Psychobiology

Psychobiology

The biological basis of consciousness, encompassing perception, action, learning, and memory.

Dualism

A philosophical theory by Descartes separating the body as physical and the mind as non-physical, with the soul located in the head.

Monism

The belief that reality is a unified whole, where the mind is a biological function of the central nervous system.

Broca's Area

A region in the inferior left frontal lobe responsible for speech output, associated with non-fluent, laborious speech in Broca's Aphasia.

Wernicke's Area

Located in the middle and posterior superior temporal gyrus, linked to impaired auditory comprehension and fluent but meaningless speech in Wernicke's Aphasia.

Neurons

Specialized cells that receive, conduct, and transmit electrochemical signals in the brain, essential for detecting information and ensuring survival.

Myelin Sheath

Insulating layer covering axons, aiding in faster message transmission and degraded in conditions like Multiple Sclerosis.

Glia

Supporting cells in the central nervous system that buffer neurons, control nutrients, and insulate axons, crucial for brain function and maintenance.

White Matter

Brain tissue composed of axons with myelin sheaths, responsible for transmitting information.

Gray Matter

Brain tissue consisting of cell bodies without myelin sheaths, involved in processing information.

Cell Membrane

Creates different internal and external chemical concentrations by pumping ions.

Adenosine Triphosphate (ATP)

Energy storing molecules used by neurons to fuel the pumps.

Membrane Potential

The stored charge resulting from the difference in charge inside and outside of the cell.

Depolarization

Process where applying a small positive charge to the neuron reduces the electrical charge, leading to the release of the membrane potential.

Action Potential

Rapid reversal of the membrane potential, causing the inside of the membrane to become positive and the outside negative, carrying messages from the soma to the brain.

Diffusion

Movement of molecules from high to low concentration regions, influencing the distribution of substances like sugar in water.

Electrostatic Pressure

Movement of ions due to opposing electrical charges, influencing the distribution of electrolytes like sodium chloride.

Sodium-Potassium Pump

Active process where sodium leaves the cell and potassium enters, maintaining the balance of ions inside and outside the cell.

Voltage-Dependent Ion Channels (VDI)

Channels that respond to changes in membrane potential, allowing the passage of ions like sodium and potassium.

All-or-Nothing Law

Principle stating that once an action potential is triggered, it travels the whole length of an axon without changing size.

Rate Law

Increased rate of firing in response to a stronger stimulus, leading to more action potentials per second.

Chemical Synapses

Communication between neurons through neurotransmitters across synapses, allowing for modifications and signal transmission.

Postsynaptic Receptors

Protein molecules where neurotransmitters attach, influencing the membrane potential by opening ion channels directly or indirectly.

Ionotropic Receptors

Receptors that directly open ion channels upon neurotransmitter binding, causing depolarizing or hyperpolarizing effects.

Neural Integration

Process of combining excitatory and inhibitory signals to determine if an action potential will be initiated in the postsynaptic neuron.

Reuptake

The rapid removal of a neurotransmitter from the synaptic cleft back into the cytoplasm of the terminal bud, which is an active process.

Enzymatic deactivation

The process where a neurotransmitter is destroyed by enzymes, particularly active on muscle fibers, such as acetylcholine.

Autoreceptors

Receptors located on terminal buttons that regulate internal processes and inhibit the release of neurotransmitters when stimulated by the release of a neurotransmitter from their own terminal bud.

Electrical Communication

Communication between cells through gap junctions, allowing direct cytoplasmic connection and synchronization of multiple cells, seen in invertebrates and myelin layers in humans.

Pharmacology of synaptic transmission

The study of drugs that alter neurotransmitter activity, including agonists that increase activity and antagonists that decrease it, affecting synaptic transmission at various stages.

Mate choice

The process influenced by natural selection, where individuals select partners based on traits signaling good genes, such as symmetry, health, and genetic quality, to enhance offspring survival.

Vision

The process of sensory transduction where sensory events are converted into changes in membrane potential, particularly in photoreceptors, allowing light to be converted into visual perception.

Dark adaptation

The process where the retina adjusts to lower light levels, transitioning from cone to rod activity, altering light sensitivity.

Photoreceptors

Cells sensitive to light; rods are very light-sensitive and cones are sensitive to direct light.

Rods

Photoreceptors concentrated in the periphery of the retina, slow response to light, contain rhodopsin, and are more numerous than cones.

Cones

Photoreceptors concentrated in the fovea, responsible for high visual acuity, color vision, and opsin-containing, fast response to light.

