Neuroscience
# Lecture Summary
Subject: Behavioral Neuroscience: Disciplines, Divisions, and the Scientific Method
## Key Learning Points
- Neuroscience focuses on brain-behavior relationships, including the structures of the nervous system, their functions, and how those structures produce behavior.
- The terms biopsychology, psychobiology, neuroscience, and behavioral neuroscience are used largely synonymously in this course, although neuroscience is the broader term.
- Neuroscience is multidisciplinary and interdisciplinary, incorporating several major disciplines:
- Neuroanatomy
- Neurophysiology
- Neurochemistry
- Neuropharmacology
- Neuroendocrinology
- Neuropathology
- Behavioral neuroscience is divided into several research approaches, including:
- Physiological psychology
- Psychopharmacology
- Neuropsychology
- Psychophysiology
- Cognitive neuroscience
- Comparative psychology
- The scientific method is especially important in physiological psychology because it is used to establish cause-and-effect relationships.
- Scientific experiments identify and manipulate independent variables, measure dependent variables, and control confounding variables.
- Physiological psychology generally manipulates the nervous system, often using animal models, to study effects on behavior.
- Neuropsychology often examines humans with naturally occurring brain damage using quasi-experimental methods and case studies.
- Psychophysiology measures physiological changes in humans, such as heart rate, respiration, perspiration, EEG activity, and eye movements, and uses them to infer internal states.
- Cognitive neuroscience uses brain-imaging methods such as functional MRI to study brain activity during cognitive tasks.
- Comparative psychology examines similarities across species to help explain human brain-behavior relationships.
- No single division is universally “best.” The appropriate approach depends on the research question, and researchers often use converging operations—multiple methods and disciplines that provide overlapping evidence.
- The lecture also reviewed how to use the lecture notebook and clarified Top Hat review-question deadlines.
## Definitions
- Neuroscience: The broad, multidisciplinary study of the nervous system, especially its structure, function, and relationship to behavior.
- Behavioral neuroscience: The study of how the nervous system produces behavior, particularly through brain-behavior and structure-function relationships.
- Biopsychology/Psychobiology: Terms used largely synonymously with neuroscience and behavioral neuroscience in this course.
- Neuroanatomy: The study of the structures and parts of the nervous system.
- Physiology: The scientific study of bodily functions or the functional aspects of an organism.
- Neurophysiology: The study of how the nervous system functions, including the functioning of individual neurons, circuits, and brain areas.
- Neurochemistry: The study of chemical reactions in the nervous system, including the synthesis and breakdown of chemical signals such as neurotransmitters.
- Neuropharmacology: The study of how substances, including drugs, affect the functions of the nervous system.
- Neuroendocrinology: The study of the relationship between the endocrine system, its glands, and nervous-system functioning.
- Neuropathology: The study of nervous-system dysfunction and what happens when neural systems go wrong.
- Physiological psychology: A division of behavioral neuroscience that directly manipulates the nervous system, usually to study cause-and-effect relationships involving behavior.
- Pure research: Research intended to identify basic mechanisms and understand how a system works, without necessarily focusing on an immediate practical application.
- Applied research: Research intended to address practical problems or improve human welfare.
- Scientific method: A systematic approach to developing and testing hypotheses, especially through controlled experiments.
- Independent variable: The variable manipulated by the investigator.
- Dependent variable: The variable measured by the investigator.
- Confounding variable: Any variable other than the intended independent variable that could influence the dependent variable.
- Hypothesis: A testable prediction about the relationship between variables.
- Lesion: Damage to or destruction of a specific area of nervous tissue, often used experimentally to examine that area’s function.
- Psychopharmacology: The study of how substances affect behavior.
- Neuropsychology: The study of brain-behavior relationships, often through human subjects who have naturally occurring brain damage.
- Quasi-experimental design: A research design in which the researcher studies preexisting groups or naturally occurring conditions rather than randomly assigning or directly manipulating the critical condition.
