Unit 5: Lecture 3 (Basics of Brain Development, & Forebrain (Prosencephalon))

Prosencephalon (Forebrain), Mesencephalon (Midbrain), and Rhombencephalon (Hindbrain).

What are the 3 primary brain vesicles at week 4 of development?

Telencephalon and diencephalon

What does the prosencephalon (forebrain) subdivide into?

Cerebrum (two cerebral hemispheres)

What makes up the telencephalon?

Epithalamus (roof), thalamus (walls), and hypothalamus (roof)

What makes up the diencephalon?

Metencephalon (pons and cerebellum) and myelencephalon (medulla oblongata)

What does the rhombencephalon (hindbrain) subdivide into?

Telencephalon, diencephalon, mesencephalon, metencephalon, myelencephalon

What is the order of the five divisions of the brain from superior to inferior?

Prosencephalon

What is the telencephalon derived from?

Telencephalon

What brain vesicle gives rise to the cerebrum, the largest region of the brain?

Motor speech production

What is Broca's Area (usually in the dominant left hemisphere) responsible for?

Comprehension of written and spoken language

What is Wernicke's Area (usually in dominant left hemisphere) responsible for?

Acruate fasiculus

What allows Broca's Area and Wernicke's Area to communicate, which is vital for language production and processing?

Medulla or spinal cord

Where do most sensory and motor pathways decussate?

Right

What side of the brain typically controls the left side of the body?

Frontal, parietal, occipital, temporal, insula

What are the five lobes of the cerebrum?

Intellectual functions, voluntary movement, sensation, memory storage, and complex behavioral traits—the foundation of one's identity and personality.

What do the lobes of the cerebrum govern?

Frontal bone, lateral sulcus, and central sulcus

What is the frontal lobe bounded by anteriorly, laterally, and posteriorly?

Voluntary motor control, aspects of personality and emotional regulation, higher-order decision making, and expressive language.

What is the frontal lobe responsible for?

Precentral gyrus

What part of the frontal lobe contains the primary motor cortex, which initiates voluntary movement?

Executive functions such as planning, problem solving, and social behavior.

What is the prefrontal cortex responsible for?

Motor planning and coordination

What is the premotor cortex responsible for?

Anterior and middle cerebral arteries

What arteries supply the frontal lobe?

Primary motor cortex

Lesions of what brain region results in contralateral weakness or paralysis, typically most evident in the face and upper extremity when the MCA is affected?

Anterior cerebral artery

What artery supplies the medial and superior aspects of the frontal lobe?

Middle cerebral artery

What artery supplies lateral and frontal lobe including the precentral gyrus?

Frontal lobe (particularly the prefrontal cortex)

What lobe was damaged in the Phineas Gage case?

Regulating personality, judgment, decision-making, and social behavior.

What is the prefrontal cortex in the frontal lobe responsible for (Phineas Gage Case)?

True

(T/F) Damage to the prefrontal cortex can impair executive functions and personality, without affecting memory or motor strength.

Central sulcus, lateral sulcus, and parieto-occipital sulcus

What is the anterior, lateral, and posterior borders of the parietal lobe?

Processing somatic sensory information, including touch, pressure, pain, temperature, vibration, and proprioception.

What is the parietal lobe responsible for?

Parietal lobe

What lobe contains the postcentral gyrus that contains the primary somatosensory cortex?

Receives and interprets signals from the contralateral body.

What is the somatosensory cortex in the parietal lobe responsible for?

Wernicke's Area

In the dominant hemisphere (typically the left), what brain region spans the posterior part of the superior temporal gyrus and the adjacent inferior parietal lobe?

Middle and anterior cerebral arteries

What arteries supply the parietal lobe?

Middle cerebral artery

What artery supplies the lateral convexity of the parietal lobe, including the postcentral gyrus and parts of Wernicke's area?

Anterior cerebral artery

What artery supplies the medial surface of the parietal lobe, especially superior parietal lobule?

Body regions with more precise motor control or sensory activity, such as the hands, lips, and face.

In the Homunculus, what body regions make up larger cortical areas?

Visual processing

What is the occipital lobe responsible for?

Occipital lobe

What lobe contains the primary visual cortex?

Temporal lobe

What lobe houses the primary auditory cortex?

Temporal lobe

What lobe houses the primary olfactory cortex?

True

(T/F) The temporal lobe plays a role in memory and emotion due to its connections with the hippocampus and amygdala.

Insula

What part of the telencephalon lies deep within the lateral sulcus and is not visible on the brain's external surface?

Insula

What part of the telencephalon contains the primary gustatory cortex, which interprets taste stimuli?

Insula

What is involved in emotional awareness, empathy, interoception (perception of internal bodily states), and risk prediction? It integrates autonomic, sensory, and affective information important for survival and social interaction.

Posterior cerebral artery

What artery supplies the occipital lobe?

