Biology and Behavior

Biology and Behavior

• The relationship between biology and behavior is circular, they influence each other
• High testosterone levels are suspected to increase aggression
• Losing a sports team game can lower testosterone levels, linking behavior to biology
• Psychology cannot be separated from biology

Dualism and Monism

• Descartes supported mind-body dualism, stating humans have unique abilities separate from the body
• Dualists believed the mind was neither physical nor scientifically accessible
• Modern neuroscience and biological psychology support monism, indicating the mind results from brain activity
• Intellect, reason, sensation, and movement come from the brain and nervous system

Neuron Doctrine

• Santiago Ramón y Cajal, a Spanish anatomist, discovered neurons comprised cell bodies with projections in the early 20th century
• He used chemicals to analyze nerve tissue under a microscope
• Neurons are separate, independent cells, rather than a connected network
• Neuron Doctrine states individual neurons are the elementary signaling elements
• Neurons communicate via chemical signals

Phrenology

• Franz Joseph Gall (1758–1828) proposed bumps on the skull correlate to brain functions below
• Personality traits may be related to head size
• Gall and followers measured skulls to prove this, which led to phrenology
• Phrenologists thought brain parts related to traits caused increased brain size
• Gall was correct that the brain is the organ of mind, and that functions localize to different brain structures

Broca's Aphasia

• Paul Broca found language function localizes in the brain in the mid-1800s
• Broca studied Leborgne, called "Tan," because that was one of few words he could say
• Autopsy revealed left inferior frontal region damage
• Broca's area is named in his honor
• Broca's aphasia is difficulty producing speech with very slow speech and great effort

Wernicke's Aphasia

• Carl Wernicke found another language deficit after Broca's discovery.
• Wernicke's aphasia affects the superior surface of the temporal lobe
• Wernicke's area is named in his honor
• Wernicke's aphasia is rapid, fluent speech that lacks meaning

Brain Localization

• Animal experiments supported brain localization
• German physiologists Fritsch and Hitzig stimulated movement in dogs by applying small electrical currents to the brain's external surface
• Ablation, or removal, of the same brain region caused muscle paralysis.
• Occipital lobe ablation caused vision loss.
• Task division exists in the brain where different areas preside over different functions

Biological Basis of Consciousness

• Cognitive neuroscience seeks to understand the biological roots of consciousness
• Consciousness is subjective, different from being awake and responsive to outside stimuli
• Focus is on how to be aware of sensory information
• Perceptual consciousness emerges via conscious experiences assembled in real-time through cognitive processing in cortical circuits

Stream of Consciousness

• William James defined consciousness (1890) as a continuous stream accessible only to the individual but analyzable by its functions involving intentionality, attention, and self-awareness
• Neurobiology studies consciousness through studying its components like selective attention

Selective Attention

• Selective attention is a useful starting point for studying consciousness
• Only a small fraction of sensory stimuli are we aware of at any given moment
• Focus is on things with particular interest, while other things get excluded
• Focalization, concentration, and intention to direct a body movement towards a target are the essence of directing actions to improve motor planning

Blindsight

• Blindsight provides insight into consciousness through neurological disorders, which enables those with primary visual cortex lesions, who cannot consciously see, to respond to visual stimuli
• Patients guess correctly when forced, showing they perceive without knowing
• They scale grasping movements without being able to report the object sizes
• Obstacles in their blind field are avoided
• Visual cortex tissue islands may function, despite not being big enough for conscious perception

Unconscious Information Processing

• Blindsight goes against the idea that perceptions require consciousness to influence behavior.
• Sensory information can guide behavior without conscious awareness.
• Consciousness is a recent evolution, compared to unconscious information processing which was the rule
• Emotional systems controlling automatic behaviors, like running away, and physiological responses, like increased heart rate, work unconsciously

Self-Awareness

• Self-awareness development is a neuropsychological goal
• In 1970, Gordon Gallup and colleagues created the mirror test to test self-awareness in chimpanzees
• The animal gets anesthetized, marked on a normally unseen body area, and then given a mirror once recovered.
• The mark being touched afterwards shows that the animal perceives its reflected image as itself rather another animal
• The rouge test is the similar test with human children
• At 18 months, an infant with a red forehead dot will touch their own forehead in the mirror to wipe it off
• Understanding that they are looking at their own image means self-recognition in mirror tasks