- Case study: An in-depth investigation of one person or one subject, often used to study unusual patterns of brain damage and behavior.
- Psychophysiology: The study of physiological changes associated with psychological states or behaviors.
- Sympathetic nervous system: The “fight or flight” component of the nervous system that prepares the body to respond to environmental threats.
- Cognitive neuroscience: The study of brain activity associated with cognitive processes, often using imaging techniques such as functional MRI.
- Comparative psychology: The study of similarities and differences across species to understand behavior and nervous-system functioning.
- Converging operations: The use of multiple research methods or divisions to investigate the same question and determine whether they produce overlapping explanations.
## Detailed Topic Notes
### Neuroscience and Brain-Behavior Relationships
The lecture began by distinguishing psychology, neuroscience, and behavioral neuroscience. Neuroscience focuses on brain-behavior relationships, including structure, function, and the relationship between the two. Researchers may study the nervous system at several levels:
- The cellular or molecular level
- The circuit level
- The behavioral level
Behavioral neuroscience is especially concerned with how the nervous system produces behavior. The terms biopsychology, psychobiology, neuroscience, and behavioral neuroscience will be used more or less synonymously throughout the course. Neuroscience is the broadest term because it includes many different disciplines and research approaches.
### Major Disciplines Within Neuroscience
Because neuroscience examines both nervous-system structures and their functions, it requires multiple specialized disciplines. These disciplines overlap, making neuroscience both multidisciplinary and interdisciplinary.
#### Neuroanatomy
Neuroanatomy applies anatomy specifically to the nervous system. It focuses on identifying the parts and structures of the nervous system, including large brain regions such as:
- The frontal lobe
- The cerebellum
- The hippocampus
- Different types of cells
Neuroanatomy is primarily concerned with what structures exist and where they are located.
#### Neurophysiology
Neurophysiology applies physiology to the nervous system. It examines how nervous-system structures function. This can involve studying:
- How individual neurons work
- How neural circuits function
- How specific brain areas operate
- How neural activity contributes to behavior
The distinction between neuroanatomy and neurophysiology is that anatomy focuses on the structures themselves, while physiology focuses on how those structures function.
#### Neurochemistry
Neurochemistry studies the chemical reactions that occur in the nervous system. Neurotransmitters are one major example of the chemical signals examined in this field.
Neurochemistry may ask questions such as:
- How are neurotransmitter molecules synthesized?
- What chemical reactions produce them?
- How are neurotransmitters broken down?
- How are neurotransmitters inactivated?
The lecture indicated that anatomy will be discussed primarily in Chapter 3, while physiology and neurochemistry will be covered largely in Chapter 4.
#### Neuropharmacology
Neuropharmacology is closely related to neurochemistry but focuses on how substances affect nervous-system functioning. These substances can include both licit and illicit drugs.
Examples mentioned in the lecture included:
- Prozac
- Fentanyl
- Alcohol
- Potentially vitamins or Tylenol, although these were not expected to receive much attention
For example, neuropharmacology could investigate how Prozac produces its effects as an antidepressant medication. It could also examine where fentanyl acts in the nervous system and how it affects specific brain areas or cellular structures.
#### Neuroendocrinology
Neuroendocrinology examines the relationship between the endocrine system and the nervous system. The endocrine system includes glands, particularly the testes and ovaries, and the field studies how endocrine functioning relates to nervous-system activity.
The course will spend approximately one chapter on neuroendocrinology.
#### Neuropathology
Neuropathology focuses on what happens when the nervous system malfunctions or becomes damaged. Although much of the final unit will be devoted to neuropathology, neuropathological concepts will be applied throughout the course.
For example, when neural signaling and neural activity are introduced, multiple sclerosis will provide a neuropathological perspective on neurophysiology. Later in the course, the class will examine disorders such as:
- Huntington’s disease
- Parkinson’s disease
- Schizophrenia
The relevant questions will include what brain changes and dysfunctions occur in these conditions.
