Brain Organization and Function Quiz

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Questions and Answers

What role does the HPA axis primarily serve in the body?

Manages reproductive hormones

Regulates metabolism and energy levels

Facilitates digestion and appetite

Controls the stress response (correct)

What hormone is NOT stored in the posterior pituitary gland?

Antidiuretic hormone (ADH)

Thyroid-stimulating hormone (TSH) (correct)

Oxytocin

Prolactin

Which aspect is NOT a characteristic of neuroplasticity?

Adaptations following behavioral changes

Changes due to environmental factors

Permanent loss of brain function after injury (correct)

Ability to develop new neural pathways

What condition is characterized by the loss of dopamine cells, affecting movement and causing cognitive deficits?

Parkinson's disease Signup and view all the answers

Which of the following abilities is typically associated with savantism?

Exceptional calendar calculating Signup and view all the answers

Which statement about Kim Peak is accurate?

He could read and remember two pages at once Signup and view all the answers

What theory suggests that damage to the nervous system can unexpectedly enhance performance?

Paradoxical Functional Facilitation Signup and view all the answers

Why do experts say that not everyone can be a genius?

Many factors influence intelligence and abilities Signup and view all the answers

What is a characteristic feature of hormones compared to neurons?

Hormones travel through blood. Signup and view all the answers

Which gland is considered the 'master gland' of the endocrine system?

Pituitary gland Signup and view all the answers

What role does the hypothalamus play in hormone regulation?

It secretes releasing factors that influence the pituitary gland. Signup and view all the answers

How do neurons primarily communicate messages within the body?

Via electrochemical action potentials. Signup and view all the answers

Which of the following correctly describes an impact of growth hormone (GH) once released into the bloodstream?

It promotes growth across many systems in the body. Signup and view all the answers

Which component of reward is primarily associated with the desire to obtain it?

Wanting Signup and view all the answers

What effect do rewards generally have on behavior according to the components of reward?

They promote behavior through reinforcement Signup and view all the answers

Which brain area produces dopamine, a key component in the reward system?

Ventral tegmental area Signup and view all the answers

What role does ghrelin play in the regulation of hunger?

Triggers hunger Signup and view all the answers

In the context of addiction, what is a key factor that keeps individuals motivated to continue behaviors like gambling?

Unpredictable rewards Signup and view all the answers

What happens to leptin levels in individuals with anorexia by the time of treatment?

They are extremely low compared to healthy controls Signup and view all the answers

Which hormone communicates with the hypothalamus to influence appetite suppression?

Insulin Signup and view all the answers

What primarily underpins the reinforcement learning associated with addiction?

Association between cues and rewards Signup and view all the answers

What are the consequences experienced by Randy Gardner after prolonged sleep deprivation?

Mood swings and hallucinations Signup and view all the answers

Which of the following describes the relationship between physical stimulus, physiological response, and sensory experience?

Physiological response mediates the sensory experience Signup and view all the answers

Which of the following is NOT considered one of the five classic senses?

Proprioception Signup and view all the answers

Which taste sensation is primarily associated with detecting the presence of spoiled food?

Sour Signup and view all the answers

What is the correct order of the gustatory pathway from taste buds to the brain?

Taste Buds → Facial Nerve + Glossopharyngeal Nerve → Medulla Oblongata → Thalamus Signup and view all the answers

Which physical mechanism characterizes the sensation of 'itch'?

Pressure applied to pain receptors Signup and view all the answers

What is a common misconception regarding taste maps on the tongue?

Different areas of the tongue sense only specific tastes Signup and view all the answers

Which type of sensory neuron is responsible for sending impulses to the central nervous system?

Sensory afferent neurons Signup and view all the answers

What did Galen believe the role of the ventricles in the brain was?

They were the seat of intellect. Signup and view all the answers

Which lobe of the brain is primarily responsible for processing visual information?

Occipital lobe Signup and view all the answers

What does the motor cortex control?

Voluntary movements of the body Signup and view all the answers

What are the primary functions of the limbic system?

Motivation, emotion, learning, and memory Signup and view all the answers

How is the concept of phrenology best described?

It established that brain function is localized but used incorrect methods. Signup and view all the answers

The role of the hippocampus is primarily associated with which of the following?

Creating new memories and integrating them. Signup and view all the answers

What is the main function of the amygdala?

Processing emotions, particularly fear and aggression. Signup and view all the answers

What is the main purpose of the pineal gland?

To secrete melatonin and regulate circadian rhythms. Signup and view all the answers

Which part of the brain is responsible for life-sustaining functions such as breathing and heartbeat?

Brainstem Signup and view all the answers

What aspect of memory is specifically tied to the hippocampus?

Episodic memory and contextual information Signup and view all the answers

Which of the following statements about the corpus callosum is true?

