Neuroscience and Mammalian Cortical Organization

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Questions and Answers

What is a characteristic feature of the cortical organization in mammals?

A simple linear arrangement of neurons

A complex mosaic-like structure (correct)

An absence of circuit motifs

Uniform thickness across all regions

Circuit motifs in neuroscience are significant because they represent what?

Isolated neural pathways without interaction

Consistent patterns that govern brain function (correct)

Uniform connections with no variability

Randomly arranged neural connections

Why might the arrangement of neural fibers be important for social cognition?

It allows for more efficient information processing. (correct)

It isolates regions from each other.

It prevents the formation of teams in cognitive tasks.

It decreases the speed of neural transmission.

How is brain weight ranked in the context of mammalian evolution?

It may correlate with specific cognitive abilities. Signup and view all the answers

What does the term 'canonical circuit' refer to in neuroscience?

A standard pattern of connections found across various species Signup and view all the answers

The ability for crows to work within a team illustrates what aspect of neural organization?

Adaptive neural arrangements facilitating cooperation Signup and view all the answers

What might 'social cognition' involve in terms of brain circuits?

Interconnected circuits integrating various social signals Signup and view all the answers

The term 'fiber patches' in the context of neuroscience refers to what?

Dense clusters of interconnected nerve fibers Signup and view all the answers

What is primarily studied in Stacho et al.'s research as mentioned?

Circuit motifs Signup and view all the answers

Which of the following is a focus of the research in relation to goals?

Completing a circuit motif Signup and view all the answers

What aspect of mammalian cortical organization is addressed in the study?

Iterative processes in circuit design Signup and view all the answers

How do circuit motifs contribute to neuroscience according to the study?

They help understand neural manipulation Signup and view all the answers

What role does iterative processing play in the context of this research?

It assists in achieving computational efficiency Signup and view all the answers

Which statement about circuit motifs is true based on the research findings?

They allow for complex manipulation of neural signals Signup and view all the answers

What potential implication does the study suggest regarding mammalian cortical organization?

It can be influenced by circuit motifs Signup and view all the answers

In the context of neuroscience, why are circuit motifs considered significant?

They provide insight into complex brain functions Signup and view all the answers

What is the role of the granular layer IV in the context of circuitry?

To enhance the sensory input processing Signup and view all the answers

Which cortical layers are primarily involved in mammalian neocortex?

Layers II/III and V/VI Signup and view all the answers

What architecture do Wulst birds display in their pallium?

Granular architecture similar to mammalian systems Signup and view all the answers

How do other regions interact with the circuitry in the neocortex?

They aggressively intervene to disrupt pairings Signup and view all the answers

In terms of hierarchy, where do the associative functions reside in avian pallium?

In both supra- and infragranular layers II/III Signup and view all the answers

Which of the following best describes the sensory DVR in birds compared to mammals?

It is less intricate than the mammalian neocortex Signup and view all the answers

Which layer primarily dominates the sensory processing in the avian pallium?

Layer IV Signup and view all the answers

What is the strategy employed by some regions to prevent new bond formations?

To increase competition among existing bonds Signup and view all the answers

What is one primary function of hormones in the endocrine system?

They act as chemical messengers. Signup and view all the answers

Which of the following statements about endocrine glands is true?

They can be found in various locations throughout the body. Signup and view all the answers

What role does the pituitary gland play in the endocrine system?

It activates the thyroid gland by releasing hormones. Signup and view all the answers

How do target tissues respond to hormones?

They adapt based on receptor availability and gender. Signup and view all the answers

Which hormone is primarily associated with metabolism regulation in the thyroid?

T3 (triiodothyronine) Signup and view all the answers

What condition is associated with an under-active thyroid?

Cretinism Signup and view all the answers

What is a consequence of iodine deficiency in relation to thyroid function?

Impaired hormone synthesis. Signup and view all the answers

Which of the following effects is NOT associated with thyroid hormones?

Direct energy storage for muscles. Signup and view all the answers

What hormone produced by the ultimobranchial body helps in lowering blood calcium levels?

Calcitonin Signup and view all the answers

Which condition is associated with under-active thyroid function in humans?

Cretinism Signup and view all the answers

What is the primary function of parathyroid hormone (PTH)?

Increases calcium and phosphorus levels in blood Signup and view all the answers

Which of the following hormones is involved in water and sodium retention in the body?

Aldosterone Signup and view all the answers

What is a potential negative outcome of steroid abuse?

Lowered hormone production Signup and view all the answers

Which of the following is a role of glucocorticoids?

Managing carbohydrate metabolism Signup and view all the answers

How does parathyroid hormone affect the intestines?

Increases calcium absorption Signup and view all the answers

In which process is thyroid hormone NOT primarily involved?

Bone resorption Signup and view all the answers

What is the primary function of epinephrine in the body?

