Chapter 13 brain and behavior

Schizophrenia

Typically diagnosed in late adolescence
Characterized by mental fragmentation and associated mental conflicts

positive symptoms

Delusions, hallucinations, disorganized speech, disorganized behavior

Negative symptoms

Asociality (not engaging in social interactions),
blunting of affect (difficulty expressing emotions)
Anhedonia (reduced ability to experience pleasure)
Alogia (lack of speech and issues with verbal fluency)

Cognitive symptoms

limitations of thought and reasoning (not central to diagnosis) = on average, slightly lower IQ, difficulty understanding and using abstract concepts,
some difficulty with executive functioning

dopamine theory

schizophrenia results from excess dopamine activity

acetylcholine theory

While ~20% of the general population smokes, 80% of schizophrenics smoke.
They also inhale more deeply.
The α 7-nicotinic receptor is 10 times less sensitive than other nicotinic receptors and would require the deeper breaths to activate

Glutamate hypothesis

schizophrenia may also result from deficient activity of glutamate synapses, especially in PFC

In many brain areas, dopamine inhibits glutamate release or glutamate stimulates neurons that inhibit dopamine release

Schizophrenia is associated with lower release of glutamate and fewer than normal receptors in the prefrontal cortex and hippocampus

neuroanatomical candidates of schizophrenia

Larger lateral ventricles
Smaller temporal lobe
Smaller frontal lobes
Slightly smaller volume of thalamus
Significant loss of gray matter during adolescence

chlorpromazine

drug that relieves the positive symptoms of schizophrenia

tardive dyskinesia

movement disorder that causes a range of repetitive muscle movements in the face, neck, arms, and legs

atypical antipsychotics

Clozapine is the most often prescribed.
Dopamine and serotonin antagonists

cognitive remediation therapy

restoring cognitive and brain functioning through various types of cognitive exercises

Major depression

Characterized by profound sadness, diminished pleasure, decreased motivation, cognitive slowing, lethargy, and suicide

diathesis stress model

the theory that mental and physical disorders develop from a genetic or biological predisposition for that illness (diathesis) combined with stressful conditions that play a precipitating or facilitating role

monamine hypothesis

depression symptoms are caused by low levels of serotonin and norepinephrine at critical synaptic sites in the brain

SSRI

block the reuptake of serotonin

MAOI's

inhibit the enzyme monoamine oxidase
The enzyme metabolizes catecholamines and serotonin into inactive forms
Must avoid foods containing tyramine

SNRI

serotonin norepinephrine reputake inhibitors

tricyclic antidepressants

Blocks the reuptake of monoamine transmitters (seratonin and noepinephrine)
Side effects drowsiness, dry mouth, difficulty urinating,
heart irregularities, & other problems

BDNF

key neurochemical in the onset of depression, low levels of it
BDNF facilitates new learning that builds new synapses and removes old ones

nucelus accumbens

Core connecting with striatum & movement system
Shell connecting to emotional circuitry
Effort-based reward theory suggests an importance of established contingencies between effort and expected rewards in the maintenance of health and adaptive functioning

PFC

Behaves abnormally in patients with depression
Associated with lack of concentration and other cognitive difficulties

electroconvulsive therapy (ECT)

Delivering electrical stimulation to anesthetized patients to induce seizures which alleviate or diminish depressive symptoms
For people with severe depression who don’t respond well to therapy or medication

subcallosal cingulate gryus

key area contributing to profound sadness

exercise and diet

leads to neurogenesis and increased nueroplasticity

type one bipolar

involves periods of severe mood episodes from mania to depression

type 2

a milder form of mood elevation, involving milder episodes of hypomania that alternate with periods of severe depression.

lithium

Drug of choice for bipolar
Increases presynaptic activity within the serotonergic system

generalized anxiety disorder

Unrealistic, excessive, and long lasting worry, motor tension, restlessness, irritability, difficulty sleeping, hypervigilance

panic disorder

Brief, recurrent, unexpected episodes of terror, fear of dying and losing control, derealization

social anxiety

Aversion, fear, autonomic arousal in unfamiliar social settings

specific phobia

aversion , fear, autonomic arousal in in specific situations

OCD

Recurrent obsessions and compulsions that are persistent in nature, inappropriate or intrusive thoughts that cause anxiety

PTSD

Following an extremely stressful event, recurrent episodes of fear often triggered by reminders of initial trauma