three.js camera rotation

HTML

<script src="https://rawgithub.com/mrdoob/three.js/master/build/three.min.js"></script>
<script src="https://rawgithub.com/RobertWHurst/KeyboardJS/master/keyboard.js"></script>

CSS

html, body, canvas {
	width: 100%;
	height: 100%;
	margin: 0;
	padding: 0;
	border-spacing: 0;
	overflow: hidden;
}

JavaScript

function degInRad(deg) {
    return deg * Math.PI / 180;
}
/////////////////////////////////
function render() {
    requestAnimationFrame(render);
    if (leftPressed) {
        neck.rotation.y += degInRad(1);
    } else if (rightPressed) {
        neck.rotation.y -= degInRad(1);
    }
    if (upPressed) {
        camera.rotation.x += degInRad(1);
    } else if (downPressed) {
        camera.rotation.x -= degInRad(1);
    }
    renderer.render(scene, camera);
}
/////////////////////////////////
var scene, camera, renderer, grass, neck;
var leftPressed = false;
var rightPressed = false;
var upPressed = false;
var downPressed = false;
/////////////////////////////////
window.onload = function() {
    scene = new THREE.Scene();
    camera = new THREE.PerspectiveCamera( 75, window.innerWidth / window.innerHeight, 0.1, 1000 );
    cameraHolder = new THREE.Object3D();
    cameraHolder.add( camera );
    renderer = new THREE.WebGLRenderer();
    renderer.rendererSize = {width: window.innerWidth, height: window.innerHeight, quality: 100, maxQuality: 400, minQuality: 20};
    renderer.setSize( renderer.rendererSize.width, renderer.rendererSize.height );
    document.body.appendChild( renderer.domElement );

    var texture, material, geometry, element;

    material = new THREE.MeshBasicMaterial( { color: 0x00ff00 } );
    material.side = THREE.DoubleSide;
    geometry = new THREE.PlaneGeometry(24, 24);   
    grass = new THREE.Mesh( geometry, material );
    grass.name = "grass";
    scene.add( grass );

    neck = new THREE.Object3D();
    neck.rotateOnAxis(new THREE.Vector3(1, 0, 0), degInRad(90));
    neck.up = new THREE.Vector3(0, 0, 1);
    neck.position.z = 1;
    neck.position.y = -5;


    neck.add(camera);
    scene.add(neck);    

    KeyboardJS.on('left', function() { leftPressed = true; }, function() { leftPressed = false; });
    KeyboardJS.on('right', function() { rightPressed = true; }, function() { rightPressed = false; });
    KeyboardJS.on('up',...