### Divisions of Behavioral Neuroscience and Physiological Psychology
The lecture then shifted from broad neuroscience disciplines to divisions of behavioral neuroscience. These divisions describe different research approaches and, in some cases, different techniques.
#### Physiological Psychology: Direct Manipulation of the Nervous System
Physiological psychology involves directly manipulating the nervous system, usually to determine cause-and-effect relationships. Because direct manipulation of the nervous system raises serious ethical concerns in humans, physiological psychology often uses animal models.
Animal models may include:
- Rodents
- Fish
- Sea slugs
- Other laboratory organisms
Animal studies allow researchers to perform more invasive procedures than would be ethically acceptable in humans. However, animal research is governed by federal, state, local, and institutional laws and regulations. The central ethical principle is that any distress experienced by the animal must be outweighed by the benefit gained from a better understanding of the research question. Animal research therefore involves a cost-benefit analysis.
Physiological psychology often focuses on pure research. A researcher may want to understand a basic mechanism, such as how a brain system works or what a particular brain structure does. For example, a pure physiological-psychology study might investigate which brain area is involved in the effects of Prozac.
Physiological psychology adheres closely to the scientific method and generally involves true scientific experiments. These experiments are designed to establish if-then relationships:
- If condition A occurs, then outcome B should result.
- If condition A does not occur, then a different outcome should result.
To establish such relationships, researchers manipulate an independent variable and measure a dependent variable while controlling for other possible influences.
#### Example: Hunger and Maze Learning
The lecture used the example of studying the effect of hunger on a rodent’s cognitive ability or maze-learning ability.
In this example:
- The researcher could deprive a group of rodents of food for 12 hours.
- Food deprivation would be the independent variable because it is manipulated by the experimenter.
- The researcher could then measure how long the animals take to run a maze or how accurately they complete it.
- Maze-running ability or maze-learning performance would be the dependent variable because it is measured.
The researcher must ensure that any differences in maze performance are caused by hunger rather than another factor. Possible confounding variables could include:
- Time of day
- Whether the animal has recently eaten
- Amount of sleep
- Stress
- A looming deadline or other contextual factor in human research
- Being startled immediately before the test
For example, startling a rodent immediately before it runs the maze could affect its performance. Because the startle response was not the variable being studied, it would be a confounding variable. Researchers attempt to control such variables so that the dependent variable can be attributed to the intended manipulation.
#### Example: The Hippocampus and Spatial Navigation
The lecture presented a hypothesis that the hippocampus is important for spatial navigation. The hippocampus was identified as a brain structure located toward the top of the rodent brain shown in the lecture image.
A physiological-psychology experiment could proceed as follows:
1. Formulate the hypothesis that the hippocampus is required for spatial navigation.
2. Inactivate, lesion, or otherwise destroy the hippocampus in an experimental group of rodents.
3. Leave the hippocampus intact in an unlesioned control group.
4. Test both groups on their ability to learn and navigate a maze.
5. Compare the performance of the two groups.
If the animals with hippocampal lesions have difficulty learning the maze while the control animals learn it successfully, the results are consistent with the hypothesis that the hippocampus is necessary for spatial navigation.
The conclusion would be that the hippocampus is required for the spatial-navigation ability being tested. This example illustrates how manipulating a neural structure and measuring behavior can produce a cause-and-effect explanation.
The terminology can also be understood by separating the root term from the modifier:
- Psychology is the scientific study of behavior.
- Physiological, as a modifier, indicates that a physiological or neural mechanism is manipulated.
- Physiological psychology therefore examines behavior after modifying a mechanism in the nervous system.
### Psychopharmacology
Psychopharmacology examines how substances affect behavior. The lecture distinguished it generally from neuropharmacology:
- Neuropharmacology asks how a substance affects brain or nervous-system function.
- Psychopharmacology asks how a substance affects behavior.