Retinal circuits

Photoreceptors and bipolar cells communicate through neurotransmitters without firing action potentials; ganglion cells generate action potentials.

Visual pathways

Information from the retina travels to the brain through the geniculostriatal pathway, involving the LGN and primary visual cortex.

Dorsal and Ventral pathways

Dorsal stream controls actions, while the ventral stream is for perception; they have a double dissociation in visual processing.

Prosopagnosia

Inability to recognize faces due to brain damage, often associated with lesions in the right IT cortex, leading to a failure in facial recognition.

Receptive fields

Areas in the visual field that influence the firing of visual neurons, with on-centre cells responding to light in the center and off-centre cells responding to light in the surround.

Bar and Edge Detection

Neurons in the visual cortex selectively respond to specific features like edges and bars, building shapes from simple cells through complex cells.

Simple Cells

Cells in the visual cortex that respond best to specific features like lines of a particular size, orientation, and location.

Complex Cells

Cells in the visual cortex that, unlike simple cells, have larger receptive fields, are less location-specific, and may be direction-selective or binocular.

Modular Organisation of V1

The visual cortex is organized into six layers, with cells in different layers receiving signals from different lateral geniculate nucleus (LGN) layers and projecting to different destinations.

Top-Down Processing

Higher-level processes, such as prior knowledge, influencing the processing of lower-level input in cognitive processes.

Visual Illusions

Perceptions that deviate from reality due to top-down processes, like the Hermann grid illusion or the scintillating grid illusion.

Predictive Processing

A theory suggesting that conscious perception is strongly influenced by top-down processes, where the brain combines prior expectations with sensory evidence to form perceptions.

Classical Conditioning

Learning process where an unconditioned stimulus (US) leads to an unconditioned response (UR) and a neutral stimulus becomes a conditioned stimulus (CS) that elicits a conditioned response (CR).

Operant Conditioning

Learning process where behaviors change based on consequences, with reinforcement (positive or negative) increasing behavior and punishment decreasing it.

Brain Mechanisms for Reinforcement

Brain regions like the septal area, amygdala, and anterior hypothalamus are involved in reinforcement, with the medial forebrain bundle (MFB) playing a crucial role in pleasure and reward.

Reward Circuit

The mesolimbic and mesocortical pathways, involving the ventral tegmental area (VTA), nucleus accumbens, and prefrontal cortex, play a key role in processing rewards and pleasure, mediated by dopamine pathways.

Mesolimbic pathway

A neural pathway involved in incentive salience, arousal, motivation, and memory consolidation.

Dopamine Pathway

A system where rewarding events activate dopamine release in the nucleus accumbens, influencing reinforcement and social rewards.

Conditioned Place Preference

A behavioral phenomenon where animals prefer a place associated with rewards, indicating reinforcement.

Reinforcement System

Functions to detect potential reinforcing stimuli and strengthen connections between neurons, crucial for motivating specific behaviors.

Neural Plasticity

Dopamine facilitates synaptic strengthening, crucial in instrumental conditioning involving discriminative stimuli, responses, and reinforcing stimuli.

Location of Synaptic Change

Involves inputs to the ventral tegmental area (VTA) and nucleus accumbens (NA) from various brain regions, influencing movement and learning.

Developmental Aspects of Reward

Changes in brain activity during childhood and adolescence affecting reward processing and decision-making.

Risk Taking

Factors influencing heightened risk-taking behavior, including dopamine activity, cognitive control, and peer influence.

Music and Reward

The impact of music on the dopaminergic system, affecting mood, pleasure, and cognitive-emotional gains.

Drug Use and Addiction

Involves the mesolimbic dopamine pathway, addictive drugs affecting DA neurons, and criteria for drug dependence and addiction.

Amph.

Single dose of Amph. in addicted rats increases DA in NA (Sato 1986)

DA Antagonists

Drugs that block the effects of dopamine in the brain

Cocaine & Amphetamine Effects

Vary based on dosage, environment, and individual experience

Nicotine

Stimulates VTA DA neurons and releases dopamine in NA

Addiction Complexity

Involves various brain regions, neurotransmitters, and behaviors

Food Addiction

Involves the mesolimbic DA pathway and can lead to chronic overeating

Reward Circuitry in Obesity

Chronic overeating can lead to alterations in the reward circuit and obesity development

Hedonic Feeding

Motivated by the rewarding properties of palatable foods, overriding weak homeostatic signals