Introduction to Cognitive Neuroscience

Cognitive neuroscience explores how the brain processes information.
Brain function arises from complex interactions of simple components known as emergent properties.
The field investigates human behavior, perception, and decision-making, and their biological underpinnings.
Advancements in research methods have made the study of neuroscience possible.

Connectional Methods study functional connections between neurons and specific brain regions.
Tracer substances are injected to map neuronal pathways, revealing input and output networks.
Brain regions must be surgically removed for microscopic observation.
Diffusion Tensor Imaging (DTI) tracks water molecule diffusion in living tissue to map connections.
Axons bundle together into tracts, facilitating water molecule movement.

Correlational methods study brain activity in real-time alongside individual behaviors.
Invasive measures like microelectrode, microdialysis, and voltammetry probes are implanted directly into brain tissue.
Positron Emission Tomography (PET) uses radioactive compounds to map chemical distributions in the brain.
Magnetic Resonance Imaging (MRI) uses magnetic pulses instead of radiation to visualize brain structures.
Functional Magnetic Resonance Imaging (fMRI) tracks blood flow and oxygenation in the brain.
Importantly, correlation does not imply causation.

Lesion methods examine impaired brain function due to damage caused by injuries, strokes, or tumors.
Paul Broca's patient exhibited impaired speech ability but retained language comprehension following a lesion.
Broca's area, a brain region crucial for language production, was damaged in this case.
Lesions rarely affect only a single brain structure, making pinpointing the specific structure responsible for an observed deficiency challenging.

Stimulation methods study the effects of stimulating specific brain regions on cognition and behavior.
Transcranial Magnetic Stimulation (TMS) uses focused magnetic pulses to activate neurons in specific brain regions.
Transcranial Direct Current Stimulation (tDCS) employs two electrodes placed on the scalp.
Cathodes (+) are inhibitory, while anodes (-) are excitatory.

It's crucial to be aware of brain biases when conducting research.
Anchoring bias refers to being heavily influenced by first impressions or information.
Confirmation bias refers to seeking information consistent with pre-existing beliefs.
Availability heuristic equates the frequency of an event with how easily or recently it was recalled.
Affect heuristic describes decisions based on emotions instead of logic.

The nervous system of some lower-level organisms, like jellyfish and sea anemones, consists of a nerve net for coordination of movement and feeding.
This reflects radial symmetry, where organisms have a top and bottom but lack front, back, left, or right defined directions.
Humans exhibit bilateral symmetry, meaning they are dual-segmented.
Segmented organisms have more complex nervous systems due to increased control requirements.
Each body segment has a local centralized network responding to sensory input.
Longitudinal information transmission occurs up and down the body segments.

Peripheral Nervous System (PNS): Nerves branching out from the brain and spinal cord, connecting to effector organs.
Somatic Nervous System: Processes information from external stimuli.
Autonomic Nervous System: Coordinates internal organ activity, divided into sympathetic and parasympathetic systems.
Sympathetic: "Fight or Flight" response - feeding, fighting, fleeing, sexual activity.
Parasympathetic: "Rest or regenerate" response - muscle relaxation, directs blood flow to the digestive system.

Afferent Neurons: Transmit sensory information from sensory organs to the brain.
Efferent Neurons: Carry signals from the brain to the peripheral nervous system to initiate actions.
Effector Organs are organs that carry out a response (e.g., muscles).

The Central Nervous System (CNS) is made of the brain and spinal cord.
Brain is the “control center” responsible for receiving sensory information, sending motor commands, and coordinating bodily functions and thoughts.
Spinal Cord is the body’s “information highway” - transmits signals from the brain to the PNS and vice versa.

The brain is divided internally into three major regions:
Forebrain: The largest region, including the cerebrum, thalamus, and hypothalamus. Controls higher-level functions like thinking, learning, and memory.
Midbrain: Located between the forebrain and hindbrain, involved in auditory and visual processing, movement control, and sleep-wake cycles.
Hindbrain: Contains the cerebellum, pons, and medulla oblongata. Controls essential functions like breathing, heart rate, and balance.

The largest part of the brain, responsible for higher-level cognitive functions.
Divided into two hemispheres, left and right, connected by the corpus callosum.
Outermost layer is the cerebral cortex: responsible for complex cognitive functions.
Four lobes:
- Frontal Lobe: Planning, decision-making, motor control, language production.
- Parietal Lobe: Somatosensory information (touch, pain, temperature), spatial awareness.
- Temporal Lobe: Auditory processing, memory, language comprehension.
- Occipital Lobe: Visual processing.

Thalamus is a relay center for sensory information.
Receives and processes information from sensory organs and then sends it to the appropriate cortex for further processing.

Hypothalamus is a homeostatic regulator, maintaining internal balance.
Controls critical functions like body temperature, hunger, thirst, and sleep-wake cycles.
Also regulates the release of hormones from the pituitary gland.

Cerebellum is located at the back of the brain, behind the brainstem.
Plays a vital role in motor control, coordination, balance, and learning new motor skills.

Contains the midbrain, pons, and medulla oblongata.
Connects the cerebrum to the spinal cord.
Essential for regulating breathing, heart rate, blood pressure, and other vital functions.

The spinal cord is a long, cylindrical structure extending from the brainstem down to the lower back.
It acts as a relay pathway for signals traveling between the brain and the PNS.
It also controls reflexes, automatic responses to stimuli bypassing the brain.

Neuroplasticity is the brain's ability to change and adapt over time, even in adulthood.
This flexibility allows the brain to learn, adapt to new experiences, and recover from injury.
There are two main types:
- Synaptic Plasticity: Changes in the strength and connections between neurons.
- Structural Plasticity: Changes in the physical structure of the brain, such as the formation of new connections or the growth of new neurons.

Cognitive neuroscience explores brain function and its link to cognition and behavior.
Diverse research methods, from connectional to stimulation, provide insights into the brain's workings.
Understanding brain biases is essential for conducting rigorous research.
The nervous system, encompassing the CNS and PNS, coordinates complex functions and allows for responses to both external and internal stimuli.
The brain, with its intricate structure and diverse regions, enables a wide range of cognitive abilities..
Neuroplasticity demonstrates the brain's remarkable ability to adapt and change throughout life.