The two terms overlap, and the course will make more specific distinctions later.
The lecture used fentanyl as an example. Psychopharmacology could examine how repeated administration of a substance causes continued seeking and use of that substance. It could also investigate the substance’s effects on behavior, including addiction and abuse potential.
Psychopharmacological research can be either pure or applied.
A pure research question might ask:
- Where does fentanyl bind?
- What structures or cellular entities does it attach to?
- What areas of the nervous system are affected?
An applied research question might ask:
- How does fentanyl produce pain relief?
- How does it produce abuse potential?
- What mechanisms are important for treating substance use and addressing the opioid epidemic?
The lecture emphasized the serious consequences of opioid use, noting that approximately 100,000 people in the United States die every year because of opioids.
### Neuropsychology
Neuropsychology generally studies human subjects who have experienced naturally occurring brain damage. Brain damage may result from:
- A stroke
- An accident
- Another medical or traumatic event
Neuropsychological research is frequently non-experimental because researchers cannot ethically manipulate brain damage in human participants. Instead, they compare people who have damage to a specific brain region with people who do not have that damage.
For example, researchers might compare:
- A group of people who experienced a stroke in a particular brain area
- A group of people without damage to that area
If the two groups differ in a particular behavior, researchers may conclude that the damaged region is important for producing that behavior. However, because the researcher did not randomly assign participants to receive brain damage, the design is quasi-experimental rather than a true experiment.
#### Example: Chronic Traumatic Encephalitis in NFL Players
The lecture discussed a recently published study on the prevalence of CTE, identified in the lecture as chronic traumatic encephalitis, among NFL players.
The study examined brains from approximately 1,000 NFL players who had died between approximately 2006 and 2011. Researchers were able to examine the brains of about 300 of these players. Almost all of the examined brains showed the pathology associated with CTE.
The findings suggested that at least 1 out of 4 NFL players may develop CTE at some point in life. The players whose brains were examined had died at very different ages, ranging from approximately 27 to 80 years old.
The lecture emphasized an important limitation: the researchers did not examine the entire sample. Since only about 300 brains were available for examination, the actual prevalence could be higher or lower. The study is quasi-experimental because the researchers examined brain pathology after the injuries and other events had already occurred. They did not experimentally induce concussions or CTE.
#### Case Studies
Case studies are another approach in neuropsychology. A case study examines a single person or subject in depth. Because there may be no control group, researchers must consider how broadly the findings can be generalized.
### Case Study: Phineas Gage
One of the most famous case studies in neuroscience is Phineas Gage, a railroad worker in the 1800s.
Gage was a railroad foreman responsible for managing workers and completing construction tasks on schedule. During an accident while blasting rock, a roughly 6-foot iron rod passed through his skull. The rod entered underneath his eye and exited through the top of his head.
Despite the severity of the injury and the limited medical knowledge of the time, Gage survived. His physician prevented infection and recorded observations of his behavior over time.
#### Behavior Before the Accident
Before the accident, Phineas Gage:
- Served as a railroad foreman
- Managed other workers
- Had substantial responsibility
- Could organize projects
- Could keep work on schedule
- Could sequence events and resources to achieve goals
#### Behavior After the Accident
After the accident, Gage showed major changes in behavior and executive functioning. He had difficulty:
- Making decisions
- Keeping activities on schedule
- Organizing sequences of events
- Completing projects
- Managing people and resources
- Working toward a goal without becoming sidetracked
He also became crude and socially inappropriate, including using foul language in front of women, which was considered especially inappropriate during that period.
Importantly, his intelligence remained intact. The injury did not appear to eliminate his general intelligence, but it significantly affected planning, decision-making, social behavior, and other higher cognitive functions.
The physician summarized the behavioral change by stating that “Gage is no longer Gage.”
