Unit 5 Flashcards
Attention
- Selective focus on one aspect of sensory input, while filtering out other stimuli
- Bottom-up and top-down attentional processes compete
Bottom-Up Attention
- A stimulus demands attention
- Ex: sudden movement in visual field, smell of gas, hearing the phone right
- Sensation–> Perception–>Interpretation–> Evaluation–> Expectation–> Prediction
Top-Down Attention
- You purposefully direct your focus to a stimulus or task
- Ex: Attend to your textbook instead of roommates talking, search for a specific shape of a puzzle piece
- Prediction–> expectation–> evaluation–> interpretation–> perception–> sensation
How does attention increase task performance?
Accelerates..
- Sensory Processing
- Decision making
How is attention detected neurally?
-fMRI can compare brain activity (BOLD response) in specific regions in response to specific attentional tasks
-Compared to “resting state”
–Not absense of activity, just default mode network
Brain region depends on: task, sensory modality, specific stimuli, employment of top down
Default Mode Network
- Brain regions active at rest are consistent across individuals
- These active regions decrease activity when task is being performed
- Medial prefrontal cortex and posterior cingulate cortex show coordinated activity at rest
- Other regions: posterior parietal cortex, hippocampus, lateral temporal cortex, amygdala
What does the default mode network do?
- Does not process sensory input
1. Sentinel hypothesis: - Constantly on the lookout for stimuli
- Depends on peripheral vision, not focus
2. Internal mentation hypothesis: - medial prefrontal cortex, posterior cingulate cortex activated when remembering past event or thinking of future event
Common Attention Tasks
- Directed shifts in attention to different stimuli
- -Response may be monitored to confirm attention/motivation
- Complete a task while being presented w/ distractors
- -Responses may be monitored to see effects on accurate performance
Brain and Multitasking
- Brain can easily and quickly shift btwn tasks, but cannot multitask
- -Especially when tasks rely on diff sensory modalities
- Errors increase when multitasking
- Time to complete tasks doubles
- Reduced recollection
Salience Map
- Top-down input refines feature combos of stimuli
- Attention directed to most salient stimuli (what image to focus on)
Fronto-Parietal Attention Network
- Attentional Pathway
- —Bottom-up attention
- ——-stimulus directs attention to eye movement
- —Top-down attention
- ——-Eye movement used to shift attention
Bottom-Up Processing for Multisensory Input and attention
- Pairing sensory stimuli demands greater attention
- –Ex: hearing a crash and seeing a moving vehicle come to a stop
Top-Down processing of multisensory input and attention
-Attention of several modalities simultaneously (limited)
Conciousness
- The awareness of specific stimuli
- Concepts associated:
- –Self-conciousness, self-awareness, awareness, concious of stimuli, attention, concious states wakefulness
- Awareness of specific stimuli= attention
- No waking versus sleeping, instead diff states of conciousness
Reductionism
- Method to study conciousness
- In search of the neural correlates of consciousness
- Individual parts summing up the whole
Holism
-Something about entire being leads to conciousness
Emergence
-Synergisitic effects add up to phenomenon of conciousness
Dualism
-Something totally separate from body that explains conciousness
Binocular Rivalry Experiments
- The brain can only “see” one percept at a time
- -Takes advantage of this
- Mokey trained to pull left lever w/ starburst, right for face
- Measure single neuron activity in inferotemporal cortex (Object ID)
- Showed impages to diff eyes
- Neuronal activity level corresponding w/ stimuli observed w/ associated lever pull
3D Glasses experiment
- Glasses determine which eye sees which image (house or face)
- If see house then face, increased activity in PPA, folowed by increased in FFA
- If see face then house, increased activity in FFA, folowed by increase in PPA
Neurpsychiatric Disorders
- Genes and environment both play role in neurodevelopment
- Common risk factors manifest differently in different individuals
- Difficult to treat disorders bcuz poor understanding of risk factors and how to intervene
- High contribution to disease burden
How are disorders studied?
- DSM-5 has signs and symptoms
- Neuropsych. assessments
- Neuroimaging
- Biomarkers
- In order to diagnos, must exclude other disorders
- -Informs treatment options
How is etiology studied?
- Environment
- Pathology
- Genetics
Multipule Hit Hypothesis
- Genes have lifelong developmental effects
- Environmental insults (infection, toxins) and exposure to trauma (stress, isolation) have developmental effects later in life
- Lead to neurotransmitter dysfunction/imbalance, neurocircuitry dysregulation, structural abnormalities
- Spectra of symptoms/severity
- *Treatment focuses on symptoms
Schizophrenia and Genes
- 80% heritable= portion of trait within pop. attributed to genetics
- Difficult to identify specific genes w/ strong associations to disorder, although genetic component is proven
- Complex behavioral traits are controlled by many genes, each with small effects
- Biomarkers not always reliable
- -Enlarged ventricles w/ schizophrena
