JH

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.