The case study suggested that the frontal lobes are important for complex higher-order abilities such as:
- Planning ahead
- Organizing behavior
- Working through problems step by step
- Avoiding distractions
- Managing people and resources
- Completing long-term goals
- Regulating socially appropriate behavior
Because Phineas Gage was a single case, researchers initially had to consider whether he was an unusual exception. However, his case became historically important because it led to more than 150 years of research examining the role of the frontal lobes in these functions.
### Psychophysiology
Psychophysiology differs from physiological psychology in what is measured and how the nervous system is studied.
Physiological psychology generally:
- Manipulates a neural mechanism
- Measures behavior
- Often uses animal models
- May involve invasive procedures
Psychophysiology generally:
- Measures physiological changes
- Often studies humans
- Uses procedures that can be conducted in a clinical or laboratory setting
- Does not directly manipulate or destroy brain tissue
The physiological changes measured may include responses associated with the sympathetic nervous system, also known as the fight-or-flight system. When a person encounters a threat, this system can alter:
- Heart rate
- Respiration
- Perspiration
- Muscle tension
- Other physiological responses
Researchers can use these changes to infer an internal psychological state. For example, if a person encounters a snake and shows increased muscle tension, heart rate, and respiration, those physiological responses may indicate fear.
Other psychophysiological measures include:
- EEG activity
- Eye movements
- Other measurable physiological components
The lecture used lie-detector techniques as an example. In a film involving Robert De Niro and Ben Stiller, De Niro’s character connects Stiller’s character to a device while asking invasive questions. Lie-detector methods rely on psychophysiological principles by measuring physiological reactions and using them to infer internal states such as stress or deception.
However, psychophysiological measures have limitations. A person’s heart rate may increase, but the researcher still needs to interpret what caused that change. The participant might also lie about what they are feeling. Thus, physiological measurements do not automatically provide a complete or certain explanation of psychological states.
### Cognitive Neuroscience
Cognitive neuroscience examines the neural mechanisms involved in cognition. It often uses imaging techniques, including functional MRI, or fMRI.
With fMRI, researchers can examine which brain areas become more or less active while people perform particular cognitive tasks. Results may be represented using different colors:
- Red areas may indicate greater activity under one task condition.
- Blue areas may indicate greater activity under another condition.
- Some regions may become more active while others become less active.
Because fMRI allows researchers to study living humans non-invasively, it is useful for investigating the neural mechanisms involved in cognition.
The lecture noted that complex cognitive tasks, especially tasks requiring people to switch strategies, often activate the frontal lobes. This finding converges with the Phineas Gage case study: damage to the frontal lobes was associated with impaired planning, sequencing, decision-making, and goal-directed behavior, while fMRI research shows frontal-lobe activity during complex cognitive tasks.
### Comparative Psychology
Comparative psychology examines similarities and differences across species. The comparative approach is based on the idea that living organisms share important biological characteristics.
One example is DNA. Humans and other organisms, including:
- Fruit flies
- Fish
- Mice
- Sea slugs
use the same fundamental DNA building blocks:
- A
- G
- C
- T
Although species differ considerably in their nervous systems, comparing them can reveal shared mechanisms and processes. Fruit flies and sea slugs do not have a brain in the same sense as humans, fish have a simpler brain, and rodents have more developed brains. Nevertheless, studying neural mechanisms across these organisms can help researchers understand human behavior.
When researchers find that a mechanism, brain area, or nervous-system process is similar across species, that similarity can inform theories about human brain-behavior relationships.
### Strengths, Limitations, and Converging Operations
The lecture concluded that none of the six divisions is automatically the best approach. The appropriate method depends on the research question.
Each approach has strengths and weaknesses:
- Physiological psychology allows researchers to directly manipulate brain tissue and study cause-and-effect relationships, but it raises ethical challenges and may require animal research.
- Psychophysiology allows researchers to measure physiological responses in humans, but physiological changes may be difficult to interpret and participants may not accurately report their internal states.
- Neuropsychology provides valuable information from naturally occurring brain damage, but researchers cannot experimentally assign brain injuries and therefore cannot establish causation as directly.
