Unit 3 Exam Study Guide for Neuroscience II

Schizophrenia

A mental disorder characterized by abnormal behaviors, including positive symptoms like auditory hallucinations and delusions, negative symptoms such as flat affect, and cognitive impairments.

Positive symptoms

Abnormal behaviors that are gained in schizophrenia, occurring during periods of psychosis, including auditory hallucinations and delusions.

Negative symptoms

Characteristics that should be present but are absent in people with schizophrenia, such as a lack of emotional or facial expressions, known as a flat affect.

Cognitive impairments

Impairments of memory, attention, social perception, or movement control, exemplified by the lack of smooth pursuit when visually tracking a moving object.

Saccadic eye movement

Jerky sudden eye movements that occur in individuals with schizophrenia instead of smooth pursuit.

Concordance rate

The rate at which schizophrenia occurs in individuals who share genetic makeup, indicating that the risk increases with closeness of relation.

Polygenic nature of schizophrenia

The concept that schizophrenia is not caused by a single gene mutation but by the variation of many genes along the human genome.

DISC1 gene

A gene that is specifically implicated in schizophrenia, affecting enlarged ventricles in mice studies.

Onset of schizophrenia

The stage in life during which schizophrenia typically appears.

Flat affect

A lack of emotional or facial expressions observed in individuals with schizophrenia.

Auditory hallucinations

A positive symptom of schizophrenia where individuals hear voices that are not present.

Delusions

False beliefs that are a positive symptom of schizophrenia.

Psychosis

A state during which positive symptoms of schizophrenia occur.

Heritable component of schizophrenia

Evidence suggesting that schizophrenia has a genetic basis, with risk increasing based on genetic relatedness.

Atypical synaptic plasticity

The abnormal synaptic changes involved in schizophrenia, related to the genes that are found to be abnormal in the disorder.

Environmental stressors

Factors that interact with genetics to increase risk, including urban living, perinatal stress, and cannabis use.

Integrative model of schizophrenia

Schizophrenia results if an individual has certain predisposing genetic variations and is exposed to environmental stressors during critical neurodevelopmental windows.

Structural differences in schizophrenic brain

Enlarged ventricles and acceleration in cortical thinning (grey matter maturation) in the brains of schizophrenics.

Functional differences in schizophrenic brain

Hypofrontality hypothesis: the frontal lobes are less active in people with schizophrenia.

First-generation antipsychotics

Block dopamine receptors and target positive symptoms only, consistent with the dopamine hypothesis.

Adverse effects of first-generation antipsychotics

Can cause motor effects such as tardive dyskinesia (slow repetitive involuntary facial movements).

Problems with the dopamine hypothesis

The speed at which dopamine receptors are blocked doesn't match the reduction of positive symptoms.

Second-generation antipsychotics

Block primarily serotonin receptors and target both negative and positive symptoms.

Psychomimetics

Drugs like phencyclidine (PCP) and ketamine mimic the symptoms of psychosis.

NMDA receptor antagonists

Drugs that support the glutamate hypothesis, suggesting schizophrenia results from underactivation of glutamate receptors.

Symptoms of depression

Characterized by persistent feelings of sadness, hopelessness, and loss of interest, leading to major depressive disorder.

Changes to sleep structure in depression

Difficulty maintaining & falling asleep, little slow wave (stage 3) sleep, and lack of regularly repeating sleep cycles.

Heritability of depression

Confirmed by concordance rates between identical vs. fraternal twins; depression is highly polygenic.

Structural biomarkers of depression

Accelerated cortical thinning in the right hemisphere, correlating with the severity of depressive symptoms.

Functional biomarkers of depression

Task-related increase in activity in brain regions associated with the task and decrease in activity in attentional neural networks.

First line of defense in depression treatment

Antidepressants and psychotherapy, such as Cognitive Behavioral Therapy.

Monoamine oxidase inhibitors (MAOIs)

Inhibit the breakdown of monoamines, allowing greater quantities to accumulate in the synaptic cleft.

Tricyclics

Block protein transporters, preventing monoamine reuptake and increasing the concentration of monoamines in the synapse.

Selective serotonin reuptake inhibitors (SSRIs)

Prevent reuptake of serotonin specifically, while not affecting other monoamine neurotransmitters.

Brain stimulation methods

Serve as a second line of defense in treatment-resistant depression.

Electroconvulsive shock therapy (ECT)

Noninvasive electrodes placed on the scalp induce whole brain seizures, but have poor spatial resolution.

Repetitive Transcranial Magnetic Stimulation (rTMS)

Noninvasive stimulation using magnetic fields.

Deep Brain Stimulation (DBS)

Electrodes neurosurgically implanted into regions that regulate mood (e.g. limbic system).

Traditional DBS

Constant stimulation delivered to brain region once electrodes are implanted.

Closed-loop DBS

Recording electrodes continuously monitor activity and detect biomarkers of depression, triggering stimulating electrodes to deliver electrical stimulation that relieves biomarkers.

Bipolar Disorder Symptoms

Oscillations between episodes of depression and mania, the latter of which share similar characteristics to the positive symptoms of schizophrenia (during psychosis).

Bipolar Disorder Heritability

Bipolar disorder has a heritable component that is polygenic.

Neural Biomarkers of Bipolar Disorder

Enlarged ventricles; accelerated cortical thinning; excess dopamine signalling.

Attention (Selective Attention)

The focusing of our awareness on a particular stimulus or location for enhanced processing.

Attentional Spotlight

The 'steerable' nature of our selective attention.