Increases heart rate and prepares the body for action Signup and view all the answers

Which hormone produced by the pancreas raises blood sugar levels?

Glucagon Signup and view all the answers

What is the role of renin produced by the kidneys?

Increases blood pressure Signup and view all the answers

What does melatonin regulate in the body?

Circadian rhythms and sleep patterns Signup and view all the answers

What is the primary outcome of a lack of insulin in the body?

Insufficient glucose for cells leading to tissue wasting Signup and view all the answers

Which component of the endocrine system acts as a link between the nervous and endocrine systems?

Pituitary gland Signup and view all the answers

What is the function of erythropoietin (EPO) produced by the kidneys?

Stimulates red blood cell production Signup and view all the answers

The pancreas has both endocrine and exocrine functions. What is its exocrine function?

Release of digestive enzymes Signup and view all the answers

What is the primary concern associated with endocrine disrupters found in the Potomac River?

They can cause birth defects and reproductive irregularities. Signup and view all the answers

Which of the following statements is true about endocrine disruptors?

They can mimic or block hormones in the body. Signup and view all the answers

What was detected in the smallmouth bass fish within the Potomac basin?

Intersex characteristics. Signup and view all the answers

What percentage of fruit consumed in the EU has been found to contain residues of endocrine disrupting pesticides?

More than one-third. Signup and view all the answers

Which of the following factors contributes to the contamination in the Potomac River?

Agricultural runoff containing pesticides. Signup and view all the answers

What effect do hormone pollutants have on the endocrine system?

They can disrupt normal hormonal functions. Signup and view all the answers

In the investigation of the Potomac River, which chemical characteristics were highlighted?

They are stable and effective in small doses. Signup and view all the answers

What role does the US Geological Survey (USGS) play in relation to the findings in the Potomac River?

It conducts studies on the cleanliness of water sources. Signup and view all the answers

Which hormone is responsible for promoting ova growth and ovulation in females?

Follicle Stimulating Hormone (FSH) Signup and view all the answers

What is the primary function of testosterone in males?

Promoting sperm production Signup and view all the answers

What effect do progesterone levels have after ovulation?

Prevents ovulation Signup and view all the answers

Which hormone acts as a chemical messenger influencing various target cells?

Oxytocin Signup and view all the answers

What does castration typically aim to achieve in domestic animals?

Improve meat quality Signup and view all the answers

What additional effects do estrogen and progesterone have beyond reproductive functions?

Affecting secondary sexual features Signup and view all the answers

What characteristic is associated with the hormones secreted by the pituitary gland?

They act as chemical messengers in low concentrations. Signup and view all the answers

Which hormone's action is often impeded by progesterone after ovulation?

Luteinizing Hormone (LH) Signup and view all the answers

What are endocrine disruptors primarily known for?

Mimicking or blocking hormones. Signup and view all the answers

Which river was found to contain endocrine-disrupting pollutants?

Potomac River Signup and view all the answers

What was one observable effect of endocrine disruptors in the Potomac basin?

Intersex characteristics in fish. Signup and view all the answers

How can endocrine disruptors impact human health?

Causing birth defects and reproductive irregularities. Signup and view all the answers

What is one challenge in dealing with endocrine disruptors?

Identifying and predicting their effects. Signup and view all the answers

Which of the following is NOT mentioned as a source of endocrine disruptors?

Common household cleaners. Signup and view all the answers

What percentage of fruit consumed in the EU is reported to be contaminated with endocrine disruptors?

More than one-third Signup and view all the answers

What is a significant property of hormones related to endocrine disruptors?

They can have precise consequences even in small doses. Signup and view all the answers

Study Notes

Nervous System - Ch.16

Two components: Central Nervous System (CNS) and Peripheral Nervous System (PNS).
CNS = brain and spinal cord.
PNS = all nerves outside of CNS. Receives information from receptors and transmits to effectors (e.g., mechanical, muscles; chemical, glands).

Cell Types

Neurons are specialized for long-distance transmission of electrical signals.
Dendrites receive stimuli.
Axon (nerve fiber) typically transmits only one impulse.
Synapses are junctions where neurons connect. A signal passes electrically—chemically—electrically. Neurotransmitters are released between cells (axon to dendrite).
Support cells:
Schwann cells form myelin sheaths.
Astrocytes pass nutrients.
Microglia engulf foreign bodies.

Peripheral Nervous System Division

Somatic - muscles
Visceral (Autonomic) - involuntary functions

Spinal Nerves

Emerge between vertebrae.
Innervate restricted area linked to myotome and dermatome (useful for injury detection).
Reflects underlying segmentation (somites).

Cranial Nerves

Have roots enclosed in brain.
Shared and consistent among all vertebrates.
A numbered set.
Early anatomists overlooked some.