Neuroscience of the Self

• Brain correlates is a model for finding brain activity essential to a sense of self
• Measure brain parts during different actions, to see whether things behave differently when one focuses on reading a text versus focusing on others reading it
• Ruby and Decety discovered patterns of brain activity accompanying consideration of our own actions in consideration to actions of others
• Brain activity patterns occurred when considering self stapling papers as opposed to the experimenter stapling papers

When the Brain Loses Itself

• Goldberg and colleagues (2006) showed participants photos and music while undergoing fMRI, which compared brain activity patterns over three conditions
• Stimuli given slowly required participants to press a button if they visually see an animal or hear a trumpet
• Stimuli were then presented three times as fast
• Participants used buttons to indicate emotional response to stimuli
• Frontal lobe activity with activation of the sensory cortex happened during slow visual stimuli and emotional responses
• Fast visual stimuli had no frontal lobe activation
• When confronted with demanding sensory and visual tasks, frontal lobe activity is switched off

Thought Authorship

• fMRI participants were falsely led to believe their thoughts came from an external device
• People experiencing thoughts as self-generated had deactivated devices
• People experiencing thoughts as externally generated had activated devices, which is typically only reported by schizophrenic patients
• Activations were found in Medial Prefrontal Cortex
• mPFC might pertain to the experience of thought authorship with similar reports correlating to schizophrenic patients

Collective Neural Effort

• Evidence lacks that there might be only one site for consciousness, to which experts suggest consciousness might require collective neural effort
• Eagleman challenged the importance of consciousness when most forms of expertise are performed properly with an absence (or lack) of consciousness
• Unconscious influences are pervasive
• Judges judging whether an individual is granted parole are more lenient if fed beforehand
• Decisions are just byproducts of unconscious neural battles among competing drives

Ten Percent of Brain Myth

• Many know that one only uses ten percent of the brain
• A person might harness the unused potential to bolster intelligence or to otherwise enhance skills
• The film Lucy depicts a character gaining abilities after hitting that 10 percent mark
• The "ten percent myth" origin is from William James’ reserve energy theory, which is the potential for people only meeting a small fraction of full mental potential, which is false

Refuting the 10% Myth Explanations

• New brain techniques in imaging demonstrate that brain parts are more active for tasks, to which they perform particular, necessary roles
• Brain parts are there for a reason or we wouldn’t have evolved them
• Brain mass may take of 5% of our body but its glucose and oxygen use is extravagantly expensive as it expends 20% of it at once
• Brain damage such as concussion damage can have highly detrimental effects and that damaging 90% to any degree would leave the individual unable to emerge from an otherwise likely coma

Brain Size and Functional Connectivity

• The most notable human characteristic is its brain size
• There appears to be no true measure of correlation between brain size and any reliable signs of intelligence
• On average, Albert Einstein’s brain mass was lower than those of controls
• Over 200,000 years since Homo Erectus appeared, there’s been very low deviation of brain size mass
• Why recent cultural advances haven’t changed or impacted brain size is still largely unknown
• Larger quantities of the population or their associated difficulties or needs means that higher transmission rates from the myelinated neurons of white matter appears to be a new connectivity strategy to elevate processing without the changing of the brains overall size

New Geography of the Mind

• Neuroscience shifts from localization to a connectome approach of brain connectivity
• This represents a revolutionary shift in the understanding of an areas of the brain
• The connectome is a representation of the brain's complex neural network
• This is similar to how a road or highway is a representation for information
• The concept was inspired by studying the human genetics, such as genomes
• High brain capacity critically relies on complex architecture
• Described by Sebastian Seung for a TED conference
• A goal is to map the human connectome with 3-D models
• The Human Connectome Project tackles mapping the human brain
• Brains are plastic with changes over one’s lifetime
• There is a great impact from experiences
• For Seng the view on this is that its a different perspective from typical genomics with everything decided from conception
• Eagleman described the 5 senses by describing peripheral play-and-plug devices
• Cochlear and visual implants mean exploitation for visual impairments and researchers even show how a person with quadriplegia can sip coffee by the action itself

Brain-Machine Interfaces (BMI)

• Over the past 15+ years, researchers have shown several cases of machines controlled by the brain
• Rats using robotic arms to pull levers, monkeys playing video games, and humans using tetraplegia to sip coffee were involved
• There have been improvements in limbs too, such as individual finger controlled devices with bending capabilities at 24+ joints
• The loss of limbs has had devastating effects for overall quality of life and BMI may give an approach to restoring lost sensory and motor abilities and allowing voluntary control across artificial limbs
• These are enabled by reading out and decoding neural signals to control robotic arms
• Motor intention is decoded to convey sensory feedback and sensory motor cortices