💕Intro to Cognitive Science Unit 6 – Brain Structure & Function in Cognition

Key Brain Structures

• Cerebrum consists of two hemispheres connected by corpus callosum, responsible for higher cognitive functions (perception, memory, language)
• Cerebellum located at the back of the brain, coordinates motor movements, balance, and posture
  • Receives input from sensory systems, spinal cord, and other parts of the brain
  • Integrates this information to fine-tune motor activity
• Brainstem connects the cerebrum and cerebellum to the spinal cord, regulates vital functions (breathing, heart rate, sleep)
  • Composed of the midbrain, pons, and medulla oblongata
• Limbic system includes structures such as the amygdala, hippocampus, and hypothalamus, involved in emotions, memory, and motivation
• Basal ganglia are a group of subcortical nuclei involved in motor control, learning, and executive functions
• Thalamus acts as a relay center, processing and directing sensory and motor signals to the cerebral cortex
• Hypothalamus regulates the autonomic nervous system, endocrine function, and homeostasis (body temperature, hunger, thirst)

Neurons and Neural Networks

• Neurons are the basic functional units of the nervous system, specialized cells that transmit and process information
  • Consist of a cell body (soma), dendrites, and an axon
  • Communicate with other neurons through synapses
• Neurotransmitters are chemical messengers released by neurons to transmit signals across synapses (glutamate, GABA, dopamine)
• Action potentials are electrical impulses that travel along the axon, enabling neurons to transmit information rapidly over long distances
• Synaptic plasticity refers to the ability of synapses to strengthen or weaken in response to activity, underlying learning and memory
• Neural networks are interconnected groups of neurons that work together to process information and generate complex behaviors
  • Parallel processing allows neural networks to perform multiple computations simultaneously
• Neurogenesis is the formation of new neurons, which continues throughout life in specific brain regions (hippocampus, olfactory bulb)
• Glial cells support and maintain neurons, providing structural support, insulation, and regulating the extracellular environment

Functional Areas of the Brain

• Frontal lobe is involved in executive functions, decision-making, problem-solving, and motor control
  • Prefrontal cortex plays a crucial role in planning, working memory, and emotional regulation
• Parietal lobe processes sensory information related to touch, pressure, and spatial awareness
  • Somatosensory cortex receives and interprets sensory input from the body
• Temporal lobe is involved in auditory processing, language comprehension, and memory formation
  • Hippocampus plays a key role in the formation and consolidation of new memories
• Occipital lobe is primarily responsible for visual processing, including color, shape, and motion perception
• Broca's area, located in the frontal lobe, is involved in speech production and language processing
• Wernicke's area, located in the temporal lobe, is involved in language comprehension and interpretation
• Motor cortex, located in the frontal lobe, controls voluntary movements and motor skills
• Association areas integrate information from multiple sensory modalities and contribute to higher cognitive functions (problem-solving, decision-making)

Brain Imaging Techniques

• Electroencephalography (EEG) measures the electrical activity of the brain using electrodes placed on the scalp
  • Provides high temporal resolution but limited spatial resolution
• Magnetoencephalography (MEG) measures the magnetic fields generated by neuronal activity
  • Offers high temporal resolution and better spatial resolution than EEG
• Positron Emission Tomography (PET) uses radioactive tracers to measure metabolic activity and neurotransmitter levels in the brain
• Functional Magnetic Resonance Imaging (fMRI) measures changes in blood flow and oxygenation related to neuronal activity
  • Provides high spatial resolution and allows for the mapping of brain activity during specific tasks
• Diffusion Tensor Imaging (DTI) maps the diffusion of water molecules in brain tissue, revealing the structure of white matter tracts
• Transcranial Magnetic Stimulation (TMS) uses magnetic fields to stimulate or inhibit specific brain regions, allowing for the study of causal relationships between brain activity and behavior
• Optogenetics is a technique that uses light to control the activity of genetically modified neurons, enabling precise manipulation of neural circuits in animal models

