UGC NET Psycology Biological basis of behavior Syllabus

What are the two main divisions of the nervous system and their subdivisions?

Central nervous system (brain and spinal cord) and Peripheral nervous system. The PNS divides into somatic (voluntary) and autonomic; the autonomic divides into sympathetic and parasympathetic.

Contrast the sympathetic and parasympathetic nervous systems.

Sympathetic mobilizes the body for 'fight or flight' (raises heart rate, dilates pupils, inhibits digestion). Parasympathetic conserves energy ('rest and digest'), slowing heart rate and promoting digestion.

What are the three major divisions of the brain?

The hindbrain (medulla, pons, cerebellum), the midbrain, and the forebrain (cerebrum, thalamus, hypothalamus, limbic system).

Name the four lobes of the cerebral cortex and a primary function of each.

Frontal lobe: planning, movement, reasoning. Parietal lobe: somatosensory processing. Temporal lobe: hearing and memory. Occipital lobe: vision.

What are the functions of the medulla oblongata?

It controls vital autonomic functions including heart rate, breathing, blood pressure, swallowing, vomiting, and other reflexes essential for survival.

What is the function of the cerebellum?

It coordinates voluntary movement, balance, posture, muscle tone, and motor learning; damage causes problems with coordination and equilibrium (ataxia).

What are invasive methods of studying the brain? Give two examples.

Methods requiring physical intrusion into the body/brain. Examples: ablation/lesioning (destroying tissue), electrical stimulation of the brain (ESB), and microelectrode single-cell recording.

What are non-invasive methods of studying the brain? Give examples.

Methods that study the brain without surgical intrusion. Examples: EEG, CT scan, MRI, fMRI, and PET scan.

Compare CT and MRI scans.

CT (computed tomography) uses X-rays to produce cross-sectional structural images. MRI uses magnetic fields and radio waves to produce more detailed, higher-resolution structural images without ionizing radiation.

Compare fMRI and PET scans.

Both measure brain activity/function. fMRI detects changes in blood oxygenation (BOLD signal) with good spatial resolution and no radioactivity. PET requires injecting a radioactive tracer to map metabolic activity such as glucose use.

What does an EEG measure and what is its main strength?

An electroencephalogram records the brain's electrical activity (brain waves) via scalp electrodes. Its main strength is excellent temporal resolution, useful for studying sleep stages and seizures.

What is the endocrine system and how does it differ from the nervous system?

A network of glands that secrete hormones into the bloodstream. It works more slowly and with longer-lasting effects than the fast, electrical nervous system, which uses neurotransmitters.

Why is the pituitary called the 'master gland', and what controls it?

The pituitary secretes hormones that regulate other endocrine glands (e.g., thyroid, adrenals, gonads) and growth. It is itself controlled by the hypothalamus.

What hormones do the adrenal glands secrete and what are their effects?

The adrenal medulla secretes epinephrine and norepinephrine (arousal, fight-or-flight). The adrenal cortex secretes cortisol (stress, metabolism) and aldosterone (salt/water balance).

What is the role of the thyroid gland and the hormone it produces?

The thyroid secretes thyroxine, which regulates the body's metabolic rate, growth, and energy levels. Hyposecretion causes sluggishness; hypersecretion causes restlessness and weight loss.

Which brain structure is the primary regulator of hunger, thirst, sex, and temperature?

The hypothalamus, which maintains homeostasis and controls many primary biological drives and the autonomic/endocrine systems.

Which hypothalamic centers control hunger and satiety?

The lateral hypothalamus (LH) is the 'hunger/feeding center'; its stimulation induces eating and its lesion causes aphagia. The ventromedial hypothalamus (VMH) is the 'satiety center'; its lesion causes overeating (hyperphagia).

What is the glucostatic theory of hunger?

Hunger is regulated by blood glucose levels: when glucose levels (or their utilization) drop, glucoreceptors signal hunger; rising glucose signals satiety.

What roles do leptin and ghrelin play in hunger regulation?

Leptin, secreted by fat cells, signals satiety and suppresses appetite (long-term fat regulation). Ghrelin, secreted by the stomach, stimulates hunger before meals.

What physiological mechanisms regulate thirst?

Two mechanisms: osmometric/cellular thirst (rising solute concentration draws water from cells, detected by hypothalamic osmoreceptors) and volumetric/extracellular thirst (loss of blood volume detected by baroreceptors and the renin-angiotensin system).

What are the two broad categories of sleep, and how do they differ?

NREM (non-rapid eye movement) sleep, with progressively deeper stages and slow brain waves; and REM (rapid eye movement) sleep, marked by fast brain waves, vivid dreaming, and muscle paralysis (atonia).

What characterizes REM sleep and why is it called 'paradoxical sleep'?

REM features rapid eye movements, vivid dreams, fast desynchronized EEG resembling wakefulness, and increased heart rate/breathing, yet the skeletal muscles are paralyzed, hence 'paradoxical sleep'.

Which brain waves dominate deep (slow-wave) sleep versus relaxed wakefulness?

Deep sleep (NREM stages 3-4) is dominated by slow, high-amplitude delta waves. Relaxed wakefulness with eyes closed shows alpha waves.

What is the physiological basis of sexual behavior in terms of hormones?

Sexual behavior is influenced by gonadal hormones: androgens (especially testosterone) in males and estrogens and progesterone in females, regulated by the hypothalamus and pituitary (gonadotropins LH/FSH).

What structures make up the limbic system and what is its overall role?

It includes the amygdala, hippocampus, hypothalamus, thalamus, cingulate gyrus, and septum. It governs emotion, motivation, memory, and drives (the 'emotional brain').

What are the specific functions of the amygdala and the hippocampus?

The amygdala processes emotions, especially fear and aggression, and emotional memory. The hippocampus is essential for forming new long-term (declarative) memories and spatial navigation.

How do hormones regulate behavior, and what is meant by organizational vs activational effects?

Hormones influence behavior such as aggression, sex, and stress. Organizational effects occur early in development, permanently shaping the brain/body (e.g., sexual differentiation); activational effects are temporary, occurring when a hormone activates behavior in a mature organism.

What is Down syndrome and its chromosomal cause?

A condition caused by trisomy 21 (an extra copy of chromosome 21), producing intellectual disability, characteristic facial features, and developmental delays.

Compare Turner syndrome and Klinefelter syndrome.

Turner syndrome: females with a single X (45,X / XO), causing short stature and underdeveloped ovaries/infertility. Klinefelter syndrome: males with an extra X (47,XXY), causing reduced testosterone, infertility, and some feminized features.

What is the nature-nurture controversy in psychology?

The debate over the relative contributions of heredity/genetics (nature) versus environment/experience (nurture) in determining behavior, intelligence, and personality. The modern view is interactionist: both interact to shape development.

What research methods are used to disentangle nature from nurture?

Twin studies (comparing identical/monozygotic vs fraternal/dizygotic twins), adoption studies (comparing children to biological vs adoptive parents), and family/heritability studies that estimate the proportion of trait variance due to genes.