Middle and posterior cerebral arteries

What arteries supply the temporal lobe?

Middle cerebral artery

Branches from what artery supplies the insula?

Cerebral or basal nuclei

What are the paired masses of gray matter embedded within the white matter of the cerebral hemispheres?

Regulation and modulation of motor output, procedural learning, emotional responses, and sensorimotor integration

What do the cerebral and basal nuclei play an essential role in?

Caudate nucleus

What is the C-shaped structure and is involved in regulating movement patterns such as walking and posture?

Lentiform nucleus

What is made up of the globus pallidus and putamen and are responsible for refining voluntary motor activity, particularly in adjusting the speed and precision of movement?

Amygdaloid body

What is functionally linked to the limbic system, it plays a central role in

the processing and storage of emotional memories, including fear and aggression?

Claustrum

What is the a thin, irregular sheet of gray matter involved in consciousness and multisensory integration?

Middle and anterior cerebral arteries

What arteries supply the basal nuclei?

Caudate nucleus and putamen

Degeneration of the ____ ____ and ____ is a hallmark of Huntington's disease, leading to involuntary movements (chorea), emotional dysregulation, and cognitive decline.

Epithalamus

What forms part of the posterior segment of the diencephalon and contributes to the roof of the third ventricle? It is positioned dorsally and is structurally and functionally distinct from the thalamus and hypothalamus.

Pineal gland

What major structure of the epithalamus is a neuroendocrine organ that secretes melatonin?

Melatonin

What does the pineal gland secrete?

Habenular nuclei

What are the small paired structures involved in olfactory, visceral, and

limbic integration? They help mediate emotional and behavioral responses to olfactory stimuli and serve as a connection between the limbic system and brainstem reticular formation.

Pineal gland

Lesions to what structure may cause sleep disturbances, delayed puberty, or visual deficits due to compression of the superior colliculi and cerebral aqueduct?

Thalamus

What is the large, paired structure of gray matter located on either side of the third ventricle?

Primary relay station for ascending sensory information (excluding olfaction) en route to the cerebral cortex.

What is the primary function of the thalamus?

True

(T/F) The thalamus plays a role in consciousness, alertness, and motor control through its connections with the basal nuclei and cerebellum.

Ventral posterior nucleus

What nuclei within the thalamus relays somatosensory information?

Lateral geniculate nucleus

What nuclei within the thalamus is responsible for visual input from the retina to the visual cortex?

Medial geniculate nucleus

What nuclei within the thalamus is responsible for auditory input to the auditory cortex?

Ventral anterior and lateral nuclei

What nuclei within the thalamus is responsible for motor signals from the basal nuclei and cerebellum to the motor cortex?

Hypothalamus

What is the key regulatory center located below the thalamus and forms the floor of the third ventricle?

Autonomic nervous system, endocrine function via pituitary, thermoregulation, hunger and thirst, circadian rhythms, emotional behavior, and sexual drive

What does the hypothalamus regulate?

Growth hormone

What hormone is synthesized in the hypothalamus and acts through anterior pituitary?

Thyroid-stimulating hormone

What hormone is synthesized in the hypothalamus and stored in anterior

pituitary?

Antidiuretic hormone

What hormone is synthesized in the hypothalamus and stored in posterior pituitary?

Follicle-stimulating hormone and luteinizing hormone

What hormones are synthesized and

released from anterior pituitary under hypothalamic stimulation?

Posterior cerebral artery

What artery supplies the diencephalon?

Posterior cerebral artery

Branches from what artery supplies both hypothalamic and thalamic regions?

Hypothalamus or pituitary

Lesions of the _____ or _____ can lead to endocrine syndromes such as diabetes insipidus (from ADH deficiency), growth disorders, or hypothyroidism. Tumors like craniopharyngiomas may compress the hypothalamic-pituitary axis.

Pituitary gigantism

What results from excessive secretion of growth hormone (GH) by the anterior pituitary before the closure of epiphyseal growth plates, typically due to a GH-secreting adenoma?

Acromegaly

What is characterized by:

- Enlargement of hands, feet, jaw, and facial bones

- Coarsened facial features and soft tissue thickening

- Metabolic complications: insulin resistance, hypertension, sleep apnea

Gigantism

What is characterized by:

- Abnormally tall stature

- Delayed puberty

- Headache and visual disturbances due to mass effect of the tumor

Elevated GH and insulin-like growth factor-1 (IGF-1) levels, with confirmation via lack of GH suppression during an oral glucose tolerance test.

What does diagnosis for pituitary gigantism or acromegaly rely on?

MRI

What type of imaging is the imaging modality of choice for identifying pituitary adenomas?

Cortex and cerebral nuclei

Where is gray matter found in the brain?

Tracts

Where is white matter found in the brain?

3

How many brain vesicles do you have at 4 weeks of development?

5

How many brain vesicles do you have at 5 weeks of development?