Endogenous Attention (Voluntary Attention)

Attention that is top-down (mediated by higher-order regions of the brain), wherein we have voluntary control over what to attend to.

Symbolic Cueing Tasks

Show that endogenous attention enhances perception of stimuli occurring at spatial locations that are the focus of our endogenous attentional spotlight but impair processing of stimuli outside of this spotlight.

Cocktail Party Effect

Within an acoustically cluttered environment, endogenous attention selects a particular auditory source for enhanced processing while suppressing irrelevant noise.

Inattentional Blindness

Evidence that endogenous attention results in missing obvious information located outside the attentional spotlight.

Divided Attention Tasks

Demonstrate how our finite attentional resources are used according to the perceptual load of a task.

Exogenous Attention (Reflexive Attention)

Attention that is bottom-up or stimulus driven, wherein a salient (unexpected or otherwise prominent) stimulus seizes our attention.

Inhibition of Return

If exogenous attention is directed to a particular location and no other event occurs at that same location within 200ms, our attentional spotlight moves on and is inhibited from returning to that same location.

Event-Related Potential (ERP)

Derived by averaging the brain response to many repeated stimulus presentations (i.e., trials) of a given condition.

Auditory N1 Effect

The N1 component of ERP is stronger in response to an attended (vs. unattended) sound.

Auditory P3 Effect

The P3 component reflects higher-order characteristics of a sound and is modulated by attention.

Visual P1 Effect

Visual objects that are attended (vs. unattended) evoke stronger P1 components if the experimental manipulation involves spatial attention.

Attention Effects on Neuronal Activity

Attention increases the neuron's signal-to-noise ratio (SNR) by boosting the activity that processes the stimulus (the signal) and reducing the neuron's random firing that is unrelated to stimulus (the noise).

SNR boost

Occurs in neurons that process whichever stimulus characteristic is being attended to.

Poor temporal resolution of fMRI

Can be overcome by sustained attention tasks to study the brain regions involved in attention.

Superior colliculus

Helps direct gaze toward attended objects.

Pulvinar

Directs covert shifts of visual attention (covert = eyes remain fixed while attention shifts elsewhere).

Dorsal frontoparietal network

Involved in top-down control of endogenous attention.

Intraparietal sulcus (IPS)

Neurons facilitate endogenous attention shifts, regardless of whether visual or auditory.

Frontal eye field (FEF)

Directs gaze toward attended objects, similar to the superior colliculus.

Right temporoparietal network

Involved in bottom-up capture of exogenous attention.

Temporoparietal junction

Activated by unexpected, sudden stimuli that capture exogenous attention.

Hemispatial neglect

Failure to attend to the left side of body or locations in the left visual field in instances of right hemisphere stroke.

Consciousness

The state of awareness of one's own existence, thoughts, emotions, and experience.

Sentience

The ability to experience sensations and feelings (both positive and negative).

Theory of mind

Insight into others' mental lives.

Metacognition

Thinking about thinking.

Cognitive-motor dissociation

Presents challenges for studying (un)consciousness in patients with disorders of consciousness (DoC).

Claustrum

A thin sheet of white matter suggested to be the seat of consciousness.

Global workspace theory (GWT)

Theorizes that consciousness depends on the ignition and broadcast of information within a global neuronal workspace.

Default mode network

Identifies the types of mental activity during which the network is/isn't active.

Easy problem of consciousness

Understanding how certain patterns of neural activity give rise to specific conscious experiences.

Hard problem of consciousness

Understanding why and how certain patterns of neural activity give rise to specific conscious experiences.

fMRI pattern classification

An experimental approach that helps solve the easy problem by analyzing brain activity patterns.

stimulus reconstruction experiments

Experimental approaches aimed at understanding how stimuli are processed in the brain.

easy problem

Understanding brain processes that correlate with observable behaviors.

hard problem

Understanding the brain processes that produce subjective experiences of perception, known as qualia.

cerebral lateralization

The specialization of certain functions in one hemisphere of the brain over the other.

contralateral processing

The phenomenon where information presented in one visual field is processed in the opposite hemisphere.

split-brained individuals (SBIs)

Individuals who have had their corpus callosum severed, leading to a lack of communication between hemispheres.

right-ear advantage

The tendency for normal-hearing listeners to report sounds presented to their right ear more frequently.

visuo-spatial processing

Cognitive processing related to visual and spatial information, typically lateralized to the right hemisphere.

planum temporale

A subregion of the auditory cortex that is larger in the left hemisphere and is involved in speech processing.

pitch specialization

The right hemisphere's specialization for processing the pitch aspect of sounds.

prosody

Patterns of pitch variation in speech, lateralized to the right auditory cortex.

congenital amusia

A lifelong inability to perceive music, particularly pitch and melody, often due to right auditory cortex damage.

astereognosis

The inability to recognize objects by touch, associated with damage to the precentral gyrus.

prosopagnosia

Inability to recognize faces, including one's own, associated with damage to the fusiform gyrus.

Broca's area

The left inferior frontal gyrus, damage to which results in nonfluent aphasia.

Wernicke's area

The posterior temporal lobe, damage to which results in fluent aphasia.

global aphasia

Total loss of language abilities due to widespread damage to the left-hemisphere language system.

spectrogram

A visual representation of the acoustic structure of vocal communication, showing time, frequency, and amplitude.

Squirrel monkeys

Have distinct calls (e.g., shriek, trilling) associated with distinct meanings.

Whalesong

Has an intricate acoustic structure and plays a role in mating behavior.

Birdsong

Consists of 'syllables' organized into sequences.

Chimpanzees

Communicate fear and playfulness with facial expressions.