Cognitive Processes and Brain Function

• Perception involves the processing and interpretation of sensory information from the environment
  • Visual perception relies on the occipital lobe and ventral stream for object recognition and dorsal stream for spatial processing
• Attention is the selective focus on specific stimuli while ignoring others, mediated by frontal and parietal regions
  • Divided attention involves simultaneously focusing on multiple tasks or stimuli
• Memory encompasses the encoding, storage, and retrieval of information
  • Short-term memory holds information for a brief period, while long-term memory stores information for extended periods
  • Working memory is the active manipulation and maintenance of information, involving the prefrontal cortex
• Language processing involves the comprehension and production of spoken and written language
  • Broca's area and Wernicke's area play key roles in language production and comprehension, respectively
• Decision-making involves evaluating options and selecting a course of action, engaging the prefrontal cortex and limbic system
• Emotion processing involves the limbic system, particularly the amygdala, in the generation and regulation of emotional responses
• Executive functions, such as planning, problem-solving, and cognitive flexibility, rely on the prefrontal cortex

Brain Plasticity and Development

• Neuroplasticity refers to the brain's ability to reorganize and adapt in response to experience, learning, and injury
  • Synaptic plasticity involves changes in the strength of connections between neurons (long-term potentiation, long-term depression)
• Critical periods are windows of time during development when the brain is particularly sensitive to specific experiences
  • Sensory systems, such as vision and hearing, have well-defined critical periods for normal development
• Experience-dependent plasticity occurs when the brain adapts in response to specific experiences or learning
  • Skill acquisition and training can lead to structural and functional changes in relevant brain regions
• Brain development follows a complex sequence of events, including neurogenesis, migration, differentiation, and synaptogenesis
  • Pruning is the process of eliminating unnecessary synapses and neurons during development, refining neural circuits
• Aging is associated with changes in brain structure and function, including a decline in gray matter volume and cognitive performance
  • Engaging in mentally stimulating activities and physical exercise may help maintain brain health and cognitive function in older adults
• Neurogenesis continues throughout life in specific brain regions, such as the hippocampus, and may contribute to learning and memory
• Environmental factors, such as stress, nutrition, and social interaction, can influence brain development and plasticity

Disorders and Brain Dysfunction

• Neurodegenerative diseases, such as Alzheimer's and Parkinson's, involve the progressive loss of neurons and cognitive decline
  • Alzheimer's disease is characterized by the accumulation of amyloid plaques and neurofibrillary tangles, leading to memory loss and cognitive impairment
• Psychiatric disorders, such as depression, anxiety, and schizophrenia, are associated with abnormalities in brain structure and function
  • Depression involves dysregulation of neurotransmitter systems (serotonin, norepinephrine) and altered activity in limbic and prefrontal regions
• Traumatic brain injury (TBI) can result in physical, cognitive, and emotional impairments, depending on the location and severity of the injury
  • Concussions are a mild form of TBI that can lead to temporary cognitive and physical symptoms
• Neurodevelopmental disorders, such as autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD), involve atypical brain development and function
  • ASD is characterized by difficulties in social interaction, communication, and restricted or repetitive behaviors
• Stroke occurs when blood flow to the brain is disrupted, leading to cell death and neurological deficits
  • Ischemic stroke is caused by a blockage in a blood vessel, while hemorrhagic stroke involves bleeding in the brain
• Addiction is a chronic disorder characterized by compulsive drug seeking and use, involving changes in reward pathways and decision-making processes
• Epilepsy is a neurological disorder characterized by recurrent seizures, resulting from abnormal electrical activity in the brain

Current Research and Future Directions

• Optogenetics and chemogenetics are emerging techniques that allow for precise control of neuronal activity in animal models
  • These tools enable researchers to investigate the causal relationships between specific neural circuits and behavior
• Brain-computer interfaces (BCIs) aim to establish direct communication between the brain and external devices
  • BCIs have potential applications in assistive technologies for individuals with motor disabilities and in the development of neuroprosthetics
• Neuromodulation techniques, such as deep brain stimulation (DBS) and transcranial direct current stimulation (tDCS), are being explored as treatments for neurological and psychiatric disorders
• Advances in neuroimaging, such as high-resolution fMRI and diffusion imaging, are providing new insights into brain structure and function
  • Connectomics aims to map the complete wiring diagram of the brain, revealing the complex networks underlying cognition and behavior
• Computational neuroscience and artificial intelligence are increasingly being used to model and simulate brain processes
  • These approaches can help generate testable hypotheses and provide a framework for understanding the mechanisms underlying cognition
• Personalized medicine approaches, based on an individual's genetic profile and brain characteristics, may lead to more targeted and effective treatments for neurological and psychiatric disorders
• Research on brain plasticity and neurogenesis is exploring ways to promote brain health and resilience throughout the lifespan
  • Interventions such as cognitive training, physical exercise, and social engagement are being investigated for their potential to maintain and enhance cognitive function