Cranial Nerves - Sensory Only

Cranial nerve 0 (zero). Terminal nerve runs to olfactory sac blood vessels in all gnathostomes except birds. It's restricted to pheromone detection, related to reproduction.
Olfactory - sense of smell to olfactory bulb.
Optic - vision to thalamus and midbrain.
Acoustic (Auditory) - inner ear, hearing, and balance & orientation.

Cranial Nerves - Motor Only - Extrinsic Eye Muscles

Oculomotor (III) - other eye muscles
Trochlear (IV) - dorsal oblique muscle
Abducens (VI) - lateral rectus muscle

Cranial Nerves - Nerves of the Visceral Arches

Trigeminal (V) - mandibular arch (1st)
Ophthalmic - around eye
Maxillary - upper jaw
Mandibular - lower jaw
Glossopharyngeal (IX) - 3rd visceral arch (first gill in fish)
Sensory neurons for taste buds.
Muscles of 3rd arch.
Vagus (X)
4th, 5th, & 6th arches
Mouth, pharynx & most of viscera (wanderer).

Cranial Nerves - Cranial Nerves - Motor Only - Amniotes

10 cranial nerves (generally).
Last 2 restricted to amniotes.
Spinal Accessory (XI) - small motor neurons for derivatives of cucullaris (branchiomeric muscles), in anamniotes combined with vagus and occipitospinal nerves.
Hypoglossal (XII) - hyoid and tongue muscles. Prominent in amniotes where needed for feeding.

Table 16.2 - Cranial Nerves & Their Associated Branchial Arches

Table showing ancient segment, current arch, dorsal, and ventral representative connections.

Table 16.4 - Functional Divisions of the Autonomic Nervous System

Table showing various organ parts, their sympathetic and parasympathetic effects.

Central Nervous System - Functions

Processing of information from three sources:
Internal (organ and muscle signals).
External (normal sensations).
Memory.
Embryology: Neurulation (ectoderm, neural plate, folding, ventricles, hollow nerve cord.)

Meninges

Brain wrapped by one layer (fish), two layers (non-mammalian tetrapods), or three layers (mammals). Mammals (pia mater, arachnoid, dura mater).

Cerebrospinal Fluid (CSF)

From blood, no RBC's.
Slightly viscous.
Small volume (150ml) in humans.
Within meninges and ventricles.
Functions:
Liquid cushion for brain and spinal cord.
Supports delicate structures.
Nourishes brain and removes waste
Blood-brain barrier (most molecules blocked except O2, CO2, glucose, amino acids).

Spinal Cord

Like brain, has gray and white matter.
Gray matter = nerve cell bodies. Butterfly pattern in cross-sections.
White matter = nerve fibers linking levels.

Midbrain (Mesencephalon)

Largest part of brain in nonmammals.
Primary integration center for nonmammals (especially sensory input).
Optic lobes (receives sensory input—optic direct but auditory, lateral line, skin, smell indirectly; relays to thalamus)
Tegmentum (floor—initiates motor output)

Forebrain (Diencephalon)

Structures around 3rd ventricle.
Epithalamus: roof
Pineal Eye Complex (median eye complex). Up to four structures (paraphysis, dorsal sac, epiphysis, parietal organ).
Epiphysis (pineal gland) - light sensitive, endocrine function (melatonin), skin pigmentation cycles.
Hypothalamus: floor
Regulates homeostasis (physiology); autonomic responses, pituitary function, and affects other glands.
Thalamus:
All sensory input flows through here. Coordination center of sensory input; important relay center to cerebral cortex.

Forebrain (Telencephalon)

Olfactory bulbs: cranial nerves 0 and I, big and important in fish, and a major relay center.
Cerebrum: paired hemispheres; ventricles I and 2. Amniotes and some anamniotes. Gets larger in reptiles, birds and mammals.

Brains - Summary

Same basic components across taxa.
Anamniotes favor large midbrain and olfaction (olfactory bulbs;).
Amniotes and advanced sharks favor cerebrum.
Specializations reflected in expansions (e.g., cerebellum for 3D movement, olfaction, and vision)

Brain Scale - EQ's

Brain scales negatively with body mass.
To compare mass across taxa (enchephalization quotient), need to consider the average brain mass for an animal of equivalent body mass.
Humans, great apes, and dolphins stand out among mammals in terms of encephalization.

Diseases Crossing Blood-Brain Barrier

Meningitis (inflammation of meninges due to viral or bacterial infection).
Transmissible spongiform encephalopathies (TSEs) caused by prions, such as CJD, BSE (mad cow disease), and kuru.

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Description

Explore the unique features of cortical organization in mammals with this quiz. Delve into circuit motifs, social cognition, and the implications of neural fiber arrangements in the brain. Understand the relevance of brain weight rankings in mammalian evolution and key research findings in neuroscience.