- Case studies provide detailed information about individual people, but it may be difficult to generalize from one person.
- Cognitive neuroscience allows non-invasive study of living human brains during cognitive tasks, but observed brain activity must still be interpreted in relation to behavior.
- Comparative psychology allows researchers to study shared biological mechanisms across species, but species differences must be considered when applying findings to humans.
The principle of converging operations involves using multiple approaches to investigate the same brain-behavior relationship. If different methods produce compatible findings, they provide stronger support for a particular explanation.
For example:
- A case study such as Phineas Gage suggests that the frontal lobes are important for planning and complex behavior.
- fMRI studies show that the frontal lobes become active during complex cognitive tasks.
- These findings come from different methods but converge on a similar explanation.
Researchers collaborate across and within disciplines to identify the most reliable explanations of nervous-system structure and function.
### Course Organization and Lecture Materials
At the end of the lecture, the instructor checked whether students could follow the lecture notebook. The instructor indicated that the notebook format appeared to be working as intended and that the materials would remain marked as reviewed.
The lecture content also connected different topics to future chapters:
- Neuroanatomy will be discussed in Chapter 3.
- Physiology and neurochemistry will be discussed largely in Chapter 4.
- Neuroendocrinology will receive approximately one chapter.
- Neuropathology will be emphasized in the final unit, while also being incorporated throughout the course.
- Neural signaling and neural activity will begin to be discussed in approximately one week.
## Questions and Answers Highlights
### Q&A Session 1 (Topic: Course Materials and Top Hat Assignments)
Q: How should students use the lecture notebook and the associated Top Hat review questions? — Source: Student/Instructor discussion
A: Students should follow along with section 1.1 during class and complete the corresponding 1.1 review questions as soon as possible after class. The review questions are coded according to their lecture section, such as “1.1” and “review questions 1.1.”
The instructor initially set specific homework due dates but later changed them because of how Top Hat handles grades after a due date. After the due date, Top Hat does not allow students to earn points. The review quizzes were therefore given deadlines extending until the night before the first exam.
Key Insight: The section labels in the lecture notes and Top Hat assignments are intended to correspond directly. Completing the review questions soon after each class is recommended even though students have until the stated exam-related deadline.
### Q&A Session 2 (Topic: Pearson REVEL and Extra Credit)
Q: Are the due dates in Pearson REVEL and the extra-credit activities intended to help students stay on track? — Source: Student/Instructor discussion
A: The due dates in Pearson REVEL are intended to help students stay on track. The instructor indicated that the extra credit in REVEL was also intended as a form of soft credit to help students maintain progress. The exact wording of the final exchange was [unclear].
Key Insight: REVEL deadlines function as pacing guidelines, and the extra-credit opportunities may provide additional support while students keep up with course material.
## Exam Callouts
- The instructor stated that the Top Hat review quizzes would remain available until the night before the first exam.
- Students were encouraged to complete each review quiz soon after covering the corresponding lecture section rather than waiting until the exam deadline.
- The hippocampus and its relationship to spatial navigation were used as a central example of hypothesis-driven research and cause-and-effect reasoning.
- The frontal lobes, Phineas Gage’s case, and cognitive neuroscience findings involving complex cognitive tasks were connected through converging operations.
## Action Items and Assignments
- Complete the Top Hat review questions for each lecture section - Due: The night before the first exam - Related to: Corresponding lecture sections, including section 1.1.
- Complete the 1.1 review questions after class - Due: As soon as possible after class; the broader deadline extends until the night before the first exam - Related to: Neuroscience disciplines, divisions of behavioral neuroscience, and the scientific method.
- Use the Pearson REVEL due dates to stay on track - Due: According to the dates listed in REVEL - Related to: Course reading and review activities.
- Complete available REVEL extra-credit activities - Due: According to the dates listed in REVEL - Related to: Maintaining progress in the course.