neuroscience lecture slides

content from lecture slides

What is cognitive science?

The scientific study of the mind and mental processes, incorporating fields like philosophy, psychology, AI, neuroscience, and anthropology.

How does cognitive psychology differ from cognitive neuroscience?

Cognitive psychology focuses on information processing and behavior through behavioral experiments, while cognitive neuroscience studies the biological underpinnings of these processes.

What is phrenology?

A theory developed by Franz Josef Gall in the late 1700s that linked the shape of the skull to personality traits and mental capacities.

What was the core premise of phrenology?

The idea that the size of different brain regions would create bulges or indentations in the skull, reflecting personality traits.

What did modern science conclude about phrenology?

It was found to be incorrect; variations in brain shape do not correlate with personality traits.

What is localization of function in the brain?

The concept that different brain functions, such as visual perception or emotional control, are governed by specific areas in the brain.

What is mass action in relation to brain function?

The idea that any area of the brain cannot be specialized for a single function, and that functions may be distributed across the brain.

What evidence supports the concept of localization of function?

Observations of specific brain injuries leading to distinct cognitive deficits, such as motor functions, visual perception, and speech.

What is the Jacksonian march?

A phenomenon where focal seizures begin in one part of the body and spread, indicating a mapped organization of motor functions in the brain.

What did Fritsch and Hitzig discover in 1870?

They found that electrical stimulation of specific areas in the frontal lobe of dogs produced movements in the opposite side of the body.

What role does the occipital lobe play in vision?

It houses the primary visual cortex, which is crucial for visual perception.

Who was Broca's patient, and what was significant about his case?

Broca's patient, Tan, could understand speech but had a specific impairment in speech production, highlighting localization of language functions.

What do the examples of localization in the brain suggest?

They indicate that there are specialized neurons for functions like vision, movement, and speech, and that neuron functions are influenced by their connections.

What are the four lobes of the brain?

Frontal, Parietal, Temporal, and Occipital lobes.

What is the role of the cerebellum?

It is located at the back of the brain and is involved in coordination and balance.

What connects the two hemispheres of the brain?

The corpus callosum.

What is equipotentiality in the context of brain function?

The idea that any piece of cortical tissue can support any brain function, challenging strict localization.

What is somatotopy?

The physical layout of motor functions on the surface of the brain, where different body parts are represented in specific areas.

How does the concept of mass action apply to kidney function?

Research showed that damage to different parts of the kidney produced similar effects on blood filtration, indicating a principle of mass action.

What is the significance of the posterior regions of the brain?

They have been shown to play a crucial role in visual perception, unlike motor control, which is localized in the frontal regions.

What did early research on dogs and monkeys reveal about visual perception?

It indicated that posterior brain regions are essential for supporting visual perception.

What is the relationship between neurons and their functions?

Neurons derive their functions from the connections they have with other neurons.

What is the main focus of affective neuroscience?

The study of the neural mechanisms underlying emotions.

What does social cognitive neuroscience examine?

The neural processes involved in social interactions and cognitive functions related to social behavior.

What is echolocation?

A navigation method used by some blind people, involving emitting sounds and listening for echoes to gather information about surroundings.

How do blind individuals use echolocation?

They emit clicks and listen for echoes, allowing them to navigate and perform activities like hiking and playing basketball.

What part of the brain is activated in blind echolocation experts?

The auditory cortex, similar to how it is used by sighted individuals for vision.

What is the central nervous system (CNS)?

The CNS includes the brain, spinal cord, and motor neurons that innervate muscles.

What is the neural tube?

A structure formed during embryonic development from the neural plate, which eventually develops into the CNS.

What are sulci and gyri?

Sulci are the grooves (sinks) in the brain, while gyri are the raised areas (humps) between the sulci.

What is the significance of the cerebral cortex?

It is a thin layer of tissue covering the brain, crucial for cognitive functions, and contains a high density of neurons.

How thick is the cerebral cortex?

Approximately 2.5 mm thick.

What is the role of the hippocampus?

It is involved in memory formation and spatial navigation.

What are brain ventricles?

Cavities within the brain that produce and store cerebrospinal fluid (CSF), which cushions and protects the brain and spinal cord.

What is the neuron doctrine?

The principle that neurons are the basic computational units of the brain.

What is the function of dendrites?

To receive messages from other neurons and form connections with their axons.

What is an action potential?

An electrical signal that travels along the axon of a neuron, leading to neurotransmitter release at the synapse.

What maintains a neuron's resting potential?

A negative voltage of approximately -70 mV, maintained by the distribution of ions across the cell membrane.

What ions are primarily involved in maintaining a neuron's resting state?

Potassium (K+) ions are in higher concentration inside the neuron, while sodium (Na+) and calcium (Ca++) ions are in lower concentrations.

What happens when a neuron is stimulated?

Positively charged ions flow into the cell, reducing the electrical gradient and potentially triggering an action potential.

What is the role of glial cells?

They support neurons, including forming the myelin sheath that insulates axons.

What is the corpus callosum?

A bundle of nerve fibers that connects the left and right hemispheres of the brain.

What is the function of the thalamus?

To relay sensory information to the appropriate areas of the cerebral cortex.

What is the hypothalamus responsible for?

Regulating vital functions such as temperature, hunger, and circadian rhythms.

What is the significance of the brain's wrinkles?

They increase the surface area of the cerebral cortex, allowing for more neurons and enhanced computational power.

What is the primary function of the axon?

To convey signals away from the neuron to other neurons.

What is the relationship between neurons and synapses?

Neurons communicate through synapses, where neurotransmitters are released to transmit signals.

What is the role of neurotransmitters?

They are chemicals released at synapses that transmit signals between neurons.