It connects the two hemispheres of the brain. Signup and view all the answers

Which component of the parietal lobe is primarily associated with touch perception?

Sensory cortex Signup and view all the answers

What is a primary characteristic of the brain's hemispheres?

They have specialized abilities for different functions. Signup and view all the answers

Which condition can result from issues with the brain's ventricles?

Hydrocephalus Signup and view all the answers

Study Notes

Brain Organization: History

Galen believed the heart produced “animal spirits” that flowed through the ventricles and were responsible for movement and sensation
Descartes proposed that reflexes were caused by sensory stimulation triggering valves in the ventricles to release animal spirits into hollow nerves, causing movements
Phrenology, developed by Franz Joseph Gall, proposed that the cerebral cortex is functionally specialized, with size correlating to function
While phrenology had the right theory but wrong methods, it influenced the study of brain localization in the mid 1800s

Cerebral Hemispheres & Cortex

The brain is divided into two hemispheres, controlling the opposite sides of the body (contralateral control).
The hemispheres are connected by the corpus callosum, composed of white matter tracts containing myelinated axons.
Hemispheres have specialized abilities despite being functionally symmetrical.
The cerebral cortex, responsible for complex processes, contains approximately 20-23 billion neurons and over 100 connections each.

Cerebral Lobes

Occipital lobe: Processes visual information
Parietal lobe: Processes information about body senses, including touch and spatial awareness.
Temporal lobe: Processes auditory information, language (Wernicke's area), and memory.
Frontal lobe: Responsible for planning, judgment, memory, reasoning, abstract thinking, movement (motor cortex).

Sensory & Motor Cortex

The sensory (somatosensory) cortex is located in the front of the parietal lobe and represents the body topographically, with larger areas dedicated to more sensitive body parts.
The motor cortex, located at the back of the frontal lobe, also represents the body topographically, with larger areas dedicated to regions requiring precise control.

Basal Ganglia

Receives input from the cerebral cortex and outputs to motor centers in the brainstem.
The striatum is involved in posture and movement control.
Plays a role in habit formation.

Limbic System

Made up of the hippocampus, amygdala, and hypothalamus
Responsible for motivation, emotion, learning, and memory.
The hippocampus creates new memories and integrates them into a knowledge network.

Episodic Memory

Involves conscious recollection and contextual information.
Automatically captures information without requiring intentional effort from the hippocampus.
Memories are protected from interference, enabling storage of highly similar episodes without hindering one another.

Emotion & Amygdala

Emotion is the affective aspect of consciousness, involving visceral physiological responses.
Emotion has adaptive benefits, such as the fight-or-flight response, better decision-making, and enhanced social interactions.
The amygdala, located on the tip of each hippocampus, plays a central role in emotional processes, especially fear and aggression.
It significantly contributes to the formation of emotional memories, attaching significance to events associated with fear, punishment, or reward.

Brainstem

Essential for life-sustaining functions.
Pons: Controls sleep, respiration, swallowing, bladder function, hearing, equilibrium, taste, eye movement, facial expressions, facial sensation, and posture.
Medulla: Controls heartbeat and breathing.
Reticular formation: Regulates sleep, wakefulness, and arousal levels.

Ventricles

Contain cerebrospinal fluid (CSF) to cushion the brain and spinal cord.
Hydrocephalus, a condition where CSF buildup occurs, can result in headaches, head enlargement, learning disability, short-term memory loss, and motion and visual problems.

Pineal Gland

Descartes considered it the “seat of the soul.”
Unlike other brain structures, it is not split in half, leading to the metaphor of the "third eye."
Secretes melatonin to regulate circadian rhythms.

Limbic System Structures & Functions

Amygdala: Processes threat and emotions.
Hippocampus: Manages memory.
Hypothalamus: Regulates the four F's: fighting, fleeing, feeding, and sexual activity.

Hormones vs. Neurons

Hormones travel slowly through the blood, have broad targets, and long-lasting effects.
Neurons have rapid, localized, and short-lived electrochemical action potentials.

Endocrine System

A communication system that influences thoughts and behaviors.
Consists of:
- Pineal gland
- Thyroid gland
- Parathyroid gland
- Adrenal glands
- Gonads
- Hypothalamus
- Pituitary gland
- Thymus
- Pancreas

Endocrine System & CNS

Hormone release is controlled by the hypothalamus and pituitary gland.
Based on neural activation, the hypothalamus secretes releasing factors (e.g., GHRH) that trigger the pituitary gland to release specific hormones (e.g., GH).
These hormones then travel to endocrine sites throughout the body, influencing various functions.

Pituitary Gland

The "master gland" of the endocrine system.
Receives hormone signals from the hypothalamus and sends signals to other glands to regulate stress, digestion, and reproduction.
Anterior pituitary: Produces GH, ACTH, TSH, FSH, LH, and prolactin.
Posterior pituitary: Stores hormones produced by the hypothalamus (ADH and oxytocin).

