of the brain and spinal cord.
The PNS is composed of the somatic and autonomic nervous systems.
The somatic nervous system interacts with the external environment.
- Afferent nerves carry sensory signals from skin, muscles, joints, eyes, and ears to the CNS.
- Efferent nerves carry motor signals from the CNS to skeletal muscles.
The autonomic nervous system regulates the body's internal environment.
- Afferent nerves carry sensory signals from internal organs to the CNS.
- Efferent nerves carry motor signals from the CNS to internal organs.
- Two types of efferent nerves:
  - Sympathetic nerves project from the lumbar and thoracic regions of the spinal cord, stimulating, organizing, and mobilizing energy resources in threatening situations.
  - Parasympathetic nerves project from the brain and the sacral region of the spinal cord, working to conserve energy.
The somatic and autonomic nervous systems work together to regulate bodily functions and control responses to stimuli.

Meninges

The brain and spinal cord are protected by three protective membranes called meninges.
The outermost tough membrane is called the dura mater.
Beneath the dura mater is the arachnoid membrane, a spider web-like membrane containing blood vessels and cerebrospinal fluid (CSF).
The innermost delicate membrane is called the pia mater and adheres to the surface of the CNS.
The CNS is protected by cerebrospinal fluid (CSF).
- CSF fills the subarachnoid space.
- CSF fills the central canal of the spinal cord.
- CSF fills the cerebral ventricles of the brain.
- The cerebral ventricles are four large internal chambers of the brain.
  - Two lateral ventricles
  - Third ventricle
  - Fourth ventricle
CSF supports and cushions the brain. Loss of CSF can cause severe headaches and pain with sudden head movements.

Hydrocephalus

Occurs when CSF flow is blocked (often by a tumor) near a narrow channel linking the ventricles, leading to the expansion of the ventricle walls and the entire brain.

Neurons

Specialized cells for the reception, conduction, and transmission of electrochemical signals.
Come in various shapes and sizes but many share similar structures.
- Neuron cell membrane
  - Composed of a lipid bilayer of fat molecules
  - Embedded with protiens
    - Channel proteins: Allow certain molecules to pass through.
    - Signal proteins: Allow transfer signals to the inside of the neuron when specific molecules bind to them on the outside of the membrane.
- Classes of Neurons
  - Multipolar neurons– Have more than two processes extending from their cell body (most common).
  - Unipolar neurons– Have one process extending from their cell body.
  - Bipolar neurons– Have two processes extending from their cell body.
  - Interneurons– (within CNS) have short axons or no axons at all and integrate neural activity within a single brain structure.
- Neurons and Neuroanatomical Structure
  - Gross neural structures are composed of either cell bodies or axons.
    - In the CNS:
      - Clusters of cell bodies are called nuclei.
      - Bundles of axons are called tracts.
    - In the PNS:
      - Clusters of cell bodies are called ganglia.
      - Bundles of axons are called nerves.
Glial cells:
- Oligodendrocytes: Located in the CNS and form myelin sheaths around axons (increasing axonal conduction) - one oligodendrocyte helps many neurons
- Schwann Cells: Located in the PNS and form the myelin sheath; plays a role in guiding axonal regeneration after nerve damage (unlike oligodendrocytes).
- Microglia: Smallest glial cells, play a role in responding to injury or disease (multiplying, engulfing cellular debris, triggering inflammatory responses, and synapse elimination).
- Astrocytes: Largest glial cells shaped like stars, whose extensions cover blood vessels and neurons, regulating chemical passage between blood and CNS neurons.
  - Supporting essential functions: Exchange chemical signals with neurons and other astrocytes; modulate neutral activity and form functional networks.

Functional Brain Imaging (fMRI)

Monitors brain activity while subjects perform language tasks.
Shows greater activation in the left hemisphere during language processing.

Cerebral Lateralization

Left Hemisphere: controls the right side of the body; is dominant for language production in 95% of right-handers.
Right Hemisphere: controls the left side of the body; often plays a role in spatial reasoning, musical aptitude and aspects of nonverbal communication.
- 80% of left-handers do NOT have left hemisphere dominance.
- Some left-handers have right-hemisphere speech dominance.
Processes sensory information from each sensory modality in both hemispheres, although slightly stronger input comes from the contralateral ear (each hemisphere receives input from both ears).
Taste and smell are uncrossed--each hemisphere recieves signals from each side of the tongue and nasal passages.
Language (speech) is usually more dominant in the left hemisphere in humans (specifically the left frontal lobe).
The Corpus Callosum and interhemispheric commissures like the anterior commissure and hippocampal commissure allow communication between hemispheres coordinating movement and processing information.
Anatomical differences between the hemispheres. The planum temporale is generally larger in the left hemisphere but is also larger in the left hemisphere of adults.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz explores key concepts in neuropsychology related to handedness and brain lateralization. Participants will answer questions about emotional processing, action potentials, and the neurological differences associated with left-handedness. Enhance your understanding of how brain functions are affected by individual differences in handedness.