Bio Anthro Ch 14-17

Language in the brain

1. A language area is any part of the brain that is activated during the production or comprehension of speech. Classical language area is found in left sylvian fissure. In the frontal lobe, there's Broca's area, which is involved in articulation 3. Wernicke's area is involved in speech comprehension

Comments on EQ

1. Actual brain size values are of limited usefulness 2. The encephalization quotient is the ratio of actual to expected brain size (e.g. > 1.00 means a larger than expected brain size 3. Humans have largest brain size in relative terms (EQ) 4. Take into account selective pressures on body size 5. EQ doesn't have a straightforward correlation to intelligence

Phase 1: Early hominins and Australopithecus

1. Brain size increases from early (400-500 cc) to robust australopithecines (475-530 cc) 2. It is difficult to calculate EQ because of the difficulty in determining body mass 3. Australopithecines were more encephalized than great apes 4. However, chewing hard objects could have increased the cranium without increasing brain size

Modern Human are set apart from other animals by our complex behaviors and material cultures

1. Complex cultural behavior is a product of the human brain 2. Language is a specific behavioral adaptation

Brain Microscopic Anatomy

1. Composed of 80-90 billion neurons. The basic cellular units of the nervous system. A neuron consists of a cell body and specialized processes called dendrites (Which receive input from other neurons) and axons (outgrowths through which neurons send impulses to other neurons. 2. There is an equal number of supporting non-neuronal cells

Phase 3: Archaic Homo Sapiens, Neandertals, and modern Homo sapiens

1. Cranial Capacities in the modern range are found in archaic H. Sapiens and Neandertals. 2. Increase from H. Erectus is quite profound. Undoubtedly exceeded increase in body size 3. Apparent paradox: Cranial capacity of Neandertal may exceed modern humans'. Important to take body size into account. Modern humans are more encephalized than Neandertals. 4. Globularization in modern humans v. Neandertals 5. Brain size increase has characterized hominin evolution for 3-4 million years

Brain reorganization

1. Functional organization of brain changes with it increasing size 2. Reorganization can occur in 3 different ways: an anatomical region associated with a certain function changes in size, functional regions can shift and change position, new behaviors may lead to new functional fields. Scaling relationships & Patterns

Primary Visual Regions

1. Having shifted in humans v. other primates 2. Also reduced in size from what we expect. Likely shift occurred to make way for occipital and parietal cortices 3. Controversy over this shift centers on when the change occurred 3. Lunate sulcuses reliably separates from the rest of the brain in primates

Phase 2: Early Homo and Homo Erectus

1. Homo cranial capacity substantially larger than australopithecines 2. Marked increase in absolute and relative brain size with H. erectus- (increased encephalization) 3. Early H. Erectus brain is much smaller than later specimens

Sex differences in primate brain size

1. In almost all primate species, males have larger brain size than females 2. A general primate trend rather than a hominin evolution 3. No indication of differences in behavioral sophistication between sexes

Olfactory bulbs

1. Knoblike structures, located on the underside of the frontal lobes that form the termination of olfactory nerves running from the nasal region of the brain 2. control our sense of smell 3. Anthropoids have small olfactory bulbs compared to overall brain size 4. Shrinking occured when smell supplanted by other senses 5. This shift was already present in early anthropoids

Brain Size & Encephalization

1. Large brain size is one of the defining features of the genus homo 2. Human cranial capacity is 1300-1400 cc 3. The largest capacity among primates, followed by gorillas

Temporal Lobe

1. The "thumb" of the brain 2. Likely increased in proportional size. Most of the increase took place in the white matter. Allows for greater connectivity. 3. Part of the basis for later development of language.

Frontal lobes

1. The frontal lobes may have expanded over hominin evolution 2. Prefrontal region has shown remarkable relative expansion- larger in human brains than would be expected given the zise. 3. However MRI studies show that human frontal lobes aren't significantly larger than other primates, although humans and great apes share a small increase in relative frontal lobe size. 4. High forehead of modern humans' v. sloping neandertal foreheads- indicates frontal lobe expansion, however Bookstein found that exterior morphology s not a strong indicator of brain shape

The brain is a complex structure that produces behavior of unparalleled sophistication

1. The human brain is larger and differently organized compared with our closest relatives 2. Some of these differences reflect the evolution of language

Cerebrum

1. The largest part of the human brain, which is split into left and right hemispheres. Seat of all "higher" brain functions. 2. Forms most of the brains volume in humans and other primates

Cerebellum/"The Little Brain"

1. The little brain tucked under the cerebrum 2. Important in control of balance, posture, and voluntary movement 3. Also controls higher cognitive function.

The evolution of grammar.

1. The place of grammar in defining language has been a point of controversy over the years. Grammar at center of linguistic universe. Children are genetically specialized to learn language? 2. Possible support for the model comes from the study of pidgins (simple can't comm) and creoles. Beyond a two word utterance, rules must exist so the listener knows what the speaker is talking about. Can merge but aren't universal.

Paleoneurology:

1. The study of evolution of brain structure and functions 2. Remains for the most part dependent on endocasts (impressions of the interior part of the cranium) 3. CT scanning makes possible virtual endocasts 4. Endocasts, however, are a poor reflection of the brain's anatomy

Cerebral Cortex

1. Visually, is the surface of the brain 2. The layer of gray matter that covers the surface of the cerebral hemispheres (outer layers of neural tissue) divided into functional regions that correspond to local patterns of neuronal organization. 3. Divided into Sulci (folds) and Gyri (not folds)

Language is an adaptation, designed by natural selection

1. We are anatomically specialized to produce and process language 2. The words we use have semantic meaning 3. Language is phonemic, words made from small sound elements called phonemes 4. Language uses grammar, an implicit set of rules that govern usage

Brain size and the fossil record

3 phases- 1. Early hominins and robust australopithecus 2. Early Homo and Homo erectus 3. Archaic Homo sapiens, Neandertals, and modern Homo sapiens

Lunate sulcus

A prominent sulcus on the lateral side of the hemisphere of most nonhuman primates which divides the primary visual cortex of the occipital lobe from the rest of the cerebrum. 1. However it is absent or loosely defined in humans.

Learning Target #1

Define and discuss the concept of encephalization and its relevance to understanding human brain evolution; compare and contrast the importance of brain size increase and brain functional reorganization in brain evolution

Prefrontal region

The association cortex of the frontal lobes, located forward of the primary motor region of the precentral gyrus and the supplemental motor areas

Encephalization Quotient (EQ)

The ratio of the actual brain size of a species to its expected brain size based on a statistical regression of brain-to-body size based on a large number of species

Spoken language

is a critical factor in complex human behavior.