HPA Axis

Hypothalamic-pituitary-adrenal axis regulates the stress response (fight/flight).
Functions using negative feedback, where output reduces upstream effects.

Neuroplasticity

Refers to the brain's ability to change neural pathways and synapses due to modifications in behavior, environment, neural processes, thinking, emotions, and injury.
The brain exhibits a high degree of neuroplasticity, enabling it to maintain function even after losing parts.

Examples of Neuroplasticity

Parkinson's disease: Neurodegenerative disorder characterized by loss of dopamine cells in the substantia nigra, resulting in movement disturbances and cognitive deficits.
Savantism: An "island of ability" contrasting with general disability, involving exceptional skills in specific areas such as calendar calculation, music, math, art, mechanical skills, or mnemonism.

Savantism: Kim Peak

Despite an overall IQ of 87, Peak demonstrated remarkable abilities in memory, reading, music recall, and had several neurological abnormalities.

Biological Basis of Savantism

While no single theory explains all types of savantism, research focuses on how brain damage can lead to unexpected changes (paradoxical functional facilitation), resulting in increased performance.

Why We Aren't All Geniuses: Extrinsic Motivation & Reward

People are driven to satisfy needs for competence and personal control.
Extrinsic rewards can undermine intrinsic motivation.
Primary needs (Maslow's Hierarchy) take precedence over secondary needs.

Reward Pathways in the Brain: Dopamine

Ventral tegmental area (VTA): Produces dopamine.
Nucleus accumbens (NAcc): Receives dopamine from the VTA and processes reward.
Prefrontal cortex (PFC): Links rewards to actions.

Reward and Addiction

Drugs like cocaine, amphetamine, opium, and heroin affect brain reward systems, reinforcing learning between environmental cues and drug-related feelings and behaviors.
Social media and gambling can also be addictive due to their unpredictable reward structures, triggering dopamine release and encouraging continued engagement.

Motivations for Eating: Hypothalamus & Hormones

The hypothalamus plays a crucial role in eating by regulating hunger and satiety signals.
Insulin: Regulates hunger and eating by decreasing blood glucose and suppressing appetite.
Ghrelin: Triggers hunger.
Leptin: Regulates fat storage.

Eating Signals Gone Awry

In anorexia, leptin levels are significantly low compared to age and BMI matched controls.
Treatment leads to disproportionate increases in leptin levels as weight is restored.

Sleep Deprivation

Chronic sleep deprivation can result in mood swings, hallucinations, paranoia, memory and attention lapses, slurred speech, difficulty reading and using hands.

Sensory Processes

General sensory processes involve:
- Physical stimulus: Energy influencing the body
- Physiological response: Chemical or electrical activity within the body.
- Sensory experience: Subjective sensation.

Senses

5 Classic senses: Touch, sight, sound, smell, taste
Other senses: Proprioception, vestibular/gravity, tension/stretch, chemoreceptors, time.

Types of Touch Senses

Pressure, temperature, pain, itch.
Some sensations are combinations: Wet = cold + pressure, tickle = light touch receptor stimulation, itch = light pain receptor stimulation, searing heat = cold receptors followed by warmth.

Sensor Mapping

- Fingertips and the front of the hand have more sensory receptors than the back of the hand and forearm, reflected in the homunculus representation.
- Sensory neurons have specialized endings that connect to the outside world, detecting mechanical stimuli and sending signals to interneurons.
-  **SAME mnemonic:** In sensory pathways, afferent neurons carry signals to the central nervous system, while efferent neurons carry signals to muscles and glands.

Taste Sensations

6 tastes: Sweet, sour, bitter, salty, umami, fat.
These sensations have evolutionary functions:
- Sweet & Fat: Calories for energy
- Sour: Protection from toxic acids, spoiled foods, unripe fruits.
- Umami: Taste of protein.
- Bitter: Indicator of potential poison or safety.
- Salty: Sodium is essential for physiological processes.

Physiology of Taste

Food is dissolved in saliva, allowing taste receptors in taste buds to sense specific flavors.
Taste maps are a myth; all six tastes can be sensed by receptors all over the tongue.

Gustatory Pathway

The human mouth has ~5,000-10,000 taste buds evenly distributed over the tongue.
Each taste bud contains 50-100 taste receptor cells.
1. Taste buds
2. Facial nerve + Glossopharyngeal nerve
3. Medulla oblongata
4. Thalamus
5. …

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Description

Explore the historical perspectives and current understanding of brain organization. This quiz covers key concepts from early theories of brain function to modern insights on the cerebral hemispheres and cortex. Test your knowledge on how these foundational ideas have shaped neuroscience today.