L12&13 brain development, emotions and stress

Lecture 12: the brain and neural development

·      What is the neural tube? When it first forms, what are the 3 main vesicles? The Neural tube is a structure that becomes the spinal cord and the brain. Its 3 main vesicles are Prosencephalon, Mesencephalon, and the Rhombencephalon

·      The 3 vesicles of the neural tube change into 5 secondary vesicles by week 5 of gestation. Explain this process, being sure to describe which of the 3 vesicles split (and into what secondary vesicles they split into) versus which do not.  The secondary vesicles are the telencephalon, diencephalon from the Prosencephalon. The Mesencephalon does not split. The Rhombencephalon splits into the Metencephalon and the Myelencephalon.

·      Be able to label the neural tube figure below:

1.   Telencephalon  2. Diencephalon  3. Mesencephalon  4. Metencephalon 5.  Myelencephalon

·      What are the 3 main parts of the brainstem (hint: we discussed this way back in lecture 2 but the crash course video from this lecture can help you find the answer quickly)? What kinds of behaviors do these regions regulate?  -The 3 main parts of the brainstem are the Midbrain, Pons, and medulla. These regions regulate breathing, heartrate, and sleep.

·      Why did we evolve wrinkles on our brain? What are those grooves and wrinkles called? (hint: the crash course video discussed this). The ridges are called gyri and the grooves are called sulci they increase the surface area for higher processing.

·      What divides the two cerebral hemispheres, allowing them to communicate with each other? They communicate with the Copus Callosum.

·      What 3 cells can neural progenitor cells become? They can become neurons, astrocytes, oligodendrocytes.

·      How does radial neuronal migration work? In your response, be sure to name any specific cell types that play a role & describe what this process is. Radial migration is when neurons travel along radial glial cells from the inner to outer layers of the brain.

·      Name two similarities and two differences between a hormone and a neurotransmitter. Give an example of one hormone and one neurotransmitter that is important for feeding or sexual behavior. After listing the hormone/neurotransmitter, in one sentence describe its role.  Two similarities are that they both affect target cells, and they both influence behavior, mood, and bodily function. Two differences are that Neurotransmitters act across synapses and Hormones travel through the bloodstream. Two examples are the hormone Leptin to signal the brain to reduce appetite and the Neurotransmitter Dopamine which promotes motivation and reward.

·      Be able to define the following terms:

o   Neurogenesis the birth of new neurons

o   Neural progenitor cell can become neurons, astrocytes, or oligodendrocytes

o   Differentiation is when a cell specializes in a specific type

o   Specialization is when a cell develops a specific structure and function

o   Synapse a gap between two neurons where they are able to communicate

o   Synaptogenesis is the formation of new synapses

o   Pluripotent can become many cell types

o   Human embryonic stem cell  is a pluripotent cell found in early embryos that can develop into any type of cell in the body

o   Induced pluripotent stem cell  is a normal adult cell like a skin cell that has been reprogramed in a lab to act like a embryonic stem cell.

·      True or False: Studies in rodents suggest that neurogenesis declines with aging True

·      True or False: Studies in rodents suggest that diet, exercise and stress can all modulate neurogenesis  True

·      Regarding the neuron you labeled back for Exam 1, what is its structural type?  Multipolar

·      Regarding the neuron you labeled for Exam 1, what is its functional type ?  Motor Neuron

·      True or False: the brain is finished developing by the time we are born (all neurodevelopment happens in utero).   False

·      In class we discussed 4 factors that can lead to neurodevelopmental disorders. List all 4 factors, then in a few sentences describe evidence for one, using an example of a neurodevelopmental disorder or congenital anomaly discussed in class.  Teratogenesis can create congenital anomalies introduced by exogenous agents, Genetic Predisposition like autism, Genetic Mutation like Down syndrome, and Infection during Pregnancy like zika virus.  

·      True/False: Experiencing a high fever while pregnant can lead to potential risk for congenital anomalies such as neural tube defects.  True

·      True/False: Autism Spectrum Disorder appears to be largely driven by environmental factors. False

Lecture 13: The Neuroscience of Emotions & Stress

·      Are emotions a product of nature or nurture? Give two examples to support your answer. Emotions are considered BOTH. Basic human emotions are present early in life- newborns are able to imitate facial expressions. Emotions also involve characteristic facial responses to positive and negative stimuli like a happy or sad event. Language is also an example of nurture and nature because we are born with the ability to learn language but we need someone to teach us parts of language.

• Who is Paul Eckman? What did he study? What did he contribute to the field? (hint: there is a video link in the slides and on Blackboard). He studied facial expressions and contributed to the understanding that emotions are universal, his findings support the idea that basic human emotions are innate and biologically determined and culturally universal.

• How do emotions affect other cognitive processes? (hint: there are a  few slides about memory and PTSD)  emotions affect other cognitive processes thru the integration of brain structures involved in emotional control like the AMYGDALA and the HIPPOCAMPUS with areas responsible for memory and decision making

• What are the three components of emotion?  PHYSIOLOGICAL (bodily changes and reactions to emotional event), BEHAVIORAL (changes in autonomic nervous system and facial responses to stimuli), COGNITIVE (subjective feelings and mental interpretation)

• What are the three theories on emotions we discussed in class and who is associated with each? (this would be good material for a matching type of question). The James-Lange Theory [body->emotion]. Cannon-Bard Theory [Body & emotion simultaneously] Schachter and Singer Two Factor Theory [body + cognitive label = emotion]

·      What did Schacter-Singer do to test their theory of emotions? (be able to describe their study in detail along with their theory)  They conducted a study that manipulated both the physiological arousal and availability of a cognitive explanation for the arousal. Participants were given adrenaline/epinephrine, that caused increased heart rate. 2 groups: informed group & Uninformed, where they were either told about the effects or not told. Then they were placed in a room with someone acting in a certain way (happy or angry). All participants experienced a reaction.

·      What are the 6 neuroanatomical structures we discussed as being part of the “limbic system”?        1. Medial Prefrontal Cortex (MPFC), 2. Ventral Basal Ganglia, 3. Mediodorsal nucleus of the thalamus, 4. Amygdala 5. Para hippocampal Gyrus, 6. Cingulate Cortex

·      What brain areas are involved in (1) formation of emotions and (2) regulating those emotions? (hint: you should name one brain region for (1) and one for (2)). The Amygdala is part of the Limbic System which is responsible for emotional control (1). The prefrontal cortex is important for self-regulation and decision making (2)

·      What does the term “lateralization” mean when it comes to neuroanatomy? When specific cognitive/ functional processes are mostly handled by one side (hemisphere) of the brain over the other.

• What is a stressor? Explain in terms of homeostasis disruption. A stressor disrupts the body’s equilibrium so the body tries to return to homeostasis.

• What is Selye’s GAS (what does that abbreviation stand for and what is the general principle it explains?)? GAS stands for general adaptation syndrome. It refers to the prolonged stress and the activation of the hypothalamic Pituitary adrenal axis (HPA). What does the body cope with a stressor. The 3 phases are: 1. Alarm reaction. 2. Resistance phase. 3. Exhaustion phase.

• Why (evolutionarily) might we have adapted a stress response? That is what’s the benefit of having a fight-or-flight reaction? Having a stress response is the bodies way of trying to escape the stressor with fight or flight to decide the best action to take to return to homeostasis.

• How can having a stress response be a bad thing? (hint: to answer, think about Robert Sapolsky’s book… we also talked about lots of effects of chronic stress on both physiological and psychological well-being) Robert Sopolsky noted that a stress response is adaptive in the short term and becomes maladaptive when the stress is prolonged. The body’s systems aren’t designed to run for long periods of time, some effects are breakdown of bodily systems, cardiac problems, digestive problems. It can also lead to psychological effects like brain toxicity and issues in memory.

• Which nucleus of the hypothalamus is important for stress? The Paraventricular Nucleus (PVN)

• Larger point writing question: What is the normal stress response? How does the HPA axis work? Be sure to describe relevant brain areas and hormones involved (at least named by their abbreviations). Know the order of events (there is a slide that walks you through it and a 2-minute neuroscience video) and be specific with regard to regions of the glands/brain areas involved.

• Be able to label the figure below, hint: Blanks 1, 2 and 3 are the glands (1 and 2 are found in the brain and 3 is located above the kidney), and the circled 4, 5 and 6 refer to the hormones those glands secrete.

The normal stress response is a fast reaction for immediate survival followed by slower hormonal cascade HPA axis that manages prolonged stress and the return to homeostasis. The stress response has 2 parts: the Fast component also called the alarm reaction mediated by the sympathetic nervous system, with the Amygdala responding to the adrenal glad creating epinephrine while the Locus Coeruleus makes norepinephrine. Then there’s the slow Component with the HPA axis, this is a hormonal response that applies to prolonged stress and is controlled by the HPA Axis. The HPA axis works by outlining the exact chain of hormonal communication between 3 structures to manage stress. The order of events include Activation with the amygdala, Hypothalamus release with the PVN, Pituitary Stimulation with the Anterior Pituitary gland, Pituitary Release with the pituitary glad, Adrenal Transport though the bloodstream, Adrenal secretion with the Adrenal Cortex, and finally Target action with the Hippocampus. The Whole process is regulated by the negative feedback loop with cortisol binding to the receptors in the Hippocampus sending an inhibitory signal back to the Hypothalamus which shuts down the stress response.

1.     Hypothalamus   2. Anterior Pituitary   3. Adrenal gland  4. CRH  5. ACTH   6. Cortisol

·      What are the two different jobs of the adrenal gland that we discussed in class? Be sure to mention relevant neurotransmitters or hormones secreted.  1. Fast, short term stress response (fight or flight) located in the adrenal medulla, it secretes epinephrine and norepinephrine, it is for the Alarm reaction phase of stress. 2. Slow, Long term stress response (resistance phase) is in the Adrenal Cortex is used for the slow component of stress response that secretes glucocorticoids like cortisol that is stimulated by ATCH from the pituitary glad to increase metabolism.