Lecture 2

Biological Psychology: Consciousness and Attention

What is Consciousness?

• Central theme in philosophy of mind.

• Different views on the relation between consciousness and matter:

• Monism: Mind is a product of matter (brain).

• Dualism: Mind and matter are distinct.

• Solipsism: Only one's own mind is sure to exist.

• Modern neuroscience supports the monistic view.

The Hard Problem of Consciousness

• Describes the gap between neural activity and subjective experience.

• Neural interactions can explain behaviors but not the experience itself.

The Real Problem of Consciousness

• Researchers focus on the phenomenology (experiential quality) versus brain function.

• Understanding this relationship may eventually solve the hard problem.

Neural Correlates of Consciousness

• Focuses on conditions under which stimuli reach conscious perception.

• Identifies contrasts in states of consciousness (conscious vs. non-conscious).

Disorders of Consciousness

• Categorized based on patient responses to stimuli and sleep-wake cycles.

General and Specific Correlates of Consciousness

• General Correlates: Found in upper brainstem, base of brain, frontal and parietal cortices; backbone of conscious experience.

• Specific Correlates: Found predominantly in sensory areas of the cortex; associated with distinct experiences.

Wakefulness and Alertness

• Wakefulness: Active interaction with environment, contrasts with sleep.

• Alertness: Variable measure of responsiveness; linked to physiological markers (oxygen, glucose levels).

Neuromodulatory Systems

• Influence neuronal activity beyond synaptic transmission.

• Neurotransmitters involved: serotonin, noradrenaline, dopamine, acetylcholine, histamine.

• These are released from brainstem and diencephalon nuclei.

Sleep Deprivation and Alertness

• Sleep deprivation leads to decreased alertness and can cause microsleeps.

The Initiation of Sleep

• Observed by Constantin von Economo: damage to anterior hypothalamus leads to insomnia.

• This area inhibits activity of neuromodulatory nuclei.

Wakefulness and Sleep

• Neuromodulatory systems activity decreases during sleep; varies across sleep stages.

• REM Sleep: Characterized by increased activity in specific acetylcholinergic nuclei.

Conscious States and Brain States

• Different conscious states (wakefulness, NREM sleep, REM sleep) coincide with varied brain states.

Understanding Attention

• Difficult to define, considered a separate cognitive function.

• Divided into three aspects:

1. Alertness

2. Orientation

3. Executive function

Overt and Covert Attention

• Helmholtz's findings: Covertly attending to stimuli enhances memory recall.

Cocktail Party Effect

• A phenomenon where one selectively processes one stream of information among many, first studied in air traffic controllers.

Attention as a Filter

• Attention acts as a filter, enabling selective information processing.

• Selection theories explore where filtering occurs in the processing hierarchy.

Attention as a Spotlight

• ERP Studies: Show greater processing of attended stimuli.

• fMRI Studies: Attention modulates neural activity; stronger BOLD response for attended stimuli.

Attention and Visual Search

• Explored in visual search paradigms; identification slows with distractors sharing attributes.

Unilateral Neglect

• Condition where patients fail to orient to stimuli in one side of their visual field.

• Potential recovery as observed in a stroke survivor painter.

Networks for Orienting Attention

• Divided into:

• Ventral Attention Network (VAN): Reflexively directs attention.

• Dorsal Attention Network (DAN): Voluntarily directs attention.

Attentional Networks

• Also known as frontoparietal networks, comprise frontal and parietal cortex areas.

• Modulates sensory activity; right hemisphere dominance explains left visual field neglect.

Frontoparietal Networks and the Default Mode Network (DMN)

• Frontoparietal networks focus on external stimuli, while DMN focuses on internal mental processes.

• Activity in these networks is often negatively correlated.

Conclusion

• Understanding consciousness, attention, and their neural correlates is essential for delving deeper into cognitive psychology. Further investigations will continue in the next lecture on short-term and working memory.