Intro Neuro Exam 4

What are some examples of brain inputs?

Light, Sound, Taste, Touch, and Smell

What are some examples of brain outputs?

Muscle contraction and hormones

How many pairs of mixed spinal nerves do humans have?

31

What are afferent nerves?

Carry sensory information from the periphery (outside world from skin receptors, etc.) to the CNS (brain)

What are efferent nerves?

Carry information from the CNS/brain to the periphery (PNS)

What is curare? What does this cause

A toxin that blocks the receptors that take up acetylcholine, causing prolonged muscle contraction

How do we know synapses release acetylcholine?

B/c toxins like Curare block receptors that will take acetylcholine, causing prolonged muscle contraction.

What is the function of descending spinal tracts?

They allow the motor cortex to cause muscle contraction?

What is the motor cortex ultimately responsible for?

Initiating all voluntary movements

What is a voluntary movement?

Anything that we decide to to (moving hands, fingers, legs, etc.)

What effect does damage to the motor cortex have on behavior?

Paralysis

What is voluntary movement control regulated through?

The lateral pathway through the spinal cord

Where do motor cortical neurons project directly/indirectly to?

To motor neurons in the spinal cord

What are the two tracts that make up the lateral pathway?

The corticospinal and rubrospinal tracts

What is the lateral pathway?

Pathway involved in voluntary movement of distal muscles

What is the most important component of the lateral pathways?

Corticospinal tract

What is the corticospinal tract?

One of the largest CNS tracts that originate in the motor cortex; **majorly** involved in voluntary movement

What is the rubrospinal tract?

Contributes to motor movement in many other species but in humans it is reduced and most functions are taken over by the corticospinal tract

Where does the corticospinal tract originate?

Motor cortex (areas 4 and 6 of the frontal lobe)

Where does the rubrospinal tract originate?

The red nucleus of the midbrain

What do both the corticospinal and rubrospinal tracts control?

Fine movements of both the arms and fingers

What type of muscle contraction does the lateral pathway control?

Voluntary

What is the function of the ventromedial pathway?

Controls muscles that are involved in maintaining posture, body/eye position and locomotion

Where does the ventromedial pathway originate/what controls it?

Brain stem

What type of muscle control does the ventromedial pathway regulate?

Involuntary movement

What is involuntary movement control regulated through?

The ventromedial pathway through the spinal card

What is the function of the vestibulospinal tract?

Maintains posture, head position, and balance

What is the function of the tectospinal tract?

Coordinates the position and movement of the head and eyes with body movement

During motor planning, what activity preceded the firing of motor cortical neurons?

The activity of premotor and supplementary motor cortical neurons

What is the primary function of the brain?

To receive sensory inputs and generate motor outputs

What does the motor cortex/brainstem innervate?

Directly innervates Motor neurons In the spinal cord

What is a psychiatric (mental) disorder?

A pattern of thoughts, feelings, or behavior that is deviant, distressful, and dysfunctional

Major depressive disorder, schizophrenia, bipolar disorder, substance use disorders and more are examples of what?

Psychiatric (mental) disorders

What is usually not apparent for psychiatric disorders?

The etiology (cause)

What is a neurological disorder?

A disorder of the nervous system

Stroke, head trauma, demyelinating disorders, Parkinson’s disease, Alzheimer’s disease and more are all examples of what?

Neurological Disorders

How can neurological disorders manifest (even though it’s not the primary diagnostic feature)?

As altered thoughts, feelings, or behaviors

What etiology is apparent and not apparent in neurological disorders?

Proximal etiology is clear (i.e. a cell has died); distal etiology is not as clear (i.e. what caused a cell to die)

What is the brain?

An organ

What happens when the brain gets sick?

Behaviors and thoughts change

How are mental disorders related to normal psychological traits?

Mental disorders exist on a continuum with normal psychological traits

What things make up your specific brain?

Your specific genes and your specific environment

What do mental disorders result from?

BOTH genetics and environment

What is the difference between predisposition and causation in terms of mental disorders?

There are no single “genes” for a given psychiatric disorder, BUT there are gene variants and environmental factors that can increase the risk of developing a disorder

How is the expression of (most) traits distributed in populations?

They’re **normally** distributed (no clear demarcation between a person with vs without a disorder)

What makes up how individuals act/think in certain ways?

Our biological makeup and our experiences both inform this

What is positive eugenics?

Preserving “good” genes by encouraging things such as reproduction

What is negative eugenics?

Getting rid of “bad” genes by preventing things such as reproduction

What is the tabula rasa theor?

The theory that **at birth, the human mind is a blank slate** and all knowledge comes from experience or perception

What was considered to be more important than who a person’s parents were (in terms of who they’d grow up to be)?

A person’s social environment and upbringing (blank-slate view)

Do genes cause behavior?

NO, they influence it

What is a key feature in diagnosis as outlined in the DSM-5?

The disorder must impair normal function

What are mood disorders characterized by?

Disordered emotions and emotional extremes

What is the monoamine hypothesis of depression?

Depression patients have lower synaptic levels of monoamines such as serotonin, norepinephrine, and dopamine

What is reserpine?