What is the significance of the auditory cortex in blind individuals?

It can adapt to process echolocation sounds, demonstrating the brain's plasticity.

What challenges does a flat cortex present?

It would lead to inefficient connections between neurons and difficulties fitting through the birth canal.

What enables the action potential in neurons?

The opening and closing of gates, such as voltage-gated Na+ channels.

Where are voltage-gated Na+ channels concentrated?

Near the axon hillock and along the axon.

What is the membrane potential of a resting neuron?

−70 mV.

What triggers the opening of Na+ channels?

Sufficient depolarization due to incoming chemical signals.

What role do Ca2+ ions play in neurotransmitter release?

They are crucial for initiating the action potential and neurotransmitter release.

What happens to neurotransmitters after they are released into the synaptic cleft?

They are reuptaken back into the presynaptic terminal.

Name the two most common types of neurotransmitters.

Glutamate (excitatory) and GABA (inhibitory).

What is synaptic plasticity?

Changes in synaptic strength that underlie learning.

What are the primary tools used in neuroscience research?

fMRI, EEG, Single Cell Recordings, Neural Networks, and Optogenetics.

What is the temporal and spatial resolution of fMRI?

Low temporal specificity and medium spatial resolution.

What is the temporal and spatial resolution of EEG?

High temporal specificity and low spatial resolution.

What is the primary advantage of single-cell recording?

High temporal and spatial resolution, but limited to one cell per electrode.

How does a PET scan measure neural activity?

By tracking the uptake of a radioactive tracer that reflects local neural metabolism.

What happens during positron emission in a PET scan?

The radioactive isotope decays, emitting positrons that collide with electrons, producing gamma photons.

What is the visual field?

The spatial extent of everything that you can see at a given moment.

What is foveal vision?

The sharpest vision occurring at the center of gaze, corresponding to the fovea of the retina.

What are the two types of photoreceptors in the retina?

Cones (sensitive to color) and rods (sensitive to low light levels).

How do rods and cones differ in function?

Cones detect color and function in bright light, while rods are colorblind and function in low light.

What is the significance of the lateral geniculate nucleus (LGN)?

It is the first stop for visual information from the retina before reaching the visual cortex.

What happens to visual information in the primary visual cortex?

It is 'flipped' with respect to the visual field, processing left-side information in the right hemisphere.

What is the relationship between the optic nerve and the optic chiasm?

The optic nerve contains the same fibers as the optic tract, while the optic chiasm is the point of crossover.

What is the effect of damage to specific areas of the occipital lobe?

It can produce partial blindness in corresponding regions of the visual field.

What does the spatial organization of V1 reflect?

It reflects the spatial organization of the retina.

How does the nervous system represent sensory information?

Through a neural code that translates sensory signals into understandable formats.

What is the role of the ventral portions of V1?

They process information about color, texture, etc. of objects.

What do the dorsal portions of V1 process?

They process information about the dirt and other background elements.

What does the term 'flipped' refer to in the visual system?

It is a guideline in organizing visual information, indicating that different parts of the visual field correspond to different areas of the retina.

What significant discovery did Hubel and Wiesel make regarding neurons?

They discovered neurons that respond specifically to the orientation of lines at particular angles.

How did Hubel and Wiesel conduct their experiments?

They used visual stimuli made from cardboard and projected them onto a screen to observe neuronal responses.

What is the significance of the line made by the edge of the slide in their experiments?

It triggered a strong response from a neuron, indicating that the neuron was sensitive to the orientation of lines.

What are feature detectors in the visual cortex?

Neurons that detect specific visual features such as slanted lines, edges, motion, depth, and color.

What is the estimated percentage of optic fibers traveling from V1 back to the thalamus?

75-90% of the fibers.

What does the feedback from V1 to LGN suggest about visual processing?

It indicates that ongoing activity in the visual cortex can shape the signals delivered by the LGN.

What is the general principle regarding sensory input and higher brain centers?

Sensory input needs to be continually assessed in the context of hypotheses formulated by higher brain centers.

What is center-surround inhibition?

A phenomenon where a neuron fires above baseline when light is in the center of its visual field and below baseline when light is off-center.

What are the two modes of firing for thalamic neurons?

Tonic mode and burst mode.

When do thalamic neurons switch to burst mode?

When maintained at a hyperpolarized level for 100 ms or longer.

What is the significance of burst-mode action potentials?

They are more effective at transmitting information than tonic-mode action potentials.

How does the visual system demonstrate the complexity of sensation and perception?

The influence of feedback projections complicates the clear-cut boundary between sensation and perception.

What is the focus of Chapter 6 in the context of the visual system?

It addresses how we recognize objects and the cognitive processes involved in that recognition.

What principle from Chapter 4 is revisited in the context of recognizing objects?

The principle that simpler elements combine to form more complex representations.

What role does memory play in recognizing objects?

Recognizing an object involves recalling where it has been seen before, linking perception with memory.

What is the relationship between lower and higher levels of visual representation?

Lower levels combine simpler features to construct progressively more complex representations at higher levels.

What is the role of the thalamus in visual processing?

It relays visual information from the eyes to the V1 portion of the visual cortex.

Which part of the brain processes visual signals from the left visual field?

The right lateral geniculate nucleus (LGN).

What are the two main pathways in visual processing?

The dorsal pathway (where) and the ventral pathway (what).

What type of neurons are involved in the dorsal pathway?

Larger magnocellular neurons.

What is the primary function of the ventral visual pathway?

To consciously perceive, recognize, and identify objects based on their intrinsic visual properties.

What does the dorsal pathway allow us to do?

Exercise visual-motor control over objects by processing their extrinsic properties.

How many cortical areas contribute to visual perception?

Nearly 30 different cortical areas.