Untitled Quiz

Mind/Body Problem

• Descartes proposed the mind and body are separate while contemporary thought considers the mind as a product of the brain
• The mind/body problem explores the relationship between mental experiences (thoughts, feelings) and the physical body, particularly the brain
• Brain injuries can significantly alter an individual's personality and behavior, suggesting a strong link between the brain and the mind

Brain Structure and Function

• The brain can be divided into three major regions: hindbrain, midbrain, and forebrain

Hindbrain

• Controls essential life functions, including motor coordination, heart rate, respiration, and sleep-wake cycles
• Contains the cerebellum, medulla, pons, and reticular formation
• The cerebellum is responsible for motor coordination and control
• The medulla controls heart rate, circulation, and respiration
• The pons relays information from the cerebellum to the rest of the brain

Midbrain

• Controls the movement of eyes, auditory and visual reflexes, and the integration of sensory information

Forebrain: Subcortical Structures

• Contains structures located beneath the cerebral cortex including the thalamus, hypothalamus, hippocampus, amygdala, and basal ganglia
• The thalamus serves as a relay center for sensory information to the cortex
• The hypothalamus regulates basic drives like hunger, thirst, and sexual behavior
• The hippocampus is crucial for forming new memories
• The amygdala is involved in emotional processing, particularly fear and aggression
• The basal ganglia are involved in planned and voluntary movement

Patient H.M.

• H.M. was a patient who had his hippocampus removed to treat severe epilepsy
• He experienced profound anterograde amnesia, meaning he could not form new memories after the surgery

Hippocampus: Forming Memories

• The hippocampus plays a crucial role in creating and integrating new memories
• Damage to the hippocampus can result in anterograde amnesia, the inability to form new memories

Clive Wearing

• Clive Wearing is a well-known case of severe amnesia due to damage to the hippocampus
• He suffers from both retrograde and anterograde amnesia, unable to recall past events or form new memories

Forebrain: Subcortical Structures: Basal Ganglia

• The basal ganglia play a role in planned and voluntary movement and is involved in reward processing

Brain Facts.org

• Brainfacts.org provides an interactive 3D brain model for exploring brain structures and functions

Forebrain: Cerebral Cortex

• The cerebral cortex is the outer layer of the brain responsible for higher-level cognitive functions
• It is highly folded to increase surface area within the limited space of the skull

Cerebral Cortex: 4 Lobes

• The cerebral cortex is divided into four lobes: frontal, parietal, temporal, and occipital

Frontal Lobe

• Located at the front of the brain
• Key functions include higher-level cognitive functions such as planning, decision-making, language, and motor control

Parietal Lobe

• Located behind the frontal lobe
• Plays a role in processing sensory information, including touch, temperature, pain, and spatial awareness

Temporal Lobe

• Located below the parietal lobe
• Involved in auditory processing, language comprehension, and memory

Occipital Lobe

• Located at the back of the brain
• Responsible for visual processing

Somatosensory Cortex

• Located in the parietal lobe and receives sensory information from the body
• The amount of cortex dedicated to a specific body part corresponds to its sensitivity
• For example, a larger area is dedicated to the hands and face due to their high sensitivity.

Brain Development

• The prefrontal cortex, responsible for executive functions, develops last
• It is not fully mature until the age of 20-25

Motor Cortex

• Located in the frontal lobe and is responsible for controlling voluntary movements
• The amount of cortex dedicated to a specific body part corresponds to its precision of movement
• For example, a larger area is dedicated to the fingers due to their complex movements

Transcranial Magnetic Stimulation (TMS)

• A non-invasive technique used to study brain function, including by stimulating or inhibiting specific brain regions
• Uses strong magnets to briefly interrupt normal brain activity
• Can be used to study various aspects of brain function, like motor control or cognitive processes

Language in the Brain

• Language production is primarily controlled by Broca's area, located in the frontal lobe
• Language comprehension is primarily controlled by Wernicke's area, located in the temporal lobe

Broca's Aphasia

• Damage to Broca's area can lead to Broca's aphasia, affecting the ability to produce speech, resulting in halting, effortful speech with impaired grammatical structure.

Wernicke's Aphasia

• Damage to Wernicke's area can lead to Wernicke's aphasia, affecting language comprehension, resulting in fluent but meaningless speech.

Case Study: Aphasia

• Aphasia is a language disorder that impairs the ability to use or understand speech and language
• Damage to specific brain regions can lead to different types of aphasia
• The study of aphasia provides insights into the neural basis of language

Brain Plasticity

• Brain plasticity refers to the brain's ability to change and adapt throughout life
• The brain can rewire itself in response to learning, experience, or injury

Cerebral Hemispheres

• The two hemispheres of the brain communicate through the corpus callosum

Right-Brained or Left-Brained?

• The concept of "right brain/left brain" dominance is an oversimplification
• While hemispheres are specialized, they work together in a complex and integrated way

Hemispheric Lateralization

• Although the brain is largely symmetrical, some functions show lateralization, meaning they are primarily controlled by one hemisphere
• The left hemisphere typically controls language, logic, and analytical skills
• The right hemisphere typically controls spatial reasoning, creativity, and emotion.

Contralateral Organization

• Each hemisphere controls the opposite side of the body
• Left hemisphere controls right side and vice versa

Split Brain

• Split-brain surgery involves severing the corpus callosum to treat severe epilepsy
• It provides insights into the independent functions of each hemisphere

Split Brain Studies

• Studies of split-brain patients have shown that the hemispheres can function both independently and together
• Researchers can present information to only one hemisphere and observe the patient's responses
• This allows for studying how information is processed and integrated by each hemisphere

Split Brain Patient Findings

• The left hemisphere typically controls verbal communication
• The right hemisphere controls spatial reasoning and nonverbal communication
• The right hemisphere is better at recognizing faces and interpreting emotional expressions

Neuron Structure

• Neurons are specialized cells that transmit information throughout the nervous system

Santiago Ramon y Cajal

• A Spanish scientist who made critical contributions to the understanding of the neuron

Parts of a Neuron

• Cell body (soma): Coordinates information processing within the neuron, containing the nucleus and other organelles.
• Dendrites: Branchlike extensions that receive information from other neurons and relay it to the cell body
• Axon: A long, slender projection that transmits electrical signals away from the cell body
• Synapse: The junction between the axon of one neuron and the dendrite (or cell body) of another neuron where communication occurs

Myelin Sheath

• A fatty substance that insulates the axons of some neurons, increasing the speed and efficiency of signal transmission
• Formed by glial cells
• Damage to the myelin sheath can cause neurological disorders like multiple sclerosis

Action Potential: The Electrical Signal

• Action potential: A brief electrical impulse that travels down the axon of a neuron
• "All-or-none" phenomenon: It either fires at full strength or not at all, meaning the magnitude of an action potential does not vary based on the strength of the stimulus
• Travels down the axon due to the movement of ions through the membrane

Resting Potential

• When a neuron is at rest, the inside of the cell is negatively charged relative to the outside
• This charge difference is maintained by the concentration of ions inside and outside the cell

Depolarization

• When a neuron is stimulated, sodium ions (Na+) rush into the cell, causing the inside to become less negative (depolarized)
• This process initiates the action potential

Repolarization

• After depolarization, potassium ions (K+) move out of the cell, restoring the negative charge inside

Transmission Across the Synapse

• When the action potential reaches the axon terminal, it triggers the release of neurotransmitters into the synaptic cleft, the gap between neurons.

Neurotransmitters

• Chemical messengers that transmit signals across the synaptic cleft from one neuron to another.
• Bind to specific receptors on the postsynaptic neuron
• Can be excitatory (increasing the likelihood of an action potential) or inhibitory (decreasing the likelihood of an action potential)

Summation of Postsynaptic Potentials

• The combined effect of multiple postsynaptic potentials on a neuron
• If the sum of excitatory postsynaptic potentials exceeds the threshold, an action potential is generated

Neurotransmitter Examples

• Acetylcholine: Involved in muscle movement, memory, and learning
• Dopamine: Regulates motor behavior, pleasure, and motivation, associated with Parkinson's disease if there is neuron degeneration.
• Serotonin: Influences sleep, wakefulness, appetite, and mood

Agonist

• A drug that enhances or mimics the effects of a neurotransmitter
• Examples: dopamine agonists used to treat Parkinson's disease

Antagonist

• A drug that blocks or reduces the effects of a neurotransmitter
• Examples: botulinum toxin (Botox) blocks the release of acetylcholine

How We Study the Brain

• MRI (Magnetic resonance imaging): A technique that uses magnetic fields and radio waves to create detailed images of brain structure
• fMRI (Functional magnetic resonance imaging): A technique that measures brain activity by detecting changes in blood flow
  • Good spatial resolution (location of brain activity) but limited temporal resolution (timing of brain activity)
• EEG (Electroencephalography): A technique that measures electrical activity in the brain through electrodes placed on the scalp
  • Good temporal resolution (timing of brain activity) but limited spatial resolution (location of brain activity)