A anti-hypertensive drug that depletes monoamines and can cause symptoms of depression

What happens if you increase the level of monoamines?

It reduces the symptoms of depression

What do SSRIs induce in the hippocampus of mice and rats?

Neurogenesis

What is neurogenesis?

The process of developing new neurons in the brain

What can Ketamine produce?

long lasting antidepressant effects quickly

What is schizophrenia?

The most severe form of psychopathology known that is characterized by long-term thought disorders, hallucinations, and disorganized speech

What are some positive symptoms (things that happen b/c of) of schizophrenia?

Symptoms observed by their present such as hallucinations, disorders, and delusions

What are some negative symptoms (things that are taken away) of schizophrenia?

Symptoms that are observed by the absence of normal behavior such as flattened affect, social withdrawal, and anhedonia

One idea regarding the cause of schizophrenia is that experiences in ______ life contributed to the development.

Early

What did Henri Laborit discover in regard to schizophrenia?

Discovered that antihistamines (including chlorpromazine) **diminished psychotic episodes and calmed patients;** also helped pre-surgery

Viral infections during the ___________ _____________ of pregnancy can increase the risk of _______ in the offspring.

Second trimester; schizophrenia

What is there less of in the brain in patients with schizophrenia?

Less white matter and gray matter

What is the size of the ventricles in individuals with schizophrenia?

Large

Patients with schizophrenia have an increase response to what?

Amphetamine

What “tone” is increased in patents with schizophrenia?

Dopaminergic/Monoaminergic tone

What activity is decreased in patients with schizophrenia?

Decreased activity in the frontal cortex

What is the most effective treatment for schizophrenia?

Antipsychotics

What do first generation antipsychotics block?

Multiple subtypes of dopamine receptors; and monoamine receptors

What extrapyramidal side effects do first generation antipsychotics cause?

Movement disorders; Slowness of movement and tremor (Parkinsonism); involuntary movements (dyskinesia)and or restlessness and irritability

What do atypical second generation antipsychotics target?

More selective for specific subtypes of dopamine/serotonin receptors; they **also cause fewer side effects**

What other kind of therapy is used to treat schizophrenia?

Cognitive behavioral therapy

What kind of behavior/process do all animals appear to display?

All appear to learn and remember

Why are invertebrates useful as animal models of learning and memory?

They have small nervous systems with big axons, there are fewer ethical concerns, and there can be robust behavioral tests

Why are flies and worms useful as animal models of learning and memory?

They have elegant genetic tools and a short generation time

Who is Eric Kandel and what did he study?

Studied basic forms of **non associative learning** by using the sea slug (A. californica)

What are the two subgroups of non associative learning?

Habituation and Sensitization

What is habituation?

A decrease in behavioral response that occurs with repeated/continuous stimulus exposure

What is sensitization?

An increased or exaggerated behavioral response that occurs with repeated/continuous stimulus exposure (usually an aversive stimulus)

What was the result of the withdrawal reflex experiment in the sea slug?

Repeatedly touching the siphon or tail causes less of a withdrawal response (displaying **habituation**)

Is a brain required for learning and memory to occur? If not, what is needed?

Brain is not required; a few neurons will complete the job

How many neurons do nematodes C elegant have?

302 neurons and they can learn

How is learning displayed in slime molds?

Slime molds will slow their movement when placed in cool, dry environments; after 3 repeated cycles of warm then cool for 1 hour each, the slime molds slowed their movement in preparation for a 4th cycle, even though cooling hadn’t occurred. **They showed anticipation of the cooling down**.

What is associative learning?

Learning the relationship or association between pairs of stimuli (classical conditioning, operant conditioning, and social learning)

What is non-associative learning?

A change in the strength of a behavioral response due to repeated exposure to a stimulus (habituation and sensitization)

What does associative learning look like in flies?

Flies receive repeated pairings where one side of a test tube is an odor with an electric shock, and the other side is a odor without a shock; as trials continue, they do not go to the side that has the odor paired with the shock

How is olfactory conditioning reduced in flies?

By ablating their mushroom bodies

What is the Morris Water Maze?

Measures the time it takes a rodent to find a hidden platform over successive trials

What is learning and memory dependent upon in the Morris Water Maze? How is this known?

The hippocampus; Known because hippocampal lesions strongly reduce water maze performance

What is neural plasticity?

Changes in the structure or function of neurons (change in the excitability of the cell whether it’s upstream or downstream)

What is included in hippocampal formation?

The hippocampus and the subiculum

Where is the site of adult neurogenesis?

Denate gyrus

What types of inputs does the hippocampus receive and **how**?

Receives input from all the primary sensory cortices by way of the **entorhinal cortex**

What is the entorhinal cortex?

Helps to deliver inputs from the primary sensory cortices to the hippocampus

What type of detector is the hippocampus described as?

A coincidence detector as it receives input from from a lot of senses and detects them

What does the hippocampus do with the information it receives?

It processes (summates) sensory and other information, and sends outputs back to the cortex and other brain regions

What does learning “change” in the brain?

It changes synaptic